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Unverdorben LV, Pirani A, Gontjes K, Moricz B, Holmes CL, Snitkin ES, Bachman MA. Klebsiella pneumoniae evolution in the gut leads to spontaneous capsule loss and decreased virulence potential. mBio 2025; 16:e0236224. [PMID: 40162782 PMCID: PMC12077207 DOI: 10.1128/mbio.02362-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2024] [Accepted: 02/26/2025] [Indexed: 04/02/2025] Open
Abstract
Klebsiella pneumoniae (Kp) is an opportunistic pathogen that poses a major threat in healthcare settings. The gut is a primary Kp reservoir in hospitalized patients, and colonization is a major risk factor for Kp infection. The stability of virulence determinants such as capsule and lipopolysaccharide during gut colonization is largely unexplored. In a murine gut colonization model, we demonstrated that spontaneous capsule loss occurs rapidly but varies by Kp pathotype. A classical Kp strain and a carbapenem-resistant strain of the epidemic sequence type 258 lineage had significant levels (median of 25% and 9.5%, respectively) of capsule loss. In contrast, a hypervirulent strain did not lose capsule to a significant degree (median 0.1%), despite readily losing capsule during in vitro passage. Insertion sequences (ISs) or mutations were found disrupting capsule operon genes of all isolates and in O-antigen encoding genes in a subset of isolates. Mouse-derived acapsular isolates from two pathotypes had significant fitness defects in a murine pneumonia model. Removal of the IS in the capsule operon in a mouse-derived acapsular classical isolate restored capsule production to wild-type levels. Genomic analysis of Klebsiella rectal isolates from hospitalized patients found that 18 of 245 strains (7%) had at least one IS disrupting the capsule operon. Combined, these data indicate that Kp capsule loss can occur during gut colonization in a strain-dependent manner, not only impacting strain virulence but also potentially altering patient infection risk. IMPORTANCE In hospitalized patients, gut colonization by the bacterial pathogen Klebsiella pneumoniae (Kp) is a major risk factor for the development of infections. The genome of Kp varies across isolates, and the presence of certain virulence genes is associated with the ability to progress from colonization to infection. Here, we identified that virulence genes encoding capsule and lipopolysaccharide, which normally protect bacteria from the immune system, are disrupted by mutations during murine gut colonization. These mutations occurred frequently in some isolates of Kp but not others, and these virulence gene mutants from the gut were defective in causing infections. An analysis of 245 human gut isolates demonstrated that this capsule loss also occurred in patients. This work highlights that mutations that decrease virulence occur during gut colonization, the propensity for these mutations differs by isolate, and that stability of virulence genes is important to consider when assessing infection risk in patients.
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Affiliation(s)
- Lavinia V. Unverdorben
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Ali Pirani
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Kyle Gontjes
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Bridget Moricz
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Caitlyn L. Holmes
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Evan S. Snitkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Michael A. Bachman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Lim C, Zhang CY, Cheam G, Chu WHW, Chen Y, Yong M, Lim KYE, Lam MMC, Teo TH, Gan YH. Essentiality of the virulence plasmid-encoded factors in disease pathogenesis of the major lineage of hypervirulent Klebsiella pneumoniae varies in different infection niches. EBioMedicine 2025; 115:105683. [PMID: 40184910 PMCID: PMC12002934 DOI: 10.1016/j.ebiom.2025.105683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2024] [Revised: 03/04/2025] [Accepted: 03/19/2025] [Indexed: 04/07/2025] Open
Abstract
BACKGROUND Hypervirulent Klebsiella pneumoniae (HvKp) can metastasise to extra-intestinal sites to cause disseminated disease such as pyogenic liver abscesses. HvKp harbours a large virulence plasmid (KpVP) that contributes to pathogenicity. We previously identified a crucial gene region that confers virulence in SGH10 (ST23, K1 capsule), spanning genes encoding the siderophores aerobactin and salmochelin, as well as the regulator of mucoidy phenotype A (iuc-rmp-iro). METHODS SGH10 isogenic mutants of aerobactin, rmpA, and salmochelin were generated and tested in vitro for their siderophore production, hypermucoviscosity and growth. We investigated the essentiality of these factors in different murine infection or colonisation models. FINDINGS In a lung pneumonia model, capsule modulation by rmpA was the primary driver of high bacterial burden in the lung. In a systemic infection setting, rmpA was still the primary driver, followed by a significant contribution by salmochelin, that conferred virulence. However, the role of aerobactin was more significant in hvKp persistence in the gut. We further examined a large collection of Kp genomes and observed that the iro loci is often co-inherited with iuc in KpVP-1, suggesting the evolutionary importance of expressing both siderophores in these lineages. INTERPRETATION HvKp typically colonises the intestinal niche, however, the acquisition of the KpVP plasmid has enabled it to thrive outside the gut and cause metastatic infections. While the iuc-rmp-iro region is pivotal in bestowing virulence, the encoded factors contribute differently to the success of the pathogen in various infection sites, where the microenvironment, nutrient availability and immune response can vary. Thus, our study demonstrates that possessing the iuc-rmp-iro gene region can be an evolutionary advantage by allowing for flexibility in modulating siderophore and capsule expression in order for K. pneumoniae to thrive in distinct host niches. FUNDING This work is funded by the National Research FoundationMOH-000925-00 to YH Gan and OFYIRG22jul-0042 by the National Medical Research Council (NMRC) to THT.
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Affiliation(s)
- Carey Lim
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore
| | - Chu-Yun Zhang
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore
| | - Guoxiang Cheam
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore
| | - Wilson H W Chu
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore; National Public Health Laboratory, National Centre for Infectious Diseases, 16 Jln Tan Tock Seng, 308442, Republic of Singapore
| | - Yahua Chen
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore
| | - Melvin Yong
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore
| | - Kai Yi E Lim
- A∗STAR Infectious Diseases Labs, Agency for Science, Technology and Research, 8A Biomedical Grove #05-13, Immunos, 138648, Republic of Singapore
| | - Margaret M C Lam
- Department of Infectious Diseases, School of Translational Medicine, Monash University, Melbourne, Victoria, 3004, Australia
| | - Teck Hui Teo
- A∗STAR Infectious Diseases Labs, Agency for Science, Technology and Research, 8A Biomedical Grove #05-13, Immunos, 138648, Republic of Singapore
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, 117545, Republic of Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, 117596, Republic of Singapore.
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3
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Zheng Y, Zhu X, Ding C, Chu W, Pang X, Zhang R, Ma J, Xu G. Multidrug-resistant hypervirulent Klebsiella pneumoniae: an evolving superbug. Future Microbiol 2025; 20:499-511. [PMID: 40135944 PMCID: PMC11980460 DOI: 10.1080/17460913.2025.2482478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2024] [Accepted: 03/18/2025] [Indexed: 03/27/2025] Open
Abstract
Multidrug-resistant hypervirulent Klebsiella pneumoniae (MDR-hvKP) combines high pathogenicity with multidrug resistance to become a new superbug. MDR-hvKP reports continue to emerge, shattering the perception that hypervirulent K. pneumoniae (hvKP) strains are antibiotic sensitive. Patients infected with MDR-hvKP strains have been reported in Asia, particularly China. Although hvKP can acquire drug resistance genes, MDR-hvKP seems to be more easily transformed from classical K. pneumoniae (cKP), which has a strong gene uptake ability. To better understand the biology of MDR-hvKP, this review discusses the virulence factors, resistance mechanisms, formation pathways, and identification of MDR-hvKP. Given their destructive and transmissible potential, continued surveillance of these organisms and enhanced control measures should be prioritized.
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Affiliation(s)
- Yu Zheng
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Xiaojue Zhu
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Chao Ding
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Weiqiang Chu
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Xiaoxiao Pang
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Ruxia Zhang
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Jiucheng Ma
- Department of Burns and Plastic Surgery, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
| | - Guoxin Xu
- Department of Clinical Laboratory, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, China
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Whitfield C, Kelly SD, Stanton TD, Wyres KL, Clarke BR, Forrester TJB, Kowalczyk A. O-antigen polysaccharides in Klebsiella pneumoniae: structures and molecular basis for antigenic diversity. Microbiol Mol Biol Rev 2025:e0009023. [PMID: 40116577 DOI: 10.1128/mmbr.00090-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2025] Open
Abstract
SUMMARYKlebsiella pneumoniae is a gram-negative species, whose isolates are found in the environment and as commensals in the human gastrointestinal tract. This bacterium is among the leading causes of a range of nosocomial and community-acquired infections, particularly in immunocompromised individuals, where it can give rise to pneumonia, urinary tract infections, septicemia, and liver abscesses. Treatment of K. pneumoniae infections is compromised by the emergence of isolates producing carbapenemase and extended-spectrum β-lactamase enzymes, making it a high priority for new therapeutic approaches including vaccination and immunoprophylaxis. One potential target for these strategies is the O-antigen polysaccharide component of lipopolysaccharides, which are important virulence determinants for K. pneumoniae. Consideration of immunotherapeutic opportunities requires a comprehensive and fundamental understanding of O-polysaccharide structures, distribution of particular O serotypes in clinical isolates, and the potential for antigenic diversification. The number of recognized K. pneumoniae O-polysaccharide antigens has varied over time, complicated by the observation that some examples share similar structural (and potentially antigenically cross-reactive) elements, and by the existence of genetic loci for which corresponding O-polysaccharide structures have yet to be determined. Here, we provide a comprehensive integration of the current carbohydrate structures and genetic information, together with a proposal for an updated classification system for K. pneumoniae O-antigens, that is being implemented in Kaptive for molecular serotyping. The accumulated insight into O-polysaccharide assembly pathways is used to describe the molecular basis for O-antigen diversity in K. pneumoniae.
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Affiliation(s)
- Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Tom D Stanton
- Department of Infectious Diseases, School of Translational Medicine, Monash University, Melbourne, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Kelly L Wyres
- Department of Infectious Diseases, School of Translational Medicine, Monash University, Melbourne, Victoria, Australia
- Centre to Impact AMR, Monash University, Clayton, Victoria, Australia
| | - Bradley R Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Taylor J B Forrester
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Agnieszka Kowalczyk
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Wang J, Wang Q, Wang R, Wang R, Kang J, Duan J, Wang H. ST11 carbapenem-resistant Klebsiella pneumoniae clone harbouring capsular type KL25 becomes the primarily prevalent capsular serotype in a tertiary teaching hospital in China. J Glob Antimicrob Resist 2025; 43:7-14. [PMID: 40049392 DOI: 10.1016/j.jgar.2025.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2024] [Revised: 02/24/2025] [Accepted: 02/24/2025] [Indexed: 05/01/2025] Open
Abstract
BACKGROUND The spread of carbapenem-resistant Klebsiella pneumoniae (CRKP) that produces K. pneumoniae carbapenemase-2 has garnered significant attention due to its increasing prevalence. In China, the dissemination of K. pneumoniae carbapenemase-2-producing CRKP is predominantly linked to sequence type 11 (ST11), with capsular serotypes KL47 and KL64 being the primary capsular identified. METHODS A total of 64 CRKP-ST11 strains were collected from 2020 to 2023 and whole-genome sequencing was performed on all isolated ST11-CRKP strains. Antibiotic susceptibility was tested using the VITEK 2 system. Growth curve tests and in vitro competition experiments were used to assess the growth adaptability of different capsular type isolates. Moreover, the biofilm assessment and phagocytosis assays were performed to evaluate CRKP isolate virulence. RESULTS During the observed period, a notable subclonal shift was perceived within the prevailing ST11-CRKP clone, wherein the previously dominant KL64 and KL47 serotypes have been largely supplanted by the KL25 serotype since 2022. The ST11-KL25-CRKP strain significantly outgrew both ST11-KL64-CRKP and ST11-KL47-CRKP. Additionally, ST11-KL25-CRKP displayed a greater enhanced capacity to form biofilms than ST11-KL64-CRKP and ST11-KL47-CRKP. Furthermore, ST11-KL25-CRKP demonstrated enhanced resistance to phagocytosis than both of its counterparts. CONCLUSIONS ST11-KL25-CRKP possesses a remarkable level of adaptability and has the potential to regionally replace ST11-KL64-CRKP as the predominant strain in the region. Additionally, this novel and high-risk ST11-KL25-CRKP strain may indicate stronger virulence.
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Affiliation(s)
- Jing Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China; Department of Pharmacy, Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Qi Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Ruiqi Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Ruobing Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Jianbang Kang
- Department of Pharmacy, Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Jinju Duan
- Department of Pharmacy, Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China.
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Zhou Y, Chai Z, Pandeya A, Yang L, Zhang Y, Zhang G, Wu C, Li Z, Wei Y. Caspase-11 and NLRP3 exacerbate systemic Klebsiella infection through reducing mitochondrial ROS production. Front Immunol 2025; 16:1516120. [PMID: 40034692 PMCID: PMC11873083 DOI: 10.3389/fimmu.2025.1516120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2024] [Accepted: 01/31/2025] [Indexed: 03/05/2025] Open
Abstract
Introduction Klebsiella pneumoniae is a Gram-negative bacterium and the third most commonly isolated microorganism in blood cultures from septic patients. Despite extensive research, the mechanisms underlying K. pneumoniae-induced sepsis and its pathogenesis remain unclear. Acute respiratory failure is a leading cause of mortality in systemic K. pneumoniae infections, highlighting the need to better understand the host immune response and bacterial clearance mechanisms. Method To investigate the impact of K. pneumoniae infection on organ function and immune response, we utilized a systemic infection model through intraperitoneal injection in mice. Bacterial loads in key organs were quantified, and lung injury was assessed. Survival analysis was performed in wild-type (WT) and gene deficient mice. Mitochondrial damage and reactive oxygen species (ROS) production, as well as cytokine levels were measured in macrophages isolated from these mice to evaluate their contribution to bacterial clearance capacity. Results Our findings demonstrate that K. pneumoniae systemic infection results in severe lung injury and significant bacterial accumulation in multiple organs, with the highest burden in the lungs. Deficiency of caspase-11 or NLRP3 led to prolonged survival, a reduction in pulmonary bacterial load, increased blood oxygen levels, and decreased IL-6 levels in the lungs compared to WT controls. Furthermore, caspase-11- and NLRP3-deficient macrophages exhibited elevated mitochondrial ROS production in response to K. pneumoniae, which correlated with more effective bacterial clearance. Discussion These results suggest that caspase-11 and NLRP3 contribute to K. pneumoniae-induced sepsis by impairing mitochondrial function and reducing ROS production in macrophages, thereby compromising bacterial clearance. The observed reduction in lung injury and increased survival in caspase-11- and NLRP3-deficient mice indicate that targeting these pathways may offer potential therapeutic strategies to improve host defense against systemic K. pneumoniae infection.
