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De K, Belardinelli JM, Pandurangan AP, Ehianeta T, Lian E, Palčeková Z, Lam H, Gonzalez-Juarrero M, Bryant JM, Blundell TL, Parkhill J, Floto RA, Lowary TL, Wheat WH, Jackson M. Lipoarabinomannan modification as a source of phenotypic heterogeneity in host-adapted Mycobacterium abscessus isolates. Proc Natl Acad Sci U S A 2024; 121:e2403206121. [PMID: 38630725 PMCID: PMC11046677 DOI: 10.1073/pnas.2403206121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 03/20/2024] [Indexed: 04/19/2024] Open
Abstract
Mycobacterium abscessus is increasingly recognized as the causative agent of chronic pulmonary infections in humans. One of the genes found to be under strong evolutionary pressure during adaptation of M. abscessus to the human lung is embC which encodes an arabinosyltransferase required for the biosynthesis of the cell envelope lipoglycan, lipoarabinomannan (LAM). To assess the impact of patient-derived embC mutations on the physiology and virulence of M. abscessus, mutations were introduced in the isogenic background of M. abscessus ATCC 19977 and the resulting strains probed for phenotypic changes in a variety of in vitro and host cell-based assays relevant to infection. We show that patient-derived mutational variations in EmbC result in an unexpectedly large number of changes in the physiology of M. abscessus, and its interactions with innate immune cells. Not only did the mutants produce previously unknown forms of LAM with a truncated arabinan domain and 3-linked oligomannoside chains, they also displayed significantly altered cording, sliding motility, and biofilm-forming capacities. The mutants further differed from wild-type M. abscessus in their ability to replicate and induce inflammatory responses in human monocyte-derived macrophages and epithelial cells. The fact that different embC mutations were associated with distinct physiologic and pathogenic outcomes indicates that structural alterations in LAM caused by nonsynonymous nucleotide polymorphisms in embC may be a rapid, one-step, way for M. abscessus to generate broad-spectrum diversity beneficial to survival within the heterogeneous and constantly evolving environment of the infected human airway.
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Affiliation(s)
- Kavita De
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Juan M. Belardinelli
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Arun Prasad Pandurangan
- Victor Phillip Dahdaleh Heart and Lung Research Institute, Biomedical Campus, Trumpington, CambridgeCB2 OBB, United Kingdom
| | - Teddy Ehianeta
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
| | - Elena Lian
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Ha Lam
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Mercedes Gonzalez-Juarrero
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Josephine M. Bryant
- Parasites and Microbes Programme, Wellcome Sanger Institute, HinxtonCB10 1SA, United Kingdom
| | - Tom L. Blundell
- Victor Phillip Dahdaleh Heart and Lung Research Institute, Biomedical Campus, Trumpington, CambridgeCB2 OBB, United Kingdom
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, CambridgeCB3 0ES, United Kingdom
| | - R. Andres Floto
- Victor Phillip Dahdaleh Heart and Lung Research Institute, Biomedical Campus, Trumpington, CambridgeCB2 OBB, United Kingdom
- Molecular Immunity Unit, Department of Medicine, Medical Research Council-Laboratory of Molecular Biology, University of Cambridge, Trumpington, CambridgeCB2 0QH, United Kingdom
- University of Cambridge Centre for AI in Medicine, Cambridge CB3 0WA, United Kingdom
- Cambridge Centre for Lung Infection, Royal Papworth Hospital, CambridgeCB2 0AY, United Kingdom
| | - Todd L. Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei106, Taiwan
| | - William H. Wheat
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO80523-1682
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2
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Ghassani A, Triponney P, Bour M, Plésiat P, Jeannot K. Mutations in genes lpxL1, bamA, and pmrB impair the susceptibility of cystic fibrosis strains of Pseudomonas aeruginosa to murepavadin. Antimicrob Agents Chemother 2024; 68:e0129823. [PMID: 38092672 PMCID: PMC10790571 DOI: 10.1128/aac.01298-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/06/2023] [Indexed: 01/11/2024] Open
Abstract
Murepavadin is a peptidomimetic exhibiting specific inhibitory activity against Pseudomonas species. In the present study, its in vitro activity was assessed on 230 cystic fibrosis (CF) strains of Pseudomonas aeruginosa isolated from 12 French hospitals, in comparison with 12 other antipseudomonal antibiotics. Although murepavadin is still in preclinical stage of development, 9.1% (n = 21) of strains had a minimum inhibitory concentration (MIC) >4 mg/L, a level at least 128-fold higher than the modal MIC value of the whole collection (≤0.06 mg/L). Whole-genome sequencing of these 21 strains along with more susceptible isogenic counterparts coexisting in the same patients revealed diverse mutations in genes involved in the synthesis (lpxL1 and lpxL2) or transport of lipopolysaccharides (bamA, lptD, and msbA), or encoding histidine kinases of two-component systems (pmrB and cbrA). Allelic replacement experiments with wild-type reference strain PAO1 confirmed that alteration of genes lpxL1, bamA, and/or pmrB can decrease the murepavadin susceptibility from 8- to 32-fold. Furthermore, we found that specific amino acid substitutions in histidine kinase PmrB (G188D, Q105P, and D45E) reduce the susceptibility of P. aeruginosa to murepavadin, colistin, and tobramycin, three antibiotics used or intended to be used (murepavadin) in aerosols to treat colonized CF patients. Whether colistin or tobramycin may select mutants resistant to murepavadin or the opposite needs to be addressed by clinical studies.
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Affiliation(s)
- Aya Ghassani
- UMR6249 CNRS Chrono-environnement, Université de Franche-Comté, Besançon, France
| | - Pauline Triponney
- Laboratoire associé au Centre National de Référence de la résistance aux antibiotiques, Besançon, France
| | - Maxime Bour
- Laboratoire associé au Centre National de Référence de la résistance aux antibiotiques, Besançon, France
| | - Patrick Plésiat
- UMR6249 CNRS Chrono-environnement, Université de Franche-Comté, Besançon, France
| | - Katy Jeannot
- UMR6249 CNRS Chrono-environnement, Université de Franche-Comté, Besançon, France
- Laboratoire associé au Centre National de Référence de la résistance aux antibiotiques, Besançon, France
- Laboratoire de Bactériologie, Centre Hospitalier Universitaire Jean Minjoz, Besançon, France
| | - MucoMicrobes study GroupCardot-MartinEmilie1CattoirVincent2CrémetLise3Doléan-JordheimAnne4FerroniAgnès5GarnierFabien6Guet-RevilletHélène7GuillardThomas8Hery-ArnaudGeneviève9ImbertGuenièvre10MarianiPatricia11Centre Hospitalier Universitaire Foch, Paris, FranceCentre Hospitalier Universitaire de Rennes, Rennes, FranceCentre Hospitalier Universitaire de Nantes, Nantes, FranceHospices civils de Lyon, Lyon, FranceCentre Hospitalier Universitaire de Necker, Paris, FranceCentre Hospitalier Universitaire de Limoges, Limoges, FranceCentre Hospitalier Universitaire de Toulouse, Toulouse, FranceCentre Hospitalier Universitaire de Reims, Reims, FranceCentre Hospitalier Universitaire de Brest, Brest, FranceCentre Hospitalier de Toulon, Toulon, FranceCentre Hospitalier Universitaire Robert Debré, Paris, France
- UMR6249 CNRS Chrono-environnement, Université de Franche-Comté, Besançon, France
- Laboratoire associé au Centre National de Référence de la résistance aux antibiotiques, Besançon, France
- Laboratoire de Bactériologie, Centre Hospitalier Universitaire Jean Minjoz, Besançon, France
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3
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Chandler CE, Hofstaedter CE, Hazen TH, Rasko DA, Ernst RK. Genomic and Functional Characterization of Longitudinal Pseudomonas aeruginosa Isolates from Young Patients with Cystic Fibrosis. Microbiol Spectr 2023; 11:e0155623. [PMID: 37358436 PMCID: PMC10433850 DOI: 10.1128/spectrum.01556-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 06/05/2023] [Indexed: 06/27/2023] Open
Abstract
Individuals with cystic fibrosis (CF) suffer from frequent and recurring microbial airway infections. The Gram-negative bacterium Pseudomonas aeruginosa is one of the most common organisms isolated from CF patient airways. P. aeruginosa establishes chronic infections that persist throughout a patient's lifetime and is a major cause of morbidity and mortality. Throughout the course of infection, P. aeruginosa must evolve and adapt from an initial state of early, transient colonization to chronic colonization of the airways. Here, we examined isolates of P. aeruginosa from children under the age of 3 years old with CF to determine genetic adaptations the bacterium undergoes during this early stage of colonization and infection. These isolates were collected when early aggressive antimicrobial therapy was not the standard of care and therefore highlight strain evolution under limited antibiotic pressure. Examination of specific phenotypic adaptations, such as lipid A palmitoylation, antibiotic resistance, and loss of quorum sensing, did not reveal a clear genetic basis for such changes. Additionally, we demonstrate that the geography of patient origin, within the United States or among other countries, does not appear to significantly influence genetic adaptation. In summary, our results support the long-standing model that patients acquire individual isolates of P. aeruginosa that subsequently become hyperadapted to the patient-specific airway environment. This study provides a multipatient genomic analysis of isolates from young CF patients in the United States and contributes data regarding early colonization and adaptation to the growing body of research about P. aeruginosa evolution in the context of CF airway disease. IMPORTANCE Chronic lung infection with Pseudomonas aeruginosa is of major concern for patients with cystic fibrosis (CF). During infection, P. aeruginosa undergoes genomic and functional adaptation to the hyperinflammatory CF airway, resulting in worsening lung function and pulmonary decline. All studies that describe these adaptations use P. aeruginosa obtained from older children or adults during late chronic lung infection; however, children with CF can be infected with P. aeruginosa as early as 3 months of age. Therefore, it is unclear when these genomic and functional adaptations occur over the course of CF lung infection, as access to P. aeruginosa isolates in children during early infection is limited. Here, we present a unique cohort of CF patients who were identified as being infected with P. aeruginosa at an early age prior to aggressive antibiotic therapy. Furthermore, we performed genomic and functional characterization of these isolates to address whether chronic CF P. aeruginosa phenotypes are present during early infection.
