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Dayton H, Kiss J, Wei M, Chauhan S, LaMarre E, Cornell WC, Morgan CJ, Janakiraman A, Min W, Tomer R, Price-Whelan A, Nirody JA, Dietrich LEP. Cellular arrangement impacts metabolic activity and antibiotic tolerance in Pseudomonas aeruginosa biofilms. PLoS Biol 2024; 22:e3002205. [PMID: 38300958 PMCID: PMC10833521 DOI: 10.1371/journal.pbio.3002205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 12/19/2023] [Indexed: 02/03/2024] Open
Abstract
Cells must access resources to survive, and the anatomy of multicellular structures influences this access. In diverse multicellular eukaryotes, resources are provided by internal conduits that allow substances to travel more readily through tissue than they would via diffusion. Microbes growing in multicellular structures, called biofilms, are also affected by differential access to resources and we hypothesized that this is influenced by the physical arrangement of the cells. In this study, we examined the microanatomy of biofilms formed by the pathogenic bacterium Pseudomonas aeruginosa and discovered that clonal cells form striations that are packed lengthwise across most of a mature biofilm's depth. We identified mutants, including those defective in pilus function and in O-antigen attachment, that show alterations to this lengthwise packing phenotype. Consistent with the notion that cellular arrangement affects access to resources within the biofilm, we found that while the wild type shows even distribution of tested substrates across depth, the mutants show accumulation of substrates at the biofilm boundaries. Furthermore, we found that altered cellular arrangement within biofilms affects the localization of metabolic activity, the survival of resident cells, and the susceptibility of subpopulations to antibiotic treatment. Our observations provide insight into cellular features that determine biofilm microanatomy, with consequences for physiological differentiation and drug sensitivity.
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Affiliation(s)
- Hannah Dayton
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Julie Kiss
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, New York, United States of America
| | - Shradha Chauhan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Emily LaMarre
- Program in Biology, The Graduate Center, City University of New York, New York, New York, United States of America
| | - William Cole Cornell
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Chase J. Morgan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Anuradha Janakiraman
- Program in Biology, The Graduate Center, City University of New York, New York, New York, United States of America
| | - Wei Min
- Department of Chemistry, Columbia University, New York, New York, United States of America
| | - Raju Tomer
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
| | - Jasmine A. Nirody
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, United States of America
| | - Lars E. P. Dietrich
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
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2
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Dayton H, Kiss J, Wei M, Chauhan S, LaMarre E, Cornell WC, Morgan CJ, Janakiraman A, Min W, Tomer R, Price-Whelan A, Nirody JA, Dietrich LE. Cell arrangement impacts metabolic activity and antibiotic tolerance in Pseudomonas aeruginosa biofilms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.20.545666. [PMID: 37645902 PMCID: PMC10462148 DOI: 10.1101/2023.06.20.545666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Cells must access resources to survive, and the anatomy of multicellular structures influences this access. In diverse multicellular eukaryotes, resources are provided by internal conduits that allow substances to travel more readily through tissue than they would via diffusion. Microbes growing in multicellular structures, called biofilms, are also affected by differential access to resources and we hypothesized that this is influenced by the physical arrangement of the cells. In this study, we examined the microanatomy of biofilms formed by the pathogenic bacterium Pseudomonas aeruginosa and discovered that clonal cells form striations that are packed lengthwise across most of a mature biofilm's depth. We identified mutants, including those defective in pilus function and in O-antigen attachment, that show alterations to this lengthwise packing phenotype. Consistent with the notion that cellular arrangement affects access to resources within the biofilm, we found that while the wild type shows even distribution of tested substrates across depth, the mutants show accumulation of substrates at the biofilm boundaries. Furthermore, we found that altered cellular arrangement within biofilms affects the localization of metabolic activity, the survival of resident cells, and the susceptibility of subpopulations to antibiotic treatment. Our observations provide insight into cellular features that determine biofilm microanatomy, with consequences for physiological differentiation and drug sensitivity.
