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Uberoi A, McCready-Vangi A, Grice EA. The wound microbiota: microbial mechanisms of impaired wound healing and infection. Nat Rev Microbiol 2024; 22:507-521. [PMID: 38575708 DOI: 10.1038/s41579-024-01035-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2024] [Indexed: 04/06/2024]
Abstract
The skin barrier protects the human body from invasion by exogenous and pathogenic microorganisms. A breach in this barrier exposes the underlying tissue to microbial contamination, which can lead to infection, delayed healing, and further loss of tissue and organ integrity. Delayed wound healing and chronic wounds are associated with comorbidities, including diabetes, advanced age, immunosuppression and autoimmune disease. The wound microbiota can influence each stage of the multi-factorial repair process and influence the likelihood of an infection. Pathogens that commonly infect wounds, such as Staphylococcus aureus and Pseudomonas aeruginosa, express specialized virulence factors that facilitate adherence and invasion. Biofilm formation and other polymicrobial interactions contribute to host immunity evasion and resistance to antimicrobial therapies. Anaerobic organisms, fungal and viral pathogens, and emerging drug-resistant microorganisms present unique challenges for diagnosis and therapy. In this Review, we explore the current understanding of how microorganisms present in wounds impact the process of skin repair and lead to infection through their actions on the host and the other microbial wound inhabitants.
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Affiliation(s)
- Aayushi Uberoi
- Departments of Dermatology and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Amelia McCready-Vangi
- Departments of Dermatology and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elizabeth A Grice
- Departments of Dermatology and Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Morales L, Cobo A, Frías MP, Gálvez A, Ortega E. The Prevalence of Antibiotic Resistance Phenotypes and Genotypes in Multidrug-Resistant Bacterial Isolates from the Academic Hospital of Jaén, Spain. Antibiotics (Basel) 2024; 13:429. [PMID: 38786157 PMCID: PMC11117780 DOI: 10.3390/antibiotics13050429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
The heterogenicity of antimicrobial resistance genes described in clinically significant bacterial isolates and their potential role in reducing the efficacy of classically effective antibiotics pose a major challenge for global healthcare, especially in infections caused by Gram-negative bacteria. We analyzed 112 multidrug-resistant (MDR) isolates from clinical samples in order to detect high resistance profiles, both phenotypically and genotypically, among four Gram-negative genera (Acinetobacter, Escherichia, Klebsiella, and Pseudomonas). We found that 9.8% of the total selected isolates were classified as extensively drug-resistant (XDR) (six isolates identified as A. baumannii and five among P. pneumoniae isolates). All other isolates were classified as MDR. Almost 100% of the isolates showed positive results for blaOXA-23 and blaNDM-1 genes among the A. baumannii samples, one resistance gene (blaCTX-M) among E. coli, and two genetic determinants (blaCTX-M and aac(6')-Ib) among Klebsiella. In contrast, P. aeruginosa showed just one high-frequency antibiotic resistance gene (dfrA), which was present in 68.42% of the isolates studied. We also describe positive associations between ampicillin and cefotaxime resistance in A. baumannii and the presence of blaVEB and blaGES genes, as well as between the aztreonam resistance phenotype and the presence of blaGES gene in E. coli. These data may be useful in achieving a better control of infection strategies and antibiotic management in clinical scenarios where these multidrug-resistant Gram-negative pathogens cause higher morbidity and mortality.
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Affiliation(s)
- Laura Morales
- Microbiolgy Unit, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, 23071 Jaén, Spain; (L.M.); (A.C.); (A.G.)
| | - Antonio Cobo
- Microbiolgy Unit, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, 23071 Jaén, Spain; (L.M.); (A.C.); (A.G.)
| | - María Pilar Frías
- Department of Statistics and Operation Research, Faculty of Experimental Sciences, University of Jaén, 23071 Jaén, Spain;
| | - Antonio Gálvez
- Microbiolgy Unit, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, 23071 Jaén, Spain; (L.M.); (A.C.); (A.G.)
| | - Elena Ortega
- Microbiolgy Unit, Department of Health Sciences, Faculty of Experimental Sciences, University of Jaén, 23071 Jaén, Spain; (L.M.); (A.C.); (A.G.)
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3
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Dekker JP. Within-Host Evolution of Bacterial Pathogens in Acute and Chronic Infection. ANNUAL REVIEW OF PATHOLOGY 2024; 19:203-226. [PMID: 37832940 DOI: 10.1146/annurev-pathmechdis-051122-111408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Bacterial pathogens undergo remarkable adaptive change in response to the selective forces they encounter during host colonization and infection. Studies performed over the past few decades have demonstrated that many general evolutionary processes can be discerned during the course of host adaptation, including genetic diversification of lineages, clonal succession events, convergent evolution, and balanced fitness trade-offs. In some cases, elevated mutation rates resulting from mismatch repair or proofreading deficiencies accelerate evolution, and active mobile genetic elements or phages may facilitate genome plasticity. The host immune response provides another critical component of the fitness landscapes guiding adaptation, and selection operating on pathogens at this level may lead to immune evasion and the establishment of chronic infection. This review summarizes recent advances in this field, with a special focus on different forms of bacterial genome plasticity in the context of infection, and considers clinical consequences of adaptive changes for the host.
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Affiliation(s)
- John P Dekker
- Bacterial Pathogenesis and Antimicrobial Resistance Unit, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA;
- National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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4
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Kragh KN, Tolker-Nielsen T, Lichtenberg M. The non-attached biofilm aggregate. Commun Biol 2023; 6:898. [PMID: 37658117 PMCID: PMC10474055 DOI: 10.1038/s42003-023-05281-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/24/2023] [Indexed: 09/03/2023] Open
Abstract
Biofilms have conventionally been perceived as dense bacterial masses on surfaces, following the five-step model of development. Initial biofilm research focused on surface-attached formations, but detached aggregates have received increasing attention in the past decade due to their pivotal role in chronic infections. Understanding their nature sparked fervent discussions in biofilm conferences and scientific literature. This review consolidates current insights on non-attached aggregates, offering examples of their occurrence in nature and diseases. We discuss their formation and dispersion mechanisms, resilience to antibiotics and immune-responses, drawing parallels to surface-attached biofilms. Moreover, we outline available in vitro models for studying non-attached aggregates.