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Affiliation(s)
- Yuqi Zhou
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Zhuodong Chai
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Ankit Pandeya
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Ling Yang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Yan Zhang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Guoying Zhang
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Congqing Wu
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Zhenyu Li
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
| | - Yinan Wei
- Department of Pharmaceutical Sciences, Irma Lerma Rangel School of Pharmacy, Texas A&M University, College Station, TX, United States
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Zierke L, Mourad R, Kohler TP, Müsken M, Hammerschmidt S. Influence of the polysaccharide capsule on virulence and fitness of Klebsiella pneumoniae. Front Microbiol 2025; 16:1450984. [PMID: 39980691 PMCID: PMC11839663 DOI: 10.3389/fmicb.2025.1450984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 01/17/2025] [Indexed: 02/22/2025] Open
Abstract
Introduction The capsular polysaccharide (CPS) of pathogenic bacteria is a critical virulence factor, often evading phagocytosis by host immune cells, while also interfering with the contact of the pathogen with host cells and contributing to biofilm formation. Klebsiella pneumoniae, a Gram-negative human pathogen associated with high antimicrobial resistances, produces 77 CPS serotypes. The CPS masks proteinaceous factors but also protects K. pneumoniae from uptake by host phagocytic cells and activation of the complement system. In addition to nosocomial, urinary tract and bloodstream infections or pneumonia hypervirulent strains have a highly mucoid phenotype and can cause soft tissue infections, liver abscesses, and meningitis as well. The CPS is therefore crucial for both escaping detection by the immune system and enhancing the virulence potential. Methods In this study, we generated a non-encapsulated mutant (Kpn2146∆wza) to observe how the CPS interferes with K. pneumoniae adhesion, survival in blood, and invasiveness in an experimental infection model. Results Infection of A549 lung epithelial cells showed similar adherence levels for the wild-type and non-capsulated strain, while our data showed a moderately higher internalization of Kpn2146Δwza when compared to the wild-type. In whole blood killing assays, we demonstrate that the K. pneumoniae capsule is essential for survival in human blood, protecting K. pneumoniae against recognition and clearance by the human immune system, as well as complement-mediated opsonization and killing. The non-encapsulated mutant, in contrast, was unable to survive in either whole blood or human plasma. Infections of Galleria mellonella larvae showed a significantly decreased virulence potential of the CPS-deficient mutant. Discussion In conclusion, our data indicate a crucial role of CPS in vivo.
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Affiliation(s)
- Lisa Zierke
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Rodi Mourad
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Thomas P. Kohler
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Mathias Müsken
- Central Facility for Microscopy, Helmholtz Center for Infection Research (HZI), Braunschweig, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
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Xu L, Li J, Wu W, Wu X, Ren J. Klebsiella pneumoniae capsular polysaccharide: Mechanism in regulation of synthesis, virulence, and pathogenicity. Virulence 2024; 15:2439509. [PMID: 39668724 PMCID: PMC11649230 DOI: 10.1080/21505594.2024.2439509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 09/04/2024] [Accepted: 12/03/2024] [Indexed: 12/14/2024] Open
Abstract
Hypervirulent Klebsiella pneumoniae exhibits strong pathogenicity and can cause severe invasive infections but is historically recognized as antibiotic-susceptible. In recent years, the escalating global prevalence of antibiotic-resistant hypervirulent K. pneumoniae has raised substantial concerns and created an urgent demand for effective treatment options. Capsular polysaccharide (CPS) is one of the main virulence determinants contributing to the hypervirulent phenotype. The structure of CPS varies widely among strains, and both the structure and composition of CPS can influence the virulence of K. pneumoniae. CPS possesses various immune evasion mechanisms that promote the survival of K. pneumoniae, as well as its colonization and dissemination. Given the proven viability of therapies that target the capsule, improving our understanding of the CPS structure is critical to effectively directing treatment strategies. In this review, the structure and typing of CPS are addressed as well as genes related to synthesis and regulation, relationships with virulence, and pathogenic mechanisms. We aim to provide a reference for research on the pathogenesis of K. pneumoniae.
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Affiliation(s)
- Li Xu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
| | - Jiayang Li
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Wenqi Wu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xiuwen Wu
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Jianan Ren
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing Medical University, Nanjing, China
- Research Institute of General Surgery, Jinling Hospital, the Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
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Shu R, Liu G, Xu Y, Liu B, Huang Z, Wang H. AcrAB Efflux Pump Plays a Crucial Role in Bile Salts Resistance and Pathogenesis of Klebsiella pneumoniae. Antibiotics (Basel) 2024; 13:1146. [PMID: 39766536 PMCID: PMC11672700 DOI: 10.3390/antibiotics13121146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2024] [Revised: 11/24/2024] [Accepted: 11/27/2024] [Indexed: 01/11/2025] Open
Abstract
Bile salts possess innate antibacterial properties and can cause significant damage to bacteria. To survive in the mammalian gut, Klebsiella pneumoniae has developed mechanisms to tolerate bile salts; however, the specific mechanisms remain unclear. Transposon library screening revealed that the efflux pump AcrAB is involved in bile salt resistance. acrA and acrB mutants exhibited high sensitivity not only to bile salts but also to SDS and various antibiotics, with a switch-loop, comprising residues G615, F616, A617, and G618, proving to be crucial in this process. A colonization defect of acrA and acrB mutants was demonstrated to be located in the mouse small intestine, where the bile salt concentration is higher compared to the large intestine. Additionally, both acrA and acrB mutants displayed reduced virulence in the Galleria mellonella model. In conclusion, our results suggest that the Resistance-Nodulation-Cell Division efflux pump serves as a critical determinant in the pathogenesis of K. pneumoniae through various aspects.
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Affiliation(s)
- Rundong Shu
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
| | - Ge Liu
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
- Zhengzhou Agricultural Science and Technology Research Institute, Zhengzhou 450015, China
| | - Yunyu Xu
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
| | - Bojun Liu
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
| | - Zhi Huang
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
| | - Hui Wang
- Sanya Institute of Nanjing Agricultural University, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (R.S.); (G.L.); (Y.X.); (B.L.)
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Wang L, Wang Z, Zhang H, Jin Q, Fan S, Liu Y, Huang X, Guo J, Cai C, Zhang JR, Wu H. A novel esterase regulates Klebsiella pneumoniae hypermucoviscosity and virulence. PLoS Pathog 2024; 20:e1012675. [PMID: 39480904 PMCID: PMC11556721 DOI: 10.1371/journal.ppat.1012675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 11/12/2024] [Accepted: 10/18/2024] [Indexed: 11/02/2024] Open
Abstract
Klebsiella pneumoniae, an emerging multidrug-resistant pathogen, exhibits hypermucoviscosity (HMV) as a critical virulence trait mediated by its capsular polysaccharide (CPS). Recent discoveries have determined acetylation as a significant modification for CPS, although its impact on HMV and virulence was previously unknown. This study elucidates the roles of two enzymes: Klebsiella pneumoniae Acetylated CPS Esterase (KpACE), an esterase that removes acetyl groups from CPS, and WcsU, an acetyltransferase that adds acetyl groups to CPS. KpACE is highly upregulated in an ompR-deficient mutant lacking HMV, and its overexpression consistently reduces HMV and diminishes virulence in a mouse model of pneumonia. The esterase domain-containing KpACE effectively deacetylates model sugar substrates and CPS-K2. Site-directed mutagenesis of the conserved catalytic histidine residue at position 370 significantly reduces its enzymatic activity. This reduction correlates with decreased HMV, affecting key virulence traits including biofilm formation and serum resistance. Similarly, a deficiency in the wcsU gene abolishes CPS acetylation, and reduces HMV and virulence. These results highlight the importance of the delicate balance between CPS acetylation by WcsU and deacetylation by KpACE in regulating the pathogenicity of K. pneumoniae. Understanding this balance provides new insights into the modulation of virulence traits and potential therapeutic targets for combating K. pneumoniae infections.
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Affiliation(s)
- Lijun Wang
- Department of Laboratory Medicine, Beijing Xiaotangshan Hospital, Beijing, China
- Center for Infectious Disease Research, School of Basic Medical Sciences, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Zhe Wang
- Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Hua Zhang
- Oregon Health and Science University School of Dentistry, Portland, Oregon, United States of America
| | - Qian Jin
- Center for Infectious Disease Research, School of Basic Medical Sciences, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Shuaihua Fan
- Tsinghua Medicine, Tsinghua University, Department of Respiratory and Critical Care Medicine, Beijing Tsinghua Changgung Hospital, Beijing, China
| | - Yanni Liu
- Center for Infectious Disease Research, School of Basic Medical Sciences, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Xueting Huang
- Center for Infectious Disease Research, School of Basic Medical Sciences, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Jun Guo
- Department of Geriatric Medicine, Beijing Tsinghua Changgung Hospital, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Chao Cai
- Shandong Key Laboratory of Glycoscience and Glycotherapeutics, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Basic Medical Sciences, Tsinghua Medicine, Tsinghua University, Beijing, China
| | - Hui Wu
- Oregon Health and Science University School of Dentistry, Portland, Oregon, United States of America
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11
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Bray AS, Zafar MA. Deciphering the gastrointestinal carriage of Klebsiella pneumoniae. Infect Immun 2024; 92:e0048223. [PMID: 38597634 PMCID: PMC11384780 DOI: 10.1128/iai.00482-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024] Open
Abstract
Bacterial infections pose a significant global health threat, accounting for an estimated 7.7 million deaths. Hospital outbreaks driven by multi-drug-resistant pathogens, notably Klebsiella pneumoniae (K. pneumoniae), are of grave concern. This opportunistic pathogen causes pneumonia, urinary tract infections, and bacteremia, particularly in immunocompromised individuals. The rise of hypervirulent K. pneumoniae adds complexity, as it increasingly infects healthy individuals. Recent epidemiological data suggest that asymptomatic gastrointestinal carriage serves as a reservoir for infections in the same individual and allows for host-to-host transmission via the fecal-oral route. This review focuses on K. pneumoniae's gastrointestinal colonization, delving into epidemiological evidence, current animal models, molecular colonization mechanisms, and the protective role of the resident gut microbiota. Moreover, the review sheds light on in vivo high-throughput approaches that have been crucial for identifying K. pneumoniae factors in gut colonization. This comprehensive exploration aims to enhance our understanding of K. pneumoniae gut pathogenesis, guiding future intervention and prevention strategies.
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Affiliation(s)
- Andrew S. Bray
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - M. Ammar Zafar
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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12
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Goh KJ, Altuvia Y, Argaman L, Raz Y, Bar A, Lithgow T, Margalit H, Gan YH. RIL-seq reveals extensive involvement of small RNAs in virulence and capsule regulation in hypervirulent Klebsiella pneumoniae. Nucleic Acids Res 2024; 52:9119-9138. [PMID: 38804271 PMCID: PMC11347178 DOI: 10.1093/nar/gkae440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 04/29/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024] Open
Abstract
Hypervirulent Klebsiella pneumoniae (hvKp) can infect healthy individuals, in contrast to classical strains that commonly cause nosocomial infections. The recent convergence of hypervirulence with carbapenem-resistance in K. pneumoniae can potentially create 'superbugs' that are challenging to treat. Understanding virulence regulation of hvKp is thus critical. Accumulating evidence suggest that posttranscriptional regulation by small RNAs (sRNAs) plays a role in bacterial virulence, but it has hardly been studied in K. pneumoniae. We applied RIL-seq to a prototypical clinical isolate of hvKp to unravel the Hfq-dependent RNA-RNA interaction (RRI) network. The RRI network is dominated by sRNAs, including predicted novel sRNAs, three of which we validated experimentally. We constructed a stringent subnetwork composed of RRIs that involve at least one hvKp virulence-associated gene and identified the capsule gene loci as a hub target where multiple sRNAs interact. We found that the sRNA OmrB suppressed both capsule production and hypermucoviscosity when overexpressed. Furthermore, OmrB base-pairs within kvrA coding region and partially suppresses translation of the capsule regulator KvrA. This agrees with current understanding of capsule as a major virulence and fitness factor. It emphasizes the intricate regulatory control of bacterial phenotypes by sRNAs, particularly of genes critical to bacterial physiology and virulence.
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Affiliation(s)
- Kwok Jian Goh
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Yael Altuvia
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Liron Argaman
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Yair Raz
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Amir Bar
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Hanah Margalit
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
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13
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Bain W, Ahn B, Peñaloza HF, McElheny CL, Tolman N, van der Geest R, Gonzalez-Ferrer S, Chen N, An X, Hosuru R, Tabary M, Papke E, Kohli N, Farooq N, Bachman W, Olonisakin TF, Xiong Z, Griffith MP, Sullivan M, Franks J, Mustapha MM, Iovleva A, Suber T, Shanks RQ, Ferreira VP, Stolz DB, Van Tyne D, Doi Y, Lee JS. In Vivo Evolution of a Klebsiella pneumoniae Capsule Defect With wcaJ Mutation Promotes Complement-Mediated Opsonophagocytosis During Recurrent Infection. J Infect Dis 2024; 230:209-220. [PMID: 39052750 PMCID: PMC11272070 DOI: 10.1093/infdis/jiae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/17/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024] Open
Abstract
BACKGROUND Klebsiella pneumoniae carbapenemase-producing K pneumoniae (KPC-Kp) bloodstream infections are associated with high mortality. We studied clinical bloodstream KPC-Kp isolates to investigate mechanisms of resistance to complement, a key host defense against bloodstream infection. METHODS We tested growth of KPC-Kp isolates in human serum. In serial isolates from a single patient, we performed whole genome sequencing and tested for complement resistance and binding by mixing study, direct enzyme-linked immunosorbent assay, flow cytometry, and electron microscopy. We utilized an isogenic deletion mutant in phagocytosis assays and an acute lung infection model. RESULTS We found serum resistance in 16 of 59 (27%) KPC-Kp clinical bloodstream isolates. In 5 genetically related bloodstream isolates from a single patient, we noted a loss-of-function mutation in the capsule biosynthesis gene, wcaJ. Disruption of wcaJ was associated with decreased polysaccharide capsule, resistance to complement-mediated killing, and surprisingly, increased binding of complement proteins. Furthermore, an isogenic wcaJ deletion mutant exhibited increased opsonophagocytosis in vitro and impaired in vivo control in the lung after airspace macrophage depletion in mice. CONCLUSIONS Loss of function in wcaJ led to increased complement resistance, complement binding, and opsonophagocytosis, which may promote KPC-Kp persistence by enabling coexistence of increased bloodstream fitness and reduced tissue virulence.
