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Higham SL, Baker S, Flight KE, Krishna A, Kellam P, Reece ST, Tregoning JS. Intranasal immunization with outer membrane vesicles (OMV) protects against airway colonization and systemic infection with Acinetobacter baumannii. J Infect 2023; 86:563-573. [PMID: 36858180 DOI: 10.1016/j.jinf.2023.02.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/08/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023]
Abstract
OBJECTIVES The multidrug-resistant bacteria Acinetobacter baumannii is a major cause of hospital-associated infection; a vaccine could significantly reduce this burden. The aim was to develop a clinically relevant model of A. baumannii respiratory tract infection and to test the impact of different immunization routes on protective immunity provided by an outer membrane vesicle (OMV) vaccine. METHODS BALB/c mice were intranasally challenged with isolates of oxa23-positive global clone GC2 A. baumannii from the lungs of patients with ventilator-associated pneumonia. Mice were immunized with OMVs by the intramuscular, subcutaneous or intranasal routes; protection was determined by measuring local and systemic bacterial load. RESULTS Infection with A. baumannii clinical isolates led to a more disseminated infection than the prototype A. baumannii strain ATCC17978; with bacteria detectable in upper and lower airways and the spleen. Intramuscular immunization induced an antibody response but did not protect against bacterial infection. However, intranasal immunization significantly reduced airway colonization and prevented systemic bacterial dissemination. CONCLUSIONS Use of clinically relevant isolates of A. baumannii provides stringent model for vaccine development. Intranasal immunization with OMVs was an effective route for providing protection, demonstrating that local immunity is important in preventing A. baumannii infection.
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Affiliation(s)
- Sophie L Higham
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, United Kingdom
| | - Katie E Flight
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom
| | - Aishwarya Krishna
- Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - Paul Kellam
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom; Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom; RQ Biotechnology Ltd, 7-12 Tavistock Square, London WC1H 9LT, United Kingdom
| | - Stephen T Reece
- Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom.
| | - John S Tregoning
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom.
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2
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Kong X, Chen T, Guo L, Zhou Y, Lu P, Xiao Y. Phenotypic and genomic comparison of dominant and nondominant sequence-type of Acinetobacter baumannii isolated in China. Front Cell Infect Microbiol 2023; 13:1118285. [PMID: 36891157 PMCID: PMC9986592 DOI: 10.3389/fcimb.2023.1118285] [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: 12/07/2022] [Accepted: 01/31/2023] [Indexed: 02/22/2023] Open
Abstract
A. baumannii is a common clinical pathogen that often causes pneumonia and bloodstream infections in ICU patients. Sequence types (ST) are used to investigate the distribution and spread of A. baumannii. Biological characteristics such as virulence and resistance may play a role in A. baumannii becoming a specific dominant ST(DST,ST191, ST195 and ST208) strain. To characterize the biological, genetic, and transcriptomic differences between the DST and non-dominant ST(NST,ST462 and ST547,etc.) strains in A. baumannii, we performed several biological experiments and genetic, and transcriptomic analyses. The DST group displayed more resistance ability to desiccation, oxidation, multiple antibiotics, and complement killing than the NST group. However, the latter had higher biofilm formation ability than the former. The genomic analysis showed the DST group exhibited more capsule-related and aminoglycoside-resistant genes. Besides, GO analysis indicated that functions involved in lipid biosynthetic, transport, and the metabolic process were up-regulated in the DST group, while KEGG analysis manifested that the two-component system related to potassium ion transport and pili were down-regulated. In short, resistance to desiccation, oxidation, multiple antibiotics, and serum complement killing are important reasons for the formation of DST. Genes related to capsule synthesis and lipid biosynthesis and metabolism play an important role at the molecular level in the formation of DST.
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Affiliation(s)
- Xiaoyang Kong
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Tao Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lihua Guo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yanzi Zhou
- Department of Rheumatology, Affiliated Hangzhou First People’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ping Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Jinan Microecological Biomedicine Shandong Laboratory, Jinan, China
- *Correspondence: Yonghong Xiao,
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Jiang Y, Ding Y, Wei Y, Jian C, Liu J, Zeng Z. Carbapenem-resistant Acinetobacter baumannii: A challenge in the intensive care unit. Front Microbiol 2022; 13:1045206. [PMID: 36439795 PMCID: PMC9684325 DOI: 10.3389/fmicb.2022.1045206] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 10/24/2022] [Indexed: 07/30/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) has become one of the leading causes of healthcare-associated infections globally, particularly in intensive care units (ICUs). Cross-transmission of microorganisms between patients and the hospital environment may play a crucial role in ICU-acquired CRAB colonization and infection. The control and treatment of CRAB infection in ICUs have been recognized as a global challenge because of its multiple-drug resistance. The main concern is that CRAB infections can be disastrous for ICU patients if currently existing limited therapeutic alternatives fail in the future. Therefore, the colonization, infection, transmission, and resistance mechanisms of CRAB in ICUs need to be systematically studied. To provide a basis for prevention and control countermeasures for CRAB infection in ICUs, we present an overview of research on CRAB in ICUs, summarize clinical infections and environmental reservoirs, discuss the drug resistance mechanism and homology of CRAB in ICUs, and evaluate contemporary treatment and control strategies.
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4
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Kim SE, Choi SM, Yu Y, Shin SU, Oh TH, Kang SJ, Park KH, Shin JH, Kim UJ, Jung SI. Replacement of the Dominant ST191 Clone by ST369 Among Carbapenem-Resistant Acinetobacter baumannii Bloodstream Isolates at a Tertiary Care Hospital in South Korea. Front Microbiol 2022; 13:949060. [PMID: 35910596 PMCID: PMC9335038 DOI: 10.3389/fmicb.2022.949060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
The clonal dissemination of carbapenem-resistant Acinetobacter baumannii (CRAB) bacteremia is a serious clinical problem worldwide. However, the factors related to the emergence and replacement of predominant CRAB clones in nosocomial settings are unclear. By multilocus sequence typing (MLST), we evaluated the genetic relatedness of CRAB bloodstream isolates at a tertiary care hospital over a 3.5-year period and investigated the clinical and microbiologic characteristics of the predominant sequence types (STs). One hundred and seventy-nine CRAB bloodstream isolates were collected from June 2016 to December 2019, and their MLSTs according to Oxford scheme and clinical data were obtained. The predominant STs were assessed for in vitro growth, competitive growth, and virulence in a mouse model of intraperitoneal infection. Two dominant clones—ST369 (n = 98) and ST191 (n = 48)—belonging to international clone 2 (IC2) were recovered from patients admitted to intensive care units (ICUs) or wards. ST191 predominated (61%, 27/43) from June 2016 to July 2017, whereas ST369 (72%, 98/136), which was first isolated from a patient admitted to the emergency room, replaced ST191 (15%, 21/136) after August 2017. In a multivariate analysis, leukopenia (OR = 3.62, 95% CI 1.04–12.6, p = 0.04) and ST191 or 369 (OR = 5.32, 95% CI 1.25–22.65, p = 0.02) were independent risk factors for 7-day mortality. Compared with non-ST369, ST369 was associated with a shorter time to bacteremia from ICU admission (7 vs. 11 days, p = 0.01), pneumonia as an origin of bacteremia (67 vs. 52%, p = 0.04), leukopenia (28 vs. 11%, p < 0.01), and a lower 7-day survival rate (41 vs. 70%, p < 0.01). In vitro, ST 369 isolates had significantly higher growth rates and enhanced competitive growth compared to ST191. Finally, ST369 had greater virulence and a higher mortality rate than other STs in a mouse infection model. We report almost-complete replacement of the predominant ST191 clone by ST369 within an 8-month period at our hospital. ST369 had a high incidence density rate of CRAB bacteremia, a short time to bacteremia after ICU admission, and a high early mortality rate, which may be in part explained by its faster competitive growth rate and higher virulence than ST191.
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Affiliation(s)
- Seong Eun Kim
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Su-Mi Choi
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Yohan Yu
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Sung Un Shin
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Tae Hoon Oh
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Seung-Ji Kang
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Kyung-Hwa Park
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
| | - Jong Hee Shin
- Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, South Korea
| | - Uh Jin Kim
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
- Uh Jin Kim,
| | - Sook In Jung
- Department of Infectious Diseases, Chonnam National University Medical School, Gwangju, South Korea
- *Correspondence: Sook In Jung,
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5
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Kadhom HA, Ali MR. Epidemiological Molecular Analysis of Acinetobacter baumannii isolates using a multilocus sequencing typing and Global lineage. BIONATURA 2022. [DOI: 10.21931/rb/2022.07.01.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The Multilocus sequence typing MLST method was used to recognize outbreaks of hospitals distinct clonal lineages of A. baumannii; these schemes appeared to provide largely concordant classifications that have been tools to evaluate the population structures of bacterial pathogens. One hundred fifty samples were collected from different specimens of patients within Baghdad hospitals (blood 40%, CSF 5%, urine 5%) between July 2019 to February 2020. Then identification all isolated as phenotypic detection and performed using PCR amplification of 16srRNA and blaOXA-51-like as genotypic detections. According to clinical and laboratory standards institute (CLSI) guidelines, Susceptibility testing was performed. Clonally analysis was performed by global lineage ICs correlated with multilocus sequence typing (MLST) when our data showed a very high rate of antimicrobial resistance in all hospital isolates, especially against colistin (8%) which determined the PDR isolates from other types also recorded 70% of isolates standing for carbapenems antibiotics (IMI 32%, MER70%& DOR 64%). Then already clustered into four groups according to multiplex PCR for two groups of three genes (ompA, csuE & blaOXA-51-like) where IC II was predominant in Iraq but in our strains founding ICI (38%) more prevalence one followed by IC0 (26%) then ICII and ICIII (20% &16% respectively). MLST used for detected the common sequence types (STs) of our selected 8 A. baumannii strains (IC0/A11, ICI/A6,48, ICII/A33,50,19 and ICIII/A1,36) were performed by using 7 housekeeping genes than were submitted in the MLST Pasteur scheme dataset (ID 5098, 5099, 5100, 5101, 5102, 5103, 5482 & 5483) followed by statistical eBurst analysis was done to study Clonal complexes (CCs). Identified 5 new STs (8, 444, 346, 1587 & 621) within Iraq and new one ST (1830) worldwide.