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Affiliation(s)
- Kasper N Kragh
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Mads Lichtenberg
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
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5
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Liang Z, Nilsson M, Kragh KN, Hedal I, Alcàcer-Almansa J, Kiilerich RO, Andersen JB, Tolker-Nielsen T. The role of individual exopolysaccharides in antibiotic tolerance of Pseudomonas aeruginosa aggregates. Front Microbiol 2023; 14:1187708. [PMID: 37333638 PMCID: PMC10272609 DOI: 10.3389/fmicb.2023.1187708] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023] Open
Abstract
The bacterium Pseudomonas aeruginosa is involved in chronic infections of cystic fibrosis lungs and chronic wounds. In these infections the bacteria are present as aggregates suspended in host secretions. During the course of the infections there is a selection for mutants that overproduce exopolysaccharides, suggesting that the exopolysaccharides play a role in the persistence and antibiotic tolerance of the aggregated bacteria. Here, we investigated the role of individual P. aeruginosa exopolysaccharides in aggregate-associated antibiotic tolerance. We employed an aggregate-based antibiotic tolerance assay on a set of P. aeruginosa strains that were genetically engineered to over-produce a single, none, or all of the three exopolysaccharides Pel, Psl, and alginate. The antibiotic tolerance assays were conducted with the clinically relevant antibiotics tobramycin, ciprofloxacin and meropenem. Our study suggests that alginate plays a role in the tolerance of P. aeruginosa aggregates toward tobramycin and meropenem, but not ciprofloxacin. However, contrary to previous studies we did not observe a role for Psl or Pel in the tolerance of P. aeruginosa aggregates toward tobramycin, ciprofloxacin, and meropenem.
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Affiliation(s)
- Ziwei Liang
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Martin Nilsson
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Nørskov Kragh
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Ida Hedal
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Júlia Alcàcer-Almansa
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Bacterial Infections: Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Rikke Overgaard Kiilerich
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Andersen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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6
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Römling U, Cao LY, Bai FW. Evolution of cyclic di-GMP signalling on a short and long term time scale. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001354. [PMID: 37384391 PMCID: PMC10333796 DOI: 10.1099/mic.0.001354] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 06/13/2023] [Indexed: 07/01/2023]
Abstract
Diversifying radiation of domain families within specific lineages of life indicates the importance of their functionality for the organisms. The foundation for the diversifying radiation of the cyclic di-GMP signalling network that occurred within the bacterial kingdom is most likely based in the outmost adaptability, flexibility and plasticity of the system. Integrative sensing of multiple diverse extra- and intracellular signals is made possible by the N-terminal sensory domains of the modular cyclic di-GMP turnover proteins, mutations in the protein scaffolds and subsequent signal reception by diverse receptors, which eventually rewires opposite host-associated as well as environmental life styles including parallel regulated target outputs. Natural, laboratory and microcosm derived microbial variants often with an altered multicellular biofilm behaviour as reading output demonstrated single amino acid substitutions to substantially alter catalytic activity including substrate specificity. Truncations and domain swapping of cyclic di-GMP signalling genes and horizontal gene transfer suggest rewiring of the network. Presence of cyclic di-GMP signalling genes on horizontally transferable elements in particular observed in extreme acidophilic bacteria indicates that cyclic di-GMP signalling and biofilm components are under selective pressure in these types of environments. On a short and long term evolutionary scale, within a species and in families within bacterial orders, respectively, the cyclic di-GMP signalling network can also rapidly disappear. To investigate variability of the cyclic di-GMP signalling system on various levels will give clues about evolutionary forces and discover novel physiological and metabolic pathways affected by this intriguing second messenger signalling system.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
| | - Feng-Wu Bai
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, PR China
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7
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Ghimire J, Hart RJ, Soldano A, Chen CH, Guha S, Hoffmann JP, Hall KM, Sun L, Nelson BJ, Lu TK, Kolls JK, Rivera M, Morici LA, Wimley WC. Optimization of Host Cell-Compatible, Antimicrobial Peptides Effective against Biofilms and Clinical Isolates of Drug-Resistant Bacteria. ACS Infect Dis 2023; 9:952-965. [PMID: 36961222 PMCID: PMC10111420 DOI: 10.1021/acsinfecdis.2c00640] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Indexed: 03/25/2023]
Abstract
Here, we describe the continued synthetic molecular evolution of a lineage of host-compatible antimicrobial peptides (AMP) intended for the treatment of wounds infected with drug-resistant, biofilm-forming bacteria. The peptides tested are variants of an evolved AMP called d-amino acid CONsensus with Glycine Absent (d-CONGA), which has excellent antimicrobial activities in vitro and in vivo. In this newest generation of rational d-CONGA variants, we tested multiple sequence-structure-function hypotheses that had not been tested in previous generations. Many of the peptide variants have lower antibacterial activity against Gram-positive or Gram-negative pathogens, especially variants that have altered hydrophobicity, secondary structure potential, or spatial distribution of charged and hydrophobic residues. Thus, d-CONGA is generally well tuned for antimicrobial activity. However, we identified a variant, d-CONGA-Q7, with a polar glutamine inserted into the middle of the sequence, that has higher activity against both planktonic and biofilm-forming bacteria as well as lower cytotoxicity against human fibroblasts. Against clinical isolates of Klebsiella pneumoniae, innate resistance to d-CONGA was surprisingly common despite a lack of inducible resistance in Pseudomonas aeruginosa reported previously. Yet, these same isolates were susceptible to d-CONGA-Q7. d-CONGA-Q7 is much less vulnerable to AMP resistance in Gram-negative bacteria than its predecessor. Consistent with the spirit of synthetic molecular evolution, d-CONGA-Q7 achieved a critical gain-of-function and has a significantly better activity profile.
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Affiliation(s)
- Jenisha Ghimire
- Department
of Biochemistry and Molecular Biology, Tulane
University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Robert J. Hart
- Department
of Microbiology and Immunology, Tulane University
School of Medicine, New Orleans, Louisiana 70112, United States
| | - Anabel Soldano
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Charles H. Chen
- Synthetic
Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, United States
| | - Shantanu Guha
- Department
of Biochemistry and Molecular Biology, Tulane
University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Joseph P. Hoffmann
- Department
of Microbiology and Immunology, Tulane University
School of Medicine, New Orleans, Louisiana 70112, United States
| | - Kalen M. Hall
- Department
of Microbiology and Immunology, Tulane University
School of Medicine, New Orleans, Louisiana 70112, United States
| | - Leisheng Sun
- Department
of Biochemistry and Molecular Biology, Tulane
University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Benjamin J. Nelson
- Department
of Biochemistry and Molecular Biology, Tulane
University School of Medicine, New Orleans, Louisiana 70112, United States
| | - Timothy K. Lu
- Synthetic
Biology Group, Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, United States
| | - Jay K. Kolls
- Department
of Medicine, Tulane University School of
Medicine, New Orleans, Louisiana 70112, United States
| | - Mario Rivera
- Department
of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Lisa A. Morici
- Department
of Microbiology and Immunology, Tulane University
School of Medicine, New Orleans, Louisiana 70112, United States
| | - William C. Wimley
- Department
of Biochemistry and Molecular Biology, Tulane
University School of Medicine, New Orleans, Louisiana 70112, United States
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8
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Emergence of Small Colony Variants Is an Adaptive Strategy Used by Pseudomonas aeruginosa to Mitigate the Effects of Redox Imbalance. mSphere 2023; 8:e0005723. [PMID: 36853007 PMCID: PMC10117050 DOI: 10.1128/msphere.00057-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
The ability to generate a subpopulation of small colony variants (SCVs) is a conserved feature of Pseudomonas aeruginosa and could represent a key adaptive strategy to colonize and persist in multiple niches. However, very little is known about the role of the SCV phenotype, the conditions that promote its emergence, and its possible involvement in an adaptive strategy. In the present work, we investigated the in vitro selective conditions promoting the emergence of SCVs from the prototypical strain PA14, which readily forms SCVs in nonagitated standing cultures. We found that O2 limitation, which causes a redox imbalance, is the main factor selecting for the SCV phenotype, which promotes survival of the population via formation of a biofilm at the air-liquid interface to access the electron acceptor. When this selective pressure is relieved by aeration or supplementation of an alternative electron acceptor, SCVs are barely detectable. We also observed that SCV emergence contributes to redox rebalancing, suggesting that it is involved in an adaptive strategy. We conclude that selection for the SCV phenotype is an adaptive solution adopted by P. aeruginosa to access poorly available O2. IMPORTANCE The bacterium Pseudomonas aeruginosa is an opportunistic pathogen that thrives in many environments. It poses a significant health concern, notably because it is a causative agent of nosocomial infections and the most prevalent pathogen found in the lungs of people with cystic fibrosis. In infected hosts, its persistence is often related to the emergence of an alternative phenotype known as small colony variant (SCV). Identification of conditions selecting for the SCV phenotype contributes to knowledge regarding adaptive mechanisms exploited by P. aeruginosa to survive in multiple niches and persist during infections. Hindering this adaptation strategy could help control persistent P. aeruginosa infections.
