1
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Hofstaedter CE, O'Keefe IP, Met CM, Wu L, Vanderwoude J, Shin S, Diggle SP, Riquelme SA, Rasko DA, Doi Y, Harro JM, Kopp BT, Ernst RK. Pseudomonas aeruginosa Lipid A Structural Variants Induce Altered Immune Responses. Am J Respir Cell Mol Biol 2024. [PMID: 38656811 DOI: 10.1165/rcmb.2024-0059oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 04/23/2024] [Indexed: 04/26/2024] Open
Abstract
Pseudomonas aeruginosa causes chronic lung infection in cystic fibrosis (CF), resulting in structural lung damage and progressive pulmonary decline. P. aeruginosa in the CF lung undergoes numerous changes, adapting to host-specific airway pressures while establishing chronic infection. P. aeruginosa undergoes lipid A structural modification during CF chronic infection, not seen in any other disease state. Lipid A, the membrane anchor of lipopolysaccharide (i.e., endotoxin), comprises the majority of the outer membrane of Gram-negative bacteria and is a potent toll-like receptor (TLR)4 agonist. The structure of P. aeruginosa lipid A is intimately linked with its recognition by TLR4, and subsequent immune response. Prior work has identified P. aeruginosa strains with altered lipid A structures that arise during chronic CF lung infection; however, the impact of P. aeruginosa lipid A structure on airway disease has not been investigated. Here, we show that P. aeruginosa lipid A lacks PagL-mediated deacylation during human airway infection using a direct-from-sample mass spectrometry approach on human bronchoalveolar lavage fluid. This structure triggers increased pro-inflammatory cytokine production by primary human macrophages. Furthermore, alterations in lipid A 2-hydroxylation impact cytokine response in a site-specific manner, independent of CFTR function. Interestingly, there is a CF-specific reduction in IL-8 secretion within the epithelial-cell compartment that only occurs in CF bronchial epithelial cells when infected with CF-adapted P. aeruginosa that lack PagL-mediated lipid A deacylation. Taken together, we show that P. aeruginosa alters its lipid A structure during acute lung infection and that this lipid A structure induces stronger signaling through TLR4.
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Affiliation(s)
- Casey E Hofstaedter
- University of Maryland School of Medicine, 12264, Baltimore, Maryland, United States
| | - Ian P O'Keefe
- University of Maryland Baltimore, 12265, Microbial Pathogenesis, Baltimore, Maryland, United States
| | - Charles M Met
- University of Maryland Baltimore, 12265, Microbial Pathogenesis, Baltimore, Maryland, United States
| | - Ling Wu
- University of Pennsylvania Perelman School of Medicine, 14640, Microbiology, Philadelphia, Pennsylvania, United States
| | | | - Sunny Shin
- University of Pennsylvania Perelman School of Medicine, 14640, Microbiology, Philadelphia, Pennsylvania, United States
| | | | | | - David A Rasko
- University of Maryland School of Medicine, 12264, Baltimore, Maryland, United States
| | - Yohei Doi
- University of Pittsburgh School of Medicine, Division of Infectious Diseases, Pittsburgh, Pennsylvania, United States
| | - Janette M Harro
- University of Maryland Baltimore, 12265, Microbial Pathogenesis, Baltimore, Maryland, United States
| | - Benjamin T Kopp
- Children's Healthcare of Atlanta Inc, 1367, Pediatrics, ATLANTA, Georgia, United States
| | - Robert K Ernst
- University of Maryland Baltimore, 12265, Microbial Pathogenesis, Baltimore, Maryland, United States;
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2
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Mutlu A, Vanderpool EJ, Rumbaugh KP, Diggle SP, Griffin AS. Exploiting cooperative pathogen behaviour for enhanced antibiotic potency: A Trojan horse approach. Microbiology (Reading) 2024; 170:001454. [PMID: 38687006 PMCID: PMC11084615 DOI: 10.1099/mic.0.001454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/03/2024] [Indexed: 05/02/2024]
Abstract
Antimicrobial resistance poses an escalating global threat, rendering traditional drug development approaches increasingly ineffective. Thus, novel alternatives to antibiotic-based therapies are needed. Exploiting pathogen cooperation as a strategy for combating resistant infections has been proposed but lacks experimental validation. Empirical findings demonstrate the successful invasion of cooperating populations by non-cooperating cheats, effectively reducing virulence in vitro and in vivo. The idea of harnessing cooperative behaviours for therapeutic benefit involves exploitation of the invasive capabilities of cheats to drive medically beneficial traits into infecting populations of cells. In this study, we employed Pseudomonas aeruginosa quorum sensing cheats to drive antibiotic sensitivity into both in vitro and in vivo resistant populations. We demonstrated the successful invasion of cheats, followed by increased antibiotic effectiveness against cheat-invaded populations, thereby establishing an experimental proof of principle for the potential application of the Trojan strategy in fighting resistant infections.
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Affiliation(s)
- Alper Mutlu
- Department of Biology, University of Oxford, Oxford, UK
| | | | | | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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3
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Vanderwoude J, Azimi S, Read TD, Diggle SP. The role of hypermutation and collateral sensitivity in antimicrobial resistance diversity of Pseudomonas aeruginosa populations in cystic fibrosis lung infection. mBio 2024; 15:e0310923. [PMID: 38171021 PMCID: PMC10865868 DOI: 10.1128/mbio.03109-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen which causes chronic, drug-resistant lung infections in cystic fibrosis (CF) patients. In this study, we explore the role of genomic diversification and evolutionary trade-offs in antimicrobial resistance (AMR) diversity within P. aeruginosa populations sourced from CF lung infections. We analyzed 300 clinical isolates from four CF patients (75 per patient) and found that genomic diversity is not a consistent indicator of phenotypic AMR diversity. Remarkably, some genetically less diverse populations showed AMR diversity comparable to those with significantly more genetic variation. We also observed that hypermutator strains frequently exhibited increased sensitivity to antimicrobials, contradicting expectations from their treatment histories. Investigating potential evolutionary trade-offs, we found no substantial evidence of collateral sensitivity among aminoglycoside, beta-lactam, or fluoroquinolone antibiotics, nor did we observe trade-offs between AMR and growth in conditions mimicking CF sputum. Our findings suggest that (i) genomic diversity is not a prerequisite for phenotypic AMR diversity, (ii) hypermutator populations may develop increased antimicrobial sensitivity under selection pressure, (iii) collateral sensitivity is not a prominent feature in CF strains, and (iv) resistance to a single antibiotic does not necessarily lead to significant fitness costs. These insights challenge prevailing assumptions about AMR evolution in chronic infections, emphasizing the complexity of bacterial adaptation during infection.IMPORTANCEUpon infection in the cystic fibrosis (CF) lung, Pseudomonas aeruginosa rapidly acquires genetic mutations, especially in genes involved in antimicrobial resistance (AMR), often resulting in diverse, treatment-resistant populations. However, the role of bacterial population diversity within the context of chronic infection is still poorly understood. In this study, we found that hypermutator strains of P. aeruginosa in the CF lung undergoing treatment with tobramycin evolved increased sensitivity to tobramycin relative to non-hypermutators within the same population. This finding suggests that antimicrobial treatment may only exert weak selection pressure on P. aeruginosa populations in the CF lung. We further found no evidence for collateral sensitivity in these clinical populations, suggesting that collateral sensitivity may not be a robust, naturally occurring phenomenon for this microbe.
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Affiliation(s)
- Jelly Vanderwoude
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Sheyda Azimi
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Biology, College of Arts and Sciences, Georgia State University, Atlanta, Georgia, USA
| | - Timothy D. Read
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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4
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Mei M, Pheng P, Kurzeja-Edwards D, Diggle SP. High prevalence of lipopolysaccharide mutants and R2-pyocin susceptible variants in Pseudomonas aeruginosa populations sourced from cystic fibrosis lung infections. Microbiol Spectr 2023; 11:e0177323. [PMID: 37877708 PMCID: PMC10714928 DOI: 10.1128/spectrum.01773-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/15/2023] [Indexed: 10/26/2023] Open
Abstract
IMPORTANCE Cystic fibrosis (CF) patients often experience chronic, debilitating lung infections caused by antibiotic-resistant Pseudomonas aeruginosa, contributing to antimicrobial resistance (AMR). The genetic and phenotypic diversity of P. aeruginosa populations in CF lungs raises questions about their susceptibility to non-traditional antimicrobials, like bacteriocins. In this study, we focused on R-pyocins, a type of bacteriocin with high potency and a narrow killing spectrum. Our findings indicate that a large number of infectious CF variants are susceptible to R2-pyocins, even within diverse bacterial populations, supporting their potential use as therapeutic agents. The absence of a clear correlation between lipopolysaccharide (LPS) phenotypes and R-pyocin susceptibility suggests that LPS packing density may play a significant role in R-pyocin susceptibility among CF variants. Understanding the relationship between LPS phenotypes and R-pyocin susceptibility is crucial for developing effective treatments for these chronic infections.