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Affiliation(s)
- Heba A. Kadhom
- Department of Biomedical Engineering, University of Technology, Baghdad, Iraq
| | - Munim R. Ali
- College of Science, Mustansiriyah University, Baghdad, Iraq
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Woon JJ, Teh CSJ, Chong CW, Abdul Jabar K, Ponnampalavanar S, Idris N. Molecular Characterization of Carbapenem-Resistant Acinetobacter baumannii Isolated from the Intensive Care Unit in a Tertiary Teaching Hospital in Malaysia. Antibiotics (Basel) 2021; 10:antibiotics10111340. [PMID: 34827278 PMCID: PMC8615160 DOI: 10.3390/antibiotics10111340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/21/2021] [Accepted: 10/26/2021] [Indexed: 12/31/2022] Open
Abstract
The emergence of carbapenem-resistant Acinetobacter baumannii (CRAB) has now become a global sentinel event. CRAB infections often instigate severe clinical complications and are potentially fatal, especially for debilitated patients. The present study aimed to conduct molecular characterization on CRAB isolated from patients in the intensive care unit from 2015 to 2016 and determine the risk factors associated with patients’ mortality. One hundred CRAB isolates were retrospectively selected and included in this study. Antimicrobial susceptibility testing showed that all isolates remained susceptible to colistin, even though 62% of them conferred resistance to all other classes of antibiotics tested. OXA carbapenemase gene was found to be the predominant carbapenemase gene, with 99% of the isolates coharbouring blaOXA-23-like and blaOXA-51-like carbapenemase genes. All isolates were carrying intact CarO genes, with the presence of various degree of nucleotide insertion, deletion and substitution. Overall, PFGE subtyped the isolates into 13 distinct pulsotypes, with the presence of 2 predominant pulsotypes. Univariate analysis implied that age, infection/colonization by CRAB, ethnicity, comorbidity and CRAB specimen source were significantly associated with in-hospital mortality. Multivariate analysis identified a higher risk of mortality for patients who are of Chinese ethnicity with diabetes as an underlying disease. As CRAB infection could lead to high rate of mortality, comprehensive infection control measures are needed to minimize the spread of this pathogen.
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Affiliation(s)
- Jia Jie Woon
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (J.J.W.); (C.S.J.T.); (K.A.J.)
| | - Cindy Shuan Ju Teh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (J.J.W.); (C.S.J.T.); (K.A.J.)
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Subang Jaya 47500, Malaysia
- Correspondence: (C.W.C.); (N.I.); Tel.: +60-379-676-671 (N.I.)
| | - Kartini Abdul Jabar
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (J.J.W.); (C.S.J.T.); (K.A.J.)
| | - Sasheela Ponnampalavanar
- Department of Infectious Diseases, University of Malaya Medical Centre, Kuala Lumpur 50603, Malaysia;
| | - Nuryana Idris
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia; (J.J.W.); (C.S.J.T.); (K.A.J.)
- Correspondence: (C.W.C.); (N.I.); Tel.: +60-379-676-671 (N.I.)
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7
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Kamuyu G, Suen Cheng Y, Willcocks S, Kewcharoenwong C, Kiratisin P, Taylor PW, Wren BW, Lertmemongkolchai G, Stabler RA, Brown J. Sequential Vaccination With Heterologous Acinetobacter baumannii Strains Induces Broadly Reactive Antibody Responses. Front Immunol 2021; 12:705533. [PMID: 34394105 PMCID: PMC8363311 DOI: 10.3389/fimmu.2021.705533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 07/08/2021] [Indexed: 12/11/2022] Open
Abstract
Antibody therapy may be an alternative treatment option for infections caused by the multi-drug resistant (MDR) bacterium Acinetobacter baumannii. As A. baumannii has multiple capsular serotypes, a universal antibody therapy would need to target conserved protein antigens rather than the capsular polysaccharides. We have immunized mice with single or multiple A. baumannii strains to induce antibody responses to protein antigens, and then assessed whether these responses provide cross-protection against a collection of genetically diverse clinical A. baumannii isolates. Immunized mice developed antibody responses to multiple protein antigens. Flow cytometry IgG binding assays and immunoblots demonstrated improved recognition of both homologous and heterologous clinical strains in sera from mice immunized with multiple strains compared to a single strain. The capsule partially inhibited bacterial recognition by IgG and the promotion of phagocytosis by human neutrophils. However, after immunization with multiple strains, serum antibodies to protein antigens promoted neutrophil phagocytosis of heterologous A. baumannii strains. In an infection model, mice immunized with multiple strains had lower bacterial counts in the spleen and liver following challenge with a heterologous strain. These data demonstrate that antibodies targeting protein antigens can improve immune recognition and protection against diverse A. baumannii strains, providing support for their use as an antibody therapy.
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Affiliation(s)
- Gathoni Kamuyu
- Centre for Inflammation and Tissue Repair, University College London (UCL) Respiratory, London, United Kingdom
| | - Yat Suen Cheng
- Centre for Inflammation and Tissue Repair, University College London (UCL) Respiratory, London, United Kingdom
| | - Sam Willcocks
- London School of Hygiene and Tropical Medicine, Infectious and Tropical Disease, Department of Infection Biology, London, United Kingdom
| | - Chidchamai Kewcharoenwong
- Cellular and Molecular Immunology Unit, Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Pattarachai Kiratisin
- Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok-Noi, Bangkok, Thailand
| | - Peter W Taylor
- School of Pharmacy, University College London, London, United Kingdom
| | - Brendan W Wren
- London School of Hygiene and Tropical Medicine, Infectious and Tropical Disease, Department of Infection Biology, London, United Kingdom
| | - Ganjana Lertmemongkolchai
- Cellular and Molecular Immunology Unit, Centre for Research and Development of Medical Diagnostic Laboratories (CMDL), Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand.,Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Richard A Stabler
- London School of Hygiene and Tropical Medicine, Infectious and Tropical Disease, Department of Infection Biology, London, United Kingdom
| | - Jeremy Brown
- Centre for Inflammation and Tissue Repair, University College London (UCL) Respiratory, London, United Kingdom
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8
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Abstract
Acinetobacter baumannii has become one of the most important multidrug-resistant nosocomial pathogens all over the world. Nonetheless, very little is known about the diversity of A. baumannii lineages coexisting in hospital settings. Here, using whole-genome sequencing, epidemiological data, and antimicrobial susceptibility tests, we uncover the transmission dynamics of extensive and multidrug-resistant A. baumannii in a tertiary hospital over a decade. Our core genome phylogeny of almost 300 genomes suggests that there were several introductions of lineages from international clone 2 into the hospital. The molecular dating analysis shows that these introductions happened in 2006, 2007, and 2013. Furthermore, using the accessory genome, we show that these lineages were extensively disseminated across many wards in the hospital. Our results demonstrate that accessory genome variation can be a very powerful tool for conducting genomic epidemiology. We anticipate future studies employing the accessory genome along with the core genome as a powerful phylogenomic strategy to track bacterial transmissions over very short microevolutionary scales. IMPORTANCE Whole-genome sequencing for epidemiological investigations (genomic epidemiology) has been of paramount importance to understand the transmission dynamics of many bacterial (and nonbacterial) pathogens. Commonly, variation in the core genome, single nucleotide polymorphisms (SNPs), is employed to carry out genomic epidemiology. However, at very short periods of time, the core genome might not have accumulated enough variation (sufficient SNPs) to tell apart isolates. In this scenario, gene content variation in the accessory genome can be an option to conduct genomic epidemiology. Here, we used the accessory genome, as well as the core genome, to uncover the transmission dynamics of extensive and multidrug-resistant A. baumannii in a tertiary hospital for a decade. Our study shows that accessory genome variation can be a very powerful tool for conducting genomic epidemiology.
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Hsieh YC, Wang SH, Chen YY, Lin TL, Shie SS, Huang CT, Lee CH, Chen YC, Quyen TLT, Pan YJ. Association of capsular types with carbapenem resistance, disease severity, and mortality in Acinetobacter baumannii. Emerg Microbes Infect 2021; 9:2094-2104. [PMID: 32912064 PMCID: PMC7534287 DOI: 10.1080/22221751.2020.1822757] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Acinetobacter baumannii emerged as one of the most
important pathogens that causes nosocomial infections due to its increased multidrug
resistance. Identifying capsular epidemiology in A.
baumannii can aid in the development of effective treatments and preventive
measures against this emerging pathogen. Here we established a wzc-based method, and combined it with wzy-PCR
to determine capsular types of A. baumannii causing
nosocomial bacteraemia collected at two medical centres in Taiwan from 2015 to 2017. Among
the 237 patients with A. baumannii bacteraemia, 98 (41.4%)
isolates were resistant to carbapenems. Four prevalent capsular types (KL2, KL10, KL22,
and KL52) accounted for 84.7% of carbapenem-resistant A.
baumannii (CRAB) and 12.2% of non-CRAB. The rate of pneumonia, intensive care
unit admission, APACHE II score, and Pitt bacteraemia score were higher in patients with
KL2/10/22/52 infection than in those with non-KL2/10/22/52 infection. Patients with
KL2/10/22/52 infection and patients with CRAB infection have a higher cumulative incidence
of attributable and all-cause in-hospital 30-day mortality. On multivariate analysis,
appropriate empirical antimicrobial therapy within 24 h was associated with a lower risk
of 30-day attributable mortality in the KL2/10/22/52 isolates (odds ratio = 0.19, 95% CI:
0.06–0.66, p = 0.008) but not in non-KL2/10/22/52 isolates.
Early recognition of carbapenem resistance-associated capsular types may help clinicians
to promptly implement appropriate antimicrobial therapy for improving the outcomes in
patients with CRAB bacteraemia.