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9
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Pseudomonas aeruginosa Strains from Both Clinical and Environmental Origins Readily Adopt a Stable Small-Colony-Variant Phenotype Resulting from Single Mutations in c-di-GMP Pathways. J Bacteriol 2022; 204:e0018522. [PMID: 36102640 PMCID: PMC9578426 DOI: 10.1128/jb.00185-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A subpopulation of small-colony variants (SCVs) is a frequently observed feature of Pseudomonas aeruginosa isolates obtained from colonized cystic fibrosis lungs. Since most SCVs have until now been isolated from clinical samples, it remains unclear how widespread the ability of P. aeruginosa strains to develop this phenotype is and what the genetic mechanism(s) behind the emergence of SCVs are according to the origin of the isolate. In the present work, we investigated the ability of 22 P. aeruginosa isolates from various environmental origins to spontaneously adopt an SCV-like smaller alternative morphotype distinguishable from that of the ancestral parent strain under laboratory culture conditions. We found that all the P. aeruginosa strains tested could adopt an SCV phenotype, regardless of their origin. Whole-genome sequencing of SCVs obtained from clinical and environmental sources revealed single mutations exclusively in two distinct c-di-GMP signaling pathways, the Wsp and YfiBNR pathways. We conclude that the ability to switch to an SCV phenotype is a conserved feature of P. aeruginosa and results from the acquisition of a stable genetic mutation, regardless of the origin of the strain. IMPORTANCE P. aeruginosa is an opportunistic pathogen that thrives in many environments. It poses a significant health concern, notably because this bacterium is the most prevalent pathogen found in the lungs of people with cystic fibrosis. In infected hosts, its persistence is considered related to the emergence of an alternative small-colony-variant (SCV) phenotype. By reporting the distribution of P. aeruginosa SCVs in various nonclinical environments and the involvement of c-di-GMP in SCV emergence from both clinical and environmental strains, this work contributes to understanding a conserved adaptation mechanism used by P. aeruginosa to adapt readily in all environments. Hindering this adaptation strategy could help control persistent infection by P. aeruginosa.
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Dostert M, Belanger CR, Pedraz L, Alford MA, Blimkie TM, Falsafi RF, Bains M, Dhillon BK, Haney CH, Lee AH, Hancock REW. BosR: A novel biofilm-specific regulator in Pseudomonas aeruginosa. Front Microbiol 2022; 13:1021021. [PMID: 36312952 PMCID: PMC9611778 DOI: 10.3389/fmicb.2022.1021021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Biofilms are the most common cause of bacterial infections in humans and notoriously hard to treat due to their ability to withstand antibiotics and host immune defenses. To overcome the current lack of effective antibiofilm therapies and guide future design, the identification of novel biofilm-specific gene targets is crucial. In this regard, transcriptional regulators have been proposed as promising targets for antimicrobial drug design. Therefore, a Transposon insertion sequencing approach was employed to systematically identify regulators phenotypically affecting biofilm growth in Pseudomonas aeruginosa PA14 using the TnSeq analysis tools Bio-TraDIS and TRANSIT. A screen of a pool of 300,000 transposon insertion mutants identified 349 genes involved in biofilm growth on hydroxyapatite, including 47 regulators. Detection of 19 regulatory genes participating in well-established biofilm pathways validated the results. An additional 28 novel prospective biofilm regulators suggested the requirement for multiple one-component transcriptional regulators. Biofilm-defective phenotypes were confirmed for five one-component transcriptional regulators and a protein kinase, which did not affect motility phenotypes. The one-component transcriptional regulator bosR displayed a conserved role in P. aeruginosa biofilm growth since its ortholog in P. aeruginosa strain PAO1 was also required for biofilm growth. Microscopic analysis of a chromosomal deletion mutant of bosR confirmed the role of this regulator in biofilm growth. Overall, our results highlighted that the gene network driving biofilm growth is complex and involves regulators beyond the primarily studied groups of two-component systems and cyclic diguanylate signaling proteins. Furthermore, biofilm-specific regulators, such as bosR, might constitute prospective new drug targets to overcome biofilm infections.
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Affiliation(s)
- Melanie Dostert
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Corrie R. Belanger
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Lucas Pedraz
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Morgan A. Alford
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Travis M. Blimkie
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Reza F. Falsafi
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Manjeet Bains
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Bhavjinder Kaur Dhillon
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
| | - Cara H. Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Amy H. Lee
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Robert E. W. Hancock,
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11
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Liu YS, Deng Y, Chen CK, Khoo BL, Chua SL. Rapid detection of microorganisms in a fish infection microfluidics platform. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128572. [PMID: 35278965 DOI: 10.1016/j.jhazmat.2022.128572] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/14/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Inadequate access to clean water is detrimental to human health and aquatic industries. Waterborne pathogens can survive prolonged periods in aquatic bodies, infect commercially important seafood, and resist water disinfection, resulting in human infections. Environmental agencies and research laboratories require a relevant, portable, and cost-effective platform to monitor microbial pathogens and assess their risk of infection on a large scale. Advances in microfluidics enable better control and higher precision than traditional culture-based pathogen monitoring approaches. We demonstrated a rapid, high-throughput fish-based teleost (fish)-microbe (TelM) microfluidic-based device that simultaneously monitors waterborne pathogens in contaminated waters and assesses their infection potential under well-defined settings. A chamber-associated port allows direct access to the animal, while the transparency of the TelM platform enables clear observation of sensor readouts. As proof-of-concept, we established a wound infection model using Pseudomonas aeruginosa-contaminated water in the TelM platform, where bacteria formed biofilms on the wound and secreted a biofilm metabolite, pyoverdine. Pyoverdine was used as fluorescent sensor to correlate P. aeruginosa contamination to infection. The TelM platform was validated with environmental waterborne microbes from marine samples. Overall, the TelM platform can be readily applied to assess microbial and chemical risk in aquatic bodies in resource-constrained settings.