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Affiliation(s)
- Courtney E. Chandler
- Department of Microbial Pathogenesis, University of Maryland—Baltimore, Baltimore, Maryland, USA
| | - Casey E. Hofstaedter
- Department of Microbial Pathogenesis, University of Maryland—Baltimore, Baltimore, Maryland, USA
- Medical Scientist Training Program, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Tracy H. Hazen
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland—Baltimore, Baltimore, Maryland, USA
| | - David A. Rasko
- Department of Microbial Pathogenesis, University of Maryland—Baltimore, Baltimore, Maryland, USA
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland—Baltimore, Baltimore, Maryland, USA
- Center for Pathogen Research, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland—Baltimore, Baltimore, Maryland, USA
- Center for Pathogen Research, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Ribeiro CMP, Higgs MG, Muhlebach MS, Wolfgang MC, Borgatti M, Lampronti I, Cabrini G. Revisiting Host-Pathogen Interactions in Cystic Fibrosis Lungs in the Era of CFTR Modulators. Int J Mol Sci 2023; 24:ijms24055010. [PMID: 36902441 PMCID: PMC10003689 DOI: 10.3390/ijms24055010] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/25/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, a new series of therapeutics that correct and potentiate some classes of mutations of the CFTR, have provided a great therapeutic advantage to people with cystic fibrosis (pwCF). The main hindrances of the present CFTR modulators are related to their limitations in reducing chronic lung bacterial infection and inflammation, the main causes of pulmonary tissue damage and progressive respiratory insufficiency, particularly in adults with CF. Here, the most debated issues of the pulmonary bacterial infection and inflammatory processes in pwCF are revisited. Special attention is given to the mechanisms favoring the bacterial infection of pwCF, the progressive adaptation of Pseudomonas aeruginosa and its interplay with Staphylococcus aureus, the cross-talk among bacteria, the bronchial epithelial cells and the phagocytes of the host immune defenses. The most recent findings of the effect of CFTR modulators on bacterial infection and the inflammatory process are also presented to provide critical hints towards the identification of relevant therapeutic targets to overcome the respiratory pathology of pwCF.
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Affiliation(s)
- Carla M. P. Ribeiro
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: (C.M.P.R.); (G.C.)
| | - Matthew G. Higgs
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marianne S. Muhlebach
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Matthew C. Wolfgang
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Monica Borgatti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Ilaria Lampronti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Giulio Cabrini
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: (C.M.P.R.); (G.C.)
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5
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Prevalence of antibiotic resistance of Pseudomonas aeruginosa in cystic fibrosis infection: A systematic review and meta-analysis. Microb Pathog 2022; 165:105461. [DOI: 10.1016/j.micpath.2022.105461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 12/16/2022]
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6
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Specific and Global RNA Regulators in Pseudomonas aeruginosa. Int J Mol Sci 2021; 22:ijms22168632. [PMID: 34445336 PMCID: PMC8395346 DOI: 10.3390/ijms22168632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/05/2021] [Accepted: 08/08/2021] [Indexed: 01/20/2023] Open
Abstract
Pseudomonas aeruginosa (Pae) is an opportunistic pathogen showing a high intrinsic resistance to a wide variety of antibiotics. It causes nosocomial infections that are particularly detrimental to immunocompromised individuals and to patients suffering from cystic fibrosis. We provide a snapshot on regulatory RNAs of Pae that impact on metabolism, pathogenicity and antibiotic susceptibility. Different experimental approaches such as in silico predictions, co-purification with the RNA chaperone Hfq as well as high-throughput RNA sequencing identified several hundreds of regulatory RNA candidates in Pae. Notwithstanding, using in vitro and in vivo assays, the function of only a few has been revealed. Here, we focus on well-characterized small base-pairing RNAs, regulating specific target genes as well as on larger protein-binding RNAs that sequester and thereby modulate the activity of translational repressors. As the latter impact large gene networks governing metabolism, acute or chronic infections, these protein-binding RNAs in conjunction with their cognate proteins are regarded as global post-transcriptional regulators.
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7
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Loss of RND-type multidrug efflux pumps triggers iron starvation and lipid A modifications in Pseudomonas aeruginosa. Antimicrob Agents Chemother 2021; 65:e0059221. [PMID: 34252310 DOI: 10.1128/aac.00592-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transporters belonging to the Resistance-Nodulation-Division (RND) superfamily of proteins are invariably present in the genomes of Gram-negative bacteria and are largely responsible for the intrinsic antibiotic resistance of these organisms. The number of genes encoding RND transporters per genome vary from one to sixteen and correlates with environmental versatilities of bacterial species. Pseudomonas aeruginosa PAO1 strain, a ubiquitous nosocomial pathogen, possesses twelve RND pumps, which are implicated in development of clinical multidrug resistance and known to contribute to virulence, quorum sensing and many other physiological functions. In this study, we analyzed how P. aeruginosa physiology adapts to the lack of RND-mediated efflux activities. A combination of transcriptomics, metabolomics, genetic and analytical approaches showed that the P. aeruginosa PΔ6 strain lacking six best characterized RND pumps activates a specific adaptation response that involves significant changes in abundance and activities of several transport systems, quorum sensing, iron acquisition and lipid A modifications. Our results demonstrate that these cells accumulate large quantities of pseudomonas quorum signal (PQS), which triggers iron starvation and activation of siderophore biosynthesis and acquisition pathways. The accumulation of iron in turn activates lipid A modification and membrane protection pathways. A transcriptionally regulated RND pump MuxABC-OpmB contributes to these transformations by controlling concentrations of coumarins. Our results suggest that these changes reduce the permeability barrier of the outer membrane and are needed to protect the cell envelope of efflux-deficient P. aeruginosa.
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Defining the Mechanistic Correlates of Protection Conferred by Whole-Cell Vaccination against Pseudomonas aeruginosa Acute Murine Pneumonia. Infect Immun 2021; 89:IAI.00451-20. [PMID: 33199354 PMCID: PMC7822147 DOI: 10.1128/iai.00451-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/09/2020] [Indexed: 12/29/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative pathogen that causes severe pulmonary infections associated with high morbidity and mortality in immunocompromised patients. The development of a vaccine against P. aeruginosa could help prevent infections caused by this highly antibiotic-resistant microorganism. Pseudomonas aeruginosa is a Gram-negative pathogen that causes severe pulmonary infections associated with high morbidity and mortality in immunocompromised patients. The development of a vaccine against P. aeruginosa could help prevent infections caused by this highly antibiotic-resistant microorganism. We propose that identifying the vaccine-induced correlates of protection against P. aeruginosa will facilitate the development of a vaccine against this pathogen. In this study, we investigated the mechanistic correlates of protection of a curdlan-adjuvanted P. aeruginosa whole-cell vaccine (WCV) delivered intranasally. The WCV significantly decreased bacterial loads in the respiratory tract after intranasal P. aeruginosa challenge and raised antigen-specific antibody titers. To study the role of B and T cells during vaccination, anti-CD4, -CD8, and -CD20 depletions were performed prior to WCV vaccination and boosting. The depletion of CD4+, CD8+, or CD20+ cells had no impact on the bacterial burden in mock-vaccinated animals. However, depletion of CD20+ B cells, but not CD8+ or CD4+ T cells, led to the loss of vaccine-mediated bacterial clearance. Also, passive immunization with serum from WCV group mice alone protected naive mice against P. aeruginosa, supporting the role of antibodies in clearing P. aeruginosa. We observed that in the absence of T cell-dependent antibody production, mice vaccinated with the WCV were still able to reduce bacterial loads. Our results collectively highlight the importance of the humoral immune response for protection against P. aeruginosa and suggest that the production of T cell-independent antibodies may be sufficient for bacterial clearance induced by whole-cell P. aeruginosa vaccination.
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9
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Díez-Aguilar M, Hernández-García M, Morosini MI, Fluit A, Tunney MM, Huertas N, del Campo R, Obrecht D, Bernardini F, Ekkelenkamp M, Cantón R. Murepavadin antimicrobial activity against and resistance development in cystic fibrosis Pseudomonas aeruginosa isolates. J Antimicrob Chemother 2020; 76:984-992. [DOI: 10.1093/jac/dkaa529] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/20/2020] [Indexed: 12/27/2022] Open
Abstract
Abstract
Background
Murepavadin, a novel peptidomimetic antibiotic, is being developed as an inhalation therapy for treatment of Pseudomonas aeruginosa respiratory infection in people with cystic fibrosis (CF). It blocks the activity of the LptD protein in P. aeruginosa causing outer membrane alterations.
Objectives
To determine the in vitro activity of murepavadin against CF P. aeruginosa isolates and to investigate potential mechanisms of resistance.
Methods
MIC values were determined by both broth microdilution and agar dilution and results compared. The effect of artificial sputum and lung surfactant on in vitro activity was also measured. Spontaneous mutation frequency was estimated. Bactericidal activity was investigated using time–kill assays. Resistant mutants were studied by WGS.
Results
The murepavadin MIC50 was 0.125 versus 4 mg/L and the MIC90 was 2 versus 32 mg/L by broth microdilution and agar dilution, respectively. Essential agreement was >90% when determining in vitro activity with artificial sputum or lung surfactant. It was bactericidal at a concentration of 32 mg/L against 95.4% of the strains within 1–5 h. Murepavadin MICs were 2–9 two-fold dilutions higher for the mutant derivatives (0.5 to >16 mg/L) than for the parental strains. Second-step mutants were obtained for the PAO mutS reference strain with an 8×MIC increase. WGS showed mutations in genes involved in LPS biosynthesis (lpxL1, lpxL2, bamA2, lptD, lpxT and msbA).
Conclusions
Murepavadin characteristics, such as its specific activity against P. aeruginosa, its unique mechanism of action and its strong antimicrobial activity, encourage the further clinical evaluation of this drug.
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Affiliation(s)
- María Díez-Aguilar
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain
| | - Marta Hernández-García
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain
| | - María-Isabel Morosini
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain
| | - Ad Fluit
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Natalia Huertas
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Rosa del Campo
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain
| | | | | | - Miquel Ekkelenkamp
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Madrid, Spain
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10
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Yang H, Chandler CE, Jackson SN, Woods AS, Goodlett DR, Ernst RK, Scott AJ. On-Tissue Derivatization of Lipopolysaccharide for Detection of Lipid A Using MALDI-MSI. Anal Chem 2020; 92:13667-13671. [PMID: 32902263 DOI: 10.1021/acs.analchem.0c02566] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We developed a method to directly detect and map the Gram-negative bacterial virulence factor lipid A derived from lipopolysaccharide (LPS) by coupling acid hydrolysis with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). As the structure of lipid A (endotoxin) determines the innate immune outcome during infection, the ability to map its location within an infected organ or animal is needed to understand localized inflammatory responses that results during host-pathogen interactions. We previously demonstrated detection of free lipid A from infected tissue; however detection of lipid A derived from intact (smooth) LPS from host-pathogen MSI studies, proved elusive. Here, we detected LPS-derived lipid A from the Gram-negative pathogens, Escherichia coli (Ec, m/z 1797) and Pseudomonas aeruginosa (Pa, m/z 1446) using on-tissue acid hydrolysis to cleave the glycosidic linkage between the polysaccharide (core and O-antigen) and lipid A moieties of LPS. Using accurate mass methods, the ion corresponding to the major Ec and Pa lipid A species (m/z 1797 and 1446, respectively) were unambiguously discriminated from complex tissue substrates. Further, we evaluated potential delocalization and signal loss of other tissue lipids and found no evidence for either, making this LPS-to-Lipid A-MSI (LLA-MSI) method, compatible with simultaneous host-pathogen lipid imaging following acid hydrolysis. This spatially sensitive technique is the first step in mapping host-influenced de novo lipid A modifications, such as those associated with antimicrobial resistance phenotypes, during Gram-negative bacterial infection and will advance our understanding of the host-pathogen interface.