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Affiliation(s)
- William Bain
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
- Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Brian Ahn
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Anschutz Medical Campus School of Medicine, Denver
| | - Hernán F Peñaloza
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | | | - Nathanial Tolman
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Rick van der Geest
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Shekina Gonzalez-Ferrer
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Nathalie Chen
- Division of Infectious Diseases, Department of Medicine
| | - Xiaojing An
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Ria Hosuru
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Mohammadreza Tabary
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Erin Papke
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Naina Kohli
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | | | | | - Tolani F Olonisakin
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Zeyu Xiong
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | | | - Mara Sullivan
- Center for Biologic Imaging, Department of Cell Biology
| | | | | | - Alina Iovleva
- Division of Infectious Diseases, Department of Medicine
| | - Tomeka Suber
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
| | - Robert Q Shanks
- Department of Ophthalmology, University of Pittsburgh, Pennsylvania
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Ohio
| | - Donna B Stolz
- Center for Biologic Imaging, Department of Cell Biology
| | | | - Yohei Doi
- Division of Infectious Diseases, Department of Medicine
| | - Janet S Lee
- Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine, University of Pittsburgh
- Division of Pulmonary and Critical Care Medicine, Washington University in St Louis, Missouri
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14
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Qin J, Hong Y, Totsika M. Determining glycosyltransferase functional order via lethality due to accumulated O-antigen intermediates, exemplified with Shigella flexneri O-antigen biosynthesis. Appl Environ Microbiol 2024; 90:e0220323. [PMID: 38747588 PMCID: PMC11218652 DOI: 10.1128/aem.02203-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/09/2024] [Indexed: 06/19/2024] Open
Abstract
The O antigen (OAg) polysaccharide is one of the most diverse surface molecules of Gram-negative bacterial pathogens. The structural classification of OAg, based on serological typing and sequence analysis, is important in epidemiology and the surveillance of outbreaks of bacterial infections. Despite the diverse chemical structures of OAg repeating units (RUs), the genetic basis of RU assembly remains poorly understood and represents a major limitation in assigning gene functions in polysaccharide biosynthesis. Here, we describe a genetic approach to interrogate the functional order of glycosyltransferases (GTs). Using Shigella flexneri as a model, we established an initial glycosyltransferase (IT)-controlled system, which allows functional order allocation of the subsequent GT in a 2-fold manner as follows: (i) first, by reporting the growth defects caused by the sequestration of UndP through disruption of late GTs and (ii) second, by comparing the molecular sizes of stalled OAg intermediates when each putative GT is disrupted. Using this approach, we demonstrate that for RfbF and RfbG, the GT involved in the assembly of S. flexneri backbone OAg RU, RfbG, is responsible for both the committed step of OAg synthesis and the third transferase for the second L-Rha. We also show that RfbF functions as the last GT to complete the S. flexneri OAg RU backbone. We propose that this simple and effective genetic approach can be also extended to define the functional order of enzymatic synthesis of other diverse polysaccharides produced both by Gram-negative and Gram-positive bacteria.IMPORTANCEThe genetic basis of enzymatic assembly of structurally diverse O antigen (OAg) repeating units (RUs) in Gram-negative pathogens is poorly understood, representing a major limitation in our understanding of gene functions for the synthesis of bacterial polysaccharides. We present a simple genetic approach to confidently assign glycosyltransferase (GT) functions and the order in which they act during assembly of the OAg RU. We employed this approach to determine the functional order of GTs involved in Shigella flexneri OAg assembly. This approach can be generally applied in interrogating GT functions encoded by other bacterial polysaccharides to advance our understanding of diverse gene functions in the biosynthesis of polysaccharides, key knowledge in advancing biosynthetic polysaccharide production.
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Affiliation(s)
- Jilong Qin
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Yaoqin Hong
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane City, Queensland, Australia
| | - Makrina Totsika
- Centre for Immunology and Infection Control, School of Biomedical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
- Max Planck Queensland Centre, Queensland University of Technology, Brisbane City, Queensland, Australia
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15
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Tang M, Yao Z, Liu Y, Ma Z, Zhao D, Mao Z, Wang Y, Chen L, Zhou T. Host immunity involvement in the outcome of phage therapy against hypervirulent Klebsiella pneumoniae infections. Antimicrob Agents Chemother 2024; 68:e0142923. [PMID: 38742895 PMCID: PMC11620495 DOI: 10.1128/aac.01429-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 04/13/2024] [Indexed: 05/16/2024] Open
Abstract
Highly encapsulated hypervirulent Klebsiella pneumoniae (hvKp) causes severe infections. Bacteriophage therapy, an antibiotic alternative, effectively treats bacterial infections. Phage φFK1979 encoding polysaccharide depolymerases can target and disarm the capsule of hvKp FK1979, showing promise against FK1979 infection. Resistant strains induced by φFK1979 are possibly eliminated by host immunity and new phage phiR3 targeting them. We constructed varied immunocompromised FK1979 infection mouse models to assess the therapy efficacy of φFK1979 alone or in combination with phiR3. Survival rates, bacterial loads, histopathology, inflammation, and immune cell distribution of mice were studied. Prompt and adequate administration of φFK1979, rather than phiR3, significantly improved survival rates in mice with different immune statuses. However, immunocompromised mice showed lower efficacy due to reduced tolerance to low-virulence φFK1979-resistant bacteria compared to immunocompetent mice. Adding phiR3 sequentially greatly enhanced therapy efficacy for them, leading to increased survival rates and notable improvements in pathology and inflammation. Immunocompetent mice exhibited the most favorable response to φFK1979 monotherapy, as their immune system cleared φFK1979-resistant bacteria while avoiding a robust response to phiR3 combating φFK1979-resistant bacteria. This study revealed host immunity involvement in the outcome of phage therapy against infections and introduced, for the first time, personalized phage therapy strategies for hvKp-infected mice with varying immune statuses.IMPORTANCEHypervirulent Klebsiella pneumoniae (hvKp), with high capsular polysaccharide production, can cause severe invasive infections. Capsule-targeting phage poses the potential to fight against hvKp. We previously elucidated that the capsule-targeting phage induces resistance in hvKp, while phage-resistant strains exhibit sensitivity to host innate immunity and new phages targeting them. This indicated that phage-resistant strains can be eliminated by the immune system in immunocompetent patients, whereas they may require treatment with phages targeting resistant bacteria in immunocompromised patients. HvKp can infect individuals with varying immune statuses, including both immunocompetent and immunocompromised/deficient patients. This study, for the first time, developed personalized phage therapy strategies for hvKp-infected mice with different immune statuses, optimizing phage therapy against hvKp infections. This research is expected to provide a theoretical foundation and novel insights for clinical phage therapy against hvKp infections, offering significant societal benefits and clinical value.
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Affiliation(s)
- Miran Tang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhuocheng Yao
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yan Liu
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhexiao Ma
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Deyi Zhao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zhenzhi Mao
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yue Wang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Lijiang Chen
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
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16
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Chen L, Wang H, Wang H, Guo Y, Chang Z. Thrombocytopenia in Klebsiella pneumoniae liver abscess: a retrospective study on its correlation with disease severity and potential causes. Front Cell Infect Microbiol 2024; 14:1351607. [PMID: 38562965 PMCID: PMC10982356 DOI: 10.3389/fcimb.2024.1351607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/04/2024] [Indexed: 04/04/2024] Open
Abstract
Objective Thrombocytopenia is commonly associated with infectious diseases and serves as an indicator of disease severity. However, reports on its manifestation in conjunction with Klebsiella pneumoniae liver abscess (KPLA) are scarce. The present study sought to elucidate the correlation between thrombocytopenia and KPLA severity and delve into the etiological factors contributing to the incidence of thrombocytopenia. Materials and methods A retrospective analysis of the clinical data from patients with KPLA admitted between June 2012 and June 2023 was performed. Baseline characteristics, biochemical assessments, therapeutic interventions, complications, and clinical outcomes were compared between patients with and without thrombocytopenia. To investigate the potential etiologies underlying thrombocytopenia, the association between platelet count reduction and thrombophlebitis was examined, with a particular focus on platelet consumption. Furthermore, bone marrow aspiration results were evaluated to assess platelet production anomalies. Results A total of 361 KPLA patients were included in the study, among whom 60 (17%) had concurrent thrombocytopenia. Those in the thrombocytopenia group exhibited significantly higher rates of thrombophlebitis (p = 0.042), extrahepatic metastatic infection (p = 0.01), septic shock (p = 0.024), admissions to the intensive care unit (p = 0.002), and in-hospital mortality (p = 0.045). Multivariate analysis revealed that thrombocytopenia (odds ratio, 2.125; 95% confidence interval, 1.114-4.056; p = 0.022) was independently associated with thrombophlebitis. Among the thrombocytopenic patients, eight underwent bone marrow aspiration, and six (75%) had impaired medullar platelet production. After treatment, 88.6% of thrombocytopenic patients (n = 47) demonstrated recovery in their platelet counts with a median recovery time of five days (interquartile range, 3-6 days). Conclusions Thrombocytopenia in patients with KPLA is indicative of increased disease severity. The underlying etiologies for thrombocytopenia may include impaired platelet production within the bone marrow and augmented peripheral platelet consumption as evidenced by the presence of thrombophlebitis.
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Affiliation(s)
| | | | | | | | - Zhihui Chang
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
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17
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Gao S, Jin W, Quan Y, Li Y, Shen Y, Yuan S, Yi L, Wang Y, Wang Y. Bacterial capsules: Occurrence, mechanism, and function. NPJ Biofilms Microbiomes 2024; 10:21. [PMID: 38480745 PMCID: PMC10937973 DOI: 10.1038/s41522-024-00497-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 03/05/2024] [Indexed: 03/17/2024] Open
Abstract
In environments characterized by extended multi-stress conditions, pathogens develop a variety of immune escape mechanisms to enhance their ability to infect the host. The capsules, polymers that bacteria secrete near their cell wall, participates in numerous bacterial life processes and plays a crucial role in resisting host immune attacks and adapting to their niche. Here, we discuss the relationship between capsules and bacterial virulence, summarizing the molecular mechanisms of capsular regulation and pathogenesis to provide new insights into the research on the pathogenesis of pathogenic bacteria.
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Affiliation(s)
- Shuji Gao
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Wenjie Jin
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yingying Quan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yue Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Yamin Shen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Shuo Yuan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
| | - Li Yi
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China
- College of Life Science, Luoyang Normal University, Luoyang, 471934, China
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
| | - Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, 471000, China.
- Henan Provincial Engineering Research Center for Detection and Prevention and Control of Emerging Infectious Diseases in Livestock and Poultry, Luoyang, 471003, China.
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18
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Gálvez-Silva M, Arros P, Berríos-Pastén C, Villamil A, Rodas PI, Araya I, Iglesias R, Araya P, Hormazábal JC, Bohle C, Chen Y, Gan YH, Chávez FP, Lagos R, Marcoleta AE. Carbapenem-resistant hypervirulent ST23 Klebsiella pneumoniae with a highly transmissible dual-carbapenemase plasmid in Chile. Biol Res 2024; 57:7. [PMID: 38475927 DOI: 10.1186/s40659-024-00485-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
BACKGROUND The convergence of hypervirulence and carbapenem resistance in the bacterial pathogen Klebsiella pneumoniae represents a critical global health concern. Hypervirulent K. pneumoniae (hvKp) strains, frequently from sequence type 23 (ST23) and having a K1 capsule, have been associated with severe community-acquired invasive infections. Although hvKp were initially restricted to Southeast Asia and primarily antibiotic-sensitive, carbapenem-resistant hvKp infections are reported worldwide. Here, within the carbapenemase production Enterobacterales surveillance system headed by the Chilean Public Health Institute, we describe the isolation in Chile of a high-risk ST23 dual-carbapenemase-producing hvKp strain, which carbapenemase genes are encoded in a single conjugative plasmid. RESULTS Phenotypic and molecular tests of this strain revealed an extensive resistance to at least 15 antibiotic classes and the production of KPC-2 and VIM-1 carbapenemases. Unexpectedly, this isolate lacked hypermucoviscosity, challenging this commonly used hvKp identification criteria. Complete genome sequencing and analysis confirmed the K1 capsular type, the KpVP-1 virulence plasmid, and the GIE492 and ICEKp10 genomic islands carrying virulence factors strongly associated with hvKp. Although this isolate belonged to the globally disseminated hvKp clonal group CG23-I, it is unique, as it formed a clade apart from a previously reported Chilean ST23 hvKp isolate and acquired an IncN KPC-2 plasmid highly disseminated in South America (absent in other hvKp genomes), but now including a class-I integron carrying blaVIM-1 and other resistance genes. Notably, this isolate was able to conjugate the double carbapenemase plasmid to an E. coli recipient, conferring resistance to 1st -5th generation cephalosporins (including combinations with beta-lactamase inhibitors), penicillins, monobactams, and carbapenems. CONCLUSIONS We reported the isolation in Chile of high-risk carbapenem-resistant hvKp carrying a highly transmissible conjugative plasmid encoding KPC-2 and VIM-1 carbapenemases, conferring resistance to most beta-lactams. Furthermore, the lack of hypermucoviscosity argues against this trait as a reliable hvKp marker. These findings highlight the rapid evolution towards multi-drug resistance of hvKp in Chile and globally, as well as the importance of conjugative plasmids and other mobile genetic elements in this convergence. In this regard, genomic approaches provide valuable support to monitor and obtain essential information on these priority pathogens and mobile elements.
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Affiliation(s)
- Matías Gálvez-Silva
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile
| | - Patricio Arros
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile
| | - Camilo Berríos-Pastén
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile
| | - Aura Villamil
- Instituto de Salud Pública Marathon, Ñuñoa, Santiago, 1000, Chile
| | - Paula I Rodas
- Instituto de Salud Pública Marathon, Ñuñoa, Santiago, 1000, Chile
| | - Ingrid Araya
- Instituto de Salud Pública Marathon, Ñuñoa, Santiago, 1000, Chile
| | - Rodrigo Iglesias
- Instituto de Salud Pública Marathon, Ñuñoa, Santiago, 1000, Chile
| | - Pamela Araya
- Instituto de Salud Pública Marathon, Ñuñoa, Santiago, 1000, Chile
| | | | | | - Yahua Chen
- Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore, Singapore
| | - Yunn-Hwen Gan
- Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore, Singapore
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile
| | - Rosalba Lagos
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile Las Palmeras, Ñuñoa, Santiago, 3425, Chile.