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Affiliation(s)
- Yang Sylvia Liu
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Yanlin Deng
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Chun Kwan Chen
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Bee Luan Khoo
- Department of Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong, China; Hong Kong Center for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China; City University of Hong Kong - Futian Shenzhen Research Institute, China.
| | - Song Lin Chua
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; State Key Laboratory of Chemical Biology and Drug Discovery, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; Research Centre for Deep Space Explorations, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China; Shenzhen Key Laboratory of Food Biological Safety Control, China.
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12
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Ma LZ, Wang D, Liu Y, Zhang Z, Wozniak DJ. Regulation of Biofilm Exopolysaccharide Biosynthesis and Degradation in Pseudomonas aeruginosa. Annu Rev Microbiol 2022; 76:413-433. [DOI: 10.1146/annurev-micro-041320-111355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial communities enmeshed in a matrix of macromolecules, termed as biofilms, are the natural setting of bacteria. Exopolysaccharide is a critical matrix component of biofilms. Here, we focus on biofilm matrix exopolysaccharides in Pseudomonas aeruginosa. This opportunistic pathogen can adapt to a wide range of environments and can form biofilms or aggregates in a variety of surfaces or environments, such as the lungs of people with cystic fibrosis, catheters, wounds, and contact lenses. The ability to synthesize multiple exopolysaccharides is one of the advantages that facilitate bacterial survival in different environments. P. aeruginosa can produce several exopolysaccharides, including alginate, Psl, Pel, and lipopolysaccharide. In this review, we highlight the roles of each exopolysaccharide in P. aeruginosa biofilm development and how bacteria coordinate the biosynthesis of multiple exopolysaccharides and bacterial motility. In addition, we present advances in antibiofilm strategies targeting matrix exopolysaccharides, with a focus on glycoside hydrolases. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Luyan Z. Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Di Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yiwei Liu
- Department of Microbial Infection and Immunity and Department of Microbiology, Ohio State University, Columbus, Ohio, USA
| | - Zhenyu Zhang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Daniel J. Wozniak
- Department of Microbial Infection and Immunity and Department of Microbiology, Ohio State University, Columbus, Ohio, USA
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13
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Santos-Lopez A, Fritz MJ, Lombardo JB, Burr AHP, Heinrich VA, Marshall CW, Cooper VS. Evolved resistance to a novel cationic peptide antibiotic requires high mutation supply. Evol Med Public Health 2022; 10:266-276. [PMID: 35712084 PMCID: PMC9198447 DOI: 10.1093/emph/eoac022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/21/2022] [Indexed: 01/30/2023] Open
Abstract
Background and Objectives A key strategy for resolving the antibiotic resistance crisis is the development of new drugs with antimicrobial properties. The engineered cationic antimicrobial peptide WLBU2 (also known as PLG0206) is a promising broad-spectrum antimicrobial compound that has completed Phase I clinical studies. It has activity against Gram-negative and Gram-positive bacteria including infections associated with biofilm. No definitive mechanisms of resistance to WLBU2 have been identified. Methodology Here, we used experimental evolution under different levels of mutation supply and whole genome sequencing (WGS) to detect the genetic pathways and probable mechanisms of resistance to this peptide. We propagated populations of wild-type and hypermutator Pseudomonas aeruginosa in the presence of WLBU2 and performed WGS of evolved populations and clones. Results Populations that survived WLBU2 treatment acquired a minimum of two mutations, making the acquisition of resistance more difficult than for most antibiotics, which can be tolerated by mutation of a single target. Major targets of resistance to WLBU2 included the orfN and pmrB genes, previously described to confer resistance to other cationic peptides. More surprisingly, mutations that increase aggregation such as the wsp pathway were also selected despite the ability of WLBU2 to kill cells growing in a biofilm. Conclusions and implications The results show how experimental evolution and WGS can identify genetic targets and actions of new antimicrobial compounds and predict pathways to resistance of new antibiotics in clinical practice.
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Affiliation(s)
- Alfonso Santos-Lopez
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Present address: Department of Microbiology, Hospital Universitario Ramon y Cajal, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- Present address: Department of Microbial Biology, National Center of Biotechnology (CNB), Madrid, Spain
| | - Melissa J Fritz
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Jeffrey B Lombardo
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Ansen H P Burr
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Victoria A Heinrich
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Christopher W Marshall
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Present address: Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, 15219 USA
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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14
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Zeng Z, Lin S, Li Q, Wang W, Wang Y, Xiao T, Guo Y. Molecular Basis of Wrinkled Variants Isolated From Pseudoalteromonas lipolytica Biofilms. Front Microbiol 2022; 13:797197. [PMID: 35295294 PMCID: PMC8919034 DOI: 10.3389/fmicb.2022.797197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Many Pseudoalteromonas species are dominant biofilm-forming Gammaproteobacteria in the ocean. The formation of Pseudoalteromonas biofilms is often accompanied by the occurrence of variants with different colony morphologies that may exhibit increased marine antifouling or anticorrosion activities. However, the genetic basis of the occurrence of these variants remains largely unexplored. In this study, we identified that wrinkled variants of P. lipolytica mainly arose due to mutations in the AT00_08765, a wspF-like gene, that are associated with decreased swimming motility and increased cellulose production. Moreover, we found that the spontaneous mutation in flhA, encoding a flagellar biosynthesis protein, also caused a wrinkled colony morphology that is associated with cellulose overproduction, indicating that flhA plays a dual role in controlling flagellar assembly and polysaccharide production in P. lipolytica. Investigation of wrinkled variants harboring spontaneous mutation in dgcB, encoding a GGDEF domain protein, also demonstrated dgcB plays an important role in regulating cellulose production and swimming motility. In addition, by screening the suppressor of the AT00_08765 variant strain, we also identified that the spontaneous mutation in cheR and bcsC directly abolished the wrinkled phenotype of the AT00_08765 variant strain, suggesting that the chemosensory signaling transduction and cellulose production are crucial for the determination of the wrinkled phenotype in P. lipolytica. Taken together, this study provides insights into the genetic variation within biofilms of P. lipolytica.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Shituan Lin
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qian Li
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Weiquan Wang
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuqi Wang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
| | - Tangfu Xiao
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, China
- State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, China
| | - Yuexue Guo
- Key Laboratory of Tropical Marine Bio-Resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Yuexue Guo,
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15
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The nutritional environment is sufficient to select coexisting biofilm and quorum-sensing mutants of Pseudomonas aeruginosa. J Bacteriol 2022; 204:e0044421. [PMID: 34978461 DOI: 10.1128/jb.00444-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The evolution of bacterial populations during infections can be influenced by various factors including available nutrients, the immune system, and competing microbes, rendering it difficult to identify the specific forces that select on evolved traits. The genomes of Pseudomonas aeruginosa isolated from the airway of patients with cystic fibrosis (CF), for example, have revealed commonly mutated genes, but which phenotypes led to their prevalence is often uncertain. Here, we focus on effects of nutritional components of the CF airway on genetic adaptations by P. aeruginosa grown in either well-mixed (planktonic) or biofilm-associated conditions. After only 80 generations of experimental evolution in a simple medium with glucose, lactate, and amino acids, all planktonic populations diversified into lineages with mutated genes common to CF infections: morA, encoding a regulator of biofilm formation, or lasR, encoding a quorum sensing regulator that modulates the expression of virulence factors. Although mutated quorum sensing is often thought to be selected in vivo due to altered virulence phenotypes or social cheating, isolates with lasR mutations demonstrated increased fitness when grown alone and outcompeted the ancestral PA14 strain. Nonsynonymous SNPs in morA increased fitness in a nutrient concentration-dependent manner during planktonic growth and surprisingly also increased biofilm production. Populations propagated in biofilm conditions also acquired mutations in loci associated with chronic infections, including lasR and cyclic-di-GMP regulators roeA and wspF. These findings demonstrate that nutrient conditions and biofilm selection are sufficient to select mutants with problematic clinical phenotypes including increased biofilm and altered quorum sensing. Importance Pseudomonas aeruginosa produces dangerous chronic infections that are known for their rapid diversification and recalcitrance to treatment. We performed evolution experiments to identify adaptations selected by two specific aspects of the CF respiratory environment: nutrient levels and surface attachment. Propagation of P. aeruginosa in nutrients present within the CF airway was sufficient to drive diversification into subpopulations with identical mutations in regulators of biofilm and quorum sensing to those arising during infection. Thus, the adaptation of opportunistic pathogens to nutrients found in the host may select mutants with phenotypes that complicate treatment and clearance of infection.