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Affiliation(s)
- Hyojik Yang
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States
| | - Courtney E Chandler
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States
| | - Shelley N Jackson
- Structural Biology Core, NIDA IRP, NIH, 333 Cassell Drive, Room 1120, Baltimore, Maryland 21224, United States
| | - Amina S Woods
- Structural Biology Core, NIDA IRP, NIH, 333 Cassell Drive, Room 1120, Baltimore, Maryland 21224, United States.,Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine. Baltimore, Maryland 21205, United States
| | - David R Goodlett
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States.,University of Gdansk, International Centre for Cancer Vaccine Science, Gdansk, Poland
| | - Robert K Ernst
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States
| | - Alison J Scott
- Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, Maryland 21201, United States.,Maastricht Multimodal Molecular Imaging (M4I) Institute, Maastricht University, Maastricht, Netherlands
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Grassi L, Pompilio A, Kaya E, Rinaldi AC, Sanjust E, Maisetta G, Crabbé A, Di Bonaventura G, Batoni G, Esin S. The Anti-Microbial Peptide (Lin-SB056-1) 2-K Reduces Pro-Inflammatory Cytokine Release through Interaction with Pseudomonas aeruginosa Lipopolysaccharide. Antibiotics (Basel) 2020; 9:antibiotics9090585. [PMID: 32911618 PMCID: PMC7557804 DOI: 10.3390/antibiotics9090585] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/31/2020] [Accepted: 09/07/2020] [Indexed: 01/09/2023] Open
Abstract
The ability of many anti-microbial peptides (AMPs) to modulate the host immune response has highlighted their possible therapeutic use to reduce uncontrolled inflammation during chronic infections. In the present study, we examined the anti-inflammatory potential of the semi-synthetic peptide lin-SB056-1 and its dendrimeric derivative (lin-SB056-1)2-K, which were previously found to have anti-microbial activity against Pseudomonas aeruginosa in in vivo-like models mimicking the challenging environment of chronically infected lungs (i.e., artificial sputum medium and 3-D lung mucosa model). The dendrimeric derivative exerted a stronger anti-inflammatory activity than its monomeric counterpart towards lung epithelial- and macrophage-cell lines stimulated with P. aeruginosa lipopolysaccharide (LPS), based on a marked decrease (up to 80%) in the LPS-induced production of different pro-inflammatory cytokines (i.e., IL-1β, IL-6 and IL-8). Accordingly, (lin-SB056-1)2-K exhibited a stronger LPS-binding affinity than its monomeric counterpart, thereby suggesting a role of peptide/LPS neutralizing interactions in the observed anti-inflammatory effect. Along with the anti-bacterial and anti-biofilm properties, the anti-inflammatory activity of (lin-SB056-1)2-K broadens its therapeutic potential in the context of chronic (biofilm-associated) infections.
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Affiliation(s)
- Lucia Grassi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56123 Pisa PI, Italy; (L.G.); (E.K.); (G.M.)
| | - Arianna Pompilio
- Department of Medical, Oral and Biotechnological Sciences, and Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti CH, Italy; (A.P.); (G.D.B.)
| | - Esingül Kaya
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56123 Pisa PI, Italy; (L.G.); (E.K.); (G.M.)
| | - Andrea C. Rinaldi
- Department of Biomedical Sciences, University of Cagliari, 09142 Monserrato CA, Italy; (A.C.R.); (E.S.)
| | - Enrico Sanjust
- Department of Biomedical Sciences, University of Cagliari, 09142 Monserrato CA, Italy; (A.C.R.); (E.S.)
| | - Giuseppantonio Maisetta
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56123 Pisa PI, Italy; (L.G.); (E.K.); (G.M.)
| | - Aurélie Crabbé
- Laboratory of Pharmaceutical Microbiology, Ghent University, 9000 Gent, Belgium;
| | - Giovanni Di Bonaventura
- Department of Medical, Oral and Biotechnological Sciences, and Center for Advanced Studies and Technology (CAST), “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti CH, Italy; (A.P.); (G.D.B.)
| | - Giovanna Batoni
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56123 Pisa PI, Italy; (L.G.); (E.K.); (G.M.)
- Correspondence: (G.B.); (S.E.)
| | - Semih Esin
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56123 Pisa PI, Italy; (L.G.); (E.K.); (G.M.)
- Correspondence: (G.B.); (S.E.)
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Lucas R, Hadizamani Y, Gonzales J, Gorshkov B, Bodmer T, Berthiaume Y, Moehrlen U, Lode H, Huwer H, Hudel M, Mraheil MA, Toque HAF, Chakraborty T, Hamacher J. Impact of Bacterial Toxins in the Lungs. Toxins (Basel) 2020; 12:toxins12040223. [PMID: 32252376 PMCID: PMC7232160 DOI: 10.3390/toxins12040223] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Bacterial toxins play a key role in the pathogenesis of lung disease. Based on their structural and functional properties, they employ various strategies to modulate lung barrier function and to impair host defense in order to promote infection. Although in general, these toxins target common cellular signaling pathways and host compartments, toxin- and cell-specific effects have also been reported. Toxins can affect resident pulmonary cells involved in alveolar fluid clearance (AFC) and barrier function through impairing vectorial Na+ transport and through cytoskeletal collapse, as such, destroying cell-cell adhesions. The resulting loss of alveolar-capillary barrier integrity and fluid clearance capacity will induce capillary leak and foster edema formation, which will in turn impair gas exchange and endanger the survival of the host. Toxins modulate or neutralize protective host cell mechanisms of both the innate and adaptive immunity response during chronic infection. In particular, toxins can either recruit or kill central players of the lung's innate immune responses to pathogenic attacks, i.e., alveolar macrophages (AMs) and neutrophils. Pulmonary disorders resulting from these toxin actions include, e.g., acute lung injury (ALI), the acute respiratory syndrome (ARDS), and severe pneumonia. When acute infection converts to persistence, i.e., colonization and chronic infection, lung diseases, such as bronchitis, chronic obstructive pulmonary disease (COPD), and cystic fibrosis (CF) can arise. The aim of this review is to discuss the impact of bacterial toxins in the lungs and the resulting outcomes for pathogenesis, their roles in promoting bacterial dissemination, and bacterial survival in disease progression.
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Affiliation(s)
- Rudolf Lucas
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
| | - Yalda Hadizamani
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
| | - Joyce Gonzales
- Department of Medicine and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Boris Gorshkov
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Thomas Bodmer
- Labormedizinisches Zentrum Dr. Risch, Waldeggstr. 37 CH-3097 Liebefeld, Switzerland;
| | - Yves Berthiaume
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montréal, QC H3T 1J4, Canada;
| | - Ueli Moehrlen
- Pediatric Surgery, University Children’s Hospital, Zürich, Steinwiesstrasse 75, CH-8032 Zürch, Switzerland;
| | - Hartmut Lode
- Insitut für klinische Pharmakologie, Charité, Universitätsklinikum Berlin, Reichsstrasse 2, D-14052 Berlin, Germany;
| | - Hanno Huwer
- Department of Cardiothoracic Surgery, Voelklingen Heart Center, 66333 Voelklingen/Saar, Germany;
| | - Martina Hudel
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Mobarak Abu Mraheil
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Haroldo Alfredo Flores Toque
- Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
- Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Trinad Chakraborty
- Justus-Liebig-University, Biomedical Research Centre Seltersberg, Schubertstr. 81, 35392 Giessen, Germany; (M.H.); (M.A.M.); (T.C.)
| | - Jürg Hamacher
- Lungen-und Atmungsstiftung, Bern, 3012 Bern, Switzerland;
- Pneumology, Clinic for General Internal Medicine, Lindenhofspital Bern, 3012 Bern, Switzerland
- Medical Clinic V-Pneumology, Allergology, Intensive Care Medicine and Environmental Medicine, Faculty of Medicine, Saarland University, University Medical Centre of the Saarland, D-66421 Homburg, Germany
- Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, D-66421 Homburg, Germany
- Correspondence: (R.L.); (J.H.); Tel.: +41-31-300-35-00 (J.H.)
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A Screen for Antibiotic Resistance Determinants Reveals a Fitness Cost of the Flagellum in Pseudomonas aeruginosa. J Bacteriol 2020; 202:JB.00682-19. [PMID: 31871033 DOI: 10.1128/jb.00682-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 12/18/2019] [Indexed: 01/09/2023] Open
Abstract
The intrinsic resistance of Pseudomonas aeruginosa to many antibiotics limits treatment options for pseudomonal infections. P. aeruginosa's outer membrane is highly impermeable and decreases antibiotic entry into the cell. We used an unbiased high-throughput approach to examine mechanisms underlying outer membrane-mediated antibiotic exclusion. Insertion sequencing (INSeq) identified genes that altered fitness in the presence of linezolid, rifampin, and vancomycin, antibiotics to which P. aeruginosa is intrinsically resistant. We reasoned that resistance to at least one of these antibiotics would depend on outer membrane barrier function, as previously demonstrated in Escherichia coli and Vibrio cholerae This approach demonstrated a critical role of the outer membrane barrier in vancomycin fitness, while efflux pumps were primary contributors to fitness in the presence of linezolid and rifampin. Disruption of flagellar assembly or function was sufficient to confer a fitness advantage to bacteria exposed to vancomycin. These findings clearly show that loss of flagellar function alone can confer a fitness advantage in the presence of an antibiotic.IMPORTANCE The cell envelopes of Gram-negative bacteria render them intrinsically resistant to many classes of antibiotics. We used insertion sequencing to identify genes whose disruption altered the fitness of a highly antibiotic-resistant pathogen, Pseudomonas aeruginosa, in the presence of antibiotics usually excluded by the cell envelope. This screen identified gene products involved in outer membrane biogenesis and homeostasis, respiration, and efflux as important contributors to fitness. An unanticipated fitness cost of flagellar assembly and function in the presence of the glycopeptide antibiotic vancomycin was further characterized. These findings have clinical relevance for individuals with cystic fibrosis who are infected with P. aeruginosa and undergo treatment with vancomycin for a concurrent Staphylococcus aureus infection.