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19
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Hu F, Pan Y, Li H, Han R, Liu X, Ma R, Wu Y, Lun H, Qin X, Li J, Wang A, Zhou M, Liu B, Zhou Z, He P. Carbapenem-resistant Klebsiella pneumoniae capsular types, antibiotic resistance and virulence factors in China: a longitudinal, multi-centre study. Nat Microbiol 2024; 9:814-829. [PMID: 38424289 PMCID: PMC10914598 DOI: 10.1038/s41564-024-01612-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 01/18/2024] [Indexed: 03/02/2024]
Abstract
Epidemiological knowledge of circulating carbapenem-resistant Klebsiella pneumoniae (CRKP) is needed to develop effective strategies against this public health threat. Here we present a longitudinal analysis of 1,017 CRKP isolates recovered from patients from 40 hospitals across China between 2016 and 2020. Virulence gene and capsule typing revealed expansion of CRKP capsule type KL64 (59.5%) alongside decreases in KL47 prevalence. Hypervirulent CRKP increased in prevalence from 28.2% in 2016 to 45.7% in 2020. Phylogenetic and spatiotemporal analysis revealed Beijing and Shanghai as transmission hubs accounting for differential geographical prevalence of KL47 and KL64 strains across China. Moderate frequency capsule or O-antigen loss was also detected among isolates. Non-capsular CRKP were more susceptible to phagocytosis, attenuated during mouse infections, but showed increased serum resistance and biofilm formation. These findings give insight into CRKP serotype prevalence and dynamics, revealing the importance of monitoring serotype shifts for the future development of immunological strategies against CRKP infections.
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Affiliation(s)
- Fupin Hu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuqing Pan
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Heng Li
- Key Laboratory of Alkene-carbon Fibers-based Technology & Application for Detection of Major Infectious Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Pasteurien College, Suzhou Medical College, Soochow University, Suzhou, China
| | - Renru Han
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiao Liu
- Key Laboratory of Alkene-carbon Fibers-based Technology & Application for Detection of Major Infectious Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Pasteurien College, Suzhou Medical College, Soochow University, Suzhou, China
| | - Ruijing Ma
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yongqin Wu
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Heyuan Lun
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaohua Qin
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China
| | - Jiayin Li
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Aixi Wang
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Min Zhou
- Department of Pulmonary and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bing Liu
- Department of Pulmonary and Critical Care Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhemin Zhou
- Key Laboratory of Alkene-carbon Fibers-based Technology & Application for Detection of Major Infectious Diseases, MOE Key Laboratory of Geriatric Diseases and Immunology, Pasteurien College, Suzhou Medical College, Soochow University, Suzhou, China.
- National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
| | - Ping He
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
- NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, China.
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20
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Dodge GJ, Anderson AJ, He Y, Liu W, Viner R, Imperiali B. Mapping the architecture of the initiating phosphoglycosyl transferase from S. enterica O-antigen biosynthesis in a liponanoparticle. eLife 2024; 12:RP91125. [PMID: 38358918 PMCID: PMC10942596 DOI: 10.7554/elife.91125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024] Open
Abstract
Bacterial cell surface glycoconjugates are critical for cell survival and for interactions between bacteria and their hosts. Consequently, the pathways responsible for their biosynthesis have untapped potential as therapeutic targets. The localization of many glycoconjugate biosynthesis enzymes to the membrane represents a significant challenge for expressing, purifying, and characterizing these enzymes. Here, we leverage cutting-edge detergent-free methods to stabilize, purify, and structurally characterize WbaP, a phosphoglycosyl transferase (PGT) from the Salmonella enterica (LT2) O-antigen biosynthesis. From a functional perspective, these studies establish WbaP as a homodimer, reveal the structural elements responsible for dimerization, shed light on the regulatory role of a domain of unknown function embedded within WbaP, and identify conserved structural motifs between PGTs and functionally unrelated UDP-sugar dehydratases. From a technological perspective, the strategy developed here is generalizable and provides a toolkit for studying other classes of small membrane proteins embedded in liponanoparticles beyond PGTs.
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Affiliation(s)
- Greg J Dodge
- Department of Biology and Department of Chemistry, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Alyssa J Anderson
- Department of Biology and Department of Chemistry, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Yi He
- Thermo Fisher ScientificSan JoseUnited States
| | - Weijing Liu
- Thermo Fisher ScientificSan JoseUnited States
| | - Rosa Viner
- Thermo Fisher ScientificSan JoseUnited States
| | - Barbara Imperiali
- Department of Biology and Department of Chemistry, Massachusetts Institute of TechnologyCambridgeUnited States
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21
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Rojas D, Marcoleta AE, Gálvez-Silva M, Varas MA, Díaz M, Hernández M, Vargas C, Nourdin-Galindo G, Koch E, Saldivia P, Vielma J, Gan YH, Chen Y, Guiliani N, Chávez FP. Inorganic Polyphosphate Affects Biofilm Assembly, Capsule Formation, and Virulence of Hypervirulent ST23 Klebsiella pneumoniae. ACS Infect Dis 2024; 10:606-623. [PMID: 38205780 DOI: 10.1021/acsinfecdis.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
The emergence of hypervirulent Klebsiella pneumoniae (hvKP) strains poses a significant threat to public health due to high mortality rates and propensity to cause severe community-acquired infections in healthy individuals. The ability to form biofilms and produce a protective capsule contributes to its enhanced virulence and is a significant challenge to effective antibiotic treatment. Polyphosphate kinase 1 (PPK1) is an enzyme responsible for inorganic polyphosphate synthesis and plays a vital role in regulating various physiological processes in bacteria. In this study, we investigated the impact of polyP metabolism on the biofilm and capsule formation and virulence traits in hvKP using Dictyostelium discoideum amoeba as a model host. We found that the PPK1 null mutant was impaired in biofilm and capsule formation and showed attenuated virulence in D. discoideum compared to the wild-type strain. We performed a proteomic analysis to gain further insights into the underlying molecular mechanism. The results revealed that the PPK1 mutant had a differential expression of proteins involved in capsule synthesis (Wzi-Ugd), biofilm formation (MrkC-D-H), synthesis of the colibactin genotoxin precursor (ClbB), as well as proteins associated with the synthesis and modification of lipid A (ArnB-LpxC-PagP). These proteomic findings corroborate the phenotypic observations and indicate that the PPK1 mutation is associated with impaired biofilm and capsule formation and attenuated virulence in hvKP. Overall, our study highlights the importance of polyP synthesis in regulating extracellular biomolecules and virulence in K. pneumoniae and provides insights into potential therapeutic targets for treating K. pneumoniae infections.
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Affiliation(s)
- Diego Rojas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Matías Gálvez-Silva
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Macarena A Varas
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Díaz
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Mauricio Hernández
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Cristian Vargas
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | | | - Elard Koch
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
| | - Pablo Saldivia
- División Biotecnología, Instituto Melisa, San Pedro de la Paz CP 9660000, Chile
- Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción CP 4070389, Chile
| | - Jorge Vielma
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Yunn-Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore CP 119077, Singapore
| | - Nicolás Guiliani
- Laboratorio de Comunicación Microbiana, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
| | - Francisco P Chávez
- Laboratorio de Microbiología de Sistemas, Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago CP 7800003, Chile
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22
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Tan YH, Arros P, Berríos-Pastén C, Wijaya I, Chu WHW, Chen Y, Cheam G, Mohamed Naim AN, Marcoleta AE, Ravikrishnan A, Nagarajan N, Lagos R, Gan YH. Hypervirulent Klebsiella pneumoniae employs genomic island encoded toxins against bacterial competitors in the gut. THE ISME JOURNAL 2024; 18:wrae054. [PMID: 38547398 PMCID: PMC11020217 DOI: 10.1093/ismejo/wrae054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/24/2024] [Accepted: 03/25/2024] [Indexed: 04/18/2024]
Abstract
The hypervirulent lineages of Klebsiella pneumoniae (HvKp) cause invasive infections such as Klebsiella-liver abscess. Invasive infection often occurs after initial colonization of the host gastrointestinal tract by HvKp. Over 80% of HvKp isolates belong to the clonal group 23 sublineage I that has acquired genomic islands (GIs) GIE492 and ICEKp10. Our analysis of 12 361 K. pneumoniae genomes revealed that GIs GIE492 and ICEKp10 are co-associated with the CG23-I and CG10118 HvKp lineages. GIE492 and ICEKp10 enable HvKp to make a functional bacteriocin microcin E492 (mccE492) and the genotoxin colibactin, respectively. We discovered that GIE492 and ICEKp10 play cooperative roles and enhance gastrointestinal colonization by HvKp. Colibactin is the primary driver of this effect, modifying gut microbiome diversity. Our in vitro assays demonstrate that colibactin and mccE492 kill or inhibit a range of Gram-negative Klebsiella species and Escherichia coli strains, including Gram-positive bacteria, sometimes cooperatively. Moreover, mccE492 and colibactin kill human anaerobic gut commensals that are similar to the taxa found altered by colibactin in the mouse intestines. Our findings suggest that GIs GIE492 and ICEKp10 enable HvKp to kill several commensal bacterial taxa during interspecies interactions in the gut. Thus, acquisition of GIE492 and ICEKp10 could enable better carriage in host populations and explain the dominance of the CG23-I HvKp lineage.
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Affiliation(s)
- Yi Han Tan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, Singapore 117545, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore 117596, Republic of Singapore
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (ASTAR), Singapore 138672, Republic of Singapore
| | - Patricio Arros
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Facultad de Ciencias, Departamento de Biología, Universidad de Chile, Las Palmeras 3425 Ñuñoa, Santiago, Chile
| | - Camilo Berríos-Pastén
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Facultad de Ciencias, Departamento de Biología, Universidad de Chile, Las Palmeras 3425 Ñuñoa, Santiago, Chile
| | - Indrik Wijaya
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (ASTAR), Singapore 138672, Republic of Singapore
| | - Wilson H W Chu
- National Public Health Laboratory, National Centre for Infectious Diseases, 16 Jln Tan Tock Seng, Singapore 308442, Republic of Singapore
| | - Yahua Chen
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, Singapore 117545, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore 117596, Republic of Singapore
| | - Guoxiang Cheam
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, Singapore 117545, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore 117596, Republic of Singapore
| | - Ahmad Nazri Mohamed Naim
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (ASTAR), Singapore 138672, Republic of Singapore
| | - Andrés E Marcoleta
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Facultad de Ciencias, Departamento de Biología, Universidad de Chile, Las Palmeras 3425 Ñuñoa, Santiago, Chile
| | - Aarthi Ravikrishnan
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (ASTAR), Singapore 138672, Republic of Singapore
| | - Niranjan Nagarajan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, Singapore 117545, Republic of Singapore
- Genome Institute of Singapore (GIS), Agency for Science, Technology and Research (ASTAR), Singapore 138672, Republic of Singapore
| | - Rosalba Lagos
- Grupo de Microbiología Integrativa, Laboratorio de Biología Estructural y Molecular BEM, Facultad de Ciencias, Departamento de Biología, Universidad de Chile, Las Palmeras 3425 Ñuñoa, Santiago, Chile
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, MD4, Level 2, Singapore 117545, Republic of Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore 117596, Republic of Singapore
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23
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Khadka S, Ring BE, Walker RS, Krzeminski LR, Pariseau DA, Hathaway M, Mobley HLT, Mike LA. Urine-mediated suppression of Klebsiella pneumoniae mucoidy is counteracted by spontaneous Wzc variants altering capsule chain length. mSphere 2023; 8:e0028823. [PMID: 37610214 PMCID: PMC10597399 DOI: 10.1128/msphere.00288-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/14/2023] [Indexed: 08/24/2023] Open
Abstract
Klebsiella pneumoniae is a hospital-associated pathogen primarily causing urinary tract infections (UTIs), pneumonia, and septicemia. Two challenging lineages include the hypervirulent strains, causing invasive community-acquired infections, and the carbapenem-resistant classical strains, most frequently isolated from UTIs. While hypervirulent strains are often characterized by a hypermucoid phenotype, classical strains usually present with low mucoidy. Since clinical UTI isolates tend to exhibit limited mucoidy, we hypothesized that environmental conditions may drive K. pneumoniae adaptation to the urinary tract and select against mucoid isolates. We found that both hypervirulent K. pneumoniae and classical Klebsiella UTI isolates significantly suppressed mucoidy when cultured in urine without reducing capsule abundance. A genetic screen identified secondary mutations in the wzc tyrosine kinase that overcome urine-suppressed mucoidy. Over-expressing Wzc variants in trans was sufficient to boost mucoidy in both hypervirulent and classical Klebsiella UTI isolates. Wzc is a bacterial tyrosine kinase that regulates capsule polymerization and extrusion. Although some Wzc variants reduced Wzc phospho-status, urine did not alter Wzc phospho-status. Urine does, however, increase K. pneumoniae capsule chain length diversity and enhance cell-surface attachment. The identified Wzc variants counteract urine-mediated effects on capsule chain length and cell attachment. Combined, these data indicate that capsule chain length correlates with K. pneumoniae mucoidy and that this extracellular feature can be fine-tuned by spontaneous Wzc mutations, which alter host interactions. Spontaneous Wzc mutation represents a global mechanism that could fine-tune K. pneumoniae niche-specific fitness in both classical and hypervirulent isolates. IMPORTANCE Klebsiella pneumoniae is high-priority pathogen causing both hospital-associated infections, such as urinary tract infections, and community-acquired infections. Clinical isolates from community-acquired infection are often characterized by a tacky, hypermucoid phenotype, while urinary tract isolates are usually not mucoid. Historically, mucoidy was attributed to capsule overproduction; however, recent reports have demonstrated that K. pneumoniae capsule abundance and mucoidy are not always correlated. Here, we report that human urine suppresses K. pneumoniae mucoidy, diversifies capsule polysaccharide chain length, and increases cell surface association. Moreover, specific mutations in the capsule biosynthesis gene, wzc, are sufficient to overcome urine-mediated suppression of mucoidy. These Wzc variants cause constitutive production of more uniform capsular polysaccharide chains and increased release of capsule from the cell surface, even in urine. These data demonstrate that K. pneumoniae regulates capsule chain length and cell surface attachment in response host cues, which can alter bacteria-host interactions.