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16
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Matilla MA, Velando F, Monteagudo-Cascales E, Krell T. Flagella, Chemotaxis and Surface Sensing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:185-221. [DOI: 10.1007/978-3-031-08491-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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β-lactam Resistance in Pseudomonas aeruginosa: Current Status, Future Prospects. Pathogens 2021; 10:pathogens10121638. [PMID: 34959593 PMCID: PMC8706265 DOI: 10.3390/pathogens10121638] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/06/2021] [Accepted: 12/16/2021] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is a major opportunistic pathogen, causing a wide range of acute and chronic infections. β-lactam antibiotics including penicillins, carbapenems, monobactams, and cephalosporins play a key role in the treatment of P. aeruginosa infections. However, a significant number of isolates of these bacteria are resistant to β-lactams, complicating treatment of infections and leading to worse outcomes for patients. In this review, we summarize studies demonstrating the health and economic impacts associated with β-lactam-resistant P. aeruginosa. We then describe how β-lactams bind to and inhibit P. aeruginosa penicillin-binding proteins that are required for synthesis and remodelling of peptidoglycan. Resistance to β-lactams is multifactorial and can involve changes to a key target protein, penicillin-binding protein 3, that is essential for cell division; reduced uptake or increased efflux of β-lactams; degradation of β-lactam antibiotics by increased expression or altered substrate specificity of an AmpC β-lactamase, or by the acquisition of β-lactamases through horizontal gene transfer; and changes to biofilm formation and metabolism. The current understanding of these mechanisms is discussed. Lastly, important knowledge gaps are identified, and possible strategies for enhancing the effectiveness of β-lactam antibiotics in treating P. aeruginosa infections are considered.
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18
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Harris KB, Flynn KM, Cooper VS. Polygenic Adaptation and Clonal Interference Enable Sustained Diversity in Experimental Pseudomonas aeruginosa Populations. Mol Biol Evol 2021; 38:5359-5375. [PMID: 34410431 PMCID: PMC8662654 DOI: 10.1093/molbev/msab248] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
How biodiversity arises and can be maintained in asexual microbial populations growing on a single resource remains unclear. Many models presume that beneficial genotypes will outgrow others and purge variation via selective sweeps. Environmental structure like that found in biofilms, which are associated with persistence during infection and other stressful conditions, may oppose this process and preserve variation. We tested this hypothesis by evolving Pseudomonas aeruginosa populations in biofilm-promoting arginine media for 3 months, using both a bead model of the biofilm life cycle and planktonic serial transfer. Surprisingly, adaptation and diversification were mostly uninterrupted by fixation events that eliminate diversity, with hundreds of mutations maintained at intermediate frequencies. The exceptions included genotypes with mutator alleles that also accelerated genetic diversification. Despite the rarity of hard sweeps, a remarkable 40 genes acquired parallel mutations in both treatments and often among competing genotypes within a population. These incomplete soft sweeps include several transporters (including pitA, pntB, nosD, and pchF) suggesting adaptation to the growth media that becomes highly alkaline during growth. Further, genes involved in signal transduction (including gacS, aer2, bdlA, and PA14_71750) reflect likely adaptations to biofilm-inducing conditions. Contrary to evolution experiments that select mutations in a few genes, these results suggest that some environments may expose a larger fraction of the genome and select for many adaptations at once. Thus, even growth on a sole carbon source can lead to persistent genetic and phenotypic variation despite strong selection that would normally purge diversity.
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Affiliation(s)
- Katrina B Harris
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kenneth M Flynn
- Department of Molecular, Cellular, and Biomedical Sciences, University of New Hampshire, Durham, NH, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, and Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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19
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Xu A, Zhang X, Wang T, Xin F, Ma LZ, Zhou J, Dong W, Jiang M. Rugose small colony variant and its hyper-biofilm in Pseudomonas aeruginosa: Adaption, evolution, and biotechnological potential. Biotechnol Adv 2021; 53:107862. [PMID: 34718136 DOI: 10.1016/j.biotechadv.2021.107862] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 10/23/2021] [Accepted: 10/24/2021] [Indexed: 12/16/2022]
Abstract
One of the hallmarks of the environmental bacterium Pseudomonas aeruginosa is its excellent ecological flexibility, which can thrive in diverse ecological niches. In different ecosystems, P. aeruginosa may use different strategies to survive, such as forming biofilms in crude oil environment, converting to mucoid phenotype in the cystic fibrosis (CF) lung, or becoming persisters when treated with antibiotics. Rugose small colony variants (RSCVs) are the adaptive mutants of P. aeruginosa, which can be frequently isolated from chronic infections. During the past years, there has been a renewed interest in using P. aeruginosa as a model organism to investigate the RSCVs formation, persistence and pathogenesis, as RSCVs represent a hyper-biofilm formation, high adaptability, high-tolerance sub-population in biofilms. This review will briefly summarize recent advances regarding the phenotypic, genetic and host interaction associated with RSCVs, with an emphasis on P. aeruginosa. Meanwhile, some non-pathogenic bacteria such as Pseudomonas fluorescence, Pseudomonas putida and Bacillus subtilis will be also included. Remarkable emphasis is given on intrinsic functions of such hyper-biofilm formation characteristic as well as its potential applications in several biocatalytic transformations including wastewater treatment, microbial fermentation, and plastic degradation. Hopefully, this review will attract the interest of researchers in various fields and shape future research focused not only on evolutionary biology but also on biotechnological applications related to RSCVs.
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Affiliation(s)
- Anming Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China.
| | - Xiaoxiao Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Tong Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Luyan Z Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China.
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China.
