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Mesas Vaz C, Guembe Mülberger A, Torrent Burgas M. The battle within: how Pseudomonas aeruginosa uses host-pathogen interactions to infect the human lung. Crit Rev Microbiol 2024:1-36. [PMID: 39381985 DOI: 10.1080/1040841x.2024.2407378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 08/11/2024] [Accepted: 09/17/2024] [Indexed: 10/10/2024]
Abstract
Pseudomonas aeruginosa is a versatile Gram-negative pathogen known for its ability to invade the respiratory tract, particularly in cystic fibrosis patients. This review provides a comprehensive analysis of the multifaceted strategies for colonization, virulence, and immune evasion used by P. aeruginosa to infect the host. We explore the extensive protein arsenal of P. aeruginosa, including adhesins, exotoxins, secreted proteases, and type III and VI secretion effectors, detailing their roles in the infective process. We also address the unique challenge of treating diverse lung conditions that provide a natural niche for P. aeruginosa on the airway surface, with a particular focus in cystic fibrosis. The review also discusses the current limitations in treatment options due to antibiotic resistance and highlights promising future approaches that target host-pathogen protein-protein interactions. These approaches include the development of new antimicrobials, anti-attachment therapies, and quorum-sensing inhibition molecules. In summary, this review aims to provide a holistic understanding of the pathogenesis of P. aeruginosa in the respiratory system, offering insights into the underlying molecular mechanisms and potential therapeutic interventions.
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Affiliation(s)
- Carmen Mesas Vaz
- The Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Alba Guembe Mülberger
- The Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Marc Torrent Burgas
- The Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
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2
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Malhotra S, Yang C, Nicholson KL, Wozniak DJ, Hayes D. Pseudomonas aeruginosa Infection and Inflammation in Cystic Fibrosis: A Pilot Study With Lung Explants and a Novel Histopathology Scoring System. Lung 2024; 202:711-722. [PMID: 39096413 DOI: 10.1007/s00408-024-00733-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 07/15/2024] [Indexed: 08/05/2024]
Abstract
PURPOSE Pseudomonas aeruginosa is the predominant bacterial pathogen colonizing the cystic fibrosis (CF) lung. Mixed populations of nonmucoid and mucoid variants of P. aeruginosa have been isolated from the CF airway. While the association between mucoid variants and pulmonary function decline is well-established, their impact on inflammation and tissue damage in advanced CF lung disease remains unclear. METHODS This pilot study utilized 1 non-CF and 3 CF lung explants to examine lobar distribution, inflammation, and histopathology related to nonmucoid and mucoid P. aeruginosa infection. To study tissue damage, we developed a novel lung histopathology scoring system, the first applied to human CF lung biopsies, which is comprised of five indicators: bronchiolar epithelial infiltrate, luminal inflammation, peribronchial/bronchiolar infiltrate, peribronchiolar fibrosis, and alveolar involvement. RESULTS Mucoid P. aeruginosa variants were distributed throughout the CF lung but associated with greater concentrations of proinflammatory cytokines, IL-1β, TNF-α, IL-6, IL-8, and IFN-γ, and one anti-inflammatory cytokine, IL-10, compared to nonmucoid variants. CF lung explants exhibited higher histopathology scores compared to a non-CF lung control. In mixed-variant infection, nonmucoid constituents associated with increased bronchiolar epithelial infiltration, one indicator of histopathology. CONCLUSION This pilot study suggests ongoing interplay between host and bacterial elements in late-stage CF pulmonary disease. Mucoid P. aeruginosa infection correlates with inflammation regardless of lung lobe, whereas nonmucoid P. aeruginosa is associated with increased inflammatory cell infiltration. The development of a novel lung histopathology scoring system lays the groundwork for future large-cohort investigations.
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Affiliation(s)
- Sankalp Malhotra
- Division of Cardiovascular Medicine, Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, USA
| | - Ching Yang
- Anatomic Pathology, College of Veterinary Medicine, Long Island University, Brooklyn, USA
| | - Kerri L Nicholson
- Lung and Heart-Lung Transplant Program, Section of Pulmonary, Department of Pediatrics, Sleep Medicine and Cystic Fibrosis, Nationwide Children's Hospital, Columbus, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University College of Medicine, Columbus, USA
| | - Don Hayes
- Lung Transplant Program, Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, 3333 Burnet Ave, MLC 7041, Cincinnati, OH, 45229, USA.