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Affiliation(s)
- Saroj Khadka
- Medical Microbiology and Immunology, University of Toledo , Toledo, Ohio, USA
| | - Brooke E Ring
- Medical Microbiology and Immunology, University of Toledo , Toledo, Ohio, USA
| | - Ryan S Walker
- Microbiology and Immunology, University of Michigan , Ann Arbor, Michigan, USA
| | | | - Drew A Pariseau
- Medical Microbiology and Immunology, University of Toledo , Toledo, Ohio, USA
| | - Matthew Hathaway
- Medical Microbiology and Immunology, University of Toledo , Toledo, Ohio, USA
| | - Harry L T Mobley
- Microbiology and Immunology, University of Michigan , Ann Arbor, Michigan, USA
| | - Laura A Mike
- Medical Microbiology and Immunology, University of Toledo , Toledo, Ohio, USA
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24
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Chu WHW, Tan YH, Tan SY, Chen Y, Yong M, Lye DC, Kalimuddin S, Archuleta S, Gan YH. Acquisition of regulator on virulence plasmid of hypervirulent Klebsiella allows bacterial lifestyle switch in response to iron. mBio 2023; 14:e0129723. [PMID: 37530523 PMCID: PMC10470599 DOI: 10.1128/mbio.01297-23] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/08/2023] [Indexed: 08/03/2023] Open
Abstract
Hypervirulent Klebsiella pneumoniae causes liver abscess and potentially devastating metastatic complications. The majority of Klebsiella-induced liver abscess are caused by the CG23-I sublineage of hypervirulent Klebsiella pneumoniae. This and some other lineages possess a >200-kb virulence plasmid. We discovered a novel protein IroP nestled in the virulence plasmid-encoded salmochelin operon that cross-regulates and suppresses the promoter activity of chromosomal type 3 fimbriae (T3F) gene transcription. IroP is itself repressed by iron through the ferric uptake regulator. Iron-rich conditions increase T3F and suppress capsule mucoviscosity, leading to biofilm formation and cell adhesion. Conversely, iron-poor conditions cause a transcriptional switch to hypermucoid capsule production and T3F repression. The likely acquisition of iroP on mobile genetic elements and successful adaptive integration into the genetic circuitry of a major lineage of hypervirulent K. pneumoniae reveal a powerful example of plasmid chromosomal cross talk that confers an evolutionary advantage. Our discovery also addresses the conundrum of how the hypermucoid capsule that impedes adhesion could be regulated to facilitate biofilm formation and colonization. The acquired ability of the bacteria to alternate between a state favoring dissemination and one that favors colonization in response to iron availability through transcriptional regulation offers novel insights into the evolutionary success of this pathogen. IMPORTANCE Hypervirulent Klebsiella pneumoniae contributes to the majority of monomicrobial-induced liver abscess infections that can lead to several other metastatic complications. The large virulence plasmid is highly stable in major lineages, suggesting that it provides survival benefits. We discovered a protein IroP encoded on the virulence plasmid that suppresses expression of the type 3 fimbriae. IroP itself is regulated by iron, and we showed that iron regulates hypermucoid capsule production while inversely regulating type 3 fimbriae expression through IroP. The acquisition and integration of this inverse transcriptional switch between fimbriae and capsule mucoviscosity shows an evolved sophisticated plasmid-chromosomal cross talk that changes the behavior of hypervirulent K. pneumoniae in response to a key nutrient that could contribute to the evolutionary success of this pathogen.
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Affiliation(s)
- Wilson H. W. Chu
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yi Han Tan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Si Yin Tan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yahua Chen
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Melvin Yong
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David C. Lye
- National Centre for Infectious Diseases, Singapore, Singapore
- Tan Tock Seng Hospital, Singapore, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Shirin Kalimuddin
- Department of Infectious Diseases, Singapore General Hospital, Singapore, Singapore
- Program in Emerging Infectious Disease, Duke-NUS Medical School, Singapore, Singapore
| | - Sophia Archuleta
- Division of Infectious Diseases, Department of Medicine, National University Hospital, National University Health System, Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yunn-Hwen Gan
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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25
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Lourenço M, Osbelt L, Passet V, Gravey F, Megrian D, Strowig T, Rodrigues C, Brisse S. Phages against Noncapsulated Klebsiella pneumoniae: Broader Host range, Slower Resistance. Microbiol Spectr 2023; 11:e0481222. [PMID: 37338376 PMCID: PMC10433977 DOI: 10.1128/spectrum.04812-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 05/23/2023] [Indexed: 06/21/2023] Open
Abstract
Klebsiella pneumoniae (Kp), a human gut colonizer and opportunistic pathogen, is a major contributor to the global burden of antimicrobial resistance. Virulent bacteriophages represent promising agents for decolonization and therapy. However, the majority of anti-Kp phages that have been isolated thus far are highly specific to unique capsular types (anti-K phages), which is a major limitation to phage therapy prospects due to the highly polymorphic capsule of Kp. Here, we report on an original anti-Kp phage isolation strategy, using capsule-deficient Kp mutants as hosts (anti-Kd phages). We show that anti-Kd phages have a broad host range, as the majority are able to infect noncapsulated mutants of multiple genetic sublineages and O-types. Additionally, anti-Kd phages induce a lower rate of resistance emergence in vitro and provide increased killing efficiency when in combination with anti-K phages. In vivo, anti-Kd phages are able to replicate in mouse guts colonized with a capsulated Kp strain, suggesting the presence of noncapsulated Kp subpopulations. The original strategy proposed here represents a promising avenue that circumvents the Kp capsule host restriction barrier, offering promise for therapeutic development. IMPORTANCE Klebsiella pneumoniae (Kp) is an ecologically generalist bacterium as well as an opportunistic pathogen that is responsible for hospital-acquired infections and a major contributor to the global burden of antimicrobial resistance. In the last decades, limited advances have been made in the use of virulent phages as alternatives or complements to antibiotics that are used to treat Kp infections. This work demonstrates the potential value of an anti-Klebsiella phage isolation strategy that addresses the issue of the narrow host range of anti-K phages. Anti-Kd phages may be active in infection sites in which capsule expression is intermittent or repressed or in combination with anti-K phages, which often induce the loss of capsule in escape mutants.
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Affiliation(s)
- Marta Lourenço
- Institut Pasteur, Université Paris Cité, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - Lisa Osbelt
- Department of Microbial Immune Regulation, Helmholtz Center for Infection Research, Braunschweig, Germany
- German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Braunschweig, Germany
| | - Virginie Passet
- Institut Pasteur, Université Paris Cité, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - François Gravey
- Dynamycure Inserm UM1311 Normandie Univ, UNICAEN, UNIROUEN, Caen, France
| | - Daniela Megrian
- Unité de Microbiologie Structurale, Institut Pasteur, CNRS UMR 3528, Université Paris Cité, Paris, France
| | - Till Strowig
- Department of Microbial Immune Regulation, Helmholtz Center for Infection Research, Braunschweig, Germany
- German Center for Infection Research (DZIF), partner site Hannover-Braunschweig, Braunschweig, Germany
| | - Carla Rodrigues
- Institut Pasteur, Université Paris Cité, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
| | - Sylvain Brisse
- Institut Pasteur, Université Paris Cité, Biodiversity and Epidemiology of Bacterial Pathogens, Paris, France
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Tang M, Huang Z, Zhang X, Kong J, Zhou B, Han Y, Zhang Y, Chen L, Zhou T. Phage resistance formation and fitness costs of hypervirulent Klebsiella pneumoniae mediated by K2 capsule-specific phage and the corresponding mechanisms. Front Microbiol 2023; 14:1156292. [PMID: 37538841 PMCID: PMC10394836 DOI: 10.3389/fmicb.2023.1156292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 07/04/2023] [Indexed: 08/05/2023] Open
Abstract
Introduction Phage is promising for the treatment of hypervirulent Klebsiella pneumoniae (hvKP) infections. Although phage resistance seems inevitable, we found that there still was optimization space in phage therapy for hvKP infection. Methods The clinical isolate K. pneumoniae FK1979 was used to recover the lysis phage ΦFK1979 from hospital sewage. Phage-resistant bacteria were obtained on LB agar and used to isolate phages from sewage. The plaque assay, transmission electron microscopy (TEM), multiplicity of infection test, one-step growth curve assay, and genome analysis were performed to characterize the phages. Colony morphology, precipitation test and scanning electron microscope were used to characterize the bacteria. The absorption test, spot test and efficiency of plating (EOP) assay were used to identify the sensitivity of bacteria to phages. Whole genome sequencing (WGS) was used to identify gene mutations of phage-resistant bacteria. The gene expression levels were detected by RT-qPCR. Genes knockout and complementation of the mutant genes were performed. The change of capsules was detected by capsule quantification and TEM. The growth kinetics, serum resistance, biofilm formation, adhesion and invasion to A549 and RAW 264.7 cells, as well as G. mellonella and mice infection models, were used to evaluate the fitness and virulence of bacteria. Results and discussion Here, we demonstrated that K2 capsule type sequence type 86 hvKP FK1979, one of the main pandemic lineages of hvKP with thick capsule, rapidly developed resistance to a K2-specific lysis phage ΦFK1979 which was well-studied in this work to possess polysaccharide depolymerase. The phage-resistant mutants showed a marked decrease in capsule expression. WGS revealed single nucleotide polymorphism (SNP) in genes encoding RfaH, galU, sugar glycosyltransferase, and polysaccharide deacetylase family protein in the mutants. RfaH and galU were further identified as being required for capsule production and phage sensitivity. Expressions of genes involved in the biosynthesis or regulation of capsule and/or lipopolysaccharide significantly decreased in the mutants. Despite the rapid and frequent development of phage resistance being a disadvantage, the attenuation of virulence and fitness in vitro and in vivo indicated that phage-resistant mutants of hvKP were more susceptible to the immunity system. Interestingly, the newly isolated phages targeting mutants changed significantly in their plaque and virus particle morphology. Their genomes were much larger than and significantly different from that of ΦFK1979. They possessed much more functional proteins and strikingly broader host spectrums than ΦFK1979. Our study suggests that K2-specific phage has the potential to function as an antivirulence agent, or a part of phage cocktails combined with phages targeting phage-resistant bacteria, against hvKP-relevant infections.
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Affiliation(s)
- Miran Tang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Zeyu Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Xiaodong Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Jingchun Kong
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Beibei Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yijia Han
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Yi Zhang
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Lijiang Chen
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University and Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
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Dodge GJ, Anderson AJ, He Y, Liu W, Viner R, Imperiali B. Mapping the architecture of the initiating phosphoglycosyl transferase from S. enterica O-antigen biosynthesis in a liponanoparticle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.16.545297. [PMID: 37398332 PMCID: PMC10312794 DOI: 10.1101/2023.06.16.545297] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Bacterial cell surface glycoconjugates are critical for cell survival and for interactions between bacteria and their hosts. Consequently, the pathways responsible for their biosynthesis have untapped potential as therapeutic targets. The localization of many glycoconjugate biosynthesis enzymes to the membrane represents a significant challenge for expressing, purifying, and characterizing these enzymes. Here, we leverage cutting-edge methods to stabilize, purify, and structurally characterize WbaP, a phosphoglycosyl transferase (PGT) from Salmonella enterica (LT2) O-antigen biosynthesis without detergent solubilization from the lipid bilayer. From a functional perspective, these studies establish WbaP as a homodimer, reveal the structural elements responsible for oligomerization, shed light on the regulatory role of a domain of unknown function embedded within WbaP, and identify conserved structural motifs between PGTs and functionally unrelated UDP-sugar dehydratases. From a technological perspective, the strategy developed here is generalizable and provides a toolkit for studying small membrane proteins embedded in liponanoparticles beyond PGTs.
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Affiliation(s)
- Greg J. Dodge
- Department of Biology and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Alyssa J. Anderson
- Department of Biology and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yi He
- Thermo Fisher Scientific, San Jose CA 95134, USA
| | - Weijing Liu
- Thermo Fisher Scientific, San Jose CA 95134, USA
| | - Rosa Viner
- Thermo Fisher Scientific, San Jose CA 95134, USA
| | - Barbara Imperiali
- Department of Biology and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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28
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Zhou K, Xue CX, Xu T, Shen P, Wei S, Wyres KL, Lam MMC, Liu J, Lin H, Chen Y, Holt KE, Xiao Y. A point mutation in recC associated with subclonal replacement of carbapenem-resistant Klebsiella pneumoniae ST11 in China. Nat Commun 2023; 14:2464. [PMID: 37117217 PMCID: PMC10147710 DOI: 10.1038/s41467-023-38061-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 04/13/2023] [Indexed: 04/30/2023] Open
Abstract
Adaptation to selective pressures is crucial for clinically important pathogens to establish epidemics, but the underlying evolutionary drivers remain poorly understood. The current epidemic of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant threat to public health. In this study we analyzed the genome sequences of 794 CRKP bloodstream isolates collected in 40 hospitals in China between 2014 and 2019. We uncovered a subclonal replacement in the predominant clone ST11, where the previously prevalent subclone OL101:KL47 was replaced by O2v1:KL64 over time in a stepwise manner. O2v1:KL64 carried a higher load of mobile genetic elements, and a point mutation exclusively detected in the recC of O2v1:KL64 significantly promotes recombination proficiency. The epidemic success of O2v1:KL64 was further associated with a hypervirulent sublineage with enhanced resistance to phagocytosis, sulfamethoxazole-trimethoprim, and tetracycline. The phenotypic alterations were linked to the overrepresentation of hypervirulence determinants and antibiotic genes conferred by the acquisition of an rmpA-positive pLVPK-like virulence plasmid and an IncFII-type multidrug-resistant plasmid, respectively. The dissemination of the sublineage was further promoted by more frequent inter-hospital transmission. The results collectively demonstrate that the expansion of O2v1:KL64 is correlated to a repertoire of genomic alterations convergent in a subpopulation with evolutionary advantages.
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Affiliation(s)
- Kai Zhou
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China.
| | - Chun-Xu Xue
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China
| | - Tingting Xu
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China
| | - Ping Shen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Sha Wei
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China
| | - Kelly L Wyres
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
| | - Margaret M C Lam
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
| | - Jinquan Liu
- Shenzhen Institute of Respiratory Diseases, Shenzhen People's Hospital (Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, 518020, China
| | - Haoyun Lin
- Department of Clinical Laboratory, Shenzhen People's Hospital, Shenzhen, China
| | - Yunbo Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310003, China.