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Affiliation(s)
- Hannah Dayton
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Julie Kiss
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Mian Wei
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Shradha Chauhan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Emily LaMarre
- Program in Biology, The Graduate Center, City University of New York, New York, NY 10016
| | | | - Chase J. Morgan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Anuradha Janakiraman
- Program in Biology, The Graduate Center, City University of New York, New York, NY 10016
| | - Wei Min
- Department of Chemistry, Columbia University, New York, NY 10025
| | - Raju Tomer
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10025
| | - Jasmine A Nirody
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10025
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3
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Chan DK, Dykema K, Fatima M, Harvey H, Qaderi I, Burrows LL. Nutrient Limitation Sensitizes Pseudomonas aeruginosa to Vancomycin. ACS Infect Dis 2023; 9:1408-1423. [PMID: 37279282 PMCID: PMC10353551 DOI: 10.1021/acsinfecdis.3c00167] [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: 04/14/2023] [Indexed: 06/08/2023]
Abstract
Traditional antibacterial screens rely on growing bacteria in nutrient-replete conditions which are not representative of the natural environment or sites of infection. Instead, screening in more physiologically relevant conditions may reveal novel activity for existing antibiotics. Here, we screened a panel of antibiotics reported to lack activity against the opportunistic Gram-negative bacterium, Pseudomonas aeruginosa, under low-nutrient and low-iron conditions, and discovered that the glycopeptide vancomycin inhibited the growth of P. aeruginosa at low micromolar concentrations through its canonical mechanism of action, disruption of peptidoglycan crosslinking. Spontaneous vancomycin-resistant mutants underwent activating mutations in the sensor kinase of the two-component CpxSR system, which induced cross-resistance to almost all classes of β-lactams, including the siderophore antibiotic cefiderocol. Other mutations that conferred vancomycin resistance mapped to WapR, an α-1,3-rhamnosyltransferase involved in lipopolysaccharide core biosynthesis. A WapR P164T mutant had a modified LPS profile compared to wild type that was accompanied by increased susceptibility to select bacteriophages. We conclude that screening in nutrient-limited conditions can reveal novel activity for existing antibiotics and lead to discovery of new and impactful resistance mechanisms.
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Affiliation(s)
- Derek
C. K. Chan
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Katherine Dykema
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Mahrukh Fatima
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Hanjeong Harvey
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Ikram Qaderi
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Lori L. Burrows
- David Braley Center for Antibiotic
Discovery, Michael G. DeGroote Institute for Infectious Disease Research,
Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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4
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Identification of the Pseudomonas aeruginosa O17 and O15 O-Specific Antigen Biosynthesis Loci Reveals an ABC Transporter-Dependent Synthesis Pathway and Mechanisms of Genetic Diversity. J Bacteriol 2020; 202:JB.00347-20. [PMID: 32690555 DOI: 10.1128/jb.00347-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Many bacterial cell surface glycans, such as the O antigen component of lipopolysaccharide (LPS), are produced via the so-called Wzx/Wzy- or ABC transporter-dependent pathways. O antigens are highly diverse polysaccharides that protect bacteria from their environment and engage in important host-pathogen interactions. The specific structure and composition of O antigens are the basis of classifying bacteria into O serotypes. In the opportunistic pathogen Pseudomonas aeruginosa, there are currently 20 known O-specific antigen (OSA) structures. The clusters of genes responsible for 18 of these O antigens have been identified, all of which follow the Wzx/Wzy-dependent pathway and are located at a common locus. In this study, we located the two unidentified O antigen biosynthesis clusters responsible for the synthesis of the O15 and the O17 OSA structures by analyzing published whole-genome sequence data. Intriguingly, these clusters were found outside the conserved OSA biosynthesis locus and were likely acquired through multiple horizontal gene transfer events. Based on data from knockout and overexpression studies, we determined that the synthesis of these O antigens follows an ABC transporter-dependent rather than a Wzx/Wzy-dependent pathway. In addition, we collected evidence to show that the O15 and O17 polysaccharide chain lengths are regulated by molecular rulers with distinct and variable domain architectures. The findings in this report are critical for a comprehensive understanding of O antigen biosynthesis in P. aeruginosa and provide a framework for future studies.IMPORTANCE P. aeruginosa is a problematic opportunistic pathogen that causes diseases in those with compromised host defenses, such as those suffering from cystic fibrosis. This bacterium produces a number of virulence factors, including a serotype-specific O antigen. Here, we identified and characterized the gene clusters that produce the O15 and O17 O antigens and show that they utilize a pathway for synthesis that is distinct from that of the 18 other known serotypes. We also provide evidence that these clusters have acquired mutations in specific biosynthesis genes and have undergone extensive horizontal gene transfer within the P. aeruginosa population. These findings expand on our understanding of O antigen biosynthesis in Gram-negative bacteria and the mechanisms that drive O antigen diversity.