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14
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Steering Phages to Combat Bacterial Pathogens. Trends Microbiol 2019; 28:85-94. [PMID: 31744662 DOI: 10.1016/j.tim.2019.10.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 10/10/2019] [Accepted: 10/17/2019] [Indexed: 12/21/2022]
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Bengoechea JA, Sa Pessoa J. Klebsiella pneumoniae infection biology: living to counteract host defences. FEMS Microbiol Rev 2019; 43:123-144. [PMID: 30452654 PMCID: PMC6435446 DOI: 10.1093/femsre/fuy043] [Citation(s) in RCA: 265] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022] Open
Abstract
Klebsiella species cause a wide range of diseases including pneumonia, urinary tract infections (UTIs), bloodstream infections and sepsis. These infections are particularly a problem among neonates, elderly and immunocompromised individuals. Klebsiella is also responsible for a significant number of community-acquired infections. A defining feature of these infections is their morbidity and mortality, and the Klebsiella strains associated with them are considered hypervirulent. The increasing isolation of multidrug-resistant strains has significantly narrowed, or in some settings completely removed, the therapeutic options for the treatment of Klebsiella infections. Not surprisingly, this pathogen has then been singled out as an 'urgent threat to human health' by several organisations. This review summarises the tremendous progress that has been made to uncover the sophisticated immune evasion strategies of K. pneumoniae. The co-evolution of Klebsiella in response to the challenge of an activated immune has made Klebsiella a formidable pathogen exploiting stealth strategies and actively suppressing innate immune defences to overcome host responses to survive in the tissues. A better understanding of Klebsiella immune evasion strategies in the context of the host-pathogen interactions is pivotal to develop new therapeutics, which can be based on antagonising the anti-immune strategies of this pathogen.
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Affiliation(s)
- José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
| | - Joana Sa Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast BT9 7BL, UK
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16
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Torrens G, Barceló IM, Pérez-Gallego M, Escobar-Salom M, Tur-Gracia S, Munar-Bestard M, González-Nicolau MDM, Cabrera-Venegas YJ, Rigo-Rumbos EN, Cabot G, López-Causapé C, Rojo-Molinero E, Oliver A, Juan C. Profiling the susceptibility of Pseudomonas aeruginosa strains from acute and chronic infections to cell-wall-targeting immune proteins. Sci Rep 2019; 9:3575. [PMID: 30837659 PMCID: PMC6401076 DOI: 10.1038/s41598-019-40440-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/06/2019] [Indexed: 02/06/2023] Open
Abstract
In the current scenario of high antibiotic resistance, the search for therapeutic options against Pseudomonas aeruginosa must be approached from different perspectives: cell-wall biology as source of bacterial weak points and our immune system as source of weapons. Our recent study suggests that once the permeability barrier has been overcome, the activity of our cell-wall-targeting immune proteins is notably enhanced, more in mutants with impaired peptidoglycan recycling. The present work aims at analyzing the activity of these proteins [lysozyme and Peptidoglycan-Recognition-Proteins (PGLYRPs)], alone or with a permeabilizer (subinhibitory colistin) in clinical strains, along with other features related to the cell-wall. We compared the most relevant and complementary scenarios: acute (bacteremia) and chronic infections [early/late isolates from lungs of cystic fibrosis (CF) patients]. Although a low activity of lysozyme/PGLYRPs per se (except punctual highly susceptible strains) was found, the colistin addition significantly increased their activity regardless of the strains’ colistin resistance levels. Our results show increased susceptibility in late CF isolates, suggesting that CF adaptation renders P. aeruginosa more vulnerable to proteins targeting the cell-wall. Thus, our work suggests that attacking some P. aeruginosa cell-wall biology-related elements to increase the activity of our innate weapons could be a promising therapeutic strategy.
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Affiliation(s)
- Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Isabel M Barceló
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Marcelo Pérez-Gallego
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Maria Escobar-Salom
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Sara Tur-Gracia
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Marta Munar-Bestard
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - María Del Mar González-Nicolau
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Yoandy José Cabrera-Venegas
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Estefany Nayarith Rigo-Rumbos
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Gabriel Cabot
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Carla López-Causapé
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Estrella Rojo-Molinero
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain
| | - Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitari Son Espases-Institut de Investigació Sanitària de Balears (IdISBa), Palma, Spain.
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17
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Velkov T, Roberts KD. Discovery of Novel Polymyxin-Like Antibiotics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1145:343-362. [PMID: 31364086 DOI: 10.1007/978-3-030-16373-0_20] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The antimicrobial lipopeptides polymyxin B and colistin (polymyxin E) are used as a 'last-line' therapy for infections caused by multidrug-resistant (MDR) Gram-negative pathogens. However, their effective use as antibiotic drugs in the clinical setting is still plagued by significant toxicity issues, in particular their potential for nephrotoxicity. Furthermore, resistance to the polymyxins has begun to emerge in the clinic, which implies a total lack of antibiotics for the treatment of life-threatening infections caused by the Gram-negative 'superbugs'. This chapter details our current understanding of polymyxin structure-activity relationships as well as recent pre-clinical and clinical drug development efforts aimed at generating new polymyxin antibiotics with improved safety and efficacy.
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Affiliation(s)
- Tony Velkov
- Department of Pharmacology and Therapeutics, University of Melbourne, Parkville, VIC, Australia.
| | - Kade D Roberts
- Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, VIC, Australia.
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18
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Turkina MV, Vikström E. Bacteria-Host Crosstalk: Sensing of the Quorum in the Context of Pseudomonas aeruginosa Infections. J Innate Immun 2018; 11:263-279. [PMID: 30428481 DOI: 10.1159/000494069] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/24/2018] [Indexed: 12/11/2022] Open
Abstract
Cell-to-cell signaling via small molecules is an essential process to coordinate behavior in single species within a community, and also across kingdoms. In this review, we discuss the quorum sensing (QS) systems used by the opportunistic pathogen Pseudomonas aeruginosa to sense bacterial population density and fitness, and regulate virulence, biofilm development, metabolite acquisition, and mammalian host defense. We also focus on the role of N-acylhomoserine lactone-dependent QS signaling in the modulation of innate immune responses connected together via calcium signaling, homeostasis, mitochondrial and cytoskeletal dynamics, and governing transcriptional and proteomic responses of host cells. A future perspective emphasizes the need for multidisciplinary efforts to bring current knowledge of QS into a more detailed understanding of the communication between bacteria and host, as well as into strategies to prevent and treat P. aeruginosa infections and reduce the rate of antibiotic resistance.
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Affiliation(s)
- Maria V Turkina
- Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden
| | - Elena Vikström
- Department of Clinical and Experimental Medicine, Faculty of Medicine and Health Sciences, Linköping University, Linköping, Sweden,
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19
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Faure E, Kwong K, Nguyen D. Pseudomonas aeruginosa in Chronic Lung Infections: How to Adapt Within the Host? Front Immunol 2018; 9:2416. [PMID: 30405616 PMCID: PMC6204374 DOI: 10.3389/fimmu.2018.02416] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/01/2018] [Indexed: 01/29/2023] Open
Abstract
Bacteria that readily adapt to different natural environments, can also exploit this versatility upon infection of the host to persist. Pseudomonas aeruginosa, a ubiquitous Gram-negative bacterium, is harmless to healthy individuals, and yet a formidable opportunistic pathogen in compromised hosts. When pathogenic, P. aeruginosa causes invasive and highly lethal disease in certain compromised hosts. In others, such as individuals with the genetic disease cystic fibrosis, this pathogen causes chronic lung infections which persist for decades. During chronic lung infections, P. aeruginosa adapts to the host environment by evolving toward a state of reduced bacterial invasiveness that favors bacterial persistence without causing overwhelming host injury. Host responses to chronic P. aeruginosa infections are complex and dynamic, ranging from vigorous activation of innate immune responses that are ineffective at eradicating the infecting bacteria, to relative host tolerance and dampened activation of host immunity. This review will examine how P. aeruginosa subverts host defenses and modulates immune and inflammatory responses during chronic infection. This dynamic interplay between host and pathogen is a major determinant in the pathogenesis of chronic P. aeruginosa lung infections.
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Affiliation(s)
- Emmanuel Faure
- Department of Medicine, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Kelly Kwong
- Department of Medicine, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Center, Montreal, QC, Canada
| | - Dao Nguyen
- Department of Medicine, McGill University, Montreal, QC, Canada
- Research Institute of the McGill University Health Center, Montreal, QC, Canada
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20
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Fernández PA, Velásquez F, Garcias-Papayani H, Amaya FA, Ortega J, Gómez S, Santiviago CA, Álvarez SA. Fnr and ArcA Regulate Lipid A Hydroxylation in Salmonella Enteritidis by Controlling lpxO Expression in Response to Oxygen Availability. Front Microbiol 2018; 9:1220. [PMID: 29937757 PMCID: PMC6002686 DOI: 10.3389/fmicb.2018.01220] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/18/2018] [Indexed: 12/22/2022] Open
Abstract
Lipid A is the bioactive component of lipopolysaccharide, and presents a dynamic structure that undergoes modifications in response to environmental signals. Many of these structural modifications influence Salmonella virulence. This is the case of lipid A hydroxylation, a modification catalyzed by the dioxygenase LpxO. Although it has been established that oxygen is required for lipid A hydroxylation acting as substrate of LpxO in Salmonella, an additional regulatory role for oxygen in lpxO expression has not been described. The existence of this regulation could be relevant considering that Salmonella faces low oxygen tension during infection. This condition leads to an adaptive response by changing the expression of numerous genes, and transcription factors Fnr and ArcA are major regulators of this process. In this work, we describe for the first time that lipid A hydroxylation and lpxO expression are modulated by oxygen availability in Salmonella enterica serovar Enteritidis (S. Enteritidis). Biochemical and genetic analyses indicate that this process is regulated by Fnr and ArcA controlling the expression of lpxO. In addition, according to our results, this regulation occurs by direct binding of both transcription factors to specific elements present in the lpxO promoter region. Altogether, our observations revealed a novel role for oxygen acting as an environment signal controlling lipid A hydroxylation in S. Enteritidis.
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Affiliation(s)
- Paulina A Fernández
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Felipe Velásquez
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Héctor Garcias-Papayani
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Fernando A Amaya
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Jaime Ortega
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Sebastián Gómez
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Carlos A Santiviago
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Sergio A Álvarez
- Laboratorio de Microbiología, Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
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21
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Zhang YF, Han K, Chandler CE, Tjaden B, Ernst RK, Lory S. Probing the sRNA regulatory landscape of P. aeruginosa: post-transcriptional control of determinants of pathogenicity and antibiotic susceptibility. Mol Microbiol 2017; 106:919-937. [PMID: 28976035 PMCID: PMC5738928 DOI: 10.1111/mmi.13857] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2017] [Indexed: 01/01/2023]
Abstract
During environmental adaptation bacteria use small regulatory RNAs (sRNAs) to repress or activate expression of a large fraction of their proteome. We extended the use of the in vivo RNA proximity ligation method toward probing global sRNA interactions with their targets in Pseudomonas aeruginosa and verified the method with a known regulon controlled by the PrrF1 sRNA. We also identified two sRNAs (Sr0161 and ErsA) that interact with the mRNA encoding the major porin OprD responsible for the uptake of carbapenem antibiotics. These two sRNAs base pair with the 5' UTR of oprD leading to increase in resistance of the bacteria to meropenem. Additional proximity ligation experiments and enrichment for Sr0161 targets identified the mRNA for the regulator of type III secretion system. Interaction between the exsA mRNA and Sr0161 leads to a block in the synthesis of a component of the T3SS apparatus and an effector. Another sRNA, Sr006, positively regulates, without Hfq, the expression of PagL, an enzyme responsible for deacylation of lipid A, reducing its pro-inflammatory property and resulting in polymyxin resistance. Therefore, an analysis of global sRNA-mRNA interactions can lead to discoveries of novel pathways controlling gene expression that are likely integrated into larger regulatory networks.