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Affiliation(s)
- Madeline Mei
- School of Biological Sciences, Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Pediatrics, Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory+Children’s Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Preston Pheng
- School of Biological Sciences, Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Detriana Kurzeja-Edwards
- School of Biological Sciences, Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Stephen P. Diggle
- School of Biological Sciences, Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
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5
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Vanderwoude J, Azimi S, Read TD, Diggle SP. The Role of Hypermutation and Collateral Sensitivity in Antimicrobial Resistance Diversity of Pseudomonas aeruginosa Populations in Cystic Fibrosis Lung Infection. bioRxiv 2023:2023.06.14.544983. [PMID: 37398156 PMCID: PMC10312765 DOI: 10.1101/2023.06.14.544983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen which causes chronic, drug-resistant lung infections in cystic fibrosis (CF) patients. In this study, we explore the role of genomic diversification and evolutionary trade-offs in antimicrobial resistance (AMR) diversity within P. aeruginosa populations sourced from CF lung infections. We analyzed 300 clinical isolates from four CF patients (75 per patient), and found that genomic diversity is not a consistent indicator of phenotypic AMR diversity. Remarkably, some genetically less diverse populations showed AMR diversity comparable to those with significantly more genetic variation. We also observed that hypermutator strains frequently exhibited increased sensitivity to antimicrobials, contradicting expectations from their treatment histories. Investigating potential evolutionary trade-offs, we found no substantial evidence of collateral sensitivity among aminoglycoside, beta-lactam, or fluoroquinolone antibiotics, nor did we observe trade-offs between AMR and growth in conditions mimicking CF sputum. Our findings suggest that (i) genomic diversity is not a prerequisite for phenotypic AMR diversity; (ii) hypermutator populations may develop increased antimicrobial sensitivity under selection pressure; (iii) collateral sensitivity is not a prominent feature in CF strains, and (iv) resistance to a single antibiotic does not necessarily lead to significant fitness costs. These insights challenge prevailing assumptions about AMR evolution in chronic infections, emphasizing the complexity of bacterial adaptation during infection.
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Affiliation(s)
- Jelly Vanderwoude
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Sheyda Azimi
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- School of Biology, Georgia State University, Atlanta, GA, USA
| | - Timothy D. Read
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA, USA
| | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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6
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Mutlu A, Vanderpool E, Rumbaugh KP, Diggle SP, Griffin AS. Exploiting Cooperative Pathogen Behavior for Enhanced Antibiotic Potency: A Trojan Horse Approach. Res Sq 2023:rs.3.rs-3466639. [PMID: 37986882 PMCID: PMC10659551 DOI: 10.21203/rs.3.rs-3466639/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Antimicrobial resistance poses an escalating global threat, rendering traditional drug development approaches increasingly ineffective. Thus, novel alternatives to antibiotic-based therapies are needed. Exploiting pathogen cooperation as a strategy for combating resistant infections has been proposed but lacks experimental validation. Empirical findings demonstrate the successful invasion of cooperating populations by non-cooperating cheats, effectively reducing virulence in vitro and in vivo. The idea of harnessing cooperative behaviors for therapeutic benefit involves exploitation of the invasive capabilities of cheats to drive medically beneficial traits into infecting populations of cells. In this study, we employed Pseudomonas aeruginosa quorum sensing cheats to drive antibiotic sensitivity into both in vitro and in vivo resistant populations. We demonstrated the successful invasion of cheats, followed by increased antibiotic effectiveness against cheat-invaded populations, thereby establishing an experimental proof of principle for the potential application of the Trojan strategy in fighting resistant infections.
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Affiliation(s)
- Alper Mutlu
- Departmemt of Biology, University of Oxford, Oxford, United Kingdom
| | - Emily Vanderpool
- Texas Tech University Health Sciences Center, Lubbock, United States
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7
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Mei M, Pheng P, Kurzeja-Edwards D, Diggle SP. High prevalence of lipopolysaccharide mutants and R2-Pyocin susceptible variants in Pseudomonas aeruginosa populations sourced from cystic fibrosis lung infections. bioRxiv 2023:2023.04.26.538445. [PMID: 37163048 PMCID: PMC10168318 DOI: 10.1101/2023.04.26.538445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Chronic, highly antibiotic-resistant infections in cystic fibrosis (CF) lungs contribute to increasing morbidity and mortality. Pseudomonas aeruginosa, a common CF pathogen, exhibits resistance to multiple antibiotics, contributing to antimicrobial resistance (AMR). These bacterial populations display genetic and phenotypic diversity, but it is unclear how this diversity affects susceptibility to bacteriocins. R-pyocins, i.e. bacteriocins produced by P. aeruginosa, are phage tail-like antimicrobials. R-pyocins have potential as antimicrobials, however recent research suggests the diversity of P. aeruginosa variants within CF lung infections leads to varying susceptibility to R-pyocins. This variation may be linked to changes in lipopolysaccharide (LPS), acting as the R-pyocin receptor. Currently, it is unknown how frequently R-pyocin-susceptible strains are in chronic CF lung infection, particularly when considering the heterogeneity within these strains. In this study, we tested R2-pyocin susceptibility of 139 P. aeruginosa variants from 17 sputum samples of seven CF patients and analyzed LPS phenotypes. We found that 83% of sputum samples did not have R2-pyocin-resistant variants, while nearly all samples contained susceptible variants. there was no correlation between LPS phenotype and R2-pyocin susceptibility, though we estimate that about 76% of sputum-derived variants lack an O-specific antigen, 40% lack a common antigen, and 24% have altered LPS cores. The absence of a correlation between LPS phenotype and R-pyocin susceptibility suggests LPS packing density may play a significant role in R-pyocin susceptibility among CF variants. Our research supports the potential of R-pyocins as therapeutic agents, as many infectious CF variants are susceptible to R2-pyocins, even within diverse bacterial populations.
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Affiliation(s)
- Madeline Mei
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Pediatrics, Division of Pulmonary, Allergy and Immunology, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory+Children’s Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Preston Pheng
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Detriana Kurzeja-Edwards
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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8
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Soto-Aceves MP, Diggle SP, Greenberg EP. Microbial Primer: LuxR-LuxI Quorum Sensing. Microbiology (Reading) 2023; 169:001343. [PMID: 37655474 PMCID: PMC10569067 DOI: 10.1099/mic.0.001343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/13/2023] [Indexed: 09/02/2023]
Abstract
Quorum sensing is a term describing bacterial cell-to-cell communication systems for monitoring and responding to changes in population density. This primer serves as an introduction to the canonical LuxR-LuxI-type quorum sensing circuits common to many species of Gram-negative bacteria. Quorum sensing can synchronize behaviours across a community. Different species employ quorum sensing strategies to control specific behaviours such as bioluminescence, virulence factor production, secondary metabolite production, and biofilm formation.
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Affiliation(s)
- Martin P. Soto-Aceves
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
| | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - E. Peter Greenberg
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA, USA
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9
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Brockhurst M, Cavet J, Diggle SP, Grainger D, Mangenelli R, Sychrova H, Martin-Verstraete I, Welch M, Palmer T, Thomas GH. Shaping microbiology for 75 years: highlights of research published in Microbiology. Part 1 - Physiology and growth. Microbiology (Reading) 2023; 169. [PMID: 37379229 DOI: 10.1099/mic.0.001356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Affiliation(s)
- Michael Brockhurst
- Division of Evolution, Infection and Genomics, University of Manchester, Michael Smith Building, Dover Street, Manchester M13 9PT, UK
| | - Jennifer Cavet
- Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Stephen P Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - David Grainger
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | - Hana Sychrova
- Institute of Physiology of the Czech Academy of Sciences, Laboratory of Membrane Transport, 14200 Prague 4, Czech Republic
| | | | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Tracy Palmer
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Gavin H Thomas
- Department of Biology, University of York, Wentworth Way, York, UK
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10
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Brockhurst M, Cavet J, Diggle SP, Grainger D, Mangenelli R, Sychrova H, Martin-Verstraete I, Welch M, Palmer T, Thomas GH. Shaping microbiology for 75 years: highlights of research published in Microbiology. Part 2 - Communities and evolution. Microbiology (Reading) 2023; 169. [PMID: 37379228 DOI: 10.1099/mic.0.001357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Affiliation(s)
- Michael Brockhurst
- Division of Evolution, Infection and Genomics, University of Manchester, Michael Smith Building, Dover Street, Manchester M13 9PT, UK
| | - Jennifer Cavet
- Lydia Becker Institute of Immunology and Inflammation, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Stephen P Diggle
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - David Grainger
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | - Hana Sychrova
- Institute of Physiology of the Czech Academy of Sciences, Laboratory of Membrane Transport, 14200 Prague 4, Czech Republic
| | | | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Tracy Palmer
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Gavin H Thomas
- Department of Biology, University of York, Wentworth Way, York, UK
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11
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Humphreys JR, Debebe BJ, Diggle SP, Winzer K. Clostridium beijerinckii strain degeneration is driven by the loss of Spo0A activity. Front Microbiol 2023; 13:1075609. [PMID: 36704551 PMCID: PMC9871927 DOI: 10.3389/fmicb.2022.1075609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023] Open
Abstract
Solventogenic clostridia represent a diverse group of anaerobic, spore-forming bacteria capable of producing acetone, butanol and ethanol through their unique biphasic metabolism. An intrinsic problem with these organisms however is their tendency to degenerate when repeatedly subcultured or when grown continuously. This phenomenon sees cells lose their ability to produce solvents and spores, posing a significant problem for industrial applications. To investigate the mechanistic and evolutionary basis of degeneration we combined comparative genomics, ultra-deep sequencing, and concepts of sociomicrobiology using Clostridium beijerinckii NCIMB 8052 as our model organism. These approaches revealed spo0A, the master regulator gene involved in spore and solvent formation, to be key to the degeneration process in this strain. Comparative genomics of 71 degenerate variants revealed four distinct hotspot regions that contained considerably more mutations than the rest of the genome. These included spo0A as well as genes suspected to regulate its expression and activity. Ultra-deep sequencing of populations during the subculturing process showed transient increases in mutations we believe linked to the spo0A network, however, these were ultimately dominated by mutations in the master regulator itself. Through frequency-dependent fitness assays, we found that spo0A mutants gained a fitness advantage, relative to the wild type, presumably allowing for propagation throughout the culture. Combined, our data provides new insights into the phenomenon of clostridial strain degeneration and the C. beijerinckii NCIMB 8052 solvent and spore regulation network.