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5
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Yang Y, Shen W, Zhong Q, Chen Q, He X, Baker JL, Xiong K, Jin X, Wang J, Hu F, Le S. Development of a Bacteriophage Cocktail to Constrain the Emergence of Phage-Resistant Pseudomonas aeruginosa. Front Microbiol 2020; 11:327. [PMID: 32194532 PMCID: PMC7065532 DOI: 10.3389/fmicb.2020.00327] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/14/2020] [Indexed: 12/31/2022] Open
Abstract
With the emergence of multidrug-resistant and extensively drug-resistant bacterial pathogens, phage therapy and other alternative or additional therapeutic modalities are receiving resurgent attention. One of the major obstacles in developing effective phage therapies is the evolution of phage resistance in the bacterial host. When Pseudomonas aeruginosa was infected with a phage that uses O-antigen as receptor, phage resistances typically achieved through changing or loss of O-antigen structure. In this study, we showed that dsRNA phage phiYY uses core lipopolysaccharide as receptor and therefore efficiently kills the O-antigen deletion mutants. Furthermore, by phage training, we obtained PaoP5-m1, a derivative of dsDNA phage PaoP5, which is able to infect mutants with truncated O-antigen. We then generated a cocktail by mixing phiYY and PaoP5-m1 with additional three wide host range P. aeruginosa phages. The phage cocktail was effective against a diverse selection of clinical isolates of P. aeruginosa, and in the short-term constrained the appearance of the phage-resistant mutants that had beleaguered the effectiveness of single phage. Resistance to the 5-phage cocktail emerges after several days, and requires mutations in both wzy and migA Thus, this study provides an alternative strategy for designing phage cocktail and phage therapy.
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Affiliation(s)
- Yuhui Yang
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Wei Shen
- Department of Medical Laboratory, The General Hospital of Western Theater Command, Chengdu, China
| | - Qiu Zhong
- Department of Clinical Laboratory, Daping Hospital, Army Medical University, Chongqing, China
| | - Qian Chen
- Biomedical Analysis Center, Army Medical University, Chongqing, China
| | - Xuesong He
- The Forsyth Institute, Cambridge, MA, United States
| | - Jonathon L Baker
- Genomic Medicine Group, J. Craig Venter Institute, La Jolla, CA, United States
| | - Kun Xiong
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Xiaoling Jin
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Jing Wang
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Fuquan Hu
- Department of Microbiology, Army Medical University, Chongqing, China
| | - Shuai Le
- Department of Microbiology, Army Medical University, Chongqing, China
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6
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Latino L, Caroff M, Pourcel C. Fine structure analysis of lipopolysaccharides in bacteriophage-resistant Pseudomonas aeruginosa PAO1 mutants. Microbiology (Reading) 2017; 163:848-855. [DOI: 10.1099/mic.0.000476] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Libera Latino
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Martine Caroff
- LPS-BioSciences, Bât 409, I2BC, Université Paris-Sud, 91405 Orsay, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Christine Pourcel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
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7
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Colmer-Hamood JA, Dzvova N, Kruczek C, Hamood AN. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:151-91. [PMID: 27571695 DOI: 10.1016/bs.pmbts.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.