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Gautam I, Huss CW, Storad ZA, Krebs M, Bassiouni O, Ramesh R, Wuescher LM, Worth RG. Activated Platelets Mediate Monocyte Killing of Klebsiella pneumoniae. Infect Immun 2023; 91:e0055622. [PMID: 36853027 PMCID: PMC10016073 DOI: 10.1128/iai.00556-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/02/2023] [Indexed: 03/01/2023] Open
Abstract
Platelets are known for essential activities in hemostasis and for their important contribution to protection against infectious pathogens. Klebsiella pneumoniae is an opportunistic pathogen widely known to cause nosocomial infections. Recently, hypervirulent strains of K. pneumoniae have been emerging, which can cause severe infections in immunocompetent individuals. Combined with the increase in antibiotic resistance, it is important to understand how K. pneumoniae affects components of the immune system. We studied the interactions of human platelets with several K. pneumoniae strains (the wild type encapsulated strain, and a nonencapsulated mutant). Thrombin-stimulated whole human and mouse blood significantly inhibited bacterial growth compared to unstimulated whole blood. Furthermore, we investigated the effect of K. pneumoniae on platelet activation. Both strains induced significant increase in activation of both unstimulated and thrombin-stimulated human platelets. Additionally, only the nonencapsulated mutant increased aggregation of platelets in response to ADP. K. pneumoniae killing assays were then performed with washed platelets in the presence or absence of thrombin. Surprisingly, washed platelets failed to exhibit any effects on the growth of K. pneumoniae. We further explored the impact of platelets on monocyte-mediated killing of K. pneumoniae. Importantly, we found that activated platelets significantly enhanced monocyte-mediated killing of K. pneumoniae. This effect was likely due to the formation of platelet-monocyte aggregates in blood upon thrombin stimulation. Overall, this study highlights the role of platelets in mediating a protective response against K. pneumoniae and reinforces the importance of platelets in modulating leukocyte behavior.
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Affiliation(s)
- Iluja Gautam
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Chadwick W. Huss
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Zachary A. Storad
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Michelle Krebs
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Omar Bassiouni
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Rochan Ramesh
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Leah M. Wuescher
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
| | - Randall G. Worth
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, Ohio, USA
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30
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Abstract
Klebsiella pneumoniae is a leading cause of nosocomial and community acquired infections, making K. pneumoniae the pathogen that is associated with the second largest number of deaths attributed to any antibiotic resistant infection. K. pneumoniae colonizes the nasopharynx and the gastrointestinal tract in an asymptomatic manner without dissemination to other tissues. Importantly, gastrointestinal colonization is a requisite for infection. Our understanding of K. pneumoniae colonization is still based on interrogating mouse models in which animals are pretreated with antibiotics to disturb the colonization resistance imposed by the gut microbiome. In these models, infections disseminate to other tissues. Here, we report a murine model to allow for the study of the gastrointestinal colonization of K. pneumoniae without tissue dissemination. Hypervirulent and antibiotic resistant strains stably colonize the gastrointestinal tract of in an inbred mouse population without antibiotic treatment. The small intestine is the primary site of colonization and is followed by a transition to the colon over time, without dissemination to other tissues. Our model recapitulates the disease dynamics of the metastatic K. pneumoniae strains that are able to disseminate from the gastrointestinal tract to other sterile sites. Colonization is associated with mild to moderate histopathology, no significant inflammation, and no effect on the richness of the microbiome. Our model sums up the clinical scenario in which antibiotic treatment disturbs the colonization of K. pneumoniae and results in dissemination to other tissues. Finally, we establish that the capsule polysaccharide is necessary for the colonization of the large intestine, whereas the type VI secretion system contributes to colonization across the gastrointestinal tract. IMPORTANCE Klebsiella pneumoniae is one of the pathogens that is sweeping the world in the antibiotic resistance pandemic. Klebsiella colonizes the nasopharynx and the gut of healthy subjects in an asymptomatic manner, making gut colonization a requisite for infection. This makes it essential to understand the gastrointestinal carriage in preventing Klebsiella infections. Current research models rely on the perturbation of the gut microbiome by antibiotics, resulting in an invasive infection. Here, we report a new model of K. pneumoniae gut colonization that recapitulates key features of the asymptomatic human gastrointestinal tract colonization. In our model, there is no need to disturb the microbiota to achieve stable colonization, and there is no dissemination to other tissues. Our model sums up the clinical scenario in which antibiotic treatment triggers invasive infection. We envision that our model will be an excellent platform upon which to investigate factors enhancing colonization and invasive infections and to test therapeutics to eliminate Klebsiella asymptomatic colonization.
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31
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Nunez C, Kostoulias X, Peleg A, Short F, Qu Y. A comprehensive comparison of biofilm formation and capsule production for bacterial survival on hospital surfaces. Biofilm 2023; 5:100105. [PMID: 36711324 PMCID: PMC9880390 DOI: 10.1016/j.bioflm.2023.100105] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 01/23/2023] Open
Abstract
Biofilm formation and capsule production are known microbial strategies used by bacterial pathogens to survive adverse conditions in the hospital environment. The relative importance of these strategies individually is unexplored. This project aims to compare the contributory roles of biofilm formation and capsule production in bacterial survival on hospital surfaces. Representative strains of bacterial species often causing hospital-acquired infections were selected, including Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. The importance of biofilm formation and capsule production on bacterial survival was evaluated by comparing capsule-positive wild-type and capsule-deficient mutant strains, and biofilm and planktonic growth modes respectively, against three adverse hospital conditions, including desiccation, benzalkonium chloride disinfection and ultraviolet (UV) radiation. Bacterial survival was quantitatively assessed using colony-forming unit (CFU) enumeration and the 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and qualitatively by scanning electron microscopy (SEM). Correlations between capsule production and biofilm formation were further investigated. Biofilm formation contributed significantly to bacterial survival on hospital surface simulators, mediating high resistance to desiccation, benzalkonium chloride disinfection and UV radiation. The role of capsule production was minor and species-specific; encapsulated A. baumannii but not K. pneumoniae cells demonstrated slightly increased resistance to desiccation, and neither showed enhanced resistance to benzalkonium chloride. Interestingly, capsule production sensitized K. pneumoniae and A. baumannii to UV radiation. The loss of capsule in K. pneumoniae and A. baumannii enhanced biofilm formation, possibly by increasing cell surface hydrophobicity. In summary, this study confirms the crucial role of biofilm formation in bacterial survival on hospital surfaces. Conversely, encapsulation plays a relatively minor role and may even negatively impact bacterial biofilm formation and hospital survival.
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Affiliation(s)
- Charles Nunez
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia
| | - Xenia Kostoulias
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Anton Peleg
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Francesca Short
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia,Corresponding author.,
| | - Yue Qu
- Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia,Corresponding author. Infection Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash University, Clayton, Victoria, 3800, Australia.
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Wang S, Ding Q, Zhang Y, Zhang A, Wang Q, Wang R, Wang X, Jin L, Ma S, Wang H. Evolution of Virulence, Fitness, and Carbapenem Resistance Transmission in ST23 Hypervirulent Klebsiella pneumoniae with the Capsular Polysaccharide Synthesis Gene wcaJ Inserted via Insertion Sequence Elements. Microbiol Spectr 2022; 10:e0240022. [PMID: 36222687 PMCID: PMC9769677 DOI: 10.1128/spectrum.02400-22] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/23/2022] [Indexed: 01/06/2023] Open
Abstract
Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) is recognized as a threat worldwide, but the mechanisms underlying its emergence remain unclear. As most CR-hvKP isolates are not hypermucoviscous, we speculated that the evolution of the capsule might result in the convergence of carbapenem resistance and hypervirulence. Here, 2,096 K. pneumoniae isolates were retrospectively collected to screen the ST23-K1 clone, and hypervirulence was roughly defined as being highly resistant to serum killing. The effect of wcaJ on the capsule, virulence, fitness, and resistance acquisition was further analyzed. The capsule gene wcaJ, inserted by ISKpn26/ISKpn74, was identified via whole-genome sequencing in four hvKP, but not hypermucoviscous, isolates. Uronic acid quantitation results revealed that these isolates produced significantly less capsular polysaccharides than NTUH-K2044. A significant increase in capsular production was observed in wcaJ-complemented isolates and confirmed by transmission electron microscopy. Further, all wcaJ-complemented isolates acquired greater resistance to macrophage phagocytosis, and one representative isolate resulted in a significantly higher mortality rate than the parental isolate in mice, indicating that wcaJ inactivation might compromise virulence. However, isolates with wcaJ interruption demonstrated a lower fitness cost and a high conjugation frequency of the blaKPC-2 plasmid, raising concerns about the emergence of carbapenem resistance in hvKP. IMPORTANCE Klebsiella pneumoniae is one of the most common nosocomial pathogens worldwide, and we speculated that the evolution of the capsule might result in the convergence of carbapenem resistance and hypervirulence of K. pneumoniae. The wcaJ gene was first reported to be interrupted by insertion sequence elements in ST23-K1 hypervirulent Klebsiella pneumoniae, resulting in little capsule synthesis, which plays an important role in virulence. We examined the effect of wcaJ on the capsule, virulence, and fitness. Isolates with wcaJ interruption might compromise virulence and demonstrated a lower fitness cost and a high conjugation frequency of the blaKPC-2 plasmid, highlighting its role as a potential factor facilitating hypervirulence and carbapenem resistance.
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Affiliation(s)
- Shuyi Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
| | - Qi Ding
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Yawei Zhang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Anru Zhang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Qi Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Ruobing Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Xiaojuan Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Longyang Jin
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Shuai Ma
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
- Institute of Medical Technology, Peking University Health Science Center, Beijing, China
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33
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Wei S, Xu T, Chen Y, Zhou K. Autophagy, cell death, and cytokines in K. pneumoniae infection: Therapeutic Perspectives. Emerg Microbes Infect 2022; 12:2140607. [DOI: 10.1080/22221751.2022.2140607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Sha Wei
- Shenzhen Institute of Respiratory Diseases, Second Clinical Medical College (Shenzhen People’s Hospital), Jinan University; the First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Tingting Xu
- Shenzhen Institute of Respiratory Diseases, Second Clinical Medical College (Shenzhen People’s Hospital), Jinan University; the First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Yuxin Chen
- Department of Laboratory Medicine, Nanjing Drum Tower Hospital Clinical College of Jiangsu University, Nanjing, Jiangsu, China
| | - Kai Zhou
- Shenzhen Institute of Respiratory Diseases, Second Clinical Medical College (Shenzhen People’s Hospital), Jinan University; the First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
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34
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Nucci A, Rocha EPC, Rendueles O. Adaptation to novel spatially-structured environments is driven by the capsule and alters virulence-associated traits. Nat Commun 2022; 13:4751. [PMID: 35963864 PMCID: PMC9376106 DOI: 10.1038/s41467-022-32504-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 08/02/2022] [Indexed: 12/14/2022] Open
Abstract
The extracellular capsule is a major virulence factor, but its ubiquity in free-living bacteria with large environmental breadths suggests that it shapes adaptation to novel niches. Yet, how it does so, remains unexplored. Here, we evolve three Klebsiella strains and their capsule mutants in parallel. Their comparison reveals different phenotypic and genotypic evolutionary changes that alter virulence-associated traits. Non-capsulated populations accumulate mutations that reduce exopolysaccharide production and increase biofilm formation and yield, whereas most capsulated populations become hypermucoviscous, a signature of hypervirulence. Hence, adaptation to novel environments primarily occurs by fine-tuning expression of the capsular locus. The same evolutionary conditions selecting for mutations in the capsular gene wzc leading to hypermucoviscosity also result in increased susceptibility to antibiotics by mutations in the ramA regulon. This implies that general adaptive processes outside the host can affect capsule evolution and its role in virulence and infection outcomes may be a by-product of such adaptation. Phenotypic and genotypic evolution in worrisome Klebsiella spp. is influenced by the capsule. Here the authors show that adaptation outside the host can impact virulence-associated traits, including de novo emergence of hypermucoviscosity.
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Affiliation(s)
- Amandine Nucci
- Institut Pasteur, Université de Paris, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université de Paris, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France
| | - Olaya Rendueles
- Institut Pasteur, Université de Paris, CNRS, UMR3525, Microbial Evolutionary Genomics, F-75015, Paris, France.
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Herrera V, Olavarría N, Saavedra J, Yuivar Y, Bustos P, Almarza O, Mancilla M. Complete Lipopolysaccharide of Piscirickettsia salmonis Is Required for Full Virulence in the Intraperitoneally Challenged Atlantic Salmon, Salmo salar, Model. Front Cell Infect Microbiol 2022; 12:845661. [PMID: 35372121 PMCID: PMC8972169 DOI: 10.3389/fcimb.2022.845661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Bacterial cell envelopes play a critical role in host-pathogen interactions. Macromolecular components of these structures have been closely linked to the virulence of pathogens. Piscirickettsia salmonis is a relevant salmonid pathogen with a worldwide distribution. This bacterium is the etiological agent of piscirickettsiosis, a septicemic disease that causes a high economic burden, especially for the Chilean salmon farming industry. Although P. salmonis has been discovered long ago, its pathogenicity and virulence mechanisms are not completely understood. In this work, we present a genetic approach for producing in-frame deletion mutants on genes related to the biosynthesis of membrane-associated polysaccharides. We provide a detailed in vitro phenotype description of knock-out mutants on wzx and wcaJ genes, which encode predicted lipopolysaccharide (LPS) flippase and undecaprenyl-phosphate glucose phosphotransferase enzymes, respectively. We exhibit evidence that the wzx mutant strain carries a defect in the probably most external LPS moiety, while the wcaJ mutant proved to be highly susceptible to the bactericidal action of serum but retained the ability of biofilm production. Beyond that, we demonstrate that the deletion of wzx, but not wcaJ, impairs the virulence of P. salmonis in an intraperitoneally infected Atlantic salmon, Salmo salar, model of piscirickettsiosis. Our findings support a role for LPS in the virulence of P. salmonis during the onset of piscirickettsiosis.
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Affiliation(s)
| | - Nicole Olavarría
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - José Saavedra
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Yassef Yuivar
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Patricio Bustos
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
| | - Oscar Almarza
- Blue Genomics SpA, Puerto Varas, Chile
- *Correspondence: Oscar Almarza, ; Marcos Mancilla,
| | - Marcos Mancilla
- Laboratorio de Diagnóstico y Biotecnología, R & D Department, ADL Diagnostic Chile, Puerto Montt, Chile
- *Correspondence: Oscar Almarza, ; Marcos Mancilla,
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36
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Lim DRX, Chen Y, Ng LF, Gruber J, Gan Y. Glutathione catabolism by
Enterobacteriaceae
species to hydrogen sulfide adversely affects viability of host systems in the presence of 5’fluorodeoxyuridine. Mol Microbiol 2022; 117:1089-1103. [PMID: 35279884 PMCID: PMC9313583 DOI: 10.1111/mmi.14893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 11/29/2022]
Abstract
Reduced glutathione (GSH) plays an essential role in relieving oxidative insult from the generation of free radicals via normal physiological processes. However, GSH can be exploited by bacteria as a signalling molecule for the regulation of virulence. We describe findings arising from a serendipitous observation that when GSH and Escherichia coli were incubated with 5′fluorodeoxyuridine (FUdR)‐synchronised populations of Caenorhabditis elegans, the nematodes underwent rapid death. Death was mediated by the production of hydrogen sulphide mainly through the action of tnaA, a tryptophanase‐encoding gene in E. coli. Other Enterobacteriaceae species possess similar cysteine desulfhydrases that can catabolise l‐cysteine‐containing compounds to hydrogen sulphide and mediate nematode killing when worms had been pre‐treated with FUdR. When colonic epithelial cell lines were infected, hydrogen sulphide produced by these bacteria in the presence of GSH was also able to inhibit ATP synthesis in these cells particularly when cells had been treated with FUdR. Therefore, bacterial production of hydrogen sulphide could act in concert with a commonly used genotoxic cancer drug to exert host cell impairment. Hydrogen sulphide also increases bacterial adhesion to the intestinal cells. These findings could have implications for patients undergoing chemotherapy using FUdR analogues that could result in intestinal damage.