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Affiliation(s)
- Yi-Fan Zhang
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - Kook Han
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Courtney E. Chandler
- Department of Microbial Pathogenesis, University of Maryland – Baltimore, School of Dentistry, Baltimore, Maryland, USA
| | - Brian Tjaden
- Computer Science Department, Wellesley College, Wellesley, Massachusetts, USA
| | - Robert K. Ernst
- Department of Microbial Pathogenesis, University of Maryland – Baltimore, School of Dentistry, Baltimore, Maryland, USA
| | - Stephen Lory
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA
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22
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Zhu L, Li Y, Wang J, Wang X. Identification of two secondary acyltransferases of lipid A in Pseudomonas putida
KT2442. J Appl Microbiol 2017; 123:478-490. [DOI: 10.1111/jam.13499] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 05/16/2017] [Accepted: 05/16/2017] [Indexed: 12/18/2022]
Affiliation(s)
- L. Zhu
- School of Biotechnology; Jiangnan University; Wuxi China
| | - Y. Li
- State Key Laboratory of Food Science and Technology; Wuxi China
| | - J. Wang
- School of Biotechnology; Jiangnan University; Wuxi China
| | - X. Wang
- School of Biotechnology; Jiangnan University; Wuxi China
- State Key Laboratory of Food Science and Technology; Wuxi China
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23
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Antibiotic-non-antibiotic combinations for combating extremely drug-resistant Gram-negative 'superbugs'. Essays Biochem 2017; 61:115-125. [PMID: 28258235 DOI: 10.1042/ebc20160058] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 11/02/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022]
Abstract
The emergence of antimicrobial resistance of Gram-negative pathogens has become a worldwide crisis. The status quo for combating resistance is to employ synergistic combinations of antibiotics. Faced with this fast-approaching post-antibiotic era, it is critical that we devise strategies to prolong and maximize the clinical efficacy of existing antibiotics. Unfortunately, reports of extremely drug-resistant (XDR) Gram-negative pathogens have become more common. Combining antibiotics such as polymyxin B or the broad-spectrum tetracycline and minocycline with various FDA-approved non-antibiotic drugs have emerged as a novel combination strategy against otherwise untreatable XDR pathogens. This review surveys the available literature on the potential benefits of employing antibiotic-non-antibiotic drug combination therapy. The apex of this review highlights the clinical utility of this novel therapeutic strategy for combating infections caused by 'superbugs'.
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Lipid A structural modifications in extreme conditions and identification of unique modifying enzymes to define the Toll-like receptor 4 structure-activity relationship. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1439-1450. [PMID: 28108356 DOI: 10.1016/j.bbalip.2017.01.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/10/2017] [Accepted: 01/12/2017] [Indexed: 01/23/2023]
Abstract
Strategies utilizing Toll-like receptor 4 (TLR4) agonists for treatment of cancer, infectious diseases, and other targets report promising results. Potent TLR4 antagonists are also gaining attention as therapeutic leads. Though some principles for TLR4 modulation by lipid A have been described, a thorough understanding of the structure-activity relationship (SAR) is lacking. Only through a complete definition of lipid A-TLR4 SAR is it possible to predict TLR4 signaling effects of discrete lipid A structures, rendering them more pharmacologically relevant. A limited 'toolbox' of lipid A-modifying enzymes has been defined and is largely composed of enzymes from mesophile human and zoonotic pathogens. Expansion of this 'toolbox' will result from extending the search into lipid A biosynthesis and modification by bacteria living at the extremes. Here, we review the fundamentals of lipid A structure, advances in lipid A uses in TLR4 modulation, and the search for novel lipid A-modifying systems in extremophile bacteria. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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25
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Evolution of Ecological Diversity in Biofilms of Pseudomonas aeruginosa by Altered Cyclic Diguanylate Signaling. J Bacteriol 2016; 198:2608-18. [PMID: 27021563 PMCID: PMC5019052 DOI: 10.1128/jb.00048-16] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 03/22/2016] [Indexed: 11/29/2022] Open
Abstract
The ecological and evolutionary forces that promote and maintain diversity in biofilms are not well understood. To quantify these forces, three Pseudomonas aeruginosa populations were experimentally evolved from strain PA14 in a daily cycle of attachment, assembly, and dispersal for 600 generations. Each biofilm population evolved diverse colony morphologies and mutator genotypes defective in DNA mismatch repair. This diversity enhanced population fitness and biofilm output, owing partly to rare, early colonizing mutants that enhanced attachment of others. Evolved mutants exhibited various levels of the intracellular signal cyclic-di-GMP, which associated with their timing of adherence. Manipulating cyclic-di-GMP levels within individual mutants revealed a network of interactions in the population that depended on various attachment strategies related to this signal. Diversification in biofilms may therefore arise and be reinforced by initial colonists that enable community assembly.
IMPORTANCE How biofilm diversity assembles, evolves, and contributes to community function is largely unknown. This presents a major challenge for understanding evolution during chronic infections and during the growth of all surface-associated microbes. We used experimental evolution to probe these dynamics and found that diversity, partly related to altered cyclic-di-GMP levels, arose and persisted due to the emergence of ecological interdependencies related to attachment patterns. Clonal isolates failed to capture population attributes, which points to the need to account for diversity in infections. More broadly, this study offers an experimental framework for linking phenotypic variation to distinct ecological strategies in biofilms and for studying eco-evolutionary interactions.
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26
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SenGupta S, Hittle LE, Ernst RK, Uriarte SM, Mitchell TC. A Pseudomonas aeruginosa hepta-acylated lipid A variant associated with cystic fibrosis selectively activates human neutrophils. J Leukoc Biol 2016; 100:1047-1059. [PMID: 27538572 DOI: 10.1189/jlb.4vma0316-101r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/20/2016] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa (PA) infection in cystic fibrosis (CF) lung disease causes airway neutrophilia and hyperinflammation without effective bacterial clearance. We evaluated the immunostimulatory activities of lipid A, the membrane anchor of LPS, isolated from mutants of PA that synthesize structural variants, present in the airways of patients with CF, to determine if they correlate with disease severity and progression. In a subset of patients with a severe late stage of CF disease, a unique hepta-acylated lipid A, hepta-1855, is synthesized. In primary human cell cultures, we found that hepta-1855 functioned as a potent TLR4 agonist by priming neutrophil respiratory burst and stimulating strong IL-8 from monocytes and neutrophils. hepta-1855 also had a potent survival effect on neutrophils. However, it was less efficient in stimulating neutrophil granule exocytosis and also less potent in triggering proinflammatory TNF-α response from monocytes. In PA isolates that do not synthesize hepta-1855, a distinct CF-specific adaptation favors synthesis of a penta-1447 and hexa-1685 LPS mixture. We found that penta-1447 lacked immunostimulatory activity but interfered with inflammatory IL-8 synthesis in response to hexa-1685. Together, these observations suggest a potential contribution of hepta-1855 to maintenance of the inflammatory burden in late-stage CF by recruiting neutrophils via IL-8 and promoting their survival, an effect presumably amplified by the absence of penta-1447. Moreover, the relative inefficiency of hepta-1855 in triggering neutrophil degranulation may partly explain the persistence of PA in CF disease, despite extensive airway neutrophilia.
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Affiliation(s)
- Shuvasree SenGupta
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Lauren E Hittle
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA
| | - Silvia M Uriarte
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA; .,Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky, USA; and
| | - Thomas C Mitchell
- Department of Microbiology and Immunology, University of Louisville School of Medicine, Louisville, Kentucky, USA;
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27
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Colonization of CF patients’ upper airways with S. aureus contributes more decisively to upper airway inflammation than P. aeruginosa. Med Microbiol Immunol 2016; 205:485-500. [DOI: 10.1007/s00430-016-0463-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 06/20/2016] [Indexed: 01/29/2023]
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28
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Maldonado RF, Sá-Correia I, Valvano MA. Lipopolysaccharide modification in Gram-negative bacteria during chronic infection. FEMS Microbiol Rev 2016; 40:480-93. [PMID: 27075488 PMCID: PMC4931227 DOI: 10.1093/femsre/fuw007] [Citation(s) in RCA: 350] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/23/2015] [Accepted: 03/10/2016] [Indexed: 12/16/2022] Open
Abstract
The Gram-negative bacterial lipopolysaccharide (LPS) is a major component of the outer membrane that plays a key role in host-pathogen interactions with the innate immune system. During infection, bacteria are exposed to a host environment that is typically dominated by inflammatory cells and soluble factors, including antibiotics, which provide cues about regulation of gene expression. Bacterial adaptive changes including modulation of LPS synthesis and structure are a conserved theme in infections, irrespective of the type or bacteria or the site of infection. In general, these changes result in immune system evasion, persisting inflammation and increased antimicrobial resistance. Here, we review the modifications of LPS structure and biosynthetic pathways that occur upon adaptation of model opportunistic pathogens (Pseudomonas aeruginosa, Burkholderia cepacia complex bacteria, Helicobacter pylori and Salmonella enterica) to chronic infection in respiratory and gastrointestinal sites. We also discuss the molecular mechanisms of these variations and their role in the host-pathogen interaction.