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Sommerfield AG, Wang M, Mamana J, Darwin AJ. In vivo and in vitro analyses of the role of the Prc protease in inducing mucoidy in Pseudomonas aeruginosa. J Bacteriol 2024:e0022224. [PMID: 39287400 DOI: 10.1128/jb.00222-24] [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: 05/27/2024] [Accepted: 08/20/2024] [Indexed: 09/19/2024] Open
Abstract
In Pseudomonas aeruginosa, alginate biosynthesis gene expression is inhibited by the transmembrane anti-sigma factor MucA, which sequesters the AlgU sigma factor. Cell envelope stress initiates cleavage of the MucA periplasmic domain by site-1 protease AlgW, followed by further MucA degradation to release AlgU. However, after colonizing the lungs of people with cystic fibrosis, P. aeruginosa converts to a mucoid form that produces alginate constitutively. Mucoid isolates often have mucA mutations, with the most common being mucA22, which truncates the periplasmic domain. MucA22 is degraded constitutively, and genetic studies suggested that the Prc protease is responsible. Some studies also suggested that Prc contributes to induction in strains with wild-type MucA, whereas others suggested the opposite. However, missing from all previous studies is a demonstration that Prc cleaves any protein directly, which leaves open the possibility that the effect of a prc null mutation is indirect. To address the ambiguities and shortfalls, we reevaluated the roles of AlgW and Prc as MucA and MucA22 site-1 proteases. In vivo analyses using three different assays and two different inducing conditions all suggested that AlgW is the only site-1 protease for wild-type MucA in any condition. In contrast, genetics suggested that AlgW or Prc act as MucA22 site-1 proteases in inducing conditions, whereas Prc is the only MucA22 site-1 protease in non-inducing conditions. For the first time, we also show that Prc is unable to degrade the periplasmic domain of wild-type MucA but does degrade the mutated periplasmic domain of MucA22 directly. IMPORTANCE After colonizing the lungs of individuals with cystic fibrosis, Pseudomonas aeruginosa undergoes mutagenic conversion to a mucoid form, worsening the prognosis. Most mucoid isolates have a truncated negative regulatory protein MucA, which leads to constitutive production of the extracellular polysaccharide alginate. The protease Prc has been implicated, but not shown, to degrade the most common MucA variant, MucA22, to trigger alginate production. This work provides the first demonstration that the molecular mechanism of Prc involvement is direct degradation of the MucA22 periplasmic domain and perhaps other truncated MucA variants as well. MucA truncation and degradation by Prc might be the predominant mechanism of mucoid conversion in cystic fibrosis infections, suggesting that Prc activity could be a useful therapeutic target.
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Affiliation(s)
- Alexis G Sommerfield
- Department of Microbiology, NYU Grossman School of Medicine, New York, New York, USA
| | - Michelle Wang
- Department of Microbiology, NYU Grossman School of Medicine, New York, New York, USA
| | - Julia Mamana
- Department of Microbiology, NYU Grossman School of Medicine, New York, New York, USA
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4
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Tan Y, Dai Z. Pseudomonas aeruginosa mucinous phenotypes and algUmucABD operon mutant characteristics obtained from inpatients with bronchiectasis and their correlation with acute aggravation. Front Cell Infect Microbiol 2024; 14:1402348. [PMID: 39135639 PMCID: PMC11317387 DOI: 10.3389/fcimb.2024.1402348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 06/13/2024] [Indexed: 08/15/2024] Open
Abstract
Objective Although the mechanism is unclear, Pseudomonas aeruginosa (PA) infection directly affects the frequency of acute exacerbations in patients with bronchiectasis. The aims of this article are to analyze the genetic mutation characteristics of the algUmucABD operon in PA, isolated from hospitalized patients with bronchiectasis, and to explore independent risk factors for frequent acute exacerbations of bronchiectasis. Methods Based on the number of acute exacerbations that occurred in the past year, these patients with bronchiectasis were divided into those with frequent acute exacerbations (Group A) and those with non-frequent acute exacerbations (Group B). We identified the distribution of mucoid phenotypes (MPs) and alginate morphotypes (AMs) in PA, and classified them into I-IV categories based on their different AMs; otherwise, the gene mutation types (GMTs) of the algUmucABD operon were tested. Subsequently, the relationship between GMT, MP, and AM and the independent risk factors for frequent acute exacerbations in patients with bronchiectasis were explored. Results A total of 93 patients and 75 PA strains, from January 2019 to August 2023, were included in this study. The MP and AM distributions of PA were as follows: 64 strains (85.33%) of mucoid (the AMs were 38 strains of type I, 3 strains of type II, and 23 strains of type IV) and 11 strains of non-mucoid (the AM was type III only). Mucoid PA with algU, mucA, mucB, and mucD mutations accounted for 19.61%, 74.51%, 31.37%, and 50.98%, respectively. GMT was divided into the following: mucA mutations only, mucA combined with other gene mutations, other gene mutations without mucA mutations, and without gene mutations. In 91.7% of PA with type I of AM, only mucA mutations occurred, and in both separate MP and AM, the GMT differences were statistically significant. Lastly, the number of lung lobes with bronchiectasis and the number of PA with mucA mutations only were the independent risk factors for frequent acute exacerbations. Conclusion The mucA mutation was primarily responsible for the mucoid of MP and type I of AM in PA, and it was also an independent risk factor for frequent exacerbations of bronchiectasis.