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211800, China
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20
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Evolutionary Divergence of the Wsp Signal Transduction Systems in Beta- and Gammaproteobacteria. Appl Environ Microbiol 2021; 87:e0130621. [PMID: 34495711 PMCID: PMC8552884 DOI: 10.1128/aem.01306-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria rapidly adapt to their environment by integrating external stimuli through diverse signal transduction systems. Pseudomonas aeruginosa, for example, senses surface contact through the Wsp signal transduction system to trigger the production of cyclic di-GMP. Diverse mutations in wsp genes that manifest enhanced biofilm formation are frequently reported in clinical isolates of P. aeruginosa and in biofilm studies of Pseudomonas spp. and Burkholderia cenocepacia. In contrast to the convergent phenotypes associated with comparable wsp mutations, we demonstrate that the Wsp system in B. cenocepacia does not impact intracellular cyclic di-GMP levels, unlike that in Pseudomonas spp. Our current mechanistic understanding of the Wsp system is based entirely on the study of four Pseudomonas spp., and its phylogenetic distribution remains unknown. Here, we present a broad phylogenetic analysis to show that the Wsp system originated in the betaproteobacteria and then horizontally transferred to Pseudomonas spp., the sole member of the gammaproteobacteria. Alignment of 794 independent Wsp systems with reported mutations from the literature identified key amino acid residues that fall within and outside annotated functional domains. Specific residues that are highly conserved but uniquely modified in B. cenocepacia likely define mechanistic differences among Wsp systems. We also find the greatest sequence variation in the extracellular sensory domain of WspA, indicating potential adaptations to diverse external stimuli beyond surface contact sensing. This study emphasizes the need to better understand the breadth of functional diversity of the Wsp system as a major regulator of bacterial adaptation beyond B. cenocepacia and select Pseudomonas spp. IMPORTANCE The Wsp signal transduction system serves as an important model system for studying how bacteria adapt to living in densely structured communities known as biofilms. Biofilms frequently cause chronic infections and environmental fouling, and they are very difficult to eradicate. In Pseudomonas aeruginosa, the Wsp system senses contact with a surface, which in turn activates specific genes that promote biofilm formation. We demonstrate that the Wsp system in Burkholderia cenocepacia regulates biofilm formation uniquely from that in Pseudomonas species. Furthermore, a broad phylogenetic analysis reveals the presence of the Wsp system in diverse bacterial species, and sequence analyses of 794 independent systems suggest that the core signaling components function similarly but with key differences that may alter what or how they sense. This study shows that Wsp systems are highly conserved and more broadly distributed than previously thought, and their unique differences likely reflect adaptations to distinct environments.
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21
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Xu A, Wang D, Wang Y, Zhang L, Xie Z, Cui Y, Bhamse P, Yu H, Zhang XX, Li D, Ma LZ. Mutations in surface-sensing receptor WspA lock the Wsp signal transduction system into a constitutively active state. Environ Microbiol 2021; 24:1150-1165. [PMID: 34499799 DOI: 10.1111/1462-2920.15763] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 08/26/2021] [Accepted: 09/04/2021] [Indexed: 12/31/2022]
Abstract
Pseudomonas aeruginosa rugose small-colony variants (RSCVs) are frequently isolated from chronic infections, yet, they are rarely reported in environmental isolates. Here, during the comparative genomic analysis of two P. aeruginosa strains isolated from crude oil, we discovered a spontaneous in-frame deletion, wspAΔ280-307 , which led to hyper-biofilm and RSCV phenotypes. WspA is a homologue of methyl-accepting chemotaxis proteins (MCPs) that senses surfaces to regulate biofilm formation by stimulating cyclic-di-guanosine monophosphate (c-di-GMP) synthesis through the Wsp system. However, the methylation sites of WspA have never been identified. In this study, we identified E280 and E294 of WspA as methylation sites. The wspAΔ280-307 mutation enabled the Wsp system to lock into a constitutively active state that is independent of regulation by methylation. The result is an enhanced production of c-di-GMP. Sequence alignment revealed three conserved repeat sequences within the amino acid residues 280-313 (aa280-313) region of WspA homologues, suggesting that a spontaneous deletion within this DNA encoding region was likely a result of intragenic recombination and that similar mutations might occur in several related bacterial genera. Our results provide a plausible explanation for the selection of RSCVs and a mechanism to confer a competitive advantage for P. aeruginosa in a crude-oil environment.
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Affiliation(s)
- Anming Xu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Di Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yunhao Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li Zhang
- Liaoning University, Shenyang, 110136, China
| | - Zhensheng Xie
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yifan Cui
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Pramod Bhamse
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haiying Yu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xue-Xian Zhang
- School of Natural and Computational Sciences, Massey University, Auckland, 0745, New Zealand
| | - Defeng Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Luyan Z Ma
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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22
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Ióca LP, Dai Y, Kunakom S, Diaz‐Espinosa J, Krunic A, Crnkovic CM, Orjala J, Sanchez LM, Ferreira AG, Berlinck RGS, Eustáquio AS. A Family of Nonribosomal Peptides Modulate Collective Behavior in
Pseudovibrio
Bacteria Isolated from Marine Sponges**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202017320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Laura P. Ióca
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Instituto de Química de São Carlos Universidade de São Paulo São Carlos SP 13560-970 Brazil
| | - Yitao Dai
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Sylvia Kunakom
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Jennifer Diaz‐Espinosa
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Aleksej Krunic
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Camila M. Crnkovic
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Jimmy Orjala
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Laura M. Sanchez
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
| | - Antonio G. Ferreira
- Departamento de Química Universidade Federal de São Carlos São Carlos SP 13565-905 Brazil
| | - Roberto G. S. Berlinck
- Instituto de Química de São Carlos Universidade de São Paulo São Carlos SP 13560-970 Brazil
| | - Alessandra S. Eustáquio
- Department of Pharmaceutical Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
- Center for Biomolecular Sciences College of Pharmacy University of Illinois at Chicago Chicago IL 60607 USA
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23
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Ióca LP, Dai Y, Kunakom S, Diaz-Espinosa J, Krunic A, Crnkovic CM, Orjala J, Sanchez LM, Ferreira AG, Berlinck RGS, Eustáquio AS. A Family of Nonribosomal Peptides Modulate Collective Behavior in Pseudovibrio Bacteria Isolated from Marine Sponges*. Angew Chem Int Ed Engl 2021; 60:15891-15898. [PMID: 33961724 PMCID: PMC8269750 DOI: 10.1002/anie.202017320] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/01/2021] [Indexed: 11/08/2022]
Abstract
Although swarming motility and biofilms are opposed collective behaviors, both contribute to bacterial survival and host colonization. Pseudovibrio bacteria have attracted attention because they are part of the microbiome of healthy marine sponges. Two-thirds of Pseudovibrio genomes contain a member of a nonribosomal peptide synthetase-polyketide synthase gene cluster family, which is also found sporadically in Pseudomonas pathogens of insects and plants. After developing reverse genetics for Pseudovibrio, we isolated heptapeptides with an ureido linkage and related nonadepsipeptides we termed pseudovibriamides A and B, respectively. A combination of genetics and imaging mass spectrometry experiments showed heptapetides were excreted, promoting motility and reducing biofilm formation. In contrast to lipopeptides widely known to affect motility/biofilms, pseudovibriamides are not surfactants. Our results expand current knowledge on metabolites mediating bacterial collective behavior.