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Affiliation(s)
- Yu-Chia Hsieh
- Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan
| | - Shi-Heng Wang
- Department of Occupational Safety and Health and Public Health, College of Public Health, China Medical University, Taichung, Taiwan
| | - Yi-Yin Chen
- Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan
| | - Tzu-Lung Lin
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Shian-Sen Shie
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital, Taipei, Taoyuan, Taiwan
| | - Ching-Tai Huang
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital, Taipei, Taoyuan, Taiwan
| | - Chen-Hsiang Lee
- Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital - Kaohsiung Medical Center, Chang Gung University, Kaohsiung, Taiwan
| | - Yi-Ching Chen
- Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan
| | - Tran Lam Tu Quyen
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Yi-Jiun Pan
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
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10
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Moragues-Solanas L, Scotti R, O'Grady J. Rapid metagenomics for diagnosis of bloodstream and respiratory tract nosocomial infections: current status and future prospects. Expert Rev Mol Diagn 2021; 21:371-380. [PMID: 33740391 DOI: 10.1080/14737159.2021.1906652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Introduction: Nosocomial infections represent a major problem for the health-care systems worldwide. Currently, diagnosis relies on microbiological culture, which is slow and has poor sensitivity. While waiting for a diagnosis, patients are treated with empiric broad spectrum antimicrobials, which are often inappropriate for the infecting pathogen. This results in poor patient outcomes, poor antimicrobial stewardship and increased costs for health-care systems.Areas covered: Clinical metagenomics (CMg), the application of metagenomic sequencing for the diagnosis of infection, has the potential to become a viable alternative to culture that can offer rapid results with high accuracy. In this article, we review current CMg methods for the diagnosis of nosocomial bloodstream (BSI) and lower respiratory-tract infections (LRTI).Expert opinion: CMg approaches are more accurate in LRTI compared to BSI. This is because BSIs are caused by low pathogen numbers in a high background of human cells. To overcome this, most approaches focus on cell-free DNA, but, to date, these tests are not accurate enough yet to replace blood culture. The higher pathogen numbers in LRTI samples make this a more suitable for CMg and accurate approaches have been developed, which are likely to be implemented in hospitals within the next 2-5 years.
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Affiliation(s)
| | - Riccardo Scotti
- Quadram Institute of Bioscience, Norwich Research Park, Norwich, Norfolk, UK
| | - Justin O'Grady
- Quadram Institute of Bioscience, Norwich Research Park, Norwich, Norfolk, UK.,Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK
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11
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Khuntayaporn P, Kanathum P, Houngsaitong J, Montakantikul P, Thirapanmethee K, Chomnawang MT. Predominance of international clone 2 multidrug-resistant Acinetobacter baumannii clinical isolates in Thailand: a nationwide study. Ann Clin Microbiol Antimicrob 2021; 20:19. [PMID: 33743736 PMCID: PMC7980754 DOI: 10.1186/s12941-021-00424-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/14/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii has emerged as one of the common multidrug resistance pathogens causing hospital-acquired infections. This study was conducted to elucidate the distribution of antimicrobial resistance genes in the bacterial population in Thailand. Multidrug-resistant A. baumannii (MDR A. baumannii) isolates were characterized phenotypically, and the molecular epidemiology of clinical isolates in 11 tertiary hospitals was investigated at a country-wide level. METHODS A total of 135 nonrepetitive MDR A. baumannii isolates collected from tertiary care hospitals across 5 regions of Thailand were examined for antibiotic susceptibility, resistance genes, and sequence types. Multilocus sequence typing (MLST) was performed to characterize the spread of regional lineages. RESULTS ST2 belonging to IC2 was the most dominant sequence type in Thailand (65.19%), and to a lesser extent, there was also evidence of the spread of ST164 (10.37%), ST129 (3.70%), ST16 (2.96%), ST98 (2.96%), ST25 (2.96%), ST215 (2.22%), ST338 (1.48%), and ST745 (1.48%). The novel sequence types ST1551, ST1552, ST1553, and ST1557 were also identified in this study. Among these, the blaoxa-23 gene was by far the most widespread in MDR A. baumannii, while the blaoxa-24/40 and blaoxa-58 genes appeared to be less dominant in this region. The results demonstrated that the predominant class D carbapenemase was blaOXA-23, followed by the class B carbapenemase blaNDM-like, while the mcr-1 gene was not observed in any isolate. Most of the MDR A. baumannii isolates were resistant to ceftazidime (99.23%), gentamicin (91.85%), amikacin (82.96%), and ciprofloxacin (97.78%), while all of them were resistant to carbapenems. The results suggested that colistin could still be effective against MDR A. baumannii in this region. CONCLUSION This is the first molecular epidemiological analysis of MDR A. baumannii clinical isolates at the national level in Thailand to date. Studies on the clonal relatedness of MDR A. baumannii isolates could generate useful data to understand the local epidemiology and international comparisons of nosocomial outbreaks.
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Affiliation(s)
- Piyatip Khuntayaporn
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand
| | - Pohnvipa Kanathum
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand
| | - Jantana Houngsaitong
- Department of Pharmacy, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand
| | - Preecha Montakantikul
- Department of Pharmacy, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand
| | - Krit Thirapanmethee
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand
| | - Mullika Traidej Chomnawang
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri Ayudthya Rd, Rajathevi, Bangkok, 10400, Thailand.
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12
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Recent Advances in the Pursuit of an Effective Acinetobacter baumannii Vaccine. Pathogens 2020; 9:pathogens9121066. [PMID: 33352688 PMCID: PMC7766458 DOI: 10.3390/pathogens9121066] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii has been a major cause of nosocomial infections for decades. The absence of an available vaccine coupled with emerging multidrug resistance has prevented the medical community from effectively controlling this human pathogen. Furthermore, the ongoing pandemic caused by SARS-CoV-2 has increased the risk of hospitalized patients developing ventilator-associated pneumonia caused by bacterial opportunists including A. baumannii. The shortage of antibiotics in the development pipeline prompted the World Health Organization to designate A. baumannii a top priority for the development of new medical countermeasures, such as a vaccine. There are a number of important considerations associated with the development of an A. baumannii vaccine, including strain characteristics, diverse disease manifestations, and target population. In the past decade, research efforts have revealed a number of promising new immunization strategies that could culminate in a safe and protective vaccine against A. baumannii. In this review, we highlight the recent progress in the development of A. baumannii vaccines, discuss potential challenges, and propose future directions to achieve an effective intervention against this human pathogen.
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13
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Overexpression of bla OXA-58 Gene Driven by IS Aba3 Is Associated with Imipenem Resistance in a Clinical Acinetobacter baumannii Isolate from Vietnam. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7213429. [PMID: 32802871 PMCID: PMC7420922 DOI: 10.1155/2020/7213429] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/02/2020] [Accepted: 06/29/2020] [Indexed: 02/06/2023]
Abstract
The aim of this study was to investigate genetic structures and expression of blaOXA-58 gene in five Acinetobacter baumannii clinical isolates recovered from two hospitals in southern Vietnam during 2012-2014. A. baumannii isolates were identified by automated microbiology systems and confirmed by PCR. All isolates were characterized as multidrug resistant by antimicrobial testing using the disk diffusion method. Four imipenem susceptible and one nonsusceptible isolates (MIC > 32 μg·ml−1) were identified by E-test. PCR amplification of blaOXA-58 gene upstream and downstream sequences revealed the presence of ISAba3 at both locations in one multidrug-resistant isolate. Semiquantitation of blaOXA-51 and blaOXA-58 gene expression was performed by the 2-ΔΔCt method. The blaOXA-51 gene expression of five isolates showed little difference, but the isolate bearing ISAba3-blaOXA-58-ISAba3 exhibited significantly higher blaOXA-58 mRNA level. Higher β-lactamases activity in periplasmic than cytoplasmic fraction was found in most isolates. The isolate overexpressing blaOXA-58 gene possessed very high periplasmic enzyme activity. In conclusion, the A. baumannii isolate bearing ISAba3-blaOXA-58 gene exhibited high resistance to imipenem, corresponding to an overexpression of blaOXA-58 gene and very high periplasmic β-lactamase activity.
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14
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Dhesi Z, Enne VI, O'Grady J, Gant V, Livermore DM. Rapid and Point-of-Care Testing in Respiratory Tract Infections: An Antibiotic Guardian? ACS Pharmacol Transl Sci 2020; 3:401-417. [PMID: 32551433 PMCID: PMC7233852 DOI: 10.1021/acsptsci.0c00027] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Indexed: 12/15/2022]
Abstract
![]()
This
is a narrative review on the potential of rapid and point-of-care
microbiological testing in pneumonia patients, focusing particularly
on hospital-acquired and ventilator-associated pneumonia, which have
substantial mortality and diverse microbiology. This work is written
from a United Kingdom perspective, but much of it is generalizable
internationally. In a world where antimicrobial resistance is a major
international threat, the use of rapid molecular diagnostics has great
potential to improve both the management of pneumonia patients and
the stewardship of antibiotics. Rapid tests potentially can distinguish
patients with bacterial versus viral infection and can swiftly identify
bacterial pathogens and their resistances. We seek to answer the question:
“Can such tests be used as an antibiotic guardian?”
Their availability at the bedside rather than in the laboratory should
best ensure that results are swiftly used to optimize patient management
but will raise new challenges, not the least with respect to maintaining
quality control and microbiology/infection control input. A further
challenge lies in assessing the degree of trust that treating clinicians
will place in these molecular diagnostic tests, particularly when
early de-escalation of antibiotic therapy is indicated.
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Affiliation(s)
- Zaneeta Dhesi
- University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Virve I Enne
- University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Justin O'Grady
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UA, United Kingdom
| | - Vanya Gant
- University College London Hospitals NHS Foundation Trust, London NW1 2PG, United Kingdom
| | - David M Livermore
- University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
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15
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Hamidian M, Nigro SJ. Emergence, molecular mechanisms and global spread of carbapenem-resistant Acinetobacter baumannii. Microb Genom 2020; 5. [PMID: 31599224 PMCID: PMC6861865 DOI: 10.1099/mgen.0.000306] [Citation(s) in RCA: 146] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Acinetobacter baumannii is a nosocomial pathogen that has emerged as a global threat because of high levels of resistance to many antibiotics, particularly those considered to be last-resort antibiotics, such as carbapenems. Although alterations in the efflux pump and outer membrane proteins can cause carbapenem resistance, the main mechanism is the acquisition of carbapenem-hydrolyzing oxacillinase-encoding genes. Of these, oxa23 is by far the most widespread in most countries, while oxa24 and oxa58 appear to be dominant in specific regions. Historically, much of the global spread of carbapenem resistance has been due to the dissemination of two major clones, known as global clones 1 and 2, although new lineages are now common in some parts of the world. The analysis of all publicly available genome sequences performed here indicates that ST2, ST1, ST79 and ST25 account for over 71 % of all genomes sequenced to date, with ST2 by far the most dominant type and oxa23 the most widespread carbapenem resistance determinant globally, regardless of clonal type. Whilst this highlights the global spread of ST1 and ST2, and the dominance of oxa23 in both clones, it could also be a result of preferential selection of carbapenem-resistant strains, which mainly belong to the two major clones. Furthermore, ~70 % of the sequenced strains have been isolated from five countries, namely the USA, PR China, Australia, Thailand and Pakistan, with only a limited number from other countries. These genomes are a vital resource, but it is currently difficult to draw an accurate global picture of this important superbug, highlighting the need for more comprehensive genome sequence data and genomic analysis.