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Affiliation(s)
- Yuxue Tan
- Department of Internal Medicine, The First People’s Hospital of Fuquan City, Fuquan, Guizhou, , China
| | - Zhongshang Dai
- Department of Infectious Diseases, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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5
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Sommerfield AG, Wang M, Mamana J, Darwin AJ. In vivo and in vitro analysis of the role of the Prc protease in inducing mucoidy in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596254. [PMID: 38854061 PMCID: PMC11160602 DOI: 10.1101/2024.05.28.596254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
In Pseudomonas aeruginosa, alginate biosynthesis gene expression is inhibited by the transmembrane anti-sigma factor MucA, which sequesters the AlgU sigma factor. Cell envelope stress initiates cleavage of the MucA periplasmic domain by site-1 protease AlgW, followed by further MucA degradation to release AlgU. However, after colonizing the lungs of people with cystic fibrosis, P. aeruginosa converts to a mucoid form that produces alginate constitutively. Mucoid isolates often have mucA mutations, with the most common being mucA22 , which truncates the periplasmic domain. MucA22 is degraded constitutively, and genetic studies suggested that the Prc protease is responsible. Some studies also suggested that Prc contributes to induction in strains with wild type MucA, whereas others suggested the opposite. However, missing from all previous studies is a demonstration that Prc cleaves any protein directly, which leaves open the possibility that the effect of a prc null mutation is indirect. To address the ambiguities and shortfalls, we reevaluated the roles of AlgW and Prc as MucA and MucA22 site-1 proteases. In vivo analyses using three different assays, and two different inducing conditions, all suggested that AlgW is the only site-1 protease for wild type MucA in any condition. In contrast, genetics suggested that AlgW or Prc act as MucA22 site-1 proteases in inducing conditions, whereas Prc is the only MucA22 site-1 protease in non-inducing conditions. For the first time, we also show that Prc is unable to degrade the periplasmic domain of wild type MucA, but does degrade the mutated periplasmic domain of MucA22 directly. IMPORTANCE After colonizing the lungs of individuals with cystic fibrosis, P. aeruginosa undergoes mutagenic conversion to a mucoid form, worsening the prognosis. Most mucoid isolates have a truncated negative regulatory protein MucA, which leads to constitutive production of the extracellular polysaccharide alginate. The protease Prc has been implicated, but not shown, to degrade the most common MucA variant, MucA22, to trigger alginate production. This work provides the first demonstration that the molecular mechanism of Prc involvement is direct degradation of the MucA22 periplasmic domain, and perhaps other truncated MucA variants as well. MucA truncation and degradation by Prc might be the predominant mechanism of mucoid conversion in cystic fibrosis infections, suggesting that Prc activity could be a useful therapeutic target.
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Schwartbeck B, Rumpf CH, Hait RJ, Janssen T, Deiwick S, Schwierzeck V, Mellmann A, Kahl BC. Various mutations in icaR, the repressor of the icaADBC locus, occur in mucoid Staphylococcus aureus isolates recovered from the airways of people with cystic fibrosis. Microbes Infect 2024; 26:105306. [PMID: 38316375 DOI: 10.1016/j.micinf.2024.105306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/16/2024] [Accepted: 01/29/2024] [Indexed: 02/07/2024]
Abstract
Staphylococcus aureus is one of the major pathogens isolated from the airways of people with cystic fibrosis (pwCF). Recently, we described a mucoid S. aureus phenotype from respiratory specimens of pwCF, which constitutively overproduced biofilm that consisted of polysaccharide intercellular adhesin (PIA) due to a 5bp-deletion (5bp-del) in the intergenic region of the intercellular adhesin (ica) locus. Since we were not able to identify the 5bp-del in mucoid isolates of two pwCF with long-term S. aureus persistence and in a number of mucoid isolates of pwCF from a prospective multicenter study, these strains were (i) characterized phenotypically, (ii) investigated for biofilm formation, and (iii) molecular typed by spa-sequence typing. To screen for mutations responsible for mucoidy, the ica operon of all mucoid isolates was analyzed by Sanger sequencing. Whole genome sequencing was performed for selected isolates. For all mucoid isolates without the 5 bp-del, various mutations in icaR, which is the transcriptional repressor of the icaADBC operon. Mucoid and non-mucoid strains belonged to the same spa-type. Transformation of PIA-overproducing S. aureus with a vector expressing the intact icaR gene restored the non-mucoid phenotype. Altogether, we demonstrated a new mechanism for the emergence of mucoid S. aureus isolates of pwCF.