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Affiliation(s)
- Laura P. Ióca
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP 13560-970, Brazil
| | - Yitao Dai
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Sylvia Kunakom
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Jennifer Diaz-Espinosa
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Aleksej Krunic
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Camila M. Crnkovic
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Jimmy Orjala
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Laura M. Sanchez
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Antonio G. Ferreira
- Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP 13565-905, Brazil
| | - Roberto G. S. Berlinck
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP 13560-970, Brazil
| | - Alessandra S. Eustáquio
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
- Center for Biomolecular Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL 60607, USA
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24
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Marshall CW, Gloag ES, Lim C, Wozniak DJ, Cooper VS. Rampant prophage movement among transient competitors drives rapid adaptation during infection. SCIENCE ADVANCES 2021; 7:7/29/eabh1489. [PMID: 34272240 PMCID: PMC8284892 DOI: 10.1126/sciadv.abh1489] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 06/03/2021] [Indexed: 05/11/2023]
Abstract
Interactions between bacteria, their close competitors, and viral parasites are common in infections, but understanding of these eco-evolutionary dynamics is limited. Most examples of adaptations caused by phage lysogeny are through the acquisition of new genes. However, integrated prophages can also insert into functional genes and impart a fitness benefit by disrupting their expression, a process called active lysogeny. Here, we show that active lysogeny can fuel rapid, parallel adaptations in establishing a chronic infection. These recombination events repeatedly disrupted genes encoding global regulators, leading to increased cyclic di-GMP levels and elevated biofilm production. The implications of prophage-mediated adaptation are broad, as even transient members of microbial communities can alter the course of evolution and generate persistent phenotypes associated with poor clinical outcomes.
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Affiliation(s)
| | - Erin S Gloag
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
| | - Christina Lim
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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25
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An AY, Choi KYG, Baghela AS, Hancock REW. An Overview of Biological and Computational Methods for Designing Mechanism-Informed Anti-biofilm Agents. Front Microbiol 2021; 12:640787. [PMID: 33927701 PMCID: PMC8076610 DOI: 10.3389/fmicb.2021.640787] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Accepted: 03/23/2021] [Indexed: 12/29/2022] Open
Abstract
Bacterial biofilms are complex and highly antibiotic-resistant aggregates of microbes that form on surfaces in the environment and body including medical devices. They are key contributors to the growing antibiotic resistance crisis and account for two-thirds of all infections. Thus, there is a critical need to develop anti-biofilm specific therapeutics. Here we discuss mechanisms of biofilm formation, current anti-biofilm agents, and strategies for developing, discovering, and testing new anti-biofilm agents. Biofilm formation involves many factors and is broadly regulated by the stringent response, quorum sensing, and c-di-GMP signaling, processes that have been targeted by anti-biofilm agents. Developing new anti-biofilm agents requires a comprehensive systems-level understanding of these mechanisms, as well as the discovery of new mechanisms. This can be accomplished through omics approaches such as transcriptomics, metabolomics, and proteomics, which can also be integrated to better understand biofilm biology. Guided by mechanistic understanding, in silico techniques such as virtual screening and machine learning can discover small molecules that can inhibit key biofilm regulators. To increase the likelihood that these candidate agents selected from in silico approaches are efficacious in humans, they must be tested in biologically relevant biofilm models. We discuss the benefits and drawbacks of in vitro and in vivo biofilm models and highlight organoids as a new biofilm model. This review offers a comprehensive guide of current and future biological and computational approaches of anti-biofilm therapeutic discovery for investigators to utilize to combat the antibiotic resistance crisis.
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Affiliation(s)
| | | | | | - Robert E. W. Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada
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26
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Induction of Native c-di-GMP Phosphodiesterases Leads to Dispersal of Pseudomonas aeruginosa Biofilms. Antimicrob Agents Chemother 2021; 65:AAC.02431-20. [PMID: 33495218 DOI: 10.1128/aac.02431-20] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/15/2021] [Indexed: 01/07/2023] Open
Abstract
A decade of research has shown that the molecule c-di-GMP functions as a central second messenger in many bacteria. A high level of c-di-GMP is associated with biofilm formation, whereas a low level of c-di-GMP is associated with a planktonic single-cell bacterial lifestyle. c-di-GMP is formed by diguanylate cyclases and is degraded by specific phosphodiesterases. We previously presented evidence that the ectopic expression of the Escherichia coli phosphodiesterase YhjH in Pseudomonas aeruginosa results in biofilm dispersal. More recently, however, evidence has been presented that the induction of native c-di-GMP phosphodiesterases does not lead to a dispersal of P. aeruginosa biofilms. The latter result may discourage attempts to use c-di-GMP signaling as a target for the development of antibiofilm drugs. However, here, we demonstrate that the induction of the P. aeruginosa c-di-GMP phosphodiesterases PA2133 and BifA indeed results in the dispersal of P. aeruginosa biofilms in both a microtiter tray biofilm assay and a flow cell biofilm system.
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27
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Moser C, Jensen PØ, Thomsen K, Kolpen M, Rybtke M, Lauland AS, Trøstrup H, Tolker-Nielsen T. Immune Responses to Pseudomonas aeruginosa Biofilm Infections. Front Immunol 2021; 12:625597. [PMID: 33692800 PMCID: PMC7937708 DOI: 10.3389/fimmu.2021.625597] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/20/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a key pathogen of chronic infections in the lungs of cystic fibrosis patients and in patients suffering from chronic wounds of diverse etiology. In these infections the bacteria congregate in biofilms and cannot be eradicated by standard antibiotic treatment or host immune responses. The persistent biofilms induce a hyper inflammatory state that results in collateral damage of the adjacent host tissue. The host fails to eradicate the biofilm infection, resulting in hindered remodeling and healing. In the present review we describe our current understanding of innate and adaptive immune responses elicited by P. aeruginosa biofilms in cystic fibrosis lung infections and chronic wounds. This includes the mechanisms that are involved in the activation of the immune responses, as well as the effector functions, the antimicrobial components and the associated tissue destruction. The mechanisms by which the biofilms evade immune responses, and potential treatment targets of the immune response are also discussed.