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Affiliation(s)
- Mohammad Hamidian
- The ithree institute, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Steven J Nigro
- Communicable Diseases Branch, Health Protection NSW, St Leonards, NSW 2065, Australia
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16
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The Current Burden of Carbapenemases: Review of Significant Properties and Dissemination among Gram-Negative Bacteria. Antibiotics (Basel) 2020; 9:antibiotics9040186. [PMID: 32316342 PMCID: PMC7235769 DOI: 10.3390/antibiotics9040186] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 11/16/2022] Open
Abstract
Carbapenemases are β-lactamases belonging to different Ambler classes (A, B, D) and can be encoded by both chromosomal and plasmid-mediated genes. These enzymes represent the most potent β-lactamases, which hydrolyze a broad variety of β-lactams, including carbapenems, cephalosporins, penicillin, and aztreonam. The major issues associated with carbapenemase production are clinical due to compromising the activity of the last resort antibiotics used for treating serious infections, and epidemiological due to their dissemination into various bacteria across almost all geographic regions. Carbapenemase-producing Enterobacteriaceae have received more attention upon their first report in the early 1990s. Currently, there is increased awareness of the impact of nonfermenting bacteria, such as Acinetobacter baumannii and Pseudomonas aeruginosa, as well as other Gram-negative bacteria that are carbapenemase-producers. Outside the scope of clinical importance, carbapenemases are also detected in bacteria from environmental and zoonotic niches, which raises greater concerns over their prevalence, and the need for public health measures to control consequences of their propagation. The aims of the current review are to define and categorize the different families of carbapenemases, and to overview the main lines of their spread across different bacterial groups.
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17
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Loraine J, Heinz E, Soontarach R, Blackwell GA, Stabler RA, Voravuthikunchai SP, Srimanote P, Kiratisin P, Thomson NR, Taylor PW. Genomic and Phenotypic Analyses of Acinetobacter baumannii Isolates From Three Tertiary Care Hospitals in Thailand. Front Microbiol 2020; 11:548. [PMID: 32328045 PMCID: PMC7153491 DOI: 10.3389/fmicb.2020.00548] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/13/2020] [Indexed: 12/24/2022] Open
Abstract
Antibiotic resistant strains of Acinetobacter baumannii are responsible for a large and increasing burden of nosocomial infections in Thailand and other countries of Southeast Asia. New approaches to their control and treatment are urgently needed and an attractive strategy is to remove the bacterial polysaccharide capsule, and thus the protection from the host's immune system. To examine phylogenetic relationships, distribution of capsule chemotypes, acquired antibiotic resistance determinants, susceptibility to complement and other traits associated with systemic infection, we sequenced 191 isolates from three tertiary referral hospitals in Thailand and used phenotypic assays to characterize key aspects of infectivity. Several distinct lineages were circulating in three hospitals and the majority belonged to global clonal group 2 (GC2). Very high levels of resistance to carbapenems and other front-line antibiotics were found, as were a number of widespread plasmid replicons. A high diversity of capsule genotypes was encountered, with only three of these (KL6, KL10, and KL47) showing more than 10% frequency. Almost 90% of GC2 isolates belonged to the most common capsule genotypes and were fully resistant to the bactericidal action of human serum complement, most likely protected by their polysaccharide capsule, which represents a key determinant of virulence for systemic infection. Our study further highlights the importance to develop therapeutic strategies to remove the polysaccharide capsule from extensively drug-resistant A. baumanii during the course of systemic infection.
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Affiliation(s)
- Jessica Loraine
- School of Pharmacy, University College London, London, United Kingdom
| | - Eva Heinz
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | | | - Grace A Blackwell
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, Cambridge, United Kingdom
| | - Richard A Stabler
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Potjanee Srimanote
- Faculty of Allied Health Sciences, Thammasat University, Pathumtanee, Thailand
| | | | - Nicholas R Thomson
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter W Taylor
- School of Pharmacy, University College London, London, United Kingdom
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18
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Wyres KL, Cahill SM, Holt KE, Hall RM, Kenyon JJ. Identification of Acinetobacter baumannii loci for capsular polysaccharide (KL) and lipooligosaccharide outer core (OCL) synthesis in genome assemblies using curated reference databases compatible with Kaptive. Microb Genom 2020; 6:e000339. [PMID: 32118530 PMCID: PMC7200062 DOI: 10.1099/mgen.0.000339] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 01/28/2020] [Indexed: 12/17/2022] Open
Abstract
Multiply antibiotic-resistant Acinetobacter baumannii infections are a global public health concern and accurate tracking of the spread of specific lineages is needed. Variation in the composition and structure of capsular polysaccharide (CPS), a critical determinant of virulence and phage susceptibility, makes it an attractive epidemiological marker. The outer core (OC) of lipooligosaccharide also exhibits variation. To take better advantage of the untapped information available in whole genome sequences, we have created a curated reference database of 92 publicly available gene clusters at the locus encoding proteins responsible for biosynthesis and export of CPS (K locus), and a second database for 12 gene clusters at the locus for outer core biosynthesis (OC locus). Each entry has been assigned a unique KL or OCL number, and is fully annotated using a simple, transparent and standardized nomenclature. These databases are compatible with Kaptive, a tool for in silico typing of bacterial surface polysaccharide loci, and their utility was validated using (a) >630 assembled A. baumannii draft genomes for which the KL and OCL regions had been previously typed manually, and (b) 3386 A. baumannii genome assemblies downloaded from NCBI. Among the previously typed genomes, Kaptive was able to confidently assign KL and OCL types with 100 % accuracy. Among the genomes retrieved from NCBI, Kaptive detected known KL and OCL in 87 and 90 % of genomes, respectively, indicating that the majority of common KL and OCL types are captured within the databases; 13 of the 92 KL in the database were not detected in any publicly available whole genome assembly. The failure to assign a KL or OCL type may indicate incomplete or poor-quality genomes. However, further novel variants may remain to be documented. Combining outputs with multilocus sequence typing (Institut Pasteur scheme) revealed multiple KL and OCL types in collections of a single sequence type (ST) representing each of the two predominant globally distributed clones, ST1 of GC1 and ST2 of GC2, and in collections of other clones comprising >20 isolates each (ST10, ST25, and ST140), indicating extensive within-clone replacement of these loci. The databases are available at https://github.com/katholt/Kaptive and will be updated as further locus types become available.
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Affiliation(s)
- Kelly L. Wyres
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Australia
| | - Sarah M. Cahill
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Kathryn E. Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Australia
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Ruth M. Hall
- School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Johanna J. Kenyon
- Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
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19
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Gaiarsa S, Batisti Biffignandi G, Esposito EP, Castelli M, Jolley KA, Brisse S, Sassera D, Zarrilli R. Comparative Analysis of the Two Acinetobacter baumannii Multilocus Sequence Typing (MLST) Schemes. Front Microbiol 2019; 10:930. [PMID: 31130931 PMCID: PMC6510311 DOI: 10.3389/fmicb.2019.00930] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/12/2019] [Indexed: 01/22/2023] Open
Abstract
Acinetobacter species assigned to the Acinetobacter calcoaceticus-baumannii (Acb) complex, are Gram-negative bacteria responsible for a large number of human infections. The population structure of Acb has been studied using two 7-gene MLST schemes, introduced by Bartual and coworkers (Oxford scheme) and by Diancourt and coworkers (Pasteur scheme). The schemes have three genes in common but underlie two coexisting nomenclatures of sequence types and clonal complexes, which complicates communication on A. baumannii genotypes. The aim of this study was to compare the characteristics of the two schemes to make a recommendation about their usage. Using genome sequences of 730 strains of the Acb complex, we evaluated the phylogenetic congruence of MLST schemes, the correspondence between sequence types, their discriminative power and genotyping reliability from genomic sequences. In silico ST re-assignments highlighted the presence of a second copy of the Oxford gdhB locus, present in 553/730 genomes that has led to the creation of artefactual profiles and STs. The reliability of the two MLST schemes was tested statistically comparing MLST-based phylogenies to two reference phylogenies (core-genome genes and genome-wide SNPs) using topology-based and likelihood-based tests. Additionally, each MLST gene fragment was evaluated by correlating the pairwise nucleotide distances between each pair of genomes calculated on the core-genome and on each single gene fragment. The Pasteur scheme appears to be less discriminant among closely related isolates, but less affected by homologous recombination and more appropriate for precise strain classification in clonal groups, which within this scheme are more often correctly monophyletic. Statistical tests evaluate the tree deriving from the Oxford scheme as more similar to the reference genome trees. Our results, together with previous work, indicate that the Oxford scheme has important issues: gdhB paralogy, recombination, primers sequences, position of the genes on the genome. While there is no complete agreement in all analyses, when considered as a whole the above results indicate that the Pasteur scheme is more appropriate for population biology and epidemiological studies of A. baumannii and related species and we propose that it should be the scheme of choice during the transition toward, and in parallel with, core genome MLST.