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Affiliation(s)
- Rita F. Maldonado
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Isabel Sá-Correia
- Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisbon 1049-001, Portugal
| | - Miguel A. Valvano
- Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
- Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 7BL, UK
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29
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Bruscia EM, Zhang PX, Barone C, Scholte BJ, Homer R, Krause DS, Egan ME. Increased susceptibility of Cftr-/- mice to LPS-induced lung remodeling. Am J Physiol Lung Cell Mol Physiol 2016; 310:L711-9. [PMID: 26851259 DOI: 10.1152/ajplung.00284.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 01/29/2016] [Indexed: 01/05/2023] Open
Abstract
Cystic fibrosis (CF) is caused by homozygous mutations of the CF transmembrane conductance regulator (CFTR) Cl(-) channel, which result in chronic pulmonary infection and inflammation, the major cause of morbidity and mortality. Although these processes are clearly related to each other, each is likely to contribute to the pathology differently. Understanding the contribution of each of these processes to the overall pathology has been difficult, because they are usually so intimately connected. Various CF mouse models have demonstrated abnormal immune responses compared with wild-type (WT) littermates when challenged with live bacteria or bacterial products acutely. However, these studies have not investigated the consequences of persistent inflammation on lung tissue in CF mice, which may better model the lung pathology in patients. We characterized the lung pathology and immune response of Cftr(-/-) (CF) and Cftr(+/+) (WT) mice to chronic administration of Pseudomonas aeruginosa lipopolysaccharide (LPS). We show that, after long-term repeated LPS exposure, CF mice develop an abnormal and persistent immune response, which is associated with more robust structural changes in the lung than those observed in WT mice. Although CF mice and their WT littermates develop lung pathology after chronic exposure to LPS, the inflammation and damage resolve in WT mice. However, CF mice do not recover efficiently, and, as a consequence of their chronic inflammation, CF mice are more susceptible to morphological changes and lung remodeling. This study shows that chronic inflammation alone contributes significantly to aspects of CF lung pathology.
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Affiliation(s)
- Emanuela M Bruscia
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | - Ping-Xia Zhang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Christina Barone
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | - Bob J Scholte
- Department of Cell Biology, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Robert Homer
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut
| | - Diane S Krause
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut; Department of Pathology, Yale University School of Medicine, New Haven, Connecticut
| | - Marie E Egan
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut; and
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30
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Abstract
The outcome of an infection depends on host recognition of the pathogen, hence leading to the activation of signaling pathways controlling defense responses. A long-held belief is that the modification of the lipid A moiety of the lipopolysaccharide could help Gram-negative pathogens to evade innate immunity. However, direct evidence that this happens in vivo is lacking. Here we report the lipid A expressed in the tissues of infected mice by the human pathogen Klebsiella pneumoniae. Our findings demonstrate that Klebsiella remodels its lipid A in a tissue-dependent manner. Lipid A species found in the lungs are consistent with a 2-hydroxyacyl-modified lipid A dependent on the PhoPQ-regulated oxygenase LpxO. The in vivo lipid A pattern is lost in minimally passaged bacteria isolated from the tissues. LpxO-dependent modification reduces the activation of inflammatory responses and mediates resistance to antimicrobial peptides. An lpxO mutant is attenuated in vivo thereby highlighting the importance of this lipid A modification in Klebsiella infection biology. Colistin, one of the last options to treat multidrug-resistant Klebsiella infections, triggers the in vivo lipid A pattern. Moreover, colistin-resistant isolates already express the in vivo lipid A pattern. In these isolates, LpxO-dependent lipid A modification mediates resistance to colistin. Deciphering the lipid A expressed in vivo opens the possibility of designing novel therapeutics targeting the enzymes responsible for the in vivo lipid A pattern.
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31
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Nowicki EM, O'Brien JP, Brodbelt JS, Trent MS. Extracellular zinc induces phosphoethanolamine addition to Pseudomonas aeruginosa lipid A via the ColRS two-component system. Mol Microbiol 2015; 97:166-78. [PMID: 25846400 DOI: 10.1111/mmi.13018] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2015] [Indexed: 01/01/2023]
Abstract
Gram-negative bacteria survive harmful environmental stressors by modifying their outer membrane. Much of this protection is afforded upon remodeling of the lipid A region of the major surface molecule lipopolysaccharide (LPS). For example, the addition of cationic substituents, such as 4-amino-4-deoxy-L-arabinose (L-Ara4N) and phosphoehthanolamine (pEtN) at the lipid A phosphate groups, is often induced in response to specific environmental flux stabilizing the outer membrane. The work herein represents the first report of pEtN addition to Pseudomonas aeruginosa lipid A. We have identified the key pEtN transferase which we named EptAPa and characterized its strict activity on only one position of lipid A, contrasting from previously studied EptA enzymes. We further show that transcription of eptAP a is regulated by zinc via the ColRS two-component system instead of the PmrAB system responsible for eptA regulation in E. coli and Salmonella enterica. Further, although L-Ara4N is readily added to the same position of lipid A as pEtN under certain environmental conditions, ColR specifically induces pEtN addition to lipid A in lieu of L-Ara4N when Zn2+ is present. The unique, specific regulation of eptAP a transcription and enzymatic activity described in this work demonstrates the tight yet inducible control over LPS modification in P. aeruginosa.
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Affiliation(s)
- Emily M Nowicki
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA
| | - John P O'Brien
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | | | - M Stephen Trent
- Department of Infectious Diseases, University of Georgia, College of Veterinary Medicine, Athens, GA, USA
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32
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Wang Y, Wang J, Li Y, Wang B, Tao G, Wang X. Structure characterization of phospholipids and lipid A of Pseudomonas putida KT2442. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2015; 21:739-746. [PMID: 26579930 DOI: 10.1255/ejms.1390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Pseudomonas putida KT2442 is an important bacterium for producing various types of polyhydroxyalkanoate polymers. Phospholipids and lipid A in membranes of P. putida play important roles in stress responses, but detailed structural information of these lipids is not known. In this study, phospholipids and lipid A were isolated from P. putida KT2442, and their structures were analyzed using thin layer chromatography, high performance liquid chromatography, and electrospray ionization/mass spectrometry. Major phospholipids in P. putida KT2442 were phosphatidylethanolamine (79.9%), phosphatidylglycero1 (12.7%), and cardiolipin (7.4%), with C16:1 and/or C18:1 acyl chains. Four lipid A species were found in P. putida KT2442: two are hexa-acylated, and the other two are penta-acylated. Compared with lipid A of P. aeruginosa, P. putida lipid A has less hydroxylation on the secondary acyl chains and less modification. Therefore, P. putida lipid A could be used as a base structure to investigate lipid A modification of P. aeruginosa for understanding its pathogenesis.
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Affiliation(s)
- Yuqian Wang
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
| | - Jianli Wang
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, Chinaof Biotechnology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
| | - Ye Li
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, Chinaotechnology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
| | - Biwen Wang
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, Chinaotechnology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
| | - Guanjun Tao
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, Chinaotechnology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, and School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, Chinaechnology, State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi 21422, China.
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33
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Nowicki EM, O'Brien JP, Brodbelt JS, Trent MS. Characterization of Pseudomonas aeruginosa LpxT reveals dual positional lipid A kinase activity and co-ordinated control of outer membrane modification. Mol Microbiol 2014; 94:728-41. [PMID: 25223756 DOI: 10.1111/mmi.12796] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2014] [Indexed: 01/01/2023]
Abstract
Gram-negative bacteria have evolved modification machinery to promote a dynamic outer membrane in response to a continually fluctuating environment. The kinase LpxT, for example, adds a phosphate group to the lipid A moiety of some Gram-negatives including Escherichia coli and Salmonella enterica. LpxT activity is inhibited under conditions that compromise membrane integrity, resulting instead in the addition of positively charged groups to lipid A that increase membrane stability and provide resistance to cationic antimicrobial peptides. We have now identified a functional lpxT orthologue in P. aeruginosa. LpxTPa has unique enzymatic characteristics, as it is able to phosphorylate P. aeruginosa lipid A at two sites of the molecule. Surprisingly, a previously uncharacterized lipid A 4'-dephospho-1-triphosphate species was detected. LpxTPa activity is inhibited by magnesium independently of lpxTPa transcription. Modulation of LpxTPa activity is influenced by transcription of the lipid A aminoarabinose transferase ArnT, known to be activated in response to limiting magnesium. These results demonstrate a divergent activity of LpxTPa , and suggest the existence of a co-ordinated regulatory mechanism that permits adaptation to a changing environment.
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Affiliation(s)
- Emily M Nowicki
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas, USA
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34
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Mulcahy LR, Isabella VM, Lewis K. Pseudomonas aeruginosa biofilms in disease. MICROBIAL ECOLOGY 2014; 68:1-12. [PMID: 24096885 PMCID: PMC3977026 DOI: 10.1007/s00248-013-0297-x] [Citation(s) in RCA: 299] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/17/2013] [Indexed: 05/19/2023]
Abstract
Pseudomonas aeruginosa is a ubiquitous organism that is the focus of intense research because of its prominent role in disease. Due to its relatively large genome and flexible metabolic capabilities, this organism exploits numerous environmental niches. It is an opportunistic pathogen that sets upon the human host when the normal immune defenses are disabled. Its deadliness is most apparent in cystic fibrosis patients, but it also is a major problem in burn wounds, chronic wounds, chronic obstructive pulmonary disorder, surface growth on implanted biomaterials, and within hospital surface and water supplies, where it poses a host of threats to vulnerable patients (Peleg and Hooper, N Engl J Med 362:1804-1813, 2010; Breathnach et al., J Hosp Infect 82:19-24, 2012). Once established in the patient, P. aeruginosa can be especially difficult to treat. The genome encodes a host of resistance genes, including multidrug efflux pumps (Poole, J Mol Microbiol Biotechnol 3:255-264, 2001) and enzymes conferring resistance to beta-lactam and aminoglycoside antibotics (Vahdani et al., Annal Burns Fire Disast 25:78-81, 2012), making therapy against this gram-negative pathogen particularly challenging due to the lack of novel antimicrobial therapeutics (Lewis, Nature 485: 439-440, 2012). This challenge is compounded by the ability of P. aeruginosa to grow in a biofilm, which may enhance its ability to cause infections by protecting bacteria from host defenses and chemotherapy. Here, we review recent studies of P. aeruginosa biofilms with a focus on how this unique mode of growth contributes to its ability to cause recalcitrant infections.
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Affiliation(s)
- Lawrence R. Mulcahy
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
| | - Vincent M. Isabella
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
| | - Kim Lewis
- Antimicrobial Discovery Center, Department of Biology. Northeastern University, 306C Mugar Life Sciences, 360 Huntington Avenue, Boston, MA 02115 USA
- Corresponding Author: Kim Lewis, Ph.D., 617.373.8238,
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35
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Velkov T, Roberts KD, Nation RL, Wang J, Thompson PE, Li J. Teaching 'old' polymyxins new tricks: new-generation lipopeptides targeting gram-negative 'superbugs'. ACS Chem Biol 2014; 9:1172-7. [PMID: 24601489 PMCID: PMC4033650 DOI: 10.1021/cb500080r] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The antimicrobial lipopeptides polymyxin
B and E (colistin) are
being used as a ‘last-line’ therapy for infections caused
by multidrug-resistant Gram-negative pathogens. Polymyxin resistance
implies a total lack of antibiotics for the treatment of life-threatening
infections caused by the Gram-negative ‘superbugs’.
This report details the structure–activity relationships (SAR)
based design, in toto synthesis, and preclinical
evaluation of a series of novel polymyxin lipopeptides with better
antibacterial activity against polymyxin-resistant Gram-negative bacteria.