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Affiliation(s)
- Bianca Schwartbeck
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | - Christine H Rumpf
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | | | - Timo Janssen
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | - Susanne Deiwick
- Institute of Medical Microbiology, University Hospital Muenster, Germany
| | | | | | - Barbara C Kahl
- Institute of Medical Microbiology, University Hospital Muenster, Germany.
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Higazy D, Pham AD, van Hasselt C, Høiby N, Jelsbak L, Moser C, Ciofu O. In vivo evolution of antimicrobial resistance in a biofilm model of Pseudomonas aeruginosa lung infection. THE ISME JOURNAL 2024; 18:wrae036. [PMID: 38478426 PMCID: PMC10980832 DOI: 10.1093/ismejo/wrae036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/10/2024] [Accepted: 02/29/2024] [Indexed: 04/01/2024]
Abstract
The evolution of antimicrobial resistance (AMR) in biofilms has been repeatedly studied by experimental evolution in vitro, but rarely in vivo. The complex microenvironment at the infection site imposes selective pressures on the bacterial biofilms, potentially influencing the development of AMR. We report here the development of AMR in an in vivo mouse model of Pseudomonas aeruginosa biofilm lung infection. The P. aeruginosa embedded in seaweed alginate beads underwent four successive lung infection passages with or without ciprofloxacin (CIP) exposure. The development of CIP resistance was assessed at each passage by population analysis of the bacterial populations recovered from the lungs of CIP-treated and control mice, with subsequent whole-genome sequencing of selected isolates. As inflammation plays a crucial role in shaping the microenvironment at the infection site, its impact was explored through the measurement of cytokine levels in the lung homogenate. A rapid development of AMR was observed starting from the second passage in the CIP-treated mice. Genetic analysis revealed mutations in nfxB, efflux pumps (mexZ), and two-component systems (parS) contribution to CIP resistance. The control group isolates exhibited mutations in the dipA gene, likely associated with biofilm dispersion. In the initial two passages, the CIP-treated group exhibited an elevated inflammatory response compared to the control group. This increase may potentially contribute to the release of mutagenic reactive oxygen species and the development of AMR. In conclusion, this study illustrates the complex relationship between infection, antibiotic treatment, and immune response.
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Affiliation(s)
- Doaa Higazy
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Microbiology, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Anh Duc Pham
- Division of Systems Pharmacology & Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Coen van Hasselt
- Division of Systems Pharmacology & Pharmacy, Leiden Academic Centre for Drug Research, Leiden University, 2300 RA Leiden, The Netherlands
| | - Niels Høiby
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Lars Jelsbak
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Claus Moser
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
- Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Ø Copenhagen, Denmark
| | - Oana Ciofu
- Costerton Biofilm Center, Department of Immunology and Microbiology, University of Copenhagen, 2200 N Copenhagen, Denmark
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Pellielo G, Agyapong ED, Pinton P, Rimessi A. Control of mitochondrial functions by Pseudomonas aeruginosa in cystic fibrosis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2023; 377:19-43. [PMID: 37268349 DOI: 10.1016/bs.ircmb.2023.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Cystic fibrosis (CF) is a genetic disease characterized by mutations of cystic fibrosis transmembrane conductance regulator (CFTR) gene, which lead to a dysfunctional chloride and bicarbonate channel. Abnormal mucus viscosity, persistent infections and hyperinflammation that preferentially affect the airways, referred to the pathogenesis of CF lung disease. It has largely demonstrated that Pseudomonas aeruginosa (P. aeruginosa) represents the most important pathogen that affect CF patients, leading to worsen inflammation by stimulating pro-inflammatory mediators release and tissue destruction. The conversion to mucoid phenotype and formation of biofilms, together with the increased frequency of mutations, are only few changes that characterize the P. aeruginosa's evolution during CF lung chronic infection. Recently, mitochondria received increasing attention due to their involvement in inflammatory-related diseases, including in CF. Alteration of mitochondrial homeostasis is sufficient to stimulate immune response. Exogenous or endogenous stimuli that perturb mitochondrial activity are used by cells, which, through the mitochondrial stress, potentiate immunity programs. Studies show the relationship between mitochondria and CF, supporting the idea that mitochondrial dysfunction endorses the exacerbation of inflammatory responses in CF lung. In particular, evidences suggest that mitochondria in CF airway cells are more susceptible to P. aeruginosa infection, with consequent detrimental effects that lead to amplify the inflammatory signals. This review discusses the evolution of P. aeruginosa in relationship with the pathogenesis of CF, a fundamental step to establish chronic infection in CF lung disease. Specifically, we focus on the role of P. aeruginosa in the exacerbation of inflammatory response, by triggering mitochondria in CF.