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Affiliation(s)
- Daniel Rui Xiang Lim
- Department of Biochemistry, Yong Loo Lin School of Medicine National University of Singapore Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine National University of Singapore Singapore
| | - Li Fang Ng
- Science Divisions, Yale NUS College Singapore 138527 Singapore
| | - Jan Gruber
- Department of Biochemistry, Yong Loo Lin School of Medicine National University of Singapore Singapore
- Science Divisions, Yale NUS College Singapore 138527 Singapore
| | - Yunn‐Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine National University of Singapore Singapore
- Infectious Diseases Translational Research Programme, Yong Loo Lin School of Medicine National University of Singapore Singapore
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Nicolò S, Mattiuz G, Antonelli A, Arena F, Di Pilato V, Giani T, Baccani I, Clemente AM, Castronovo G, Tanturli M, Cozzolino F, Rossolini GM, Torcia MG. Hypervirulent Klebsiella pneumoniae Strains Modulate Human Dendritic Cell Functions and Affect TH1/TH17 Response. Microorganisms 2022; 10:microorganisms10020384. [PMID: 35208839 PMCID: PMC8877041 DOI: 10.3390/microorganisms10020384] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
Hypervirulent Klebsiella pneumoniae (Hv-Kp) strains have emerged as pathogens causing life-threatening, invasive disease even in immunocompetent hosts. Systemic dissemination usually occurs following perturbations of the gut microbiota and is facilitated by Hv-Kp resistance to phagocytosis and complement activity. Hv-Kp are usually associated with K1 or K2 capsular types, produce several iron uptake systems (e.g., aerobactin and salmochelin) and are often but not invariably, capsular material hyper-producers (hypermucoviscous phenotype: HMV). Whether Hv-Kp escape the immune response at mucosal site is unknown. In this work, we studied the effects of Hv-Kp on human dendritic cells (DCs), central players of the IL-23/IL-17 and IL-12/IFN-γ axis at mucosal sites, essential for pathogen clearance. Four Hv-Kp and HMV strains were selected and their activity on DC maturation and cytokine production was compared to that of non-virulent Kp strains with classic or HMV phenotypes. While the maturation process was equally induced by all Kp strains, significant differences between virulent and non-virulent strains were found in the expression of genes for cytokines involved in T-cell activation and differentiation. The non-virulent KP04C62 and the classic Kp, KPC157 induced high expression of TH1 (IL-12p70 and TNFα) and TH17 cytokines (IL-23, IL-1β and IL-6), while Hv-Kp poorly activated these cytokine genes. Moreover, conditioned media from DCs cultured with non-virulent Kp, either classical or hypercapsulated, induced the activation of IL-17 and IFN-γ genes in preactivated CD4+-cells suggesting their TH17/TH1 differentiation. Conditioned media from Hv-Kp poorly activated IL-17 and IFN-γ genes. In summary, our data indicate that Hv-Kp interfere with DC functions and T-cell differentiation and suggest that the escape from the IL-23/IL-17 and IL-12/IFN-γ axes may contribute to pathogen dissemination in immunocompetent hosts.
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Affiliation(s)
- Sabrina Nicolò
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
| | - Giorgio Mattiuz
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
| | - Alberto Antonelli
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
- Clinical Microbiology and Virology Unit, Careggi University Hospital, 50134 Florence, Italy;
| | - Fabio Arena
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, 50143 Florence, Italy
| | - Vincenzo Di Pilato
- Clinical Microbiology and Virology Unit, Careggi University Hospital, 50134 Florence, Italy;
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, 16132 Genoa, Italy
| | - Tommaso Giani
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
- Clinical Microbiology and Virology Unit, Careggi University Hospital, 50134 Florence, Italy;
| | - Ilaria Baccani
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
- Clinical Microbiology and Virology Unit, Careggi University Hospital, 50134 Florence, Italy;
| | - Ann Maria Clemente
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
| | - Giuseppe Castronovo
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50139 Florence, Italy; (G.C.); (M.T.); (F.C.)
| | - Michele Tanturli
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50139 Florence, Italy; (G.C.); (M.T.); (F.C.)
| | - Federico Cozzolino
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Florence, 50139 Florence, Italy; (G.C.); (M.T.); (F.C.)
| | - Gian Maria Rossolini
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
- Clinical Microbiology and Virology Unit, Careggi University Hospital, 50134 Florence, Italy;
| | - Maria Gabriella Torcia
- Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy; (S.N.); (G.M.); (A.A.); (T.G.); (I.B.); (A.M.C.); (G.M.R.)
- Correspondence:
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High-Throughput Mutagenesis and Cross-Complementation Experiments Reveal Substrate Preference and Critical Residues of the Capsule Transporters in Streptococcus pneumoniae. mBio 2021; 12:e0261521. [PMID: 34724815 PMCID: PMC8561386 DOI: 10.1128/mbio.02615-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
MOP (Multidrug/Oligosaccharidyl-lipid/Polysaccharide) family transporters are found in almost all life forms. They are responsible for transporting lipid-linked precursors across the cell membrane to support the synthesis of various glycoconjugates. While significant progress has been made in elucidating their transport mechanism, how these transporters select their substrates remains unclear. Here, we systematically tested the MOP transporters in the Streptococcus pneumoniae capsule pathway for their ability to translocate noncognate capsule precursors. Sequence similarity cannot predict whether these transporters are interchangeable. We showed that subtle changes in the central aqueous cavity of the transporter are sufficient to accommodate a different cargo. These changes can occur naturally, suggesting a potential mechanism of expanding substrate selectivity. A directed evolution experiment was performed to identify gain-of-function variants that translocate a noncognate cargo. Coupled with a high-throughput mutagenesis and sequencing (Mut-seq) experiment, residues that are functionally important for the capsule transporter were revealed. Lastly, we showed that the expression of a flippase that can transport unfinished precursors resulted in an increased susceptibility to bacitracin and mild cell shape defects, which may be a driving force to maintain transporter specificity. IMPORTANCE All licensed pneumococcal vaccines target the capsular polysaccharide (CPS). This layer is highly variable and is important for virulence in many bacterial pathogens. Most of the CPSs are produced by the Wzx/Wzy mechanism. In this pathway, CPS repeating units are synthesized in the cytoplasm, which must be flipped across the cytoplasmic membrane before polymerization. This step is mediated by the widely conserved MOP (Multidrug/Oligosaccharidyl-lipid/Polysaccharide) family transporters. Here, we systematically evaluated the interchangeability of these transporters and identified the residues important for substrate specificity and function. Understanding how CPS is synthesized will inform glycoengineering, vaccine development, and antimicrobial discovery.
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Song L, Yang X, Huang J, Zhu X, Han G, Wan Y, Xu Y, Luan G, Jia X. Phage Selective Pressure Reduces Virulence of Hypervirulent Klebsiella pneumoniae Through Mutation of the wzc Gene. Front Microbiol 2021; 12:739319. [PMID: 34690983 PMCID: PMC8526901 DOI: 10.3389/fmicb.2021.739319] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/09/2021] [Indexed: 01/11/2023] Open
Abstract
Hypervirulent Klebsiella pneumoniae (hvKp), one of the major community-acquired pathogens, can cause invasive infections such as liver abscess. In recent years, bacteriophages have been used in the treatment of K. pneumoniae, but the characteristics of the phage-resistant bacteria produced in the process of phage therapy need to be evaluated. In this study, two Podoviridae phages, hvKpP1 and hvKpP2, were isolated and characterized. In vitro and in vivo experiments demonstrated that the virulence of the resistant bacteria was significantly reduced compared with that of the wild type. Comparative genomic analysis of monoclonal sequencing showed that nucleotide deletion mutations of wzc and wcaJ genes led to phage resistance, and the electron microscopy and mucoviscosity results showed that mutations led to the loss of the capsule. Meanwhile, animal assay indicated that loss of capsule reduced the virulence of hvKp. These findings contribute to a better understanding of bacteriophage therapy, which not only can kill bacteria directly but also can reduce the virulence of bacteria by phage screening.
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Affiliation(s)
- Lingjie Song
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
| | - Xianggui Yang
- Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Jinwei Huang
- Department of Respiratory Diseases, Sixth Affiliated Hospital of Wenzhou Medical University, Lishui, China
| | - Xiaokui Zhu
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
| | - Guohui Han
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
| | - Yan Wan
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
| | - Ying Xu
- Department of Laboratory Medicine, Clinical Medical College and the First Affiliated Hospital of Chengdu Medical College, Chengdu, China
| | - Guangxin Luan
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
| | - Xu Jia
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, China
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40
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Xu Q, Yang X, Chan EWC, Chen S. The hypermucoviscosity of hypervirulent K. pneumoniae confers the ability to evade neutrophil-mediated phagocytosis. Virulence 2021; 12:2050-2059. [PMID: 34339346 PMCID: PMC8331041 DOI: 10.1080/21505594.2021.1960101] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hypervirulent Klebsiella pneumoniae (HvKP), which causes highly fatal infections, is a new threat to human health. In an attempt to investigate the underlying mechanisms of resistance to neutrophil-mediated killing and hence expression of high-level virulence by HvKP, we tested the binding affinity of HvKP strains to various types of human cells. Our data showed that HvKP exhibited weaker binding to both lung epithelial cells, intestinal Caco-2 cells and macrophages when compared to the classic, non-hypervirulent strains (cKP). Consistently, transconjugants that have acquired a rmpA or rmpA2-bearing plasmid were found to exhibit decreased adhesion to various types of human cells, and hence higher survival rate upon exposure to neutrophil cells. We further found that over production of hypermucoviscosity (HMV), but not capsular polysaccharide (CPS), contributed to the reduced binding and phagocytosis. The effect of hypermucoviscosity on enhancing HvKP virulence was further shown in human serum survival assays and animal experiments. Findings in this study therefore confirmed that rmpA/A2-mediated hypermucoviscosity in HvKP plays a key role in the pathogenesis of this organism through conferring the ability to evade neutrophil binding and phagocytosis.
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Affiliation(s)
- Qi Xu
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Xuemei Yang
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Edward Wai Chi Chan
- State Key Lab of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Sheng Chen
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
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41
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Haudiquet M, Buffet A, Rendueles O, Rocha EPC. Interplay between the cell envelope and mobile genetic elements shapes gene flow in populations of the nosocomial pathogen Klebsiella pneumoniae. PLoS Biol 2021; 19:e3001276. [PMID: 34228700 PMCID: PMC8259999 DOI: 10.1371/journal.pbio.3001276] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/07/2021] [Indexed: 01/01/2023] Open
Abstract
Mobile genetic elements (MGEs) drive genetic transfers between bacteria using mechanisms that require a physical interaction with the cellular envelope. In the high-priority multidrug-resistant nosocomial pathogens (ESKAPE), the first point of contact between the cell and virions or conjugative pili is the capsule. While the capsule can be a barrier to MGEs, it also evolves rapidly by horizontal gene transfer (HGT). Here, we aim at understanding this apparent contradiction by studying the covariation between the repertoire of capsule genes and MGEs in approximately 4,000 genomes of Klebsiella pneumoniae (Kpn). We show that capsules drive phage-mediated gene flow between closely related serotypes. Such serotype-specific phage predation also explains the frequent inactivation of capsule genes, observed in more than 3% of the genomes. Inactivation is strongly epistatic, recapitulating the capsule biosynthetic pathway. We show that conjugative plasmids are acquired at higher rates in natural isolates lacking a functional capsular locus and confirmed experimentally this result in capsule mutants. This suggests that capsule inactivation by phage pressure facilitates its subsequent reacquisition by conjugation. Accordingly, capsule reacquisition leaves long recombination tracts around the capsular locus. The loss and regain process rewires gene flow toward other lineages whenever it leads to serotype swaps. Such changes happen preferentially between chemically related serotypes, hinting that the fitness of serotype-swapped strains depends on the host genetic background. These results enlighten the bases of trade-offs between the evolution of virulence and multidrug resistance and caution that some alternatives to antibiotics by selecting for capsule inactivation may facilitate the acquisition of antibiotic resistance genes (ARGs). A study of how the complex interaction between capsules and mobile genetic elements shapes gene flow in populations of Klebsiella pneumoniae reveals that capsule inactivation by phage pressure facilitates its subsequent re-acquisition by conjugation, and this loss and re-gain process influences the gene flow towards other lineages whenever it leads to serotype changes.
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Affiliation(s)
- Matthieu Haudiquet
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris, France
- Ecole Doctoral FIRE–Programme Bettencourt, CRI, Paris, France
- * E-mail:
| | - Amandine Buffet
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris, France
| | - Olaya Rendueles
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris, France
| | - Eduardo P. C. Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris, France
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42
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From Klebsiella pneumoniae Colonization to Dissemination: An Overview of Studies Implementing Murine Models. Microorganisms 2021; 9:microorganisms9061282. [PMID: 34204632 PMCID: PMC8231111 DOI: 10.3390/microorganisms9061282] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/31/2022] Open
Abstract
Klebsiella pneumoniae is a Gram-negative pathogen responsible for community-acquired and nosocomial infections. The strains of this species belong to the opportunistic group, which is comprised of the multidrug-resistant strains, or the hypervirulent group, depending on their accessory genome, which determines bacterial pathogenicity and the host immune response. The aim of this survey is to present an overview of the murine models mimicking K. pneumoniae infectious processes (i.e., gastrointestinal colonization, urinary, pulmonary, and systemic infections), and the bacterial functions deployed to colonize and disseminate into the host. These in vivo approaches are pivotal to develop new therapeutics to limit K. pneumoniae infections via a modulation of the immune responses and/or microbiota.