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Affiliation(s)
- Stefano Gaiarsa
- Microbiology and Virology Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | | | - Eliana Pia Esposito
- Department of Public Health, University of Naples "Federico II", Naples, Italy
| | - Michele Castelli
- Romeo and Enrica Invernizzi Pediatric Research Center, Department of Biosciences, University of Milan, Milan, Italy
| | - Keith A Jolley
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Sylvain Brisse
- Biodiversity and Epidemiology of Bacterial Pathogens, Institut Pasteur, Paris, France
| | - Davide Sassera
- Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples "Federico II", Naples, Italy
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20
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Adams MD, Wright MS, Karichu JK, Venepally P, Fouts DE, Chan AP, Richter SS, Jacobs MR, Bonomo RA. Rapid Replacement of Acinetobacter baumannii Strains Accompanied by Changes in Lipooligosaccharide Loci and Resistance Gene Repertoire. mBio 2019; 10:e00356-19. [PMID: 30914511 PMCID: PMC6437055 DOI: 10.1128/mbio.00356-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/14/2022] Open
Abstract
The population structure of health care-associated pathogens reflects patterns of diversification, selection, and dispersal over time. Empirical data detailing the long-term population dynamics of nosocomial pathogens provide information about how pathogens adapt in the face of exposure to diverse antimicrobial agents and other host and environmental pressures and can inform infection control priorities. Extensive sequencing of clinical isolates from one hospital spanning a decade and a second hospital in the Cleveland, OH, metropolitan area over a 3-year time period provided high-resolution genomic analysis of the Acinetobacter baumannii metapopulation. Genomic analysis demonstrated an almost complete replacement of the predominant strain groups with a new, genetically distinct strain group during the study period. The new group, termed clade F, differs from other global clone 2 (GC2) strains of A. baumannii in several ways, including its antibiotic resistance and lipooligosaccharide biosynthesis genes. Clade F strains are part of a large phylogenetic group with broad geographic representation. Phylogenetic analysis of single-nucleotide variants in core genome regions showed that although the Cleveland strains are phylogenetically distinct from those isolated from other locations, extensive intermixing of strains from the two hospital systems was apparent, suggesting either substantial exchange of strains or a shared, but geographically restricted, external pool from which infectious isolates were drawn. These findings document the rapid evolution of A. baumannii strains in two hospitals, with replacement of the predominant clade by a new clade with altered lipooligosaccharide loci and resistance gene repertoires.IMPORTANCE Multidrug-resistant (MDR) A. baumannii is a difficult-to-treat health care-associated pathogen. Knowing the resistance genes present in isolates causing infection aids in empirical treatment selection. Furthermore, knowledge of the genetic background can assist in tracking patterns of transmission to limit the spread of infections in hospitals. The appearance of a new genetic background in A. baumannii strains with a different set of resistance genes and cell surface structures suggests that strong selective pressures exist, even in highly MDR pathogens. Because the new strains have levels of antimicrobial resistance similar to those of the strains that were displaced, we hypothesize that other features, including host colonization and infection, may confer additional selective advantages and contribute to their increased prevalence.
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Affiliation(s)
- Mark D Adams
- The J. Craig Venter Institute, La Jolla, California, USA
| | | | - James K Karichu
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | | | | | - Agnes P Chan
- The J. Craig Venter Institute, Rockville, Maryland, USA
| | - Sandra S Richter
- Department of Laboratory Medicine, Cleveland Clinic, Cleveland, Ohio, USA
| | - Michael R Jacobs
- Department of Pathology, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Robert A Bonomo
- Department of Medicine, Case Western Reserve University and CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
- Department of Pharmacology, Case Western Reserve University and CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University and CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
- Department of Biochemistry, Case Western Reserve University and CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
- Center for Proteomics, Case Western Reserve University and CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
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21
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Meumann EM, Anstey NM, Currie BJ, Piera KA, Kenyon JJ, Hall RM, Davis JS, Sarovich DS. Genomic epidemiology of severe community-onset Acinetobacter baumannii infection. Microb Genom 2019; 5. [PMID: 30806611 PMCID: PMC6487312 DOI: 10.1099/mgen.0.000258] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Acinetobacter baumannii causes severe, fulminant, community-acquired pneumonia (CAP) in tropical and subtropical regions. We compared the population structure, virulence and antimicrobial resistance determinants of northern Australian community-onset A. baumannii strains with local and global strains. We performed whole-genome sequencing on 55 clinical and five throat colonization A. baumannii isolates collected in northern Australia between 1994 and 2016. Clinical isolates included CAP (n=41), healthcare-associated pneumonia (n=7) and nosocomial bloodstream (n=7) isolates. We also included 93 publicly available international A. baumannii genome sequences in the analyses. Patients with A. baumannii CAP were almost all critically unwell; 82 % required intensive care unit admission and 18 % died during their inpatient stay. Whole-genome phylogenetic analysis demonstrated that community-onset strains were not phylogenetically distinct from nosocomial strains. Some non-multidrug-resistant local strains were closely related to multidrug-resistant strains from geographically distant locations. Pasteur sequence type (ST)10 was the dominant ST and accounted for 31/60 (52 %) northern Australian strains; the remainder belonged to a diverse range of STs. The most recent common ancestor for ST10 was estimated to have occurred in 1738 (95 % highest posterior density, 1626–1826), with evidence of multiple introduction events between Australia and Southeast Asia between then and the present day. Virulence genes associated with biofilm formation and the type 6 secretion system (T6SS) were absent in many strains, and were not associated with in-hospital mortality. All strains were susceptible to gentamicin and meropenem; none carried an AbaR resistance island. Our results suggest that international dissemination of A. baumannii is occurring in the community on a contemporary timescale. Genes associated with biofilm formation and the T6SS may not be required for survival in community niches. The relative contributions of host and bacterial factors to the clinical severity of community-onset A. baumannii infection require further investigation.
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Affiliation(s)
- Ella M Meumann
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia.,2Department of Infectious Diseases, Royal Darwin Hospital, Darwin 0810, Australia
| | - Nicholas M Anstey
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia.,2Department of Infectious Diseases, Royal Darwin Hospital, Darwin 0810, Australia
| | - Bart J Currie
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia.,2Department of Infectious Diseases, Royal Darwin Hospital, Darwin 0810, Australia
| | - Kim A Piera
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia
| | - Johanna J Kenyon
- 3School of Biomedical Sciences, Queensland University of Technology, Brisbane 4001, Australia
| | - Ruth M Hall
- 4School of Life and Environmental Sciences, The University of Sydney, Sydney 2006, Australia
| | - Joshua S Davis
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia.,5Department of Infectious Diseases, John Hunter Hospital and the University of Newcastle, Newcastle 2305, Australia
| | - Derek S Sarovich
- 1Global and Tropical Health Division, Menzies School of Health Research, Darwin 0810, Australia.,6Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Sippy Downs 4072, Australia
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22
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Klotz P, Higgins PG, Schaubmar AR, Failing K, Leidner U, Seifert H, Scheufen S, Semmler T, Ewers C. Seasonal Occurrence and Carbapenem Susceptibility of Bovine Acinetobacter baumannii in Germany. Front Microbiol 2019; 10:272. [PMID: 30853949 PMCID: PMC6395434 DOI: 10.3389/fmicb.2019.00272] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/01/2019] [Indexed: 01/06/2023] Open
Abstract
Acinetobacter baumannii is one of the leading causes of nosocomial infections in humans. To investigate its prevalence, distribution of sequence types (STs), and antimicrobial resistance in cattle, we sampled 422 cattle, including 280 dairy cows, 59 beef cattle, and 83 calves over a 14-month period. Metadata, such as the previous use of antimicrobial agents and feeding, were collected to identify putative determining factors. Bacterial isolates were identified via MALDI-TOF/MS and PCR, antimicrobial susceptibility was evaluated via VITEK2 and antibiotic gradient tests, resistance genes were identified by PCR. Overall, 15.6% of the cattle harbored A. baumannii, predominantly in the nose (60.3% of the A. baumannii isolates). It was more frequent in dairy cows (21.1%) than in beef cattle (6.8%) and calves (2.4%). A seasonal occurrence was shown with a peak between May and August. The rate of occurrence of A. baumannii was correlated with a history of use of 3rd generation cephalosporins in the last 6 months prior to sampling Multilocus sequence typing (Pasteur scheme) revealed 83 STs among 126 unique isolates. Nine of the bovine STs have previously been implicated in human infections. Besides known intrinsic resistance of the species, the isolates did not show additional resistance to the antimicrobial substances tested, including carbapenems. Our data suggest that cattle are not a reservoir for nosocomial A. baumannii but carry a highly diverse population of this species. Nevertheless, some STs seem to be able to colonize both cattle and humans.
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Affiliation(s)
- Peter Klotz
- Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Giessen, Germany
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
| | - Andreas R Schaubmar
- Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Klaus Failing
- Unit for Biomathematics and Data Processing, Faculty of Veterinary Medicine, Justus Liebig University Giessen, Giessen, Germany
| | - Ursula Leidner
- Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Giessen, Germany
| | - Harald Seifert
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Cologne, Germany
| | - Sandra Scheufen
- Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Giessen, Germany.,Institute for Hygiene and Microbiology, University of Würzburg, Würzburg, Germany
| | - Torsten Semmler
- NG1 Microbial Genomics, Robert Koch Institute, Berlin, Germany
| | - Christa Ewers
- Institute of Hygiene and Infectious Diseases of Animals, Justus Liebig University Giessen, Giessen, Germany
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23
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Boinett CJ, Cain AK, Hawkey J, Do Hoang NT, Khanh NNT, Thanh DP, Dordel J, Campbell JI, Lan NPH, Mayho M, Langridge GC, Hadfield J, Chau NVV, Thwaites GE, Parkhill J, Thomson NR, Holt KE, Baker S. Clinical and laboratory-induced colistin-resistance mechanisms in Acinetobacter baumannii. Microb Genom 2019; 5. [PMID: 30720421 PMCID: PMC6421349 DOI: 10.1099/mgen.0.000246] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The increasing incidence and emergence of multi-drug resistant (MDR) Acinetobacter baumannii has become a major global health concern. Colistin is a historic antimicrobial that has become commonly used as a treatment for MDR A. baumannii infections. The increase in colistin usage has been mirrored by an increase in colistin resistance. We aimed to identify the mechanisms associated with colistin resistance in A. baumannii using multiple high-throughput-sequencing technologies, including transposon-directed insertion site sequencing (TraDIS), RNA sequencing (RNAseq) and whole-genome sequencing (WGS) to investigate the genotypic changes of colistin resistance in A. baumannii. Using TraDIS, we found that genes involved in drug efflux (adeIJK), and phospholipid (mlaC, mlaF and mlaD) and lipooligosaccharide synthesis (lpxC and lpsO) were required for survival in sub-inhibitory concentrations of colistin. Transcriptomic (RNAseq) analysis revealed that expression of genes encoding efflux proteins (adeI, adeC, emrB, mexB and macAB) was enhanced in in vitro generated colistin-resistant strains. WGS of these organisms identified disruptions in genes involved in lipid A (lpxC) and phospholipid synthesis (mlaA), and in the baeS/R two-component system (TCS). We additionally found that mutations in the pmrB TCS genes were the primary colistin-resistance-associated mechanisms in three Vietnamese clinical colistin-resistant A. baumannii strains. Our results outline the entire range of mechanisms employed in A. baumannii for resistance against colistin, including drug extrusion and the loss of lipid A moieties by gene disruption or modification.