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Affiliation(s)
- J A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
| | - N Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - C Kruczek
- Honors College, Texas Tech University, Lubbock, TX, United States
| | - A N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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8
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Single-Nucleotide Polymorphisms Found in the migA and wbpX Glycosyltransferase Genes Account for the Intrinsic Lipopolysaccharide Defects Exhibited by Pseudomonas aeruginosa PA14. J Bacteriol 2015; 197:2780-91. [PMID: 26078447 DOI: 10.1128/jb.00337-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/09/2015] [Indexed: 01/31/2023] Open
Abstract
UNLABELLED Pseudomonas aeruginosa PA14 is widely used by researchers in many laboratories because of its enhanced virulence over strain PAO1 in a wide range of hosts. Although lipopolysaccharide (LPS) is an important virulence factor of all P. aeruginosa strains, the LPS of PA14 has not been characterized fully. A recent study showed that the structure of its O-specific antigen (OSA) belongs to serotype O19. We found that the OSA gene cluster of PA14 shares ∼99% identity with those of the O10/O19 group. These two serotypes share the same O-unit structure, except for an O-acetyl substitution in one of the sugars in O10. Here we showed that both PA14 and O19 LPS cross-reacted with the O10-specific monoclonal antibody MF76-2 in Western blots. Analysis by SDS-PAGE and silver staining showed that PA14 LPS exhibited modal chain lengths that were different from those of O19 LPS, in that only "very long" and "short" chain lengths were observed, while "medium" and "long" chain lengths were not detected. Two other novel observations included the lack of the uncapped core oligosaccharide epitope and of common polysaccharide antigen (CPA) LPS. The lack of the uncapped core oligosaccharide was caused by point mutations in the glycosyltransferase gene migA, while the CPA-negative phenotype was correlated with a single amino acid substitution, G20R, in the glycosyltransferase WbpX. Additionally, we showed that restoring CPA biosynthesis in PA14 significantly stimulated mature biofilm formation after 72 h, while outer membrane vesicle production was not affected. IMPORTANCE P. aeruginosa PA14 is a clinical isolate that has become an important reference strain used by many researchers worldwide. LPS of PA14 has not been characterized fully, and hence, confusion about its phenotype exists in the literature. In the present study, we set out to characterize the O-specific antigen (OSA), the common polysaccharide antigen (CPA), and the core oligosaccharide produced by PA14. We present evidence that PA14 produces an LPS consisting of "very-long-chain" and some "short-chain" OSA belonging to the O19 serotype but is devoid of CPA and the uncapped core oligosaccharide epitope. These intrinsic defects in PA14 LPS were due to single-nucleotide polymorphisms (SNPs) in the genes that encode glycosyltransferases in the corresponding biosynthesis pathways. Since sugars in CPA and the uncapped core are receptors for different bacteriocins and pyocins, the lack of CPA and an intact core may contribute to the increased virulence of PA14. Restoring CPA production in PA14 was found to stimulate mature biofilm formation.
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9
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Dettman JR, Rodrigue N, Kassen R. Genome-wide patterns of recombination in the opportunistic human pathogen Pseudomonas aeruginosa. Genome Biol Evol 2014; 7:18-34. [PMID: 25480685 PMCID: PMC4316616 DOI: 10.1093/gbe/evu260] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The bacterium Pseudomonas aeruginosa is a significant cause of acute nosocomial infections as well as chronic respiratory infections in patients with cystic fibrosis (CF). Recent reports of the intercontinental spread of a CF-specific epidemic strain, combined with high intrinsic levels of antibiotic resistance, have made this opportunistic pathogen an important public health concern. Strain-specific differences correlate with variation in clinical outcomes of infected CF patients, increasing the urgency to understand the evolutionary origin of genetic factors conferring important phenotypes that enable infection, virulence, or resistance. Here, we describe the genome-wide patterns of homologous and nonhomologous recombination in P. aeruginosa, and the extent to which the genomes are affected by these diversity-generating processes. Based on whole-genome sequence data from 32 clinical isolates of P. aeruginosa, we examined the rate and distribution of recombination along the genome, and its effect on the reconstruction of phylogenetic relationships. Multiple lines of evidence suggested that recombination was common and usually involves short stretches of DNA (200-300 bp). Although mutation was the main source of nucleotide diversity, the import of polymorphisms by homologous recombination contributed nearly as much. We also identified the genomic regions with frequent recombination, and the specific sequences of recombinant origin within epidemic strains. The functional characteristics of the genes contained therein were examined for potential associations with a pathogenic lifestyle or adaptation to the CF lung environment. A common link between many of the high-recombination genes was their functional affiliation with the cell wall, suggesting that the products of recombination may be maintained by selection for variation in cell-surface molecules that allows for evasion of the host immune system.