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43
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Buffet A, Rocha EPC, Rendueles O. Nutrient conditions are primary drivers of bacterial capsule maintenance in Klebsiella. Proc Biol Sci 2021; 288:20202876. [PMID: 33653142 PMCID: PMC7935059 DOI: 10.1098/rspb.2020.2876] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 02/05/2021] [Indexed: 02/06/2023] Open
Abstract
The fitness cost associated with the production of bacterial capsules is considered to be offset by the protection provided by these extracellular structures against biotic aggressions or abiotic stress. However, it is unknown if the capsule contributes to fitness in the absence of these. Here, we explored conditions favouring the maintenance of the capsule in Klebsiella pneumoniae, where the capsule is known to be a major virulence factor. Using short-term experimental evolution on different Klebsiella strains, we showed that small environmental variations have a strong impact on the maintenance of the capsule. Capsule inactivation is frequent in nutrient-rich, but scarce in nutrient-poor media. Competitions between wild-type and capsule mutants in nine different strains confirmed that the capsule is costly in nutrient-rich media. Surprisingly, these results also showed that the presence of a capsule provides a clear fitness advantage in nutrient-poor conditions by increasing both growth rates and population yields. The comparative analyses of the wild-type and capsule mutants reveal complex interactions between the environment, genetic background and serotype even in relation to traits known to be relevant during pathogenesis. In conclusion, our data suggest there are novel roles for bacterial capsules yet to be discovered and further supports the notion that the capsule's role in virulence may be a by-product of its contribution to bacterial adaptation outside the host.
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Affiliation(s)
- Amandine Buffet
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
| | - Eduardo P. C. Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
| | - Olaya Rendueles
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris 75015, France
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Mike LA, Stark AJ, Forsyth VS, Vornhagen J, Smith SN, Bachman MA, Mobley HLT. A systematic analysis of hypermucoviscosity and capsule reveals distinct and overlapping genes that impact Klebsiella pneumoniae fitness. PLoS Pathog 2021; 17:e1009376. [PMID: 33720976 PMCID: PMC7993769 DOI: 10.1371/journal.ppat.1009376] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/25/2021] [Accepted: 02/12/2021] [Indexed: 12/11/2022] Open
Abstract
Hypervirulent K. pneumoniae (hvKp) is a distinct pathotype that causes invasive community-acquired infections in healthy individuals. Hypermucoviscosity (hmv) is a major phenotype associated with hvKp characterized by copious capsule production and poor sedimentation. Dissecting the individual functions of CPS production and hmv in hvKp has been hindered by the conflation of these two properties. Although hmv requires capsular polysaccharide (CPS) biosynthesis, other cellular factors may also be required and some fitness phenotypes ascribed to CPS may be distinctly attributed to hmv. To address this challenge, we systematically identified genes that impact capsule and hmv. We generated a condensed, ordered transposon library in hypervirulent strain KPPR1, then evaluated the CPS production and hmv phenotypes of the 3,733 transposon mutants, representing 72% of all open reading frames in the genome. We employed forward and reverse genetic screens to evaluate effects of novel and known genes on CPS biosynthesis and hmv. These screens expand our understanding of core genes that coordinate CPS biosynthesis and hmv, as well as identify central metabolism genes that distinctly impact CPS biosynthesis or hmv, specifically those related to purine metabolism, pyruvate metabolism and the TCA cycle. Six representative mutants, with varying effect on CPS biosynthesis and hmv, were evaluated for their impact on CPS thickness, serum resistance, host cell association, and fitness in a murine model of disseminating pneumonia. Altogether, these data demonstrate that hmv requires both CPS biosynthesis and other cellular factors, and that hmv and CPS may serve distinct functions during pathogenesis. The integration of hmv and CPS to the metabolic status of the cell suggests that hvKp may require certain nutrients to specifically cause deep tissue infections.
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Affiliation(s)
- Laura A. Mike
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrew J. Stark
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Valerie S. Forsyth
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Jay Vornhagen
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sara N. Smith
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Michael A. Bachman
- Department of Pathology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Harry L. T. Mobley
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
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Microbiota-mediated protection against antibiotic-resistant pathogens. Genes Immun 2021; 22:255-267. [PMID: 33947987 PMCID: PMC8497270 DOI: 10.1038/s41435-021-00129-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/19/2021] [Accepted: 04/09/2021] [Indexed: 02/03/2023]
Abstract
Colonization by the microbiota provides one of our most effective barriers against infection by pathogenic microbes. The microbiota protects against infection by priming immune defenses, by metabolic exclusion of pathogens from their preferred niches, and through direct antimicrobial antagonism. Disruption of the microbiota, especially by antibiotics, is a major risk factor for bacterial pathogen colonization. Restoration of the microbiota through microbiota transplantation has been shown to be an effective way to reduce pathogen burden in the intestine but comes with a number of drawbacks, including the possibility of transferring other pathogens into the host, lack of standardization, and potential disruption to host metabolism. More refined methods to exploit the power of the microbiota would allow us to utilize its protective power without the drawbacks of fecal microbiota transplantation. To achieve this requires detailed understanding of which members of the microbiota protect against specific pathogens and the mechanistic basis for their effects. In this review, we will discuss the clinical and experimental evidence that has begun to reveal which members of the microbiota protect against some of the most troublesome antibiotic-resistant pathogens: Klebsiella pneumoniae, vancomycin-resistant enterococci, and Clostridioides difficile.
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Su T, Nakamoto R, Chun YY, Chua WZ, Chen JH, Zik JJ, Sham LT. Decoding capsule synthesis in Streptococcus pneumoniae. FEMS Microbiol Rev 2020; 45:6041728. [PMID: 33338218 DOI: 10.1093/femsre/fuaa067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 12/07/2020] [Indexed: 12/20/2022] Open
Abstract
Streptococcus pneumoniae synthesizes more than one hundred types of capsular polysaccharides (CPS). While the diversity of the enzymes and transporters involved is enormous, it is not limitless. In this review, we summarized the recent progress on elucidating the structure-function relationships of CPS, the mechanisms by which they are synthesized, how their synthesis is regulated, the host immune response against them, and the development of novel pneumococcal vaccines. Based on the genetic and structural information available, we generated provisional models of the CPS repeating units that remain unsolved. In addition, to facilitate cross-species comparisons and assignment of glycosyltransferases, we illustrated the biosynthetic pathways of the known CPS in a standardized format. Studying the intricate steps of pneumococcal CPS assembly promises to provide novel insights for drug and vaccine development as well as improve our understanding of related pathways in other species.
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Affiliation(s)
- Tong Su
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Rei Nakamoto
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Ye Yu Chun
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Wan Zhen Chua
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Jia Hui Chen
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Justin J Zik
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 117545, Singapore
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Animal Model To Study Klebsiella pneumoniae Gastrointestinal Colonization and Host-to-Host Transmission. Infect Immun 2020; 88:IAI.00071-20. [PMID: 32839189 PMCID: PMC7573435 DOI: 10.1128/iai.00071-20] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 08/17/2020] [Indexed: 02/07/2023] Open
Abstract
An important yet poorly understood facet of the life cycle of a successful pathogen is host-to-host transmission. Hospital-acquired infections (HAI) resulting from the transmission of drug-resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae, a Gram-negative bacterium, is notorious for causing HAI, with many of these infections difficult to treat, as K. pneumoniae has become multidrug resistant. Epidemiological studies suggest that K. pneumoniae host-to-host transmission requires close contact and generally occurs through the fecal-oral route. An important yet poorly understood facet of the life cycle of a successful pathogen is host-to-host transmission. Hospital-acquired infections (HAI) resulting from the transmission of drug-resistant pathogens affect hundreds of millions of patients worldwide. Klebsiella pneumoniae, a Gram-negative bacterium, is notorious for causing HAI, with many of these infections difficult to treat, as K. pneumoniae has become multidrug resistant. Epidemiological studies suggest that K. pneumoniae host-to-host transmission requires close contact and generally occurs through the fecal-oral route. Here, we describe a murine model that can be utilized to study mucosal (oropharynx and gastrointestinal [GI]) colonization, shedding within feces, and transmission of K. pneumoniae through the fecal-oral route. Using an oral route of inoculation, and fecal shedding as a marker for GI colonization, we showed that K. pneumoniae can asymptomatically colonize the GI tract in immunocompetent mice and modifies the host GI microbiota. Colonization density within the GI tract and levels of shedding in the feces differed among the clinical isolates tested. A hypervirulent K. pneumoniae isolate was able to translocate from the GI tract and cause hepatic infection that mimicked the route of human infection. Expression of the capsule was required for colonization and, in turn, robust shedding. Furthermore, K. pneumoniae carrier mice were able to transmit to uninfected cohabitating mice. Lastly, treatment with antibiotics led to changes in the host microbiota and development of a transient supershedder phenotype, which enhanced transmission efficiency. Thus, this model can be used to determine the contribution of host and bacterial factors toward K. pneumoniae dissemination.
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Genomic Profiling Reveals Distinct Routes To Complement Resistance in Klebsiella pneumoniae. Infect Immun 2020; 88:IAI.00043-20. [PMID: 32513855 PMCID: PMC7375759 DOI: 10.1128/iai.00043-20] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/28/2020] [Indexed: 12/19/2022] Open
Abstract
The serum complement system is a first line of defense against bacterial invaders. Resistance to killing by serum enhances the capacity of Klebsiella pneumoniae to cause infection, but it is an incompletely understood virulence trait. Identifying and characterizing the factors responsible for preventing activation of, and killing by, serum complement could inform new approaches to treatment of K. pneumoniae infections. Here, we used functional genomic profiling to define the genetic basis of complement resistance in four diverse serum-resistant K. pneumoniae strains (NTUH-K2044, B5055, ATCC 43816, and RH201207), and explored their recognition by key complement components. The serum complement system is a first line of defense against bacterial invaders. Resistance to killing by serum enhances the capacity of Klebsiella pneumoniae to cause infection, but it is an incompletely understood virulence trait. Identifying and characterizing the factors responsible for preventing activation of, and killing by, serum complement could inform new approaches to treatment of K. pneumoniae infections. Here, we used functional genomic profiling to define the genetic basis of complement resistance in four diverse serum-resistant K. pneumoniae strains (NTUH-K2044, B5055, ATCC 43816, and RH201207), and explored their recognition by key complement components. More than 90 genes contributed to resistance in one or more strains, but only three, rfaH, lpp, and arnD, were common to all four strains. Deletion of the antiterminator rfaH, which controls the expression of capsule and O side chains, resulted in dramatic complement resistance reductions in all strains. The murein lipoprotein gene lpp promoted capsule retention through a mechanism dependent on its C-terminal lysine residue; its deletion led to modest reductions in complement resistance. Binding experiments with the complement components C3b and C5b-9 showed that the underlying mechanism of evasion varied in the four strains: B5055 and NTUH-K2044 appeared to bypass recognition by complement entirely, while ATCC 43816 and RH201207 were able to resist killing despite being associated with substantial levels of C5b-9. All rfaH and lpp mutants bound C3b and C5b-9 in large quantities. Our findings show that, even among this small selection of isolates, K. pneumoniae adopts differing mechanisms and utilizes distinct gene sets to avoid complement attack.
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Rendueles O. Deciphering the role of the capsule of Klebsiella pneumoniae during pathogenesis: A cautionary tale. Mol Microbiol 2020; 113:883-888. [PMID: 31997409 PMCID: PMC7317218 DOI: 10.1111/mmi.14474] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 01/20/2020] [Accepted: 01/20/2020] [Indexed: 01/31/2023]
Abstract
Extracellular capsule polysaccharides increase the cellular fitness under abiotic stresses and during competition with other bacteria. They are best-known for their role in virulence, particularly in human hosts. Specifically, capsules facilitate tissue invasion by enhancing bacterial evasion from phagocytosis and protect cells from biocidal molecules. Klebsiella pneumoniae is a worrisome nosocomial pathogen with few known virulence factors, but the most important one is its capsule. In this issue, Tan et al. assess the fitness advantage of the capsule by competing a wild-type strain against four different mutants where capsule production is interrupted at different stages of the biosynthetic pathway. Strikingly, not all mutants provide a fitness advantage. They suggest that some mutants have secondary defects altering virulence-associated phenotypes and blurring the role of the capsule in pathogenesis. This study indicates that the K1 capsule in K. pneumoniae is not required for gut colonization but that it is critical for bloodstream dissemination to other organs. These results contribute to clarify the contradictory literature on the role of the Klebsiella capsule during infection. Finally, the varying fitness effects of different capsule mutations observed for K. pneumoniae K1 might apply also to other capsulated diderm bacteria that are facultative or emerging pathogens.
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Affiliation(s)
- Olaya Rendueles
- Microbial Evolutionary Genomics, Institut Pasteur, CNRS, UMR3525, Paris, France
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50
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Tan YH, Chen Y, Chu WHW, Sham LT, Gan YH. Cell envelope defects of different capsule-null mutants in K1 hypervirulent Klebsiella pneumoniae can affect bacterial pathogenesis. Mol Microbiol 2020; 113:889-905. [PMID: 31912541 PMCID: PMC7317392 DOI: 10.1111/mmi.14447] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 01/08/2023]
Abstract
Hypervirulent Klebsiella pneumoniae (hvKP) causes Klebsiella‐induced liver abscess. Capsule is important for the pathogenesis of Klebsiella in systemic infection, but its role in gut colonisation is not well understood. By generating ΔwcaJ, Δwza and Δwzy capsule‐null mutants in a prototypical K1 hypervirulent isolate, we show that inactivation of wza (capsule exportase) and wzy (capsule polymerase) confer cell envelope defects in addition to capsule loss, making them susceptible to bile salts and detergent stress. Bile salt resistance is restored when the initial glycosyltransferase wcaJ was inactivated together with wzy, indicating that build‐up of capsule intermediates contribute to cell envelope defects. Mouse gut colonisation competition assays show that the capsule and its regulator RmpA were not required for hvKP to persist in the gut, although initial colonisation was decreased in the mutants. Both ΔrmpA and ΔwcaJ mutants gradually outcompeted the wild type in the gut, whereas Δwza and Δwzy mutants were less fit than wild type. Together, our results advise caution in using the right capsule‐null mutant for determination of capsule's role in bacterial pathogenesis. With the use of ΔwcaJ mutant, we found that although the capsule is important for bacterial survival outside the gut environment, it imposes a fitness cost in the gut.
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Affiliation(s)
- Yi Han Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yahua Chen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Wilson H W Chu
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Lok-To Sham
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yunn-Hwen Gan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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