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Affiliation(s)
- Claus Moser
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kim Thomsen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Morten Rybtke
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Sofie Lauland
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Hannah Trøstrup
- Department of Plastic Surgery and Breast Surgery, Zealand University Hospital, Roskilde, Denmark
| | - Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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28
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Pseudomonas aeruginosa as a Model To Study Chemosensory Pathway Signaling. Microbiol Mol Biol Rev 2021; 85:85/1/e00151-20. [PMID: 33441490 DOI: 10.1128/mmbr.00151-20] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria have evolved a variety of signal transduction mechanisms that generate different outputs in response to external stimuli. Chemosensory pathways are widespread in bacteria and are among the most complex signaling mechanisms, requiring the participation of at least six proteins. These pathways mediate flagellar chemotaxis, in addition to controlling alternative functions such as second messenger levels or twitching motility. The human pathogen Pseudomonas aeruginosa has four different chemosensory pathways that carry out different functions and are stimulated by signal binding to 26 chemoreceptors. Recent research employing a diverse range of experimental approaches has advanced enormously our knowledge on these four pathways, establishing P. aeruginosa as a primary model organism in this field. In the first part of this article, we review data on the function and physiological relevance of chemosensory pathways as well as their involvement in virulence, whereas the different transcriptional and posttranscriptional regulatory mechanisms that govern pathway function are summarized in the second part. The information presented will be of help to advance the understanding of pathway function in other organisms.
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29
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Westra ER, Levin BR. It is unclear how important CRISPR-Cas systems are for protecting natural populations of bacteria against infections by mobile genetic elements. Proc Natl Acad Sci U S A 2020; 117:27777-27785. [PMID: 33122438 PMCID: PMC7668106 DOI: 10.1073/pnas.1915966117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Articles on CRISPR commonly open with some variant of the phrase "these short palindromic repeats and their associated endonucleases (Cas) are an adaptive immune system that exists to protect bacteria and archaea from viruses and infections with other mobile genetic elements." There is an abundance of genomic data consistent with the hypothesis that CRISPR plays this role in natural populations of bacteria and archaea, and experimental demonstrations with a few species of bacteria and their phage and plasmids show that CRISPR-Cas systems can play this role in vitro. Not at all clear are the ubiquity, magnitude, and nature of the contribution of CRISPR-Cas systems to the ecology and evolution of natural populations of microbes and the strength of selection mediated by different types of phage and plasmids to the evolution and maintenance of CRISPR-Cas systems. In this perspective, with the aid of heuristic mathematical-computer simulation models, we explore the a priori conditions under which exposure to lytic and temperate phage and conjugative plasmids will select for and maintain CRISPR-Cas systems in populations of bacteria and archaea. We review the existing literature addressing these ecological and evolutionary questions and highlight the experimental and other evidence needed to fully understand the conditions responsible for the evolution and maintenance of CRISPR-Cas systems and the contribution of these systems to the ecology and evolution of bacteria, archaea, and the mobile genetic elements that infect them.
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Affiliation(s)
- Edze R Westra
- Environment and Sustainability Institute, Biosciences, University of Exeter, Penryn, TR10 9FE Cornwall, United Kingdom;
| | - Bruce R Levin
- Department of Biology, Emory University, Atlanta, GA 30307
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30
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Gdaniec BG, Allard PM, Queiroz EF, Wolfender JL, van Delden C, Köhler T. Surface sensing triggers a broad-spectrum antimicrobial response in Pseudomonas aeruginosa. Environ Microbiol 2020; 22:3572-3587. [PMID: 32573899 PMCID: PMC7496599 DOI: 10.1111/1462-2920.15139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 06/15/2020] [Accepted: 06/21/2020] [Indexed: 12/14/2022]
Abstract
Interspecies bacterial competition may occur via cell‐associated or secreted determinants and is key to successful niche colonization. We previously evolved Pseudomonas aeruginosa in the presence of Staphylococcus aureus and identified mutations in the Wsp surface‐sensing signalling system. Surprisingly, a ΔwspF mutant, characterized by increased c‐di‐GMP levels and biofilm formation capacity, showed potent killing activity towards S. aureus in its culture supernatant. Here, we used an unbiased metabolomic analysis of culture supernatants to identify rhamnolipids, alkyl quinoline N‐oxides and two siderophores as members of four chemical clusters, which were more abundant in the ΔwspF mutant supernatants. Killing activities were quorum‐sensing controlled but independent of c‐di‐GMP levels. Based on the metabolomic analysis, we formulated a synthetic cocktail of four compounds, showing broad‐spectrum anti‐bacterial killing, including both Gram‐positive and Gram‐negative bacteria. The combination of quorum‐sensing‐controlled killing and Wsp‐system mediated biofilm formation endows P. aeruginosa with capacities essential for niche establishment and host colonization.
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Affiliation(s)
- Bartosz Gerard Gdaniec
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Pierre-Marie Allard
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Emerson Ferreira Queiroz
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Jean-Luc Wolfender
- School of Pharmaceutical Sciences, EPGL, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Christian van Delden
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Thilo Köhler
- Transplant Infectious Diseases Unit, University Hospital Geneva, Geneva, Switzerland.,Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
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31
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Trøstrup H, Laulund ASB, Moser C. Insights into Host-Pathogen Interactions in Biofilm-Infected Wounds Reveal Possibilities for New Treatment Strategies. Antibiotics (Basel) 2020; 9:E396. [PMID: 32664205 PMCID: PMC7400121 DOI: 10.3390/antibiotics9070396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/26/2022] Open
Abstract
Normal wound healing occurs in three phases-the inflammatory, the proliferative, and the remodeling phase. Chronic wounds are, for unknown reasons, arrested in the inflammatory phase. Bacterial biofilms may cause chronicity by arresting healing in the inflammatory state by mechanisms not fully understood. Pseudomonas aeruginosa, a common wound pathogen with remarkable abilities in avoiding host defense and developing microbial resistance by biofilm formation, is detrimental to wound healing in clinical studies. The host response towards P. aeruginosa biofilm-infection in chronic wounds and impact on wound healing is discussed and compared to our own results in a chronic murine wound model. The impact of P. aeruginosa biofilms can be described by determining alterations in the inflammatory response, growth factor profile, and count of leukocytes in blood. P. aeruginosa biofilms are capable of reducing the host response to the infection, despite a continuously sustained inflammatory reaction and resulting local tissue damage. A recent observation of in vivo synergism between immunomodulatory and antimicrobial S100A8/A9 and ciprofloxacin suggests its possible future therapeutic potential.
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Affiliation(s)
- Hannah Trøstrup
- Department of Plastic Surgery and Breast Surgery, Zealand University Hospital, 4000 Roskilde, Denmark
| | - Anne Sofie Boe Laulund
- Department of Clinical Microbiology, Copenhagen University Hospital, 2200 Copenhagen, Denmark; (A.S.B.L.); (C.M.)
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, 2200 Copenhagen, Denmark; (A.S.B.L.); (C.M.)
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32
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Soares A, Caron F, Etienne M. Commentary: Tolerance and Resistance of Pseudomonas aeruginosa Biofilms to Antimicrobial Agents-How P. aeruginosa Can Escape Antibiotics. Front Microbiol 2019; 10:2164. [PMID: 31620114 PMCID: PMC6759825 DOI: 10.3389/fmicb.2019.02164] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/03/2019] [Indexed: 01/13/2023] Open
Affiliation(s)
- Anaïs Soares
- GRAM 2.0, EA 2656, Normandie Univ, UNIROUEN, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - François Caron
- GRAM 2.0, EA 2656, Normandie Univ, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
| | - Manuel Etienne
- GRAM 2.0, EA 2656, Normandie Univ, UNIROUEN, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
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