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Affiliation(s)
- Jeremy R Dettman
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicolas Rodrigue
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - Rees Kassen
- Department of Biology and Centre for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, Canada
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10
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Herbst FA, Søndergaard MT, Kjeldal H, Stensballe A, Nielsen PH, Dueholm MS. Major Proteomic Changes Associated with Amyloid-Induced Biofilm Formation in Pseudomonas aeruginosa PAO1. J Proteome Res 2014; 14:72-81. [DOI: 10.1021/pr500938x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Florian-Alexander Herbst
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
| | - Mads T. Søndergaard
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
| | - Henrik Kjeldal
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
| | - Allan Stensballe
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
| | - Per H. Nielsen
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
| | - Morten S. Dueholm
- Center for Microbial Communities; ‡Department of Biotechnology, Chemistry, and
Environmental Engineering; and §Department of Health Science and Technology, Aalborg University, DK-9000 Aalborg, Denmark
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11
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Fernández L, Álvarez-Ortega C, Wiegand I, Olivares J, Kocíncová D, Lam JS, Martínez JL, Hancock REW. Characterization of the polymyxin B resistome of Pseudomonas aeruginosa. Antimicrob Agents Chemother 2013; 57:110-9. [PMID: 23070157 PMCID: PMC3535977 DOI: 10.1128/aac.01583-12] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/08/2012] [Indexed: 11/20/2022] Open
Abstract
Multidrug resistance in Pseudomonas aeruginosa is increasingly becoming a threat for human health. Indeed, some strains are resistant to almost all currently available antibiotics, leaving very limited choices for antimicrobial therapy. In many such cases, polymyxins are the only available option, although as their utilization increases so does the isolation of resistant strains. In this study, we screened a comprehensive PA14 mutant library to identify genes involved in changes of susceptibility to polymyxin B in P. aeruginosa. Surprisingly, our screening revealed that the polymyxin B resistome of this microorganism is fairly small. Thus, only one resistant mutant and 17 different susceptibility/intrinsic resistance determinants were identified. Among the susceptible mutants, a significant number carried transposon insertions in lipopolysaccharide (LPS)-related genes. LPS analysis revealed that four of these mutants (galU, lptC, wapR, and ssg) had an altered banding profile in SDS-polyacrylamide gels and Western blots, with three of them exhibiting LPS core truncation and lack of O-antigen decoration. Further characterization of these four mutants showed that their increased susceptibility to polymyxin B was partly due to increased basal outer membrane permeability. Additionally, these mutants also lacked the aminoarabinose-substituted lipid A species observed in the wild type upon growth in low magnesium. Overall, our results emphasize the importance of LPS integrity and lipid A modification in resistance to polymyxins in P. aeruginosa, highlighting the relevance of characterizing the genes that affect biosynthesis of cell surface structures in this pathogen to follow the evolution of peptide resistance in the clinic.
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Affiliation(s)
- Lucía Fernández
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carolina Álvarez-Ortega
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, and CIBERESP, Madrid, Spain
| | - Irith Wiegand
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jorge Olivares
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, and CIBERESP, Madrid, Spain
| | - Dana Kocíncová
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Joseph S. Lam
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - José Luis Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, and CIBERESP, Madrid, Spain
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, British Columbia, Canada
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