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Affiliation(s)
- Jonathan R. Humphreys
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, United Kingdom
| | - Bisrat J. Debebe
- DeepSeq, Centre for Genetics and Genomics, The University of Nottingham, Nottingham, United Kingdom
| | - Stephen P. Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Klaus Winzer
- BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, University Park, The University of Nottingham, Nottingham, United Kingdom,*Correspondence: Klaus Winzer, ✉
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12
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O'Connor K, Zhao CY, Mei M, Diggle SP. Frequency of quorum-sensing mutations in Pseudomonas aeruginosa strains isolated from different environments. Microbiology (Reading) 2022; 168. [PMID: 36748632 DOI: 10.1099/mic.0.001265] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pseudomonas aeruginosa uses quorum sensing (QS) to coordinate the expression of multiple genes necessary for establishing and maintaining infection. It has previously been shown that lasR QS mutations frequently arise in cystic fibrosis (CF) lung infections, however, there has been far less emphasis on determining whether other QS system mutations arise during infection or in other environments. To test this, we utilized 852 publicly available sequenced P. aeruginosa genomes from the Pseudomonas International Consortium Database (IPCD) to study P. aeruginosa QS mutational signatures. To study isolates by source, we focused on a subset of 654 isolates collected from CF, wounds, and non-infection environmental isolates, where we could clearly identify their source. We also worked with a small collection of isolates in vitro to determine the impact of lasR and pqs mutations on isolate phenotypes. We found that lasR mutations are common across all environments and are not specific to infection nor a particular infection type. We also found that the pqs system proteins PqsA, PqsH, PqsL and MexT, a protein of increasing importance to the QS field, are highly variable. Conversely, RsaL, a negative transcriptional regulator of the las system, was found to be highly conserved, suggesting selective pressure to repress las system activity. Overall, our findings suggest that QS mutations in P. aeruginosa are common and not limited to the las system; however, LasR is unique in the frequency of putative loss-of-function mutations.
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Affiliation(s)
- Kathleen O'Connor
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Conan Y Zhao
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Madeline Mei
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Stephen P Diggle
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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13
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Diggle SP, Whiteley M. Corrigendum: Microbe Profile: Pseudomonas aeruginosa: opportunistic pathogen and lab rat. Microbiology (Reading) 2021; 167. [PMID: 34382929 PMCID: PMC8489588 DOI: 10.1099/mic.0.001073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Stephen P Diggle
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Marvin Whiteley
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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14
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Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen and a model bacterium for studying virulence and bacterial social traits. While it can be isolated in low numbers from a wide variety of environments including soil and water, it can readily be found in almost any human/animal-impacted environment. It is a major cause of illness and death in humans with immunosuppressive and chronic conditions, and infections in these patients are difficult to treat due to a number of antibiotic resistance mechanisms and the organism’s propensity to form multicellular biofilms.
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Affiliation(s)
- Stephen P Diggle
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Marvin Whiteley
- Center for Microbial Dynamics & Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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15
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Vanderwoude J, Fleming D, Azimi S, Trivedi U, Rumbaugh KP, Diggle SP. The evolution of virulence in Pseudomonas aeruginosa during chronic wound infection. Proc Biol Sci 2020; 287:20202272. [PMID: 33081616 DOI: 10.1098/rspb.2020.2272] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Opportunistic pathogens are associated with a number of chronic human infections, yet the evolution of virulence in these organisms during chronic infection remains poorly understood. Here, we tested the evolution of virulence in the human opportunistic pathogen Pseudomonas aeruginosa in a murine chronic wound model using a two-part serial passage and sepsis experiment, and found that virulence evolved in different directions in each line of evolution. We also assessed P. aeruginosa adaptation to a chronic wound after 42 days of evolution and found that morphological diversity in our evolved populations was limited compared with that previously described in cystic fibrosis (CF) infections. Using whole-genome sequencing, we found that genes previously implicated in P. aeruginosa pathogenesis (lasR, pilR, fleQ, rpoN and pvcA) contained mutations during the course of evolution in wounds, with selection occurring in parallel across all lines of evolution. Our findings highlight that: (i) P. aeruginosa heterogeneity may be less extensive in chronic wounds than in CF lungs; (ii) genes involved in P. aeruginosa pathogenesis acquire mutations during chronic wound infection; (iii) similar genetic adaptations are employed by P. aeruginosa across multiple infection environments; and (iv) current models of virulence may not adequately explain the diverging evolutionary trajectories observed in an opportunistic pathogen during chronic wound infection.
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Affiliation(s)
- Jelly Vanderwoude
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Derek Fleming
- Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Sheyda Azimi
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Urvish Trivedi
- Section of Microbiology, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kendra P Rumbaugh
- Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Stephen P Diggle
- Center for Microbial Dynamics and Infection, School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
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16
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Abstract
Bacteria are highly interactive and possess an extraordinary repertoire of intercellular communication and social behaviors, including quorum sensing (QS). QS has been studied in detail at the molecular level, so mechanistic details are well understood in many species and are often involved in virulence. The use of different animal host models has demonstrated QS-dependent control of virulence determinants and virulence in several human pathogenic bacteria. QS also controls virulence in several plant pathogenic species. Despite the role QS plays in virulence during animal and plant laboratory-engineered infections, QS mutants are frequently isolated from natural infections, demonstrating that the function of QS during infection and its role in pathogenesis remain poorly understood and are fruitful areas for future research. We discuss the role of QS during infection in various organisms and highlight approaches to better understand QS during human infection. This is an important consideration in an era of growing antimicrobial resistance, when we are looking for new ways to target bacterial infections.
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Affiliation(s)
- Sheyda Azimi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA; , .,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Alexander D Klementiev
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA; , .,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Marvin Whiteley
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA; , .,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.,Emory-Children's Cystic Fibrosis Center, Atlanta, Georgia 30329, USA
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332, USA; , .,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
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17
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Gurney J, Azimi S, Brown SP, Diggle SP. Combinatorial quorum sensing in Pseudomonas aeruginosa allows for novel cheating strategies. Microbiology (Reading) 2020; 166:777-784. [PMID: 32511085 DOI: 10.1099/mic.0.000941] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing (QS) is a social trait that is exploitable by non-cooperating cheats. Previously it has been shown that by linking QS to the production of both public and private goods, cheats can be prevented from invading populations of cooperators and this was described by Dandekar et al. (Science 2012;338:264-266) as 'a metabolic incentive to cooperate'. We hypothesized that P. aeruginosa could evolve novel cheating strategies to circumvent private goods metabolism by rewiring its combinatorial response to two QS signals (3O-C12-HSL and C4-HSL). We performed a selection experiment that cycled P. aeruginosa between public and private goods growth media and evolved an isolate that rewired its control of cooperative protease expression from a synergistic (AND-gate) response to dual-signal input to a 3O-C12-HSL-only response. We show that this isolate circumvents metabolic incentives to cooperate and acts as a combinatorial signalling cheat, with higher fitness in competition with its ancestor. Our results show three important principles: first, combinatorial QS allows for diverse social strategies to emerge; second, restrictions levied by private goods are not sufficient to explain the maintenance of cooperation in natural populations; and third, modifying combinatorial QS responses could result in important physiological outcomes in bacterial populations.