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Affiliation(s)
- Tony Velkov
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Kade D. Roberts
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Roger L. Nation
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Jiping Wang
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Philip E. Thompson
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
| | - Jian Li
- Drug Delivery, Disposition and Dynamics, ‡Medicinal Chemistry, Monash Institute
of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville 3052, Victoria, Australia
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36
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Subashchandrabose S, Smith SN, Spurbeck RR, Kole MM, Mobley HLT. Genome-wide detection of fitness genes in uropathogenic Escherichia coli during systemic infection. PLoS Pathog 2013; 9:e1003788. [PMID: 24339777 PMCID: PMC3855560 DOI: 10.1371/journal.ppat.1003788] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/10/2013] [Indexed: 12/16/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is a leading etiological agent of bacteremia in humans. Virulence mechanisms of UPEC in the context of urinary tract infections have been subjected to extensive research. However, understanding of the fitness mechanisms used by UPEC during bacteremia and systemic infection is limited. A forward genetic screen was utilized to detect transposon insertion mutants with fitness defects during colonization of mouse spleens. An inoculum comprised of 360,000 transposon mutants in the UPEC strain CFT073, cultured from the blood of a patient with pyelonephritis, was used to inoculate mice intravenously. Transposon insertion sites in the inoculum (input) and bacteria colonizing the spleen (output) were identified using high-throughput sequencing of transposon-chromosome junctions. Using frequencies of representation of each insertion mutant in the input and output samples, 242 candidate fitness genes were identified. Co-infection experiments with each of 11 defined mutants and the wild-type strain demonstrated that 82% (9 of 11) of the tested candidate fitness genes were required for optimal fitness in a mouse model of systemic infection. Genes involved in biosynthesis of poly-N-acetyl glucosamine (pgaABCD), major and minor pilin of a type IV pilus (c2394 and c2395), oligopeptide uptake periplasmic-binding protein (oppA), sensitive to antimicrobial peptides (sapABCDF), putative outer membrane receptor (yddB), zinc metallopeptidase (pqqL), a shikimate pathway gene (c1220) and autotransporter serine proteases (pic and vat) were further characterized. Here, we report the first genome-wide identification of genes that contribute to fitness in UPEC during systemic infection in a mammalian host. These fitness factors may represent targets for developing novel therapeutics against UPEC. Uropathogenic E. coli is a major cause of bacterial bloodstream infections in humans. Dissemination of E. coli into the bloodstream during urinary tract infections may lead to potentially fatal complications. This pathogen is becoming increasingly resistant to currently used antibiotics. To develop additional tools to treat such infections, a thorough understanding of the mechanism of pathogenesis is required. Here, we report major progress towards that goal by identifying bacterial genes that are critical for the ability of this pathogen to cause bloodstream infections using a mouse model of infection. This study sheds light on the conditions encountered by E. coli during systemic infection. Further research on the genes identified in this study may reveal bacterial targets that can be used to develop novel therapeutics against bloodstream infections caused by E. coli.
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Affiliation(s)
- Sargurunathan Subashchandrabose
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sara N. Smith
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Rachel R. Spurbeck
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Monica M. Kole
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Harry L. T. Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
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Thaipisuttikul I, Hittle LE, Chandra R, Zangari D, Dixon CL, Garrett TA, Rasko DA, Dasgupta N, Moskowitz SM, Malmström L, Goodlett DR, Miller SI, Bishop RE, Ernst RK. A divergent Pseudomonas aeruginosa palmitoyltransferase essential for cystic fibrosis-specific lipid A. Mol Microbiol 2013; 91:158-74. [PMID: 24283944 DOI: 10.1111/mmi.12451] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2013] [Indexed: 12/25/2022]
Abstract
Strains of Pseudomonas aeruginosa (PA) isolated from the airways of cystic fibrosis patients constitutively add palmitate to lipid A, the membrane anchor of lipopolysaccharide. The PhoPQ regulated enzyme PagP is responsible for the transfer of palmitate from outer membrane phospholipids to lipid A. This enzyme had previously been identified in many pathogenic Gram-negative bacteria, but in PA had remained elusive, despite abundant evidence that its lipid A contains palmitate. Using a combined genetic and biochemical approach, we identified PA1343 as the PA gene encoding PagP. Although PA1343 lacks obvious primary structural similarity with known PagP enzymes, the β-barrel tertiary structure with an interior hydrocarbon ruler appears to be conserved. PA PagP transfers palmitate to the 3' position of lipid A, in contrast to the 2 position seen with the enterobacterial PagP. Palmitoylated PA lipid A alters host innate immune responses, including increased resistance to some antimicrobial peptides and an elevated pro-inflammatory response, consistent with the synthesis of a hexa-acylated structure preferentially recognized by the TLR4/MD2 complex. Palmitoylation commonly confers resistance to cationic antimicrobial peptides, however, increased cytokine production resulting in inflammation is not seen with other palmitoylated lipid A, indicating a unique role for this modification in PA pathogenesis.
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Affiliation(s)
- Iyarit Thaipisuttikul
- Department of Microbial Pathogenesis, University of Maryland, School of Dentistry, University of Maryland, Baltimore, MD, 21201, USA; Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Prannok Road, Bangkoknoi, Bangkok, 10700, Thailand
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38
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De Soyza A, Hall AJ, Mahenthiralingam E, Drevinek P, Kaca W, Drulis-Kawa Z, Stoitsova SR, Toth V, Coenye T, Zlosnik JEA, Burns JL, Sá-Correia I, De Vos D, Pirnay JP, Kidd TJ, Reid D, Manos J, Klockgether J, Wiehlmann L, Tümmler B, McClean S, Winstanley C. Developing an international Pseudomonas aeruginosa reference panel. Microbiologyopen 2013; 2:1010-23. [PMID: 24214409 PMCID: PMC3892346 DOI: 10.1002/mbo3.141] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 09/27/2013] [Accepted: 10/07/2013] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa is a major opportunistic pathogen in cystic fibrosis (CF) patients and causes a wide range of infections among other susceptible populations. Its inherent resistance to many antimicrobials also makes it difficult to treat infections with this pathogen. Recent evidence has highlighted the diversity of this species, yet despite this, the majority of studies on virulence and pathogenesis focus on a small number of strains. There is a pressing need for a P. aeruginosa reference panel to harmonize and coordinate the collective efforts of the P. aeruginosa research community. We have collated a panel of 43 P. aeruginosa strains that reflects the organism's diversity. In addition to the commonly studied clones, this panel includes transmissible strains, sequential CF isolates, strains with specific virulence characteristics, and strains that represent serotype, genotype or geographic diversity. This focussed panel of P. aeruginosa isolates will help accelerate and consolidate the discovery of virulence determinants, improve our understanding of the pathogenesis of infections caused by this pathogen, and provide the community with a valuable resource for the testing of novel therapeutic agents.
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Affiliation(s)
- Anthony De Soyza
- Institute of Cellular Medicine, Newcastle University, Newcastle, U.K
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39
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Deletion of the β-acetoacetyl synthase FabY in Pseudomonas aeruginosa induces hypoacylation of lipopolysaccharide and increases antimicrobial susceptibility. Antimicrob Agents Chemother 2013; 58:153-61. [PMID: 24145528 DOI: 10.1128/aac.01804-13] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The β-acetoacetyl-acyl carrier protein synthase FabY is a key enzyme in the initiation of fatty acid biosynthesis in Pseudomonas aeruginosa. Deletion of fabY results in an increased susceptibility of P. aeruginosa in vitro to a number of antibiotics, including vancomycin and cephalosporins. Because antibiotic susceptibility can be influenced by changes in membrane lipid composition, we determined the total fatty acid profile of the ΔfabY mutant, which suggested alterations in the lipid A region of the lipopolysaccharide. The majority of lipid A species in the ΔfabY mutant lacked a single secondary lauroyl group, resulting in hypoacylated lipid A. Adding exogenous fatty acids to the growth media restored the wild-type antibiotic susceptibility profile and the wild-type lipid A fatty acid profile. We suggest that incorporation of hypoacylated lipid A species into the outer membrane contributes to the shift in the antibiotic susceptibility profile of the ΔfabY mutant.
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40
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Polymyxin resistance of Pseudomonas aeruginosa phoQ mutants is dependent on additional two-component regulatory systems. Antimicrob Agents Chemother 2013; 57:2204-15. [PMID: 23459479 DOI: 10.1128/aac.02353-12] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas aeruginosa can develop resistance to polymyxin as a consequence of mutations in the PhoPQ regulatory system, mediated by covalent lipid A modification. Transposon mutagenesis of a polymyxin-resistant phoQ mutant defined 41 novel loci required for resistance, including two regulatory systems, ColRS and CprRS. Deletion of the colRS genes, individually or in tandem, abrogated the polymyxin resistance of a ΔphoQ mutant, as did individual or tandem deletion of cprRS. Individual deletion of colR or colS in a ΔphoQ mutant also suppressed 4-amino-L-arabinose addition to lipid A, consistent with the known role of this modification in polymyxin resistance. Surprisingly, tandem deletion of colRS or cprRS in the ΔphoQ mutant or individual deletion of cprR or cprS failed to suppress 4-amino-L-arabinose addition to lipid A, indicating that this modification alone is not sufficient for PhoPQ-mediated polymyxin resistance in P. aeruginosa. Episomal expression of colRS or cprRS in tandem or of cprR individually complemented the Pm resistance phenotype in the ΔphoQ mutant, while episomal expression of colR, colS, or cprS individually did not. Highly polymyxin-resistant phoQ mutants of P. aeruginosa isolated from polymyxin-treated cystic fibrosis patients harbored mutant alleles of colRS and cprS; when expressed in a ΔphoQ background, these mutant alleles enhanced polymyxin resistance. These results define ColRS and CprRS as two-component systems regulating polymyxin resistance in P. aeruginosa, indicate that addition of 4-amino-L-arabinose to lipid A is not the only PhoPQ-regulated biochemical mechanism required for resistance, and demonstrate that colRS and cprS mutations can contribute to high-level clinical resistance.