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Affiliation(s)
- Giulia Pellielo
- Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies, University of Ferrara, Ferrara, Italy
| | - Esther Densu Agyapong
- Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies, University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies, University of Ferrara, Ferrara, Italy; Center of research for innovative therapies in cystic fibrosis, University of Ferrara, Ferrara, Italy
| | - Alessandro Rimessi
- Department of Medical Sciences, Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies, University of Ferrara, Ferrara, Italy; Center of research for innovative therapies in cystic fibrosis, University of Ferrara, Ferrara, Italy.
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Ghanem SM, Abd El-Baky RM, Abourehab MAS, Fadl GFM, Gamil NGFM. Prevalence of Quorum Sensing and Virulence Factor Genes Among Pseudomonas aeruginosa Isolated from Patients Suffering from Different Infections and Their Association with Antimicrobial Resistance. Infect Drug Resist 2023; 16:2371-2385. [PMID: 37113530 PMCID: PMC10128085 DOI: 10.2147/idr.s403441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Purpose Antimicrobial resistance and virulence genes play important roles in increasing the severity of Pseudomonas aeruginosa infections, especially in hospitalized patients with high antibiotic pressure. Most genes that encode Pseudomonas aeruginosa virulence factors are controlled and regulated by the quorum sensing (QS) system. The aim of this study was to investigate the frequency of some virulence genes (rhlR, rhlI, lasR, lasI, lasB, toxA, aprA, algD, ExoS, and plcH genes) and their association with antibiotic resistance. Methods Antimicrobial susceptibility was determined by Kirby-Bauer agar disk diffusion method. A total of 125 clinical isolates of P. aeruginosa were tested for some virulence genes using polymerase chain reaction (PCR). Results The highest resistance was observed against cefepime (92.8%). Multi-drug resistant (MDR) P. aeruginosa represented 63.2% of total isolates with high distribution among wound isolates (21/79, 26.3% of MDR isolates). LasB was the most prevalent virulence gene among the tested isolates (89.6%) followed by aprA (85.6%), exoS (84%), algD (80%), toxA (76.8%), and plcH (75.2). Furthermore, a significant association (P < 0.05) among most of the tested virulence genes and MDR isolates was found. The presence of more than 5 virulence genes was highly observed among wound infections, otitis media, and respiratory tract infection isolates. Conclusion The complex association of virulence genes including QS system regulating genes with antibiotic resistance indicates the importance of the tested factors in the progression of infections, which is considered a great challenge for the health-care team with the need for specific studies for each area having different antibiotic resistance profiles and the development of effective treatment strategies such as anti-virulent and quorum sensing inhibiting drugs against P. aeruginosa infections.
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Affiliation(s)
- Shimaa M Ghanem
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Rehab Mahmoud Abd El-Baky
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
- Department of Microbiology and Immunology, Faculty of Pharmacy, Deraya University, Minia, Egypt
| | - Mohamed A S Abourehab
- Department of Pharmaceutics, College of Pharmacy, Umm Al-Qura University, Makkah, 21955, Saudi Arabia
- Correspondence: Mohamed AS Abourehab, Email
| | - Gamal F M Fadl
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Nancy G F M Gamil
- Department of Microbiology and Immunology, Faculty of Pharmacy, Minia University, Minia, Egypt
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10
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Liu Y, Gloag ES, Hill PJ, Parsek MR, Wozniak DJ. Interbacterial Antagonism Mediated by a Released Polysaccharide. J Bacteriol 2022; 204:e0007622. [PMID: 35446119 PMCID: PMC9112932 DOI: 10.1128/jb.00076-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/06/2022] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa and Staphylococcus aureus are two common pathogens causing chronic infections in the lungs of people with cystic fibrosis (CF) and in wounds, suggesting that these two organisms coexist in vivo. However, P. aeruginosa utilizes various mechanisms to antagonize S. aureus when these organisms are grown together in vitro. Here, we suggest a novel role for Psl in antagonizing S. aureus growth. Psl is an exopolysaccharide that exists in both cell-associated and cell-free forms and is important for biofilm formation in P. aeruginosa. When grown in planktonic coculture with a P. aeruginosa psl mutant, S. aureus had increased survival compared to when it was grown with wild-type P. aeruginosa. We found that cell-free Psl was critical for the killing, as purified cell-free Psl was sufficient to kill S. aureus. Transmission electron microscopy of S. aureus treated with Psl revealed disrupted cell envelopes, suggesting that Psl causes S. aureus cell lysis. This was independent of known mechanisms used by P. aeruginosa to antagonize S. aureus. Cell-free Psl could also promote S. aureus killing during growth in in vivo-like conditions. We also found that Psl production in P. aeruginosa CF clinical isolates positively