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Affiliation(s)
- Christine J Boinett
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Amy K Cain
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,4Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi
| | - Jane Hawkey
- 5Centre for Systems Genomics, University of Melbourne, Melbourne, Victoria, Australia.,6Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia.,7Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Nhu Tran Do Hoang
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Nhu Nguyen Thi Khanh
- 8School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane, Queensland, Australia
| | - Duy Pham Thanh
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Janina Dordel
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,9Department of Biology, Drexel University, Philadelphia 19104, PA, USA
| | - James I Campbell
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Nguyen Phu Huong Lan
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,10Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - Matthew Mayho
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Gemma C Langridge
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,11Norwich Medical School, University of East Anglia, Norwich, UK
| | - James Hadfield
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | | | - Guy E Thwaites
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
| | - Julian Parkhill
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Nicholas R Thomson
- 1Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.,12Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Kathryn E Holt
- 5Centre for Systems Genomics, University of Melbourne, Melbourne, Victoria, Australia.,6Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen Baker
- 2Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam.,13Medicine, The University of Cambridge, Cambridge, UK.,3Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, Oxford University, Oxford, UK
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24
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Hamidian M, Hawkey J, Wick R, Holt KE, Hall RM. Evolution of a clade of Acinetobacter baumannii global clone 1, lineage 1 via acquisition of carbapenem- and aminoglycoside-resistance genes and dispersion of ISAba1. Microb Genom 2019; 5. [PMID: 30648939 PMCID: PMC6412058 DOI: 10.1099/mgen.0.000242] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Resistance to carbapenem and aminoglycoside antibiotics is a critical problem in Acinetobacter baumannii, particularly when genes conferring resistance are acquired by multiply or extensively resistant members of successful globally distributed clonal complexes, such as global clone 1 (GC1) . Here, we investigate the evolution of an expanding clade of lineage 1 of the GC1 complex via repeated acquisition of carbapenem- and aminoglycoside-resistance genes. Lineage 1 arose in the late 1970s and the Tn6168/OCL3 clade arose in the late 1990s from an ancestor that had already acquired resistance to third-generation cephalosporins and fluoroquinolones. Between 2000 and 2002, two distinct subclades have emerged, and they are distinguishable via the presence of an integrated phage genome in subclade 1 and AbaR4 (carrying the oxa23 carbapenem-resistance gene in Tn2006) at a specific chromosomal location in subclade 2. Part or all of the original resistance gene cluster in the chromosomally located AbaR3 has been lost from some isolates, but plasmids carrying alternate resistance genes have been gained. In one group in subclade 2, the chromosomally located AbGRI3, carrying the armA aminoglycoside-resistance gene, has been acquired from a GC2 isolate and incorporated via homologous recombination. ISAba1 entered the common ancestor of this clade as part of the cephalosporin-resistance transposon Tn6168 and has dispersed differently in each subclade. Members of subclade 1 share an ISAba1 in one specific position in the chromosome and in subclade 2 two different ISAba1 locations are shared. Further shared ISAba1 locations distinguish further divisions, potentially providing simple markers for epidemiological studies.
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Affiliation(s)
- Mohammad Hamidian
- 1School of Life and Environmental Sciences, University of Sydney, Sydney, Australia.,2The ithree Institute, University of Technology Sydney, Ultimo, NSW, Australia
| | - Jane Hawkey
- 3Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - Ryan Wick
- 3Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Melbourne, Australia
| | - Kathryn E Holt
- 3Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Melbourne, Australia.,4London School of Hygiene and Tropical Medicine, London, UK
| | - Ruth M Hall
- 1School of Life and Environmental Sciences, University of Sydney, Sydney, Australia
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25
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Kim SJ, Kim YJ, Ko KS. Genomic Analysis of Consecutive Acinetobacter baumannii Strains From a Single Patient. Front Microbiol 2018; 9:2840. [PMID: 30542330 PMCID: PMC6277775 DOI: 10.3389/fmicb.2018.02840] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 11/05/2018] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is one of the most important nosocomial pathogens, and thus it is required to investigate how it disseminate in hospitals and infect patients. We performed whole genome sequencing for 24 A. baumannii strains isolated successively from the blood of a single patient to evaluate whether repeated infections were due to re-infection or relapse infection and to investigate within-host evolution. The whole genome of the first strain, BL1, was sequenced de novo using the PacBio RSII system. BL2-BL24, were sequenced with an Illumina Hiseq4000 and mapped to the genome sequences of BL1. We identified 42 single-nucleotide variations among the strains. The SNVs differentiated the strains into three groups, BL1, BL2-BL16, and BL17-BL24, indicating that the patient suffered from re-infections or co-infections by similar, but different strains. The results also showed that A. baumannii strains in each group were rather stable at the genomic level. Our study emphasizes the importance of intensive infection control.
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Affiliation(s)
- Sun Ju Kim
- Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Yae-Jean Kim
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Kwan Soo Ko
- Department of Molecular Cell Biology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Suwon, South Korea
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26
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Ahmad S, Shaker B, Ahmad F, Raza S, Azam SS. Moleculer dynamics simulaiton revealed reciever domain of Acinetobacter baumannii BfmR enzyme as the hot spot for future antibiotics designing. J Biomol Struct Dyn 2018; 37:2897-2912. [DOI: 10.1080/07391102.2018.1498805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Sajjad Ahmad
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Bilal Shaker
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Faisal Ahmad
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Saad Raza
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Syed Sikander Azam
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
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27
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Skariyachan S, Manjunath M, Bachappanavar N. Screening of potential lead molecules against prioritised targets of multi-drug-resistant-Acinetobacter baumannii - insights from molecular docking, molecular dynamic simulations and in vitro assays. J Biomol Struct Dyn 2018. [PMID: 29529934 DOI: 10.1080/07391102.2018.1451387] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Acinetobacter baumannii, an opportunistic pathogen, has become multi-drug resistant (MDR) to major classes of antibacterial and poses grave threat to public health. The current study focused to screen novel phytotherapeutics against prioritised targets of Acinetobacter baumannii by computational investigation. Fourteen potential drug targets were screened based on their functional role in various biosynthetic pathways and the 3D structures of 9 targets were retrieved from Protein Data Bank and others were computationally predicted. By extensive literature survey, 104 molecules from 48 herbal sources were screened and subjected to virtual screening. Ten clinical isolates of A. baumannii were tested for antibiotic susceptibility towards clinafloxacin, imipenem and polymyxin-E. Computational screening suggested that Ajmalicine ((19α)-16, 17-didehydro-19-methyloxayohimban-16-carboxylic acid methyl ester from Rauwolfia serpentina), Strictamin (Akuammilan-17-oic acid methyl ester from Alstonia scholaris) and Limonin (7, 16-dioxo-7, 16-dideoxylimondiol from Citrus sps) exhibited promising binding towards multiple drug targets of A. baumannii in comparison with the binding between standard drugs and their targets. Limonin displayed promising binding potential (binding energy -9.8 kcal/mol) towards diaminopimelate epimerase (DapF) and UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA). Ajmalicine and Strictamin demonstrated good binding potential (-9.5, -8.5 kcal/mol, respectively) towards MurA and shikimate dehydrogenase (-7.8 kcal/mol). Molecular dynamic simulations further validated the docking results. In vitro assay suggested that the tested isolates exhibited resistance to clinafloxacin, imipenem and polymyxin-E and the herbal preparations (crude extract) demonstrated a significant antibacterial potential (p ≤ .05). The study suggests that the aforementioned lead candidates and targets can be used for structure-based drug screening towards MDR A. baumannii.
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Affiliation(s)
- Sinosh Skariyachan
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
| | - Meghna Manjunath
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
| | - Nikhil Bachappanavar
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
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28
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Hawkey J, Ascher DB, Judd LM, Wick RR, Kostoulias X, Cleland H, Spelman DW, Padiglione A, Peleg AY, Holt KE. Evolution of carbapenem resistance in Acinetobacter baumannii during a prolonged infection. Microb Genom 2018; 4. [PMID: 29547094 PMCID: PMC5885017 DOI: 10.1099/mgen.0.000165] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Acinetobacter baumannii is a common causative agent of hospital-acquired infections and a leading cause of infection in burns patients. Carbapenem-resistant A. baumannii is considered a major public-health threat and has been identified by the World Health Organization as the top priority organism requiring new antimicrobials. The most common mechanism for carbapenem resistance in A. baumannii is via horizontal acquisition of carbapenemase genes. In this study, we sampled 20 A. baumannii isolates from a patient with extensive burns, and characterized the evolution of carbapenem resistance over a 45 day period via Illumina and Oxford Nanopore sequencing. All isolates were multidrug resistant, carrying two genomic islands that harboured several antibiotic-resistance genes. Most isolates were genetically identical and represented a single founder genotype. We identified three novel non-synonymous substitutions associated with meropenem resistance: F136L and G288S in AdeB (part of the AdeABC efflux pump) associated with an increase in meropenem MIC to ≥8 µg ml−1; and A515V in FtsI (PBP3, a penicillin-binding protein) associated with a further increase in MIC to 32 µg ml−1. Structural modelling of AdeB and FtsI showed that these mutations affected their drug-binding sites and revealed mechanisms for meropenem resistance. Notably, one of the adeB mutations arose prior to meropenem therapy but following ciprofloxacin therapy, suggesting exposure to one drug whose resistance is mediated by the efflux pump can induce collateral resistance to other drugs to which the bacterium has not yet been exposed.