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Affiliation(s)
- James Gurney
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Sheyda Azimi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Sam P Brown
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta,, USA.,Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, USA
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18
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Azimi S, Roberts AEL, Peng S, Weitz JS, McNally A, Brown SP, Diggle SP. Allelic polymorphism shapes community function in evolving Pseudomonas aeruginosa populations. ISME J 2020; 14:1929-1942. [PMID: 32341475 DOI: 10.1038/s41396-020-0652-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 03/23/2020] [Accepted: 03/31/2020] [Indexed: 12/31/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that chronically infects the lungs of individuals with cystic fibrosis (CF) by forming antibiotic-resistant biofilms. Emergence of phenotypically diverse isolates within CF P. aeruginosa populations has previously been reported; however, the impact of heterogeneity on social behaviors and community function is poorly understood. Here we describe how this heterogeneity impacts on behavioral traits by evolving the strain PAO1 in biofilms grown in a synthetic sputum medium for 50 days. We measured social trait production and antibiotic tolerance, and used a metagenomic approach to analyze and assess genomic changes over the duration of the evolution experiment. We found that (i) evolutionary trajectories were reproducible in independently evolving populations; (ii) over 60% of genomic diversity occurred within the first 10 days of selection. We then focused on quorum sensing (QS), a well-studied P. aeruginosa trait that is commonly mutated in strains isolated from CF lungs. We found that at the population level, (i) evolution in sputum medium selected for decreased the production of QS and QS-dependent traits; (ii) there was a significant correlation between lasR mutant frequency, the loss of protease, and the 3O-C12-HSL signal, and an increase in resistance to clinically relevant β-lactam antibiotics, despite no previous antibiotic exposure. Overall, our findings provide insights into the effect of allelic polymorphism on community functions in diverse P. aeruginosa populations. Further, we demonstrate that P. aeruginosa population and evolutionary dynamics can impact on traits important for virulence and can lead to increased tolerance to β-lactam antibiotics.
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Affiliation(s)
- Sheyda Azimi
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Aled E L Roberts
- Microbiology & Infectious Diseases Group, Institute of Life Science, Swansea University Medical School, Swansea, UK
| | - Shengyun Peng
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Joshua S Weitz
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.,School of Physics, Georgia Institute of Technology, Atlanta, GA, USA
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Samuel P Brown
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stephen P Diggle
- Center for Microbial Dynamics & Infection, Georgia Institute of Technology, Atlanta, GA, USA. .,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
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19
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Chiba A, Bawaneh A, Velazquez C, Clear KY, Wilson AS, Howard-McNatt M, Levine EA, Levi-Polyachenko N, Yates-Alston SA, Diggle SP, Soto-Pantoja DR, Cook KL. Neoadjuvant Chemotherapy Shifts Breast Tumor Microbiota Populations to Regulate Drug Responsiveness and the Development of Metastasis. Mol Cancer Res 2019; 18:130-139. [DOI: 10.1158/1541-7786.mcr-19-0451] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/26/2019] [Accepted: 10/15/2019] [Indexed: 11/16/2022]
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20
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Garge S, Azimi S, Diggle SP. A simple mung bean infection model for studying the virulence of Pseudomonas aeruginosa. Microbiology (Reading) 2018; 164:764-768. [PMID: 29629857 DOI: 10.1099/mic.0.000659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Here we highlight the development of a simple and high-throughput mung bean model to study virulence in the opportunistic pathogen Pseudomonas aeruginosa. The model is easy to set up, and infection and virulence can be monitored for up to 10 days. In a first test of the model, we found that mung bean seedlings infected with PAO1 showed poor development of roots and high mortality rates compared to uninfected controls. We also found that a quorum-sensing (QS) mutant was significantly less virulent when compared with the PAO1 wild-type. Our work introduces a new tool for studying virulence in P. aeruginosa that will allow for high-throughput virulence studies of mutants and testing of the in vivo efficacy of new therapies at a time when new antimicrobial drugs are desperately needed.
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Affiliation(s)
- Sneha Garge
- Department of Microbiology and Biotechnology Center, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, India
| | - Sheyda Azimi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30032, USA
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30032, USA
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21
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Harrison F, McNally A, da Silva AC, Heeb S, Diggle SP. Optimised chronic infection models demonstrate that siderophore 'cheating' in Pseudomonas aeruginosa is context specific. ISME J 2017; 11:2492-2509. [PMID: 28696423 PMCID: PMC5649161 DOI: 10.1038/ismej.2017.103] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/15/2017] [Accepted: 05/17/2017] [Indexed: 12/25/2022]
Abstract
The potential for siderophore mutants of Pseudomonas aeruginosa to attenuate virulence during infection, and the possibility of exploiting this for clinical ends, have attracted much discussion. This has largely been based on the results of in vitro experiments conducted in iron-limited growth medium, in which siderophore mutants act as social 'cheats:' increasing in frequency at the expense of the wild type to result in low-productivity, low-virulence populations dominated by mutants. We show that insights from in vitro experiments cannot necessarily be transferred to infection contexts. First, most published experiments use an undefined siderophore mutant. Whole-genome sequencing of this strain revealed a range of mutations affecting phenotypes other than siderophore production. Second, iron-limited medium provides a very different environment from that encountered in chronic infections. We conducted cheating assays using defined siderophore deletion mutants, in conditions designed to model infected fluids and tissue in cystic fibrosis lung infection and non-healing wounds. Depending on the environment, siderophore loss led to cheating, simple fitness defects, or no fitness effect at all. Our results show that it is crucial to develop defined in vitro models in order to predict whether siderophores are social, cheatable and suitable for clinical exploitation in specific infection contexts.
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Affiliation(s)
- Freya Harrison
- School of Life Sciences, Gibbet Hill Campus, University of Warwick, Coventry, UK
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Alan McNally
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Ana C da Silva
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Stephan Heeb
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Stephen P Diggle
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
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22
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Popat R, Harrison F, da Silva AC, Easton SAS, McNally L, Williams P, Diggle SP. Environmental modification via a quorum sensing molecule influences the social landscape of siderophore production. Proc Biol Sci 2017; 284:rspb.2017.0200. [PMID: 28404780 PMCID: PMC5394672 DOI: 10.1098/rspb.2017.0200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022] Open
Abstract
Bacteria produce a wide variety of exoproducts that favourably modify their environment and increase their fitness. These are often termed ‘public goods’ because they are costly for individuals to produce and can be exploited by non-producers (cheats). The outcome of conflict over public goods is dependent upon the prevailing environment and the phenotype of the individuals in competition. Many bacterial species use quorum sensing (QS) signalling molecules to regulate the production of public goods. QS, therefore, determines the cooperative phenotype of individuals, and influences conflict over public goods. In addition to their regulatory functions, many QS molecules have additional properties that directly modify the prevailing environment. This leads to the possibility that QS molecules could influence conflict over public goods indirectly through non-signalling effects, and the impact of this on social competition has not previously been explored. The Pseudomonas aeruginosa QS signal molecule PQS is a powerful chelator of iron which can cause an iron starvation response. Here, we show that PQS stimulates a concentration-dependent increase in the cooperative production of iron scavenging siderophores, resulting in an increase in the relative fitness of non-producing siderophore cheats. This is likely due to an increased cost of siderophore output by producing cells and a concurrent increase in the shared benefits, which accrue to both producers and cheats. Although PQS can be a beneficial signalling molecule for P. aeruginosa, our data suggest that it can also render a siderophore-producing population vulnerable to competition from cheating strains. More generally, our results indicate that the production of one social trait can indirectly affect the costs and benefits of another social trait.
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Affiliation(s)
- Roman Popat
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Freya Harrison
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.,School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, UK
| | - Ana C da Silva
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Scott A S Easton
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Luke McNally
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Paul Williams
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Stephen P Diggle
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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23
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Abstract
The ability of bacteria to move is critical for their survival in diverse environments and multiple ways have evolved to achieve this. Two forms of motility have recently been described for Staphylococcus aureus, an organism previously considered to be non-motile. One form is called spreading, which is a type of sliding motility and the second form involves comet formation, which has many observable characteristics associated with gliding motility. Darting motility has also been observed in Staphylococcus epidermidis. This review describes how motility is defined and how we distinguish between passive and active motility. We discuss the characteristics of the various forms of Staphylococci motility, the molecular mechanisms involved and the potential future research directions.