correlated with the ability to kill S. aureus. This could be a result of P. aeruginosa coevolution with S. aureus in CF lungs. In conclusion, this study defines a novel role for P. aeruginosa Psl in killing S. aureus, potentially impacting the coexistence of these two opportunistic pathogens in vivo. IMPORTANCE Pseudomonas aeruginosa and Staphylococcus aureus are two important opportunistic human pathogens commonly coisolated from clinical samples. However, P. aeruginosa can utilize various mechanisms to antagonize S. aureus in vitro. Here, we investigated the interactions between these two organisms and report a novel role for P. aeruginosa exopolysaccharide Psl in killing S. aureus. We found that cell-free Psl could kill S. aureus in vitro, possibly by inducing cell lysis. This was also observed in conditions reflective of in vivo scenarios. In accord with this, Psl production in P. aeruginosa clinical isolates positively correlated with their ability to kill S. aureus. Together, our data suggest a role for Psl in affecting the coexistence of P. aeruginosa and S. aureus in vivo.
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Affiliation(s)
- Yiwei Liu
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Erin S. Gloag
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Preston J. Hill
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Matthew R. Parsek
- Department of Microbiology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Daniel J. Wozniak
- Department of Microbiology, Ohio State University, Columbus, Ohio, USA
- Department of Microbial Infection and Immunity, Ohio State University College of Medicine, Columbus, Ohio, USA
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11
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Cabrini G, Rimessi A, Borgatti M, Pinton P, Gambari R. Overview of CF lung pathophysiology. Curr Opin Pharmacol 2022; 64:102214. [PMID: 35453033 DOI: 10.1016/j.coph.2022.102214] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 03/02/2022] [Accepted: 03/16/2022] [Indexed: 12/21/2022]
Abstract
Defects of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein affect the homeostasis of chloride, bicarbonate, sodium, and water in the airway surface liquid, influencing the mucus composition and viscosity, which induces a severe condition of infection and inflammation along the whole life of CF patients. The introduction of CFTR modulators, novel drugs directly intervening to rescue the function of CFTR protein, opens a new era of experimental research. The review summarizes the most recent advancements to understand the characteristics of the infective and inflammatory pathology of CF lungs.
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Affiliation(s)
- Giulio Cabrini
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Center of Innovative Therapies for Cystic Fibrosis, University of Ferrara, Ferrara, Italy.
| | - Alessandro Rimessi
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy; Center of Innovative Therapies for Cystic Fibrosis, University of Ferrara, Ferrara, Italy
| | - Monica Borgatti
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Center of Innovative Therapies for Cystic Fibrosis, University of Ferrara, Ferrara, Italy
| | - Paolo Pinton
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy; Center of Innovative Therapies for Cystic Fibrosis, University of Ferrara, Ferrara, Italy
| | - Roberto Gambari
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy; Center of Innovative Therapies for Cystic Fibrosis, University of Ferrara, Ferrara, Italy
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12
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Combination and nanotechnology based pharmaceutical strategies for combating respiratory bacterial biofilm infections. Int J Pharm 2022; 616:121507. [PMID: 35085729 DOI: 10.1016/j.ijpharm.2022.121507] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/31/2021] [Accepted: 01/20/2022] [Indexed: 12/14/2022]
Abstract
Respiratory infections are one of the major global health problems. Among them, chronic respiratory infections caused by biofilm formation are difficult to treat because of both drug tolerance and poor drug penetration into the complex biofilm structure. A major part of the current research on combating respiratory biofilm infections have been focused on destroying the matrix of extracellular polymeric substance and eDNA of the biofilm or promoting the penetration of antibiotics through the extracellular polymeric substance via delivery technologies in order to kill the bacteria inside. There are also experimental data showing that certain inhaled antibiotics with simple formulations can effectively penetrate EPS to kill surficially located bacteria and centrally located dormant bacteria or persisters. This article aims to review recent advances in the pharmaceutical strategies for combating respiratory biofilm infections with a focus on nanotechnology-based drug delivery approaches. The formation and characteristics of bacterial biofilm infections in the airway mucus are presented, which is followed by a brief review on the current clinical approaches to treat respiratory biofilm infections by surgical removal and antimicrobial therapy, and also the emerging clinical treatment approaches. The current combination of antibiotics and non-antibiotic adjuvants to combat respiratory biofilm infections are also discussed.