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Affiliation(s)
- Jane Hawkey
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David B Ascher
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Louise M Judd
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ryan R Wick
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Xenia Kostoulias
- 2Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia
| | - Heather Cleland
- 3Victorian Adult Burns Service, The Alfred Hospital, Melbourne, Victoria 3004, Australia.,4Department of Surgery, Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia
| | - Denis W Spelman
- 5Department of Infectious Diseases, The Alfred Hospital, Melbourne, Victoria 3004, Australia.,6Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia
| | - Alex Padiglione
- 5Department of Infectious Diseases, The Alfred Hospital, Melbourne, Victoria 3004, Australia
| | - Anton Y Peleg
- 6Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia.,2Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia.,5Department of Infectious Diseases, The Alfred Hospital, Melbourne, Victoria 3004, Australia
| | - Kathryn E Holt
- 1Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia
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29
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Saffari F, Monsen T, Karmostaji A, Azimabad FB, Widerström M. Significant spread of extensively drug-resistant Acinetobacter baumannii genotypes of clonal complex 92 among intensive care unit patients in a university hospital in southern Iran. J Med Microbiol 2017; 66:1656-1662. [PMID: 29058650 DOI: 10.1099/jmm.0.000619] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PURPOSE Infections associated with Acinetobacter baumannii represent an increasing threat in healthcare settings. Therefore, we investigated the epidemiological relationship between clinical isolates of A. baumannii obtained from patients in a university hospital in Bandar Abbas in southern Iran. METHODOLOGY Sixty-four consecutive non-duplicate clinical isolates collected during 2014-2015 were subjected to susceptibility testing, clonal relationship analysis using PFGE, multilocus variable-number tandem-repeat analysis (MLVA) and multilocus sequence typing (MLST), and examined for the presence of carbapenemases and integrons. RESULTS Almost all A. baumannii isolates were extensively drug-resistant (XDR; 98 %) and carried an OXA carbapenemase gene (blaOXA-23-like; 98 %) and class 1 integrons (48 %). PFGE and MLST analysis identified three major genotypes, all belonging to clonal complex 92 (CC92): sequence type 848 (ST848) (n=23), ST451 (n=16) and ST195 (n=8). CC92 has previously been documented in the hospital setting in northern Iran, and ST195 has been reported in Arab States of the Persian Gulf. These data suggest national and global transmission of A. baumannii CC92. CONCLUSION This report demonstrates the occurrence and potential spread of closely related XDR genotypes of A. baumannii CC92 within a university hospital in southern Iran. These genotypes were found in the majority of the investigated isolates, showed high prevalence of blaOXA-23 and integron class 1, and were associated with stay in the intensive care unit. Very few treatment options remain for healthcare-adapted XDR A. baumannii, and hence effective measures are desperately needed to reduce the spread of these strains and resultant infections in the healthcare setting.
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Affiliation(s)
- Fereshteh Saffari
- Department of Microbiology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Tor Monsen
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Afsaneh Karmostaji
- Infectious & Tropical Diseases Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | | | - Micael Widerström
- Department of Clinical Microbiology, Unit of Research, Education and Development Östersund, Umeå University, Umeå, Sweden
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30
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Kenyon JJ, Kasimova AA, Shneider MM, Shashkov AS, Arbatsky NP, Popova AV, Miroshnikov KA, Hall RM, Knirel YA. The KL24 gene cluster and a genomic island encoding a Wzy polymerase contribute genes needed for synthesis of the K24 capsular polysaccharide by the multiply antibiotic resistant Acinetobacter baumannii isolate RCH51. MICROBIOLOGY-SGM 2017; 163:355-363. [PMID: 28356169 DOI: 10.1099/mic.0.000430] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The whole-genome sequence of the multiply antibiotic resistant Acinetobacter baumannii isolate RCH51 belonging to sequence type ST103 (Institut Pasteur scheme) revealed that the set of genes at the capsule locus, KL24, includes four genes predicted to direct the synthesis of 3-acetamido-3,6-dideoxy-d-galactose (d-Fuc3NAc), and this sugar was found in the capsular polysaccharide (CPS). One of these genes, fdtE, encodes a novel bifunctional protein with an N-terminal FdtA 3,4-ketoisomerase domain and a C-terminal acetyltransferase domain. KL24 lacks a gene encoding a Wzy polymerase to link the oligosaccharide K units to form the CPS found associated with isolate RCH51, and a wzy gene was found in a small genomic island (GI) near the cpn60 gene. This GI is in precisely the same location as another GI carrying wzy and atr genes recently found in several A. baumannii isolates, but it does not otherwise resemble it. The CPS isolated from RCH51, studied by sugar analysis and 1D and 2D 1H and 13C NMR spectroscopy, revealed that the K unit has a branched pentasaccharide structure made up of Gal, GalNAc and GlcNAc residues with d-Fuc3NAc as a side branch, and the K units are linked via a β-d-GlcpNAc-(1→3)-β-d-Galp linkage formed by the Wzy encoded by the GI. The functions of the glycosyltransferases encoded by KL24 were assigned to formation of specific bonds. A correspondence between the order of the genes in KL24 and other KL and the order of the linkages they form was noted, and this may be useful in future predictions of glycosyltransferase specificities.
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Affiliation(s)
- Johanna J Kenyon
- School of Molecular Bioscience, The University of Sydney, Sydney, Australia.,Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Australia
| | - Anastasiya A Kasimova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Higher Chemical College of the Russian Academy of Sciences, D. I. Mendeleev University of Chemical Technology of Russia, Moscow, Russia
| | - Mikhail M Shneider
- M. M. Shemyakin and Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Alexander S Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Nikolay P Arbatsky
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Anastasiya V Popova
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russia.,State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russia
| | - Konstantin A Miroshnikov
- M. M. Shemyakin and Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Ruth M Hall
- School of Molecular Bioscience, The University of Sydney, Sydney, Australia.,School of Life and Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
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31
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The tet39 Determinant and the msrE-mphE Genes in Acinetobacter Plasmids Are Each Part of Discrete Modules Flanked by Inversely Oriented p dif (XerC-XerD) Sites. Antimicrob Agents Chemother 2017; 61:AAC.00780-17. [PMID: 28533235 DOI: 10.1128/aac.00780-17] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 05/15/2017] [Indexed: 01/29/2023] Open
Abstract
The tet39 tetracycline resistance determinant and the macrolide resistance genes msrE and mphE were found in an 18.2-kb plasmid, pS30-1, recovered from a global clone 2 (GC2) Acinetobacter baumannii isolate from Singapore, that conferred resistance to tetracycline and erythromycin. pS30-1 also contains mobA and mobC genes encoding MOBQ family proteins, but attempts to mobilize pS30-1 utilizing a coresident conjugative repAci6 plasmid were unsuccessful. Eight pdif sites, consisting of inversely oriented binding sites for the XerC and XerD recombinases separated by 6 bp, were detected in pS30-1. The tet39 determinant and the msrE-mphE gene pair are each surrounded by two pdif sites in inverse orientation. Identical regions in different contexts and many previously unnoticed pdif sites were found in a number of different plasmids in GenBank, showing that the tet39 and msrE-mphE dif modules are mobile. A putative toxin/antitoxin system, a gene encoding a serine recombinase, and open reading frames of unknown function were also part of dif modules in pS30-1. In general, modules with internal XerC or XerD sites alternate. Two copies of ISAjo2-1 (94% identical to ISAjo2) in pS30-1 were inserted 5 bp from a XerC site, and this appears to be the preferred insertion site for this insertion sequence (IS) group. Apparently, Acinetobacter plasmids exploit the Acinetobacter XerC-XerD recombinases to mobilize DNA units containing resistance and other genes, via an uncharacterized mechanism. The tet39 and msrE-mphE dif modules add to the oxa24 module and the oxa58 module redefined here, bringing the total of resistance gene-containing dif modules in Acinetobacter plasmids to four.
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Soudeiha MAH, Dahdouh EA, Azar E, Sarkis DK, Daoud Z. In vitro Evaluation of the Colistin-Carbapenem Combination in Clinical Isolates of A. baumannii Using the Checkerboard, Etest, and Time-Kill Curve Techniques. Front Cell Infect Microbiol 2017; 7:209. [PMID: 28596943 PMCID: PMC5442352 DOI: 10.3389/fcimb.2017.00209] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 05/09/2017] [Indexed: 11/17/2022] Open
Abstract
The worldwide increase in the emergence of carbapenem resistant Acinetobacter baumannii (CRAB) calls for the investigation into alternative approaches for treatment. This study aims to evaluate colistin-carbapenem combinations against Acinetobacter spp., in order to potentially reduce the need for high concentrations of antibiotics in therapy. This study was conducted on 100 non-duplicate Acinetobacter isolates that were collected from different patients admitted at Saint George Hospital-University Medical Center in Beirut. The isolates were identified using API 20NE strips, which contain the necessary agents to cover a panel of biochemical tests, and confirmed by PCR amplification of blaOXA−51−like. Activities of colistin, meropenem and imipenem against Acinetobacter isolates were determined by ETEST and microdilution methods, and interpreted according to the guidelines of the Clinical and Laboratory Standards Institute. In addition, PCR amplifications of the most common beta lactamases contributing to carbapenem resistance were performed. Tri locus PCR–typing was also performed to determine the international clonality of the isolates. Checkerboard, ETEST and time kill curves were then performed to determine the effect of the colistin-carbapenem combinations. The synergistic potential of the combination was then determined by calculating the Fractional Inhibitory Concentration Index (FICI), which is an index that indicates additivity, synergism, or antagonism between the antimicrobial agents. In this study, 84% of the isolates were resistant to meropenem, 78% to imipenem, and only one strain was resistant to colistin. 79% of the isolates harbored blaOXA−23−like and pertained to the International Clone II. An additive effect for the colistin-carbapenem combination was observed using all three methods. The combination of colistin-meropenem showed better effects as compared to colistin-imipenem (p < 0.05). The colistin-meropenem and colistin-imipenem combinations also showed a decrease of 2.6 and 2.8-fold, respectively in the MIC of colistin (p < 0.001). Time kill assays additionally showed synergistic effects for a few isolates, and no bacterial re-growth was detected following a 24 h incubation. Our study showed that the combination of colistin with carbapenems could be a promising antimicrobial strategy in treating CRAB infections and potentially lowering colistin toxicity related to higher doses used in colistin monotherapy.