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Affiliation(s)
- Eric J G Pollitt
- Department of Biomedical Science, Western Bank, University of Sheffield, Sheffield, UK
| | - Stephen P Diggle
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
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24
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Moreau P, Diggle SP, Friman VP. Bacterial cell-to-cell signaling promotes the evolution of resistance to parasitic bacteriophages. Ecol Evol 2017; 7:1936-1941. [PMID: 28331600 PMCID: PMC5355186 DOI: 10.1002/ece3.2818] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/19/2016] [Accepted: 01/28/2017] [Indexed: 12/21/2022] Open
Abstract
The evolution of host–parasite interactions could be affected by intraspecies variation between different host and parasite genotypes. Here we studied how bacterial host cell‐to‐cell signaling affects the interaction with parasites using two bacteria‐specific viruses (bacteriophages) and the host bacterium Pseudomonas aeruginosa that communicates by secreting and responding to quorum sensing (QS) signal molecules. We found that a QS‐signaling proficient strain was able to evolve higher levels of resistance to phages during a short‐term selection experiment. This was unlikely driven by demographic effects (mutation supply and encounter rates), as nonsignaling strains reached higher population densities in the absence of phages in our selective environment. Instead, the evolved nonsignaling strains suffered relatively higher growth reduction in the absence of the phage, which could have constrained the phage resistance evolution. Complementation experiments with synthetic signal molecules showed that the Pseudomonas quinolone signal (PQS) improved the growth of nonsignaling bacteria in the presence of a phage, while the activation of las and rhl quorum sensing systems had no effect. Together, these results suggest that QS‐signaling can promote the evolution of phage resistance and that the loss of QS‐signaling could be costly in the presence of phages. Phage–bacteria interactions could therefore indirectly shape the evolution of intraspecies social interactions and PQS‐mediated virulence in P. aeruginosa.
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Affiliation(s)
- Pierre Moreau
- Imperial College London, Silwood Park Campus Ascot Berkshire UK
| | - Stephen P Diggle
- School of Life Sciences Centre for Biomolecular Sciences University of Nottingham Nottingham UK
| | - Ville-Petri Friman
- Imperial College London, Silwood Park Campus Ascot Berkshire UK; Department of Biology The University of York York UK
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25
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Harrison F, Diggle SP. An ex vivo lung model to study bronchioles infected with Pseudomonas aeruginosa biofilms. Microbiology (Reading) 2016; 162:1755-1760. [DOI: 10.1099/mic.0.000352] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Freya Harrison
- School of Life Sciences, University of Warwick, Coventry, UK
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Stephen P. Diggle
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
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26
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Kragh KN, Hutchison JB, Melaugh G, Rodesney C, Roberts AEL, Irie Y, Jensen PØ, Diggle SP, Allen RJ, Gordon V, Bjarnsholt T. Role of Multicellular Aggregates in Biofilm Formation. mBio 2016; 7:e00237. [PMID: 27006463 PMCID: PMC4807362 DOI: 10.1128/mbio.00237-16] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 11/25/2022] Open
Abstract
UNLABELLED In traditional models ofin vitrobiofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development ofPseudomonas aeruginosabiofilms. We find that the relative fitness of aggregates depends markedly on the density of surrounding single cells, i.e., the level of competition for growth resources. When competition between aggregates and single cells is low, an aggregate has a growth disadvantage because the aggregate interior has poor access to growth resources. However, if competition is high, aggregates exhibit higher fitness, because extending vertically above the surface gives cells at the top of aggregates better access to growth resources. Other advantages of seeding by aggregates, such as earlier switching to a biofilm-like phenotype and enhanced resilience toward antibiotics and immune response, may add to this ecological benefit. Our findings suggest that current models of biofilm formation should be reconsidered to incorporate the role of aggregates in biofilm initiation. IMPORTANCE During the past decades, there has been a consensus around the model of development of a biofilm, involving attachment of single planktonic bacterial cells to a surface and the subsequent development of a mature biofilm. This study presents results that call for a modification of this rigorous model. We show how free floating biofilm aggregates can have a profound local effect on biofilm development when attaching to a surface. Our findings show that an aggregate landing on a surface will eventually outcompete the biofilm population arising from single cells attached around the aggregate and dominate the local biofilm development. These results point to a regime where preformed biofilm aggregates may have a fitness advantage over planktonic cells when it comes to accessing nutrients. Our findings add to the increasingly prominent comprehension that biofilm lifestyle is the default for bacteria and that planktonic single cells may be only a transition state at the most.
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Affiliation(s)
- Kasper N Kragh
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jaime B Hutchison
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA
| | - Gavin Melaugh
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Chris Rodesney
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA
| | - Aled E L Roberts
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Yasuhiko Irie
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Peter Ø Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Stephen P Diggle
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Rosalind J Allen
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom
| | - Vernita Gordon
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, USA Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA
| | - Thomas Bjarnsholt
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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27
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Darch SE, McNally A, Corander J, Diggle SP. Response to 'Refined analyses suggest that recombination is a minor source of genomic diversity in Pseudomonas aeruginosa chronic cystic fibrosis infections' by ). Microb Genom 2016; 2:e000054. [PMID: 28348849 PMCID: PMC5320577 DOI: 10.1099/mgen.0.000054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Sophie E Darch
- 1School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK.,2Department of Molecular Biosciences, Institute of Cellular and Molecular Biology, Center for Infectious Disease, The University of Texas at Austin, Austin, TX 78712, USA
| | - Alan McNally
- 3Pathogen Research Group, Nottingham Trent University, Nottingham, UK
| | - Jukka Corander
- 4Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Stephen P Diggle
- 1School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK
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28
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Melaugh G, Hutchison J, Kragh KN, Irie Y, Roberts A, Bjarnsholt T, Diggle SP, Gordon VD, Allen RJ. Shaping the Growth Behaviour of Biofilms Initiated from Bacterial Aggregates. PLoS One 2016; 11:e0149683. [PMID: 26934187 PMCID: PMC4774936 DOI: 10.1371/journal.pone.0149683] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/03/2016] [Indexed: 01/26/2023] Open
Abstract
Bacterial biofilms are usually assumed to originate from individual cells deposited on a surface. However, many biofilm-forming bacteria tend to aggregate in the planktonic phase so that it is possible that many natural and infectious biofilms originate wholly or partially from pre-formed cell aggregates. Here, we use agent-based computer simulations to investigate the role of pre-formed aggregates in biofilm development. Focusing on the initial shape the aggregate forms on the surface, we find that the degree of spreading of an aggregate on a surface can play an important role in determining its eventual fate during biofilm development. Specifically, initially spread aggregates perform better when competition with surrounding unaggregated bacterial cells is low, while initially rounded aggregates perform better when competition with surrounding unaggregated cells is high. These contrasting outcomes are governed by a trade-off between aggregate surface area and height. Our results provide new insight into biofilm formation and development, and reveal new factors that may be at play in the social evolution of biofilm communities.
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Affiliation(s)
- Gavin Melaugh
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
- * E-mail:
| | - Jaime Hutchison
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas 78712-1199, United States of America
| | - Kasper Nørskov Kragh
- Department of International Health, Immunology and Microbiology, Faculty Of Health Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Yasuhiko Irie
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom
| | - Aled Roberts
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Thomas Bjarnsholt
- Department of International Health, Immunology and Microbiology, Faculty Of Health Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department for Clinical Microbiology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Stephen P. Diggle
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Vernita D. Gordon
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas 78712-1199, United States of America
| | - Rosalind J. Allen
- School of Physics and Astronomy, University of Edinburgh, James Clerk Maxwell Building, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
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Roberts AE, Kragh KN, Bjarnsholt T, Diggle SP. The Limitations of In Vitro Experimentation in Understanding Biofilms and Chronic Infection. J Mol Biol 2015; 427:3646-61. [DOI: 10.1016/j.jmb.2015.09.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/12/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
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Popat R, Pollitt EJG, Harrison F, Naghra H, Hong KW, Chan KG, Griffin AS, Williams P, Brown SP, West SA, Diggle SP. Conflict of interest and signal interference lead to the breakdown of honest signaling. Evolution 2015; 69:2371-83. [PMID: 26282874 PMCID: PMC4862024 DOI: 10.1111/evo.12751] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 07/17/2015] [Accepted: 07/27/2015] [Indexed: 01/04/2023]
Abstract
Animals use signals to coordinate a wide range of behaviors, from feeding offspring to predator avoidance. This poses an evolutionary problem, because individuals could potentially signal dishonestly to coerce others into behaving in ways that benefit the signaler. Theory suggests that honest signaling is favored when individuals share a common interest and signals carry reliable information. Here, we exploit the opportunities offered by bacterial signaling to test these predictions with an experimental evolution approach. We show that: (1) reduced relatedness leads to the relative breakdown of signaling, (2) signaling breaks down by the invasion of mutants that show both reduced signaling and reduced response to signal, (3) the genetic route to signaling breakdown is variable, and (4) the addition of artificial signal, to interfere with signal information, also leads to reduced signaling. Our results provide clear support for signaling theory, but we did not find evidence for previously predicted coercion at intermediate relatedness, suggesting that mechanistic details can alter the qualitative nature of specific predictions. Furthermore, populations evolved under low relatedness caused less mortality to insect hosts, showing how signal evolution in bacterial pathogens can drive the evolution of virulence in the opposite direction to that often predicted by theory.