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13
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Fischer S, Klockgether J, Gonzalez Sorribes M, Dorda M, Wiehlmann L, Tümmler B. Sequence diversity of the Pseudomonas aeruginosa population in loci that undergo microevolution in cystic fibrosis airways. Access Microbiol 2022; 3:000286. [PMID: 35024551 PMCID: PMC8749138 DOI: 10.1099/acmi.0.000286] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 10/04/2021] [Indexed: 12/23/2022] Open
Abstract
Five hundred and thirty-four unrelated Pseudomonas aeruginosa isolates from inanimate habitats, patients with cystic fibrosis (CF) and other human infections were sequenced in 19 genes that had been identified previously as the hot spots of genomic within-host evolution in serial isolates from 12 CF lungs. Amplicon sequencing confirmed a significantly higher sequence diversity of the 19 loci in P. aeruginosa isolates from CF patients compared to those from other habitats, but this overrepresentation was mainly due to the larger share of synonymous substitutions. Correspondingly, non-synonymous substitutions were either rare (gltT, lepA, ptsP) or benign (nuoL, fleR, pelF) in some loci. Other loci, however, showed an accumulation of non-neutral coding variants. Strains from the CF habitat were often mutated at evolutionarily conserved positions in the elements of stringent response (RelA, SpoT), LPS (PagL), polyamine transport (SpuE, SpuF) and alginate biosynthesis (AlgG, AlgU). The strongest skew towards the CF lung habitat was seen for amino acid sequence variants in AlgG that clustered in the carbohydrate-binding/sugar hydrolysis domain. The master regulators of quorum sensing lasR and rhlR were frequent targets for coding variants in isolates from chronic and acute human infections. Unique variants in lasR showed strong evidence of positive selection indicated by d N/d S values of ~4. The pelA gene that encodes a multidomain enzyme involved in both the formation and dispersion of Pel biofilms carried the highest number of single-nucleotide variants among the 19 genes and was the only gene with a higher frequency of missense mutations in P. aeruginosa strains from non-CF habitats than in isolates from CF airways. PelA protein variants are widely distributed in the P. aeruginosa population. In conclusion, coding variants in a subset of the examined loci are indeed characteristic for the adaptation of P. aeruginosa to the CF airways, but for other loci the elevated mutation rate is more indicative of infections in human habitats (lasR, rhlR) or global diversifying selection (pelA).
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Affiliation(s)
- Sebastian Fischer
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Jens Klockgether
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Marina Gonzalez Sorribes
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.,Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Marie Dorda
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.,Research Core Unit Genomics, Hannover Medical School, Hannover, Germany
| | - Lutz Wiehlmann
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.,Research Core Unit Genomics, Hannover Medical School, Hannover, Germany
| | - Burkhard Tümmler
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Department for Paediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany.,Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research, Hannover Medical School, Germany
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14
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Schofield MC, Rodriguez DQ, Kidman AA, Cassin EK, Michaels LA, Campbell EA, Jorth PA, Tseng BS. The anti-sigma factor MucA is required for viability in Pseudomonas aeruginosa. Mol Microbiol 2021; 116:550-563. [PMID: 33905139 PMCID: PMC10069406 DOI: 10.1111/mmi.14732] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 12/16/2022]
Abstract
During decades-long infections in the cystic fibrosis (CF) airway, Pseudomonas aeruginosa undergoes selection. One bacterial genetic adaptation often observed in CF isolates is mucA mutations. MucA inhibits the sigma factor AlgU. Mutations in mucA lead to AlgU misregulation, resulting in a mucoid phenotype that is associated with poor CF disease outcomes. Due to its ability to be mutated, mucA is assumed to be dispensable for bacterial viability. Here we show that, paradoxically, a portion of mucA is essential in P. aeruginosa. We demonstrate that mucA is no longer required in a strain lacking algU, that mucA alleles encoding for proteins that do not bind to AlgU are insufficient for viability, and that mucA is no longer essential in mutant strains containing AlgU variants with reduced sigma factor activity. Furthermore, we found that overexpression of algU prevents cell growth in the absence of MucA, and that this phenotype can be rescued by the overproduction of RpoD, the housekeeping sigma factor. Together, these results suggest that in the absence of MucA, the inability to regulate AlgU activity results in the loss of bacterial viability. Finally, we speculate that the essentiality of anti-sigma factors that regulate envelope function may be a widespread phenomenon in bacteria.