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41
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Lewenza S. Extracellular DNA-induced antimicrobial peptide resistance mechanisms in Pseudomonas aeruginosa. Front Microbiol 2013; 4:21. [PMID: 23419933 PMCID: PMC3572637 DOI: 10.3389/fmicb.2013.00021] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2012] [Accepted: 01/28/2013] [Indexed: 12/17/2022] Open
Abstract
Extracellular DNA (eDNA) is in the environment, bodily fluids, in the matrix of biofilms, and accumulates at infection sites. eDNA can function as a nutrient source, a universal biofilm matrix component, and an innate immune effector in eDNA traps. In biofilms, eDNA is required for attachment, aggregation, and stabilization of microcolonies. We have recently shown that eDNA can sequester divalent metal cations, which has interesting implications on antibiotic resistance. eDNA binds metal cations and thus activates the Mg2+-responsive PhoPQ and PmrAB two-component systems. In Pseudomonas aeruginosa and many other Gram-negative bacteria, the PhoPQ/PmrAB systems control various genes required for virulence and resisting killing by antimicrobial peptides (APs), including the pmr genes (PA3552–PA3559) that are responsible for the addition of aminoarabinose to lipid A. The PA4773–PA4775 genes are a second DNA-induced cluster and are required for the production of spermidine on the outer surface, which protects the outer membrane from AP treatment. Both modifications mask the negative surface charges and limit membrane damage by APs. DNA-enriched biofilms or planktonic cultures have increased antibiotic resistance phenotypes to APs and aminoglycosides. These dual antibiotic resistance and immune evasion strategies may be expressed in DNA-rich environments and contribute to long-term survival.
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Affiliation(s)
- Shawn Lewenza
- Snyder Institute for Chronic Diseases, University of Calgary Calgary, AB, Canada ; Department of Microbiology, Immunology and Infectious Diseases, University of Calgary Calgary, AB, Canada
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The Pseudomonas aeruginosa PhoP-PhoQ two-component regulatory system is induced upon interaction with epithelial cells and controls cytotoxicity and inflammation. Infect Immun 2012; 80:3122-31. [PMID: 22710876 DOI: 10.1128/iai.00382-12] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The adaptation of Pseudomonas aeruginosa to its environment, including the host, is tightly controlled by its network of regulatory systems. The two-component regulatory system PhoPQ has been shown to play a role in the virulence and polymyxin resistance of P. aeruginosa as well as several other Gram-negative species. Dysregulation of this system has been demonstrated in clinical isolates, yet how it affects virulence of P. aeruginosa is unknown. To investigate this, an assay was used whereby bacteria were cocultured with human bronchial epithelial cells. The interaction of wild-type (WT) bacteria that had adhered to epithelial cells led to a large upregulation of the expression of the oprH-phoP-phoQ operon and its target, the arn lipopolysaccharide (LPS) modification operon, in a PhoQ-dependent manner, compared to cells in the supernatant that had failed to adhere. Relative to the wild type, a phoQ mutant cocultured on epithelial cells produced less secreted protease and lipase and, like the phoQ mutant, piv, lipH, and lasB mutants demonstrated reduced cytotoxicity toward epithelial cells. Mutation in phoQ also resulted in alterations to lipid A and to increased inflammatory LPS. These data indicate that mutation of phoQ results in a phenotype that is similar to the less virulent but more inflammatory phenotype of clinical strains isolated from chronic-stage cystic fibrosis lung infections.
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43
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Moskowitz SM, Brannon MK, Dasgupta N, Pier M, Sgambati N, Miller AK, Selgrade SE, Miller SI, Denton M, Conway SP, Johansen HK, Høiby N. PmrB mutations promote polymyxin resistance of Pseudomonas aeruginosa isolated from colistin-treated cystic fibrosis patients. Antimicrob Agents Chemother 2012; 56:1019-30. [PMID: 22106224 PMCID: PMC3264203 DOI: 10.1128/aac.05829-11] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 11/16/2011] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa can develop resistance to polymyxin and other cationic antimicrobial peptides. Previous work has shown that mutations in the PmrAB and PhoPQ regulatory systems can confer low to moderate levels of colistin (polymyxin E) resistance in laboratory strains and clinical isolates of this organism (MICs of 8 to 64 mg/liter). To explore the role of PmrAB in high-level clinical polymyxin resistance, P. aeruginosa isolates from chronically colistin-treated cystic fibrosis patients, most with colistin MICs of >512 mg/liter, were analyzed. These cystic fibrosis isolates contained probable gain-of-function pmrB alleles that conferred polymyxin resistance to strains with a wild-type or pmrAB deletion background. Double mutant pmrB alleles that contained mutations in both the periplasmic and dimerization-phosphotransferase domains markedly augmented polymyxin resistance. Expression of mutant pmrB alleles induced transcription from the promoter of the arnB operon and stimulated addition of 4-amino-l-arabinose to lipid A, consistent with the known role of this lipid A modification in polymyxin resistance. For some highly polymyxin-resistant clinical isolates, repeated passage without antibiotic selection pressure resulted in loss of resistance, suggesting that secondary suppressors occur at a relatively high frequency and account for the instability of this phenotype. These results indicate that pmrB gain-of-function mutations can contribute to high-level polymyxin resistance in clinical strains of P. aeruginosa.
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Affiliation(s)
- Samuel M Moskowitz
- Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA.
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PhoQ mutations promote lipid A modification and polymyxin resistance of Pseudomonas aeruginosa found in colistin-treated cystic fibrosis patients. Antimicrob Agents Chemother 2011; 55:5761-9. [PMID: 21968359 DOI: 10.1128/aac.05391-11] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa can develop resistance to polymyxin and other cationic antimicrobial peptides. Previous work has shown that mutations in the PmrAB and PhoPQ regulatory systems can confer low to moderate levels of polymyxin resistance (MICs of 8 to 64 mg/liter) in laboratory and clinical strains of this organism. To explore the role of PhoPQ in high-level clinical polymyxin resistance, P. aeruginosa strains with colistin MICs > 512 mg/liter that had been isolated from cystic fibrosis patients treated with inhaled colistin (polymyxin E) were analyzed. Probable loss-of-function phoQ alleles found in these cystic fibrosis strains conferred resistance to polymyxin. Partial and complete suppressor mutations in phoP were identified in some cystic fibrosis strains with resistance-conferring phoQ mutations, suggesting that additional loci can be involved in polymyxin resistance in P. aeruginosa. Disruption of chromosomal phoQ in the presence of an intact phoP allele stimulated 4-amino-l-arabinose addition to lipid A and induced transcription from the promoter of the pmrH (arnB) operon, consistent with the known role of this lipid A modification in polymyxin resistance. These results indicate that phoQ loss-of-function mutations can contribute to high-level polymyxin resistance in clinical strains of P. aeruginosa.
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45
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Regulation of Caenorhabditis elegans and Pseudomonas aeruginosa machinery during interactions. Arch Microbiol 2011; 194:229-42. [PMID: 21909805 DOI: 10.1007/s00203-011-0750-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 08/02/2011] [Accepted: 08/05/2011] [Indexed: 01/12/2023]
Abstract
The amenability of Caenorhabditis elegans against pathogen provides a valuable tool for studying host-pathogen interactions. Physiological experiments revealed that the P. aeruginosa was able to kill C. elegans efficiently. The effects of P. aeruginosa PA14, PAO1 and their isolated lipopolysaccharide (LPS) on the host system were analyzed. The LPS at higher concentrations (≥2 mg/ml) was toxic to the host animals. Kinetic studies using qPCR revealed the regulation of host-specific candidate antimicrobial genes during pathogen-mediated infections. In addition, the pathogen-specific virulent gene, exoT expression, was anlyzed and found to be varied during the interactions with the host system. Ability of the pathogens to modify their internal machinery in the presence of the host was analyzed by XRD, FTIR and PCA. LPS isolated from pathogens upon exposure to C. elegans showed modifications at their functional regions. LPS from PAO1 showed difference in d-spacing angle (Å) and °2Th position. FTIR spectra revealed alterations in polysaccharide (1,200-900 cm(-1)) and fatty acid (3,000-2,800 cm(-1)) regions of LPS from P. aeruginosa PAO1 exposed to the host system. These data provide additional insights on how the pathogens subvert its own and host machinery during interactions.
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46
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Damron FH, Davis MR, Withers TR, Ernst RK, Goldberg JB, Yu G, Yu HD. Vanadate and triclosan synergistically induce alginate production by Pseudomonas aeruginosa strain PAO1. Mol Microbiol 2011; 81:554-70. [PMID: 21631603 DOI: 10.1111/j.1365-2958.2011.07715.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Alginate overproduction by P. aeruginosa strains, also known as mucoidy, is associated with chronic lung infections in cystic fibrosis (CF). It is not clear how alginate induction occurs in the wild-type (wt) mucA strains. When grown on Pseudomonas isolation agar (PIA), P. aeruginosa strains PAO1 and PA14 are non-mucoid, producing minimal amounts of alginate. Here we report the addition of ammonium metavanadate (AMV), a phosphatase inhibitor, to PIA (PIA-AMV) induced mucoidy in both these laboratory strains and early lung colonizing non-mucoid isolates with a wt mucA. This phenotypic switch was reversible depending on the availability of vanadate salts and triclosan, a component of PIA. Alginate induction in PAO1 on PIA-AMV was correlated with increased proteolytic degradation of MucA, and required envelope proteases AlgW or MucP, and a two-component phosphate regulator, PhoP. Other changes included the addition of palmitate to lipid A, a phenotype also observed in chronic CF isolates. Proteomic analysis revealed the upregulation of stress chaperones, which was confirmed by increased expression of the chaperone/protease MucD. Altogether, these findings suggest a model of alginate induction and the PIA-AMV medium may be suitable for examining early lung colonization phenotypes in CF before the selection of the mucA mutants.
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Affiliation(s)
- F Heath Damron
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine at Marshall University, Huntington, WV 25755-9320, USA
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Lam JS, Taylor VL, Islam ST, Hao Y, Kocíncová D. Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide. Front Microbiol 2011; 2:118. [PMID: 21687428 PMCID: PMC3108286 DOI: 10.3389/fmicb.2011.00118] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 05/12/2011] [Indexed: 12/13/2022] Open
Abstract
Lipopolysccharide (LPS) is an integral component of the Pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this Gram-negative opportunistic pathogen. It is important for bacterium-host interactions and has been shown to be a major virulence factor for this organism. Structurally, P. aeruginosa LPS is composed of three domains, namely, lipid A, core oligosaccharide, and the distal O antigen (O-Ag). Most P. aeruginosa strains produce two distinct forms of O-Ag, one a homopolymer of D-rhamnose that is a common polysaccharide antigen (CPA, formerly termed A band), and the other a heteropolymer of three to five distinct (and often unique dideoxy) sugars in its repeat units, known as O-specific antigen (OSA, formerly termed B band). Compositional differences in the O units among the OSA from different strains form the basis of the International Antigenic Typing Scheme for classification via serotyping of different strains of P. aeruginosa. The focus of this review is to provide state-of-the-art knowledge on the genetic and resultant functional diversity of LPS produced by P. aeruginosa. The underlying factors contributing to this diversity will be thoroughly discussed and presented in the context of its contributions to host-pathogen interactions and the control/prevention of infection.
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Affiliation(s)
- Joseph S. Lam
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Véronique L. Taylor
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Salim T. Islam
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Youai Hao
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
| | - Dana Kocíncová
- Department of Molecular and Cellular Biology, University of GuelphGuelph, ON, Canada
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