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Affiliation(s)
- Roman Popat
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.,Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
| | - Eric J G Pollitt
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Freya Harrison
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Hardeep Naghra
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Kar-Wai Hong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kok-Gan Chan
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ashleigh S Griffin
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom
| | - Paul Williams
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom
| | - Sam P Brown
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, EH9 3JT, United Kingdom
| | - Stuart A West
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, United Kingdom
| | - Stephen P Diggle
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, United Kingdom.
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Darch SE, McNally A, Harrison F, Corander J, Barr HL, Paszkiewicz K, Holden S, Fogarty A, Crusz SA, Diggle SP. Recombination is a key driver of genomic and phenotypic diversity in a Pseudomonas aeruginosa population during cystic fibrosis infection. Sci Rep 2015; 5:7649. [PMID: 25578031 PMCID: PMC4289893 DOI: 10.1038/srep07649] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/27/2014] [Indexed: 12/14/2022] Open
Abstract
The Cystic Fibrosis (CF) lung harbors a complex, polymicrobial ecosystem, in which Pseudomonas aeruginosa is capable of sustaining chronic infections, which are highly resistant to multiple antibiotics. Here, we investigate the phenotypic and genotypic diversity of 44 morphologically identical P. aeruginosa isolates taken from a single CF patient sputum sample. Comprehensive phenotypic analysis of isolates revealed large variances and trade-offs in growth, virulence factors and quorum sensing (QS) signals. Whole genome analysis of 22 isolates revealed high levels of intra-isolate diversity ranging from 5 to 64 SNPs and that recombination and not spontaneous mutation was the dominant driver of diversity in this population. Furthermore, phenotypic differences between isolates were not linked to mutations in known genes but were statistically associated with distinct recombination events. We also assessed antibiotic susceptibility of all isolates. Resistance to antibiotics significantly increased when multiple isolates were mixed together. Our results highlight the significant role of recombination in generating phenotypic and genetic diversification during in vivo chronic CF infection. We also discuss (i) how these findings could influence how patient-to-patient transmission studies are performed using whole genome sequencing, and (ii) the need to refine antibiotic susceptibility testing in sputum samples taken from patients with CF.
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Affiliation(s)
- Sophie E Darch
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Alan McNally
- Pathogen Research Group, Nottingham Trent University, Nottingham, U.K
| | - Freya Harrison
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, U.K
| | - Jukka Corander
- Department of Mathematics and Statistics, University of Helsinki, Finland
| | - Helen L Barr
- Division of Respiratory Medicine, Nottingham City Hospital, Nottingham, NG5 1PB, U.K
| | - Konrad Paszkiewicz
- College of Life and Environmental Sciences, University of Exeter, Exeter
| | - Stephen Holden
- Department of Clinical Microbiology, Nottingham University NHS Trust, U.K
| | - Andrew Fogarty
- Division of Epidemiology &Public Health, Nottingham City Hospital, Nottingham, NG5 1PB, U.K
| | - Shanika A Crusz
- 1] School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, U.K. [2] Department of Clinical Microbiology, Nottingham University NHS Trust, U.K
| | - Stephen P Diggle
- School of Life Sciences, University of Nottingham, Nottingham, NG7 2RD, U.K
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Laabei M, Jamieson WD, Lewis SE, Diggle SP, Jenkins ATA. A new assay for rhamnolipid detection-important virulence factors of Pseudomonas aeruginosa. Appl Microbiol Biotechnol 2014; 98:7199-209. [PMID: 24974281 DOI: 10.1007/s00253-014-5904-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 06/17/2014] [Accepted: 06/18/2014] [Indexed: 10/25/2022]
Abstract
Rhamnolipids (RLs) are heterogeneous glycolipid molecules that are composed of one or two L-rhamnose sugars and one or two β-hydroxy fatty acids, which can vary in their length and branch size. They are biosurfactants, predominantly produced by Pseudomonas aeruginosa and are important virulence factors, playing a major role in P. aeruginosa pathogenesis. Therefore, a fast, accurate and high-throughput method of detecting such molecules is of real importance. Here, we illustrate the ability to detect RL-producing P. aeruginosa strains with high sensitivity, based on an assay involving phospholipid vesicles encapsulated with a fluorescent dye. This vesicle-lysis assay is confirmed to be solely sensitive to RLs. We illustrate a half maximum concentration for vesicle lysis (EC50) of 40 μM (23.2 μg/mL) using pure commercial RLs and highlight the ability to semi-quantify RLs directly from the culture supernatant, requiring no extra extraction or processing steps or technical expertise. We show that this method is consistent with results from thin-layer chromatography detection and dry weight analysis of RLs but find that the widely used orcinol colorimetric test significantly underestimated RL quantity. Finally, we apply this methodology to compare RL production among strains isolated from either chronic or acute infections. We confirm a positive association between RL production and acute infection isolates (p = 0.0008), highlighting the role of RLs in certain infections.
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Affiliation(s)
- Maisem Laabei
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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Scott-Phillips TC, Gurney J, Ivens A, Diggle SP, Popat R. Combinatorial communication in bacteria: implications for the origins of linguistic generativity. PLoS One 2014; 9:e95929. [PMID: 24759740 PMCID: PMC3997515 DOI: 10.1371/journal.pone.0095929] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 04/02/2014] [Indexed: 11/29/2022] Open
Abstract
Combinatorial communication, in which two signals are used together to achieve an effect that is different to the sum of the effects of the component parts, is apparently rare in nature: it is ubiquitous in human language, appears to exist in a simple form in some non-human primates, but has not been demonstrated in other species. This observed distribution has led to the pair of related suggestions, that (i) these differences in the complexity of observed communication systems reflect cognitive differences between species; and (ii) that the combinations we see in non-human primates may be evolutionary pre-cursors of human language. Here we replicate the landmark experiments on combinatorial communication in non-human primates, but in an entirely different species, unrelated to humans, and with no higher cognition: the bacterium Pseudomonas aeruginosa. Using the same general methods as the primate studies, we find the same general pattern of results: the effect of the combined signal differs from the composite effect of the two individual signals. This suggests that advanced cognitive abilities and large brains do not necessarily explain why some species have combinatorial communication systems and others do not. We thus argue that it is premature to conclude that the systems observed in non-human primates are evolutionarily related to language. Our results illustrate the value of an extremely broad approach to comparative research.
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Affiliation(s)
| | - James Gurney
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Alasdair Ivens
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | - Stephen P. Diggle
- School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Roman Popat
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
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Abstract
Here, we studied how protist predation affects cooperation in the opportunistic pathogen bacterium Pseudomonas aeruginosa, which uses quorum sensing (QS) cell-to-cell signalling to regulate the production of public goods. By competing wild-type bacteria with QS mutants (cheats), we show that a functioning QS system confers an elevated resistance to predation. Surprisingly, cheats were unable to exploit this resistance in the presence of cooperators, which suggests that resistance does not appear to result from activation of QS-regulated public goods. Instead, elevated resistance of wild-type bacteria was related to the ability to form more predation-resistant biofilms. This could be explained by the expression of QS-regulated resistance traits in densely populated biofilms and floating cell aggregations, or alternatively, by a pleiotropic cost of cheating where less resistant cheats are selectively removed from biofilms. These results show that trophic interactions among species can maintain cooperation within species, and have further implications for P. aeruginosa virulence in environmental reservoirs by potentially enriching the cooperative and highly infective strains with functional QS system.
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Abstract
Quorum sensing (QS) is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion. Signaling via acyl-homoserine lactones is the paradigm for QS in Proteobacteria and is particularly well understood in the opportunistic pathogen Pseudomonas aeruginosa. Despite thirty years of mechanistic research, empirical studies have only recently addressed the benefits of QS and provided support for the traditional assumptions regarding its social nature and its role in optimizing cell-density-dependent group behaviors. QS-controlled public-goods production has served to investigate principles that explain the evolution and stability of cooperation, including kin selection, pleiotropic constraints, and metabolic prudence. With respect to medical application, appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance. Future work will provide additional insight into the foundational assumptions of QS and relate laboratory discoveries to natural ecosystems.
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Affiliation(s)
- Martin Schuster
- Department of Microbiology, Oregon State University, Corvallis, Oregon 97331; ,
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West SA, Winzer K, Gardner A, Diggle SP. Quorum sensing and the confusion about diffusion. Trends Microbiol 2012; 20:586-94. [PMID: 23084573 DOI: 10.1016/j.tim.2012.09.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/18/2012] [Accepted: 09/20/2012] [Indexed: 11/16/2022]
Abstract
Two hypotheses, termed quorum sensing (QS) and diffusion sensing (DS), have been suggested as competing explanations for why bacterial cells use the local concentration of small molecules to regulate numerous extracellular behaviours. Here, we show that: (i) although there are important differences between QS and DS, they are not diametrically opposed; (ii) empirical attempts to distinguish between QS and DS are misguided and will lead to confusion; (iii) the fundamental distinction is not between QS and DS, but whether or not the trait being examined is social; (iv) empirical data are consistent with both social interactions and a role of diffusion; (v) alternate hypotheses, such as efficiency sensing (ES), are not required to unite QS and DS. More generally, work in this area illustrates how the use of jargon can obscure the underlying concepts and key questions.