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Affiliation(s)
| | - Elias A Dahdouh
- Animal Health Laboratory, Faculty of Veterinary, Universidad Complutense de MadridMadrid, Spain
| | - Eid Azar
- Clinical Microbiology, Faculty of Medicine and Medical Sciences, University of BalamandKoura, Lebanon
| | - Dolla K Sarkis
- Rodolphe Merieux Laboratory, School of Pharmacy, Saint-Joseph UniversityBeirut, Lebanon
| | - Ziad Daoud
- Clinical Microbiology, Faculty of Medicine and Medical Sciences, University of BalamandKoura, Lebanon
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Evolutionary dynamics and genomic features of the Elizabethkingia anophelis 2015 to 2016 Wisconsin outbreak strain. Nat Commun 2017; 8:15483. [PMID: 28537263 PMCID: PMC5458099 DOI: 10.1038/ncomms15483] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 03/30/2017] [Indexed: 11/26/2022] Open
Abstract
An atypically large outbreak of Elizabethkingia anophelis infections occurred in Wisconsin. Here we show that it was caused by a single strain with thirteen characteristic genomic regions. Strikingly, the outbreak isolates show an accelerated evolutionary rate and an atypical mutational spectrum. Six phylogenetic sub-clusters with distinctive temporal and geographic dynamics are revealed, and their last common ancestor existed approximately one year before the first recognized human infection. Unlike other E. anophelis, the outbreak strain had a disrupted DNA repair mutY gene caused by insertion of an integrative and conjugative element. This genomic change probably contributed to the high evolutionary rate of the outbreak strain and may have increased its adaptability, as many mutations in protein-coding genes occurred during the outbreak. This unique discovery of an outbreak caused by a naturally occurring mutator bacterial pathogen provides a dramatic example of the potential impact of pathogen evolutionary dynamics on infectious disease epidemiology. Elizabethkingia anophelis is an emerging pathogen of high antimicrobial resistance. Perrin and colleagues sequenced isolates of a 2015/2016 E. anophelis outbreak in Wisconsin and found substantial genetic diversity, accelerated evolutionary rate and a disruptive mutation in the DNA repair gene mutY.
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Wyres KL, Wick RR, Gorrie C, Jenney A, Follador R, Thomson NR, Holt KE. Identification of Klebsiella capsule synthesis loci from whole genome data. Microb Genom 2016; 2:e000102. [PMID: 28348840 PMCID: PMC5359410 DOI: 10.1099/mgen.0.000102] [Citation(s) in RCA: 259] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 12/06/2016] [Indexed: 12/14/2022] Open
Abstract
Klebsiella pneumoniae is a growing cause of healthcare-associated infections for which multi-drug resistance is a concern. Its polysaccharide capsule is a major virulence determinant and epidemiological marker. However, little is known about capsule epidemiology since serological typing is not widely accessible and many isolates are serologically non-typeable. Molecular typing techniques provide useful insights, but existing methods fail to take full advantage of the information in whole genome sequences. We investigated the diversity of the capsule synthesis loci (K-loci) among 2503 K. pneumoniae genomes. We incorporated analyses of full-length K-locus nucleotide sequences and also clustered protein-encoding sequences to identify, annotate and compare K-locus structures. We propose a standardized nomenclature for K-loci and present a curated reference database. A total of 134 distinct K-loci were identified, including 31 novel types. Comparative analyses indicated 508 unique protein-encoding gene clusters that appear to reassort via homologous recombination. Extensive intra- and inter-locus nucleotide diversity was detected among the wzi and wzc genes, indicating that current molecular typing schemes based on these genes are inadequate. As a solution, we introduce Kaptive, a novel software tool that automates the process of identifying K-loci based on full locus information extracted from whole genome sequences (https://github.com/katholt/Kaptive). This work highlights the extensive diversity of Klebsiella K-loci and the proteins that they encode. The nomenclature, reference database and novel typing method presented here will become essential resources for genomic surveillance and epidemiological investigations of this pathogen.
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Affiliation(s)
- Kelly L. Wyres
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Ryan R. Wick
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Claire Gorrie
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Adam Jenney
- Infectious Diseases and Microbiology Unit, The Alfred Hospital, Melbourne, Australia
| | | | - Nicholas R. Thomson
- The Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Kathryn E. Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
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Duchêne S, Holt KE, Weill FX, Le Hello S, Hawkey J, Edwards DJ, Fourment M, Holmes EC. Genome-scale rates of evolutionary change in bacteria. Microb Genom 2016; 2:e000094. [PMID: 28348834 PMCID: PMC5320706 DOI: 10.1099/mgen.0.000094] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 10/24/2016] [Indexed: 01/26/2023] Open
Abstract
Estimating the rates at which bacterial genomes evolve is critical to understanding major evolutionary and ecological processes such as disease emergence, long-term host–pathogen associations and short-term transmission patterns. The surge in bacterial genomic data sets provides a new opportunity to estimate these rates and reveal the factors that shape bacterial evolutionary dynamics. For many organisms estimates of evolutionary rate display an inverse association with the time-scale over which the data are sampled. However, this relationship remains unexplored in bacteria due to the difficulty in estimating genome-wide evolutionary rates, which are impacted by the extent of temporal structure in the data and the prevalence of recombination. We collected 36 whole genome sequence data sets from 16 species of bacterial pathogens to systematically estimate and compare their evolutionary rates and assess the extent of temporal structure in the absence of recombination. The majority (28/36) of data sets possessed sufficient clock-like structure to robustly estimate evolutionary rates. However, in some species reliable estimates were not possible even with ‘ancient DNA’ data sampled over many centuries, suggesting that they evolve very slowly or that they display extensive rate variation among lineages. The robustly estimated evolutionary rates spanned several orders of magnitude, from approximately 10−5 to 10−8 nucleotide substitutions per site year−1. This variation was negatively associated with sampling time, with this relationship best described by an exponential decay curve. To avoid potential estimation biases, such time-dependency should be considered when inferring evolutionary time-scales in bacteria.
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Affiliation(s)
- Sebastian Duchêne
- 1Marie Bashir Institute of Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia.,2Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC 3010, Australia.,3Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Kathryn E Holt
- 2Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC 3010, Australia.,3Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | | | - Simon Le Hello
- 4Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Paris 75015, France
| | - Jane Hawkey
- 2Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC 3010, Australia.,3Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - David J Edwards
- 2Centre for Systems Genomics, The University of Melbourne, Melbourne, VIC 3010, Australia.,3Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - Mathieu Fourment
- 1Marie Bashir Institute of Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
| | - Edward C Holmes
- 1Marie Bashir Institute of Infectious Diseases and Biosecurity, Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, The University of Sydney, Sydney, NSW 2006, Australia
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Related structures of neutral capsular polysaccharides of Acinetobacter baumannii isolates that carry related capsule gene clusters KL43, KL47, and KL88. Carbohydr Res 2016; 435:173-179. [DOI: 10.1016/j.carres.2016.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/13/2016] [Accepted: 10/20/2016] [Indexed: 12/15/2022]
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Kenyon JJ, Shneider MM, Senchenkova SN, Shashkov AS, Siniagina MN, Malanin SY, Popova AV, Miroshnikov KA, Hall RM, Knirel YA. K19 capsular polysaccharide of Acinetobacter baumannii is produced via a Wzy polymerase encoded in a small genomic island rather than the KL19 capsule gene cluster. MICROBIOLOGY-SGM 2016; 162:1479-1489. [PMID: 27230482 DOI: 10.1099/mic.0.000313] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Polymerization of the oligosaccharides (K units) of complex capsular polysaccharides (CPSs) requires a Wzy polymerase, which is usually encoded in the gene cluster that directs K unit synthesis. Here, a gene cluster at the Acinetobacter K locus (KL) that lacks a wzy gene, KL19, was found in Acinetobacter baumannii ST111 isolates 28 and RBH2 recovered from hospitals in the Russian Federation and Australia, respectively. However, these isolates produced long-chain capsule, and a wzy gene was found in a 6.1 kb genomic island (GI) located adjacent to the cpn60 gene. The GI also includes an acetyltransferase gene, atr25, which is interrupted by an insertion sequence (IS) in RBH2. The capsule structure from both strains was →3)-α-d-GalpNAc-(1→4)-α-d-GalpNAcA-(1→3)-β-d-QuipNAc4NAc-(1→, determined using NMR spectroscopy. Biosynthesis of the K unit was inferred to be initiated with QuiNAc4NAc, and hence the Wzy forms the β-(1→3) linkage between QuipNAc4NAc and GalpNAc. The GalpNAc residue is 6-O-acetylated in isolate 28 only, showing that atr25 is responsible for this acetylation. The same GI with or without an IS in atr25 was found in draft genomes of other KL19 isolates, as well as ones carrying a closely related CPS gene cluster, KL39, which differs from KL19 only in a gene for an acyltransferase in the QuiNAc4NR synthesis pathway. Isolates carrying a KL1 variant with the wzy and atr genes each interrupted by an ISAba125 also have this GI. To our knowledge, this study is the first report of genes involved in capsule biosynthesis normally found at the KL located elsewhere in A. baumannii genomes.
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Affiliation(s)
- Johanna J Kenyon
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.,School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Mikhail M Shneider
- M. M. Shemyakin & Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Sofya N Senchenkova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Alexander S Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Maria N Siniagina
- Interdisciplinary Center for Proteomics Research, Kazan (Volga region) Federal University, Kazan, Russian Federation
| | - Sergey Y Malanin
- Interdisciplinary Center for Proteomics Research, Kazan (Volga region) Federal University, Kazan, Russian Federation
| | - Anastasiya V Popova
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, Russian Federation.,State Research Center for Applied Microbiology and Biotechnology, Obolensk, Moscow Region, Russian Federation
| | - Konstantin A Miroshnikov
- M. M. Shemyakin & Y. A. Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Ruth M Hall
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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