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Affiliation(s)
- Stuart A West
- Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK.
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Abstract
The idea from human societies that self-interest can lead to a breakdown of cooperation at the group level is sometimes termed the public goods dilemma. We tested this idea in the opportunistic bacterial pathogen, Pseudomonas aeruginosa, by examining the influence of putative cheats that do not cooperate via cell-to-cell signalling (quorum-sensing, QS). We found that: (i) QS cheating occurs in biofilm populations owing to exploitation of QS-regulated public goods; (ii) the thickness and density of biofilms was reduced by the presence of non-cooperative cheats; (iii) population growth was reduced by the presence of cheats, and this reduction was greater in biofilms than in planktonic populations; (iv) the susceptibility of biofilms to antibiotics was increased by the presence of cheats; and (v) coercing cooperator cells to increase their level of cooperation decreases the extent to which the presence of cheats reduces population productivity. Our results provide clear support that conflict over public goods reduces population fitness in bacterial biofilms, and that this effect is greater than in planktonic populations. Finally, we discuss the clinical implications that arise from altering the susceptibility to antibiotics.
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Affiliation(s)
- Roman Popat
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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38
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Youle M, Rohwer F, Stacy A, Whiteley M, Steel BC, Delalez NJ, Nord AL, Berry RM, Armitage JP, Kamoun S, Hogenhout S, Diggle SP, Gurney J, Pollitt EJG, Boetius A, Cary SC. The Microbial Olympics. Nat Rev Microbiol 2012; 10:583-8. [PMID: 22796885 DOI: 10.1038/nrmicro2837] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Every four years, the Olympic Games plays host to competitors who have built on their natural talent by training for many years to become the best in their chosen discipline. Similar spirit and endeavour can be found throughout the microbial world, in which every day is a competition to survive and thrive. Microorganisms are trained through evolution to become the fittest and the best adapted to a particular environmental niche or lifestyle, and to innovate when the 'rules of the game' are changed by alterations to their natural habitats. In this Essay, we honour the best competitors in the microbial world by inviting them to take part in the inaugural Microbial Olympics.
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Affiliation(s)
- Merry Youle
- Rainbow Rock, Ocean View, Hawaii 96737, USA.
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Abstract
Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both produces and responds to QS signal molecules, and a lasR (signal-blind) mutant that does not release extracellular factors in response to signal. We found that: (i) QS leads to greater growth within hosts; (ii) high relatedness favours the QS wild-type; and (iii) low relatedness favours the lasR mutant. Relatedness matters in our experiment because, at relatively low relatedness, the lasR mutant is able to exploit the extracellular factors produced by the cells that respond to QS, and hence increase in frequency. Furthermore, our results suggest that because a higher relatedness favours cooperative QS, and hence leads to higher growth, this will also lead to a higher virulence, giving a relationship between relatedness and virulence that is in the opposite direction to that usually predicted by virulence theory.
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Affiliation(s)
- Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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Crusz SA, Popat R, Rybtke MT, Cámara M, Givskov M, Tolker-Nielsen T, Diggle SP, Williams P. Bursting the bubble on bacterial biofilms: a flow cell methodology. Biofouling 2012; 28:835-42. [PMID: 22877233 PMCID: PMC3438488 DOI: 10.1080/08927014.2012.716044] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/24/2012] [Indexed: 05/21/2023]
Abstract
The flow cell biofilm system is an important and widely used tool for the in vitro cultivation and evaluation of bacterial biofilms under hydrodynamic conditions of flow. This paper provides an introduction to the background and use of such systems, accompanied by a detailed guide to the assembly of the apparatus including the description of new modifications which enhance its performance. As such, this is an essential guide for the novice biofilm researcher as well as providing valuable trouble-shooting techniques for even the most experienced laboratories. The adoption of a common and reliable methodology amongst researchers would enable findings to be shared and replicated amongst the biofilm research community, with the overall aim of advancing understanding and management of these complex and widespread bacterial communities.
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Affiliation(s)
- Shanika A Crusz
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK.
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Abstract
Since quinine was first isolated, animals, plants and microorganisms producing a wide variety of quinolone compounds have been discovered, several of which possess medicinally interesting properties ranging from antiallergenic and anticancer to antimicrobial activities. Over the years, these have served in the development of many synthetic drugs, including the successful fluoroquinolone antibiotics. Pseudomonas aeruginosa and related bacteria produce a number of 2-alkyl-4(1H)-quinolones, some of which exhibit antimicrobial activity. However, quinolones such as the Pseudomonas quinolone signal and 2-heptyl-4-hydroxyquinoline act as quorum-sensing signal molecules, controlling the expression of many virulence genes as a function of cell population density. Here, we review selectively this extensive family of bicyclic compounds, from natural and synthetic antimicrobials to signalling molecules, with a special emphasis on the biology of P. aeruginosa. In particular, we review their nomenclature and biochemistry, their multiple properties as membrane-interacting compounds, inhibitors of the cytochrome bc1 complex and iron chelators, as well as the regulation of their biosynthesis and their integration into the intricate quorum-sensing regulatory networks governing virulence and secondary metabolite gene expression.
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Affiliation(s)
- Stephan Heeb
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham, UK
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Liu X, Jia J, Popat R, Ortori CA, Li J, Diggle SP, Gao K, Cámara M. Characterisation of two quorum sensing systems in the endophytic Serratia plymuthica strain G3: differential control of motility and biofilm formation according to life-style. BMC Microbiol 2011; 11:26. [PMID: 21284858 PMCID: PMC3044098 DOI: 10.1186/1471-2180-11-26] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 02/01/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND N-acylhomoserine lactone (AHL)-based quorum sensing (QS) systems have been described in many plant-associated Gram-negative bacteria to control certain beneficial phenotypic traits, such as production of biocontrol factors and plant growth promotion. However, the role of AHL-mediated signalling in the endophytic strains of plant-associated Serratia is still poorly understood. An endophytic Serratia sp. G3 with biocontrol potential and high levels of AHL signal production was isolated from the stems of wheat and the role of QS in this isolate was determined. RESULTS Strain G3 classified as Serratia plymuthica based on 16S rRNA was subjected to phylogenetic analysis. Using primers to conserved sequences of luxIR homologues from the Serratia genus, splIR and spsIR from the chromosome of strain G3 were cloned and sequenced. AHL profiles from strain G3 and Escherichia coli DH5α expressing splI or spsI from recombinant plasmids were identified by liquid chromatography-tandem mass spectrometry. This revealed that the most abundant AHL signals produced by SplI in E. coli were N-3-oxo-hexanoylhomoserine lactone (3-oxo-C6-HSL), N-3-oxo-heptanoylhomoserine lactone (3-oxo-C7-HSL), N-3-hydroxy-hexanoylhomoserine lactone (3-hydroxy-C6-HSL), N-hexanoylhomoserine lactone (C6-HSL), and N-heptanoyl homoserine lactone (C7-HSL); whereas SpsI was primarily responsible for the synthesis of N-butyrylhomoserine lactone (C4-HSL) and N-pentanoylhomoserine lactone (C5-HSL). Furthermore, a quorum quenching analysis by heterologous expression of the Bacillus A24 AiiA lactonase in strain G3 enabled the identification of the AHL-regulated biocontrol-related traits. Depletion of AHLs with this lactonase resulted in altered adhesion and biofilm formation using a microtiter plate assay and flow cells coupled with confocal laser scanning microscopy respectively. This was different from the closely related S. plymuthica strains HRO-C48 and RVH1, where biofilm formation for both strains is AHL-independent. In addition, QS in G3 positively regulated antifungal activity, production of exoenzymes, but negatively regulated production of indol-3-acetic acid (IAA), which is in agreement with previous reports in strain HRO-C48. However, in contrast to HRO-C48, swimming motility was not controlled by AHL-mediated QS. CONCLUSIONS This is the first report of the characterisation of two AHL-based quorum sensing systems in the same isolate of the genus Serratia. Our results show that the QS network is involved in the global regulation of biocontrol-related traits in the endophytic strain G3. However, although free-living and endophytic S. plymuthica share some conservation on QS phenotypic regulation, the control of motility and biofilm formation seems to be strain-specific and possible linked to the life-style of this organism.
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Affiliation(s)
- Xiaoguang Liu
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Jinli Jia
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Roman Popat
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | | | - Jun Li
- Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China
| | - Stephen P Diggle
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
| | - Kexiang Gao
- Department of Plant Pathology, Shandong Agricultural University, Taian, China
| | - Miguel Cámara
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK
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Abstract
2-alkyl-4-quinolones (AQs) such as 2-heptyl-3-hydroxy-4-quinolone (PQS) and 2-heptyl-4-quinolone (HHQ) are quorum sensing signal molecules. Here we describe two methods for AQ detection and quantification that employ thin layer chromatography (TLC) and microtitre plate assays in combination with a lux-based Pseudomonas aeruginosa AQ biosensor strain. For TLC detection, organic solvent extracts of bacterial cells or spent culture supernatants are chromatographed on TLC plates, which are then dried and overlaid with the AQ biosensor. After detection by the bioreporter, AQs appear as both luminescent and green (pyocyanin) spots. For the microtitre assay, either spent bacterial culture supernatants or extracts are added to a growth medium containing the AQ biosensor. Light output by the bioreporter is proportional to the AQ content of the sample. The assays described are simple to perform, do not require sophisticated instrumentation, and are highly amenable to screening large numbers of bacterial samples.
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Affiliation(s)
- Stephen P Diggle
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
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44
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Johansson EMV, Kadam RU, Rispoli G, Crusz SA, Bartels KM, Diggle SP, Cámara M, Williams P, Jaeger KE, Darbre T, Reymond JL. Inhibition of Pseudomonas aeruginosa biofilms with a glycopeptide dendrimer containing D-amino acids. Med Chem Commun 2011. [DOI: 10.1039/c0md00270d] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Abstract
At the heart of tackling the huge challenge posed by infectious micro-organisms is the overwhelming need to understand their nature. A major question is, why do some species of bacteria rapidly kill their host whilst others are relatively benign? For example, Yersinia pestis, the causative organism of plague, is a highly virulent human pathogen whilst the closely related Yersinia pseudotuberculosis causes a much less severe disease. Using molecular techniques such as mutating certain genes, microbiologists have made significant advances over recent decades in elucidating the mechanisms that govern the production of virulence factors involved in causing disease in many bacterial species. There are also evolutionary and ecological factors which will influence virulence. Many of these ideas have arisen through the development of evolutionary theory and yet there is strikingly little empirical evidence testing them. By applying both mechanistic and adaptive approaches to microbial behaviours we can begin to address questions such as, what factors influence cooperation and the evolution of virulence in microbes and can we exploit these factors to develop new antimicrobial strategies?
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Affiliation(s)
- Stephen P Diggle
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University Park, University of Nottingham, NG7 2RD, UK
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46
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Jiricny N, Diggle SP, West SA, Evans BA, Ballantyne G, Ross-Gillespie A, Griffin AS. Fitness correlates with the extent of cheating in a bacterium. J Evol Biol 2010; 23:738-47. [PMID: 20210835 DOI: 10.1111/j.1420-9101.2010.01939.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is growing awareness of the importance of cooperative behaviours in microbial communities. Empirical support for this insight comes from experiments using mutant strains, termed 'cheats', which exploit the cooperative behaviour of wild-type strains. However, little detailed work has gone into characterising the competitive dynamics of cooperative and cheating strains. We test three specific predictions about the fitness consequences of cheating to different extents by examining the production of the iron-scavenging siderophore molecule, pyoverdin, in the bacterium Pseudomonas aeruginosa. We create a collection of mutants that differ in the amount of pyoverdin that they produce (from 1% to 96% of the production of paired wild types) and demonstrate that these production levels correlate with both gene activity and the ability to bind iron. Across these mutants, we found that (1) when grown in a mixed culture with a cooperative wild-type strain, the relative fitness of a mutant is negatively correlated with the amount of pyoverdin that it produces; (2) the absolute and relative fitness of the wild-type strain in the mixed culture is positively correlated with the amount of pyoverdin that the mutant produces; and (3) when grown in a monoculture, the absolute fitness of the mutant is positively correlated with the amount of pyoverdin that it produces. Overall, we demonstrate that cooperative pyoverdin production is exploitable and illustrate how variation in a social behaviour determines fitness differently, depending on the social environment.
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Affiliation(s)
- N Jiricny
- Department of Zoology, Oxford University, Oxford, UK
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Abstract
Medical science is typically pitted against the evolutionary forces acting upon infective populations of bacteria. As an alternative strategy, we could exploit our growing understanding of population dynamics of social traits in bacteria to help treat bacterial disease. In particular, population dynamics of social traits could be exploited to introduce less virulent strains of bacteria, or medically beneficial alleles into infective populations. We discuss how bacterial strains adopting different social strategies can invade a population of cooperative wild-type, considering public good cheats, cheats carrying medically beneficial alleles (Trojan horses) and cheats carrying allelopathic traits (anti-competitor chemical bacteriocins or temperate bacteriophage viruses). We suggest that exploitation of the ability of cheats to invade cooperative, wild-type populations is a potential new strategy for treating bacterial disease.
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Affiliation(s)
- Sam P. Brown
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Stuart A. West
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Stephen P. Diggle
- School of Molecular Medical Sciences, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Ashleigh S. Griffin
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
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Rumbaugh KP, Diggle SP, Watters CM, Ross-Gillespie A, Griffin AS, West SA. Quorum sensing and the social evolution of bacterial virulence. Curr Biol 2009; 19:341-5. [PMID: 19230668 DOI: 10.1016/j.cub.2009.01.050] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 01/01/2023]
Abstract
The ability of pathogenic bacteria to exploit their hosts depends upon various virulence factors, released in response to the concentration of small autoinducer molecules that are also released by the bacteria [1-5]. In vitro experiments suggest that autoinducer molecules are signals used to coordinate cooperative behaviors and that this process of quorum sensing (QS) can be exploited by individual cells that avoid the cost of either producing or responding to signal [6, 7]. However, whether QS is an exploitable social trait in vivo, and the implications for the evolution of virulence [5, 8-10], remains untested. We show that in mixed infections of the bacterium Pseudomonas aeruginosa, containing quorum-sensing bacteria and mutants that do not respond to signal, virulence in an animal (mouse) model is reduced relative to that of an infection containing no mutants. We show that this is because mutants act as cheats, exploiting the cooperative production of signal and virulence factors by others, and hence increase in frequency. This supports the idea that the invasion of QS mutants in infections of humans [11-13] is due to their social fitness consequences [6, 7, 14] and predicts that increased strain diversity will select for lower virulence.
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Affiliation(s)
- Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, 79430, USA
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Skindersoe ME, Zeuthen LH, Brix S, Fink LN, Lazenby J, Whittall C, Williams P, Diggle SP, Froekiaer H, Cooley M, Givskov M. Pseudomonas aeruginosa quorum-sensing signal molecules interfere with dendritic cell-induced T-cell proliferation. FEMS Immunol Med Microbiol 2009; 55:335-45. [PMID: 19187218 DOI: 10.1111/j.1574-695x.2008.00533.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Pseudomonas aeruginosa releases a wide array of toxins and tissue-degrading enzymes. Production of these malicious virulence factors is controlled by interbacterial communication in a process known as quorum sensing. An increasing body of evidence reveals that the bacterial signal molecule N-(3-oxododecanoyl)-L-homoserine lactone (OdDHL) exhibits both quorum-sensing signalling and immune-modulating properties. Recently, yet another quorum-sensing signal molecule, the Pseudomonas quinolone signal (PQS), has been shown to affect cytokine release by mitogen-stimulated human T cells. In the present article we demonstrate that both OdDHL and PQS decrease the production of interleukin-12 (IL-12) by Escherichia coli lipopolysaccharide-stimulated bone marrow-derived dendritic cells (BM-DCs) without altering their IL-10 release. Moreover, BM-DCs exposed to PQS and OdDHL during antigen stimulation exhibit a decreased ability to induce T-cell proliferation in vitro. Collectively, this suggests that OdDHL and PQS change the maturation pattern of stimulated DCs away from a proinflammatory T-helper type I directing response, thereby decreasing the antibacterial activity of the adaptive immune defence. OdDHL and PQS thus seem to possess dual activities in the infection process: as inducers of virulence factors as well as immune-modulators facilitating the infective properties of this pathogen.
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Affiliation(s)
- Mette E Skindersoe
- Center for Biomedical Microbiology, Technical University of Denmark, Lyngby, Denmark
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Johansson EM, Crusz SA, Kolomiets E, Buts L, Kadam RU, Cacciarini M, Bartels KM, Diggle SP, Cámara M, Williams P, Loris R, Nativi C, Rosenau F, Jaeger KE, Darbre T, Reymond JL. Inhibition and Dispersion of Pseudomonas aeruginosa Biofilms by Glycopeptide Dendrimers Targeting the Fucose-Specific Lectin LecB. ACTA ACUST UNITED AC 2008; 15:1249-57. [DOI: 10.1016/j.chembiol.2008.10.009] [Citation(s) in RCA: 182] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 09/25/2008] [Accepted: 10/03/2008] [Indexed: 11/30/2022]
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