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Affiliation(s)
| | | | - Amanda A Kidman
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Erin K Cassin
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Lia A Michaels
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Elizabeth A Campbell
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY, USA
| | - Peter A Jorth
- Departments of Pathology and Laboratory Medicine, Medicine, and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Boo Shan Tseng
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
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15
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Demers EG, Stajich JE, Ashare A, Occhipinti P, Hogan DA. Balancing Positive and Negative Selection: In Vivo Evolution of Candida lusitaniae MRR1. mBio 2021; 12:e03328-20. [PMID: 33785623 PMCID: PMC8092287 DOI: 10.1128/mbio.03328-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
The evolution of pathogens in response to selective pressures present during chronic infections can influence their persistence and virulence and the outcomes of antimicrobial therapy. Because subpopulations within an infection can be spatially separated and the host environment can fluctuate, an appreciation of the pathways under selection may be most easily revealed through the analysis of numerous isolates from single infections. Here, we continued our analysis of a set of clonally derived Clavispora (Candida) lusitaniae isolates from a single chronic lung infection with a striking enrichment in the number of alleles of MRR1 Genetic and genomic analyses found evidence for repeated acquisition of gain-of-function mutations that conferred constitutive Mrr1 activity. In the same population, there were multiple alleles with both gain-of-function mutations and secondary suppressor mutations that either attenuated or abolished the constitutive activity, suggesting the presence of counteracting selective pressures. Our studies demonstrated trade-offs between high Mrr1 activity, which confers resistance to the antifungal fluconazole, host factors, and bacterial products through its regulation of MDR1, and resistance to hydrogen peroxide, a reactive oxygen species produced in the neutrophilic environment associated with this infection. This inverse correlation between high Mrr1 activity and hydrogen peroxide resistance was observed in multiple Candida species and in serially collected populations from this individual over 3 years. These data lead us to propose that dynamic or variable selective pressures can be reflected in population genomics and that these dynamics can complicate the drug resistance profile of the population.IMPORTANCE Understanding microbial evolution within patients is critical for managing chronic infections and understanding host-pathogen interactions. Here, our analysis of multiple MRR1 alleles in isolates from a single Clavispora (Candida) lusitaniae infection revealed the selection for both high and low Mrr1 activity. Our studies reveal trade-offs between high Mrr1 activity, which confers resistance to the commonly used antifungal fluconazole, host antimicrobial peptides, and bacterial products, and resistance to hydrogen peroxide. This work suggests that spatial or temporal differences within chronic infections can support a large amount of dynamic and parallel evolution and that Mrr1 activity is under both positive and negative selective pressure to balance different traits that are important for microbial survival.
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Affiliation(s)
- Elora G Demers
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Jason E Stajich
- Department of Microbiology & Plant Pathology and Institute for Integrative Genome Biology, University of California-Riverside, Riverside, California, USA
| | - Alix Ashare
- Dartmouth-Hitchcock Medical Center, Section of Pulmonary and Critical Care Medicine, Lebanon, New Hampshire, USA
| | - Patricia Occhipinti
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Deborah A Hogan
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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16
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Camus L, Vandenesch F, Moreau K. From genotype to phenotype: adaptations of Pseudomonas aeruginosa to the cystic fibrosis environment. Microb Genom 2021; 7:mgen000513. [PMID: 33529147 PMCID: PMC8190622 DOI: 10.1099/mgen.0.000513] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is one of the main microbial species colonizing the lungs of cystic fibrosis patients and is responsible for the decline in respiratory function. Despite the hostile pulmonary environment, P. aeruginosa is able to establish chronic infections thanks to its strong adaptive capacity. Various longitudinal studies have attempted to compare the strains of early infection with the adapted strains of chronic infection. Thanks to new '-omics' techniques, convergent genetic mutations, as well as transcriptomic and proteomic dysregulations have been identified. As a consequence of this evolution, the adapted strains of P. aeruginosa have particular phenotypes that promote persistent infection.
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Affiliation(s)
- Laura Camus
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
| | - François Vandenesch
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
- Centre National de Référence des Staphylocoques, Hospices Civils de Lyon, Lyon, France
- Institut des Agents Infectieux, Hospices Civils de Lyon, Lyon, France
| | - Karen Moreau
- CIRI – Centre International de Recherche en Infectiologie, Université de Lyon/Inserm U1111/Université Claude Bernard Lyon 1/CNRS UMR5308/ENS de Lyon, Lyon, France
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17
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Overproduction of the AlgT Sigma Factor Is Lethal to Mucoid Pseudomonas aeruginosa. J Bacteriol 2020; 202:JB.00445-20. [PMID: 32747430 DOI: 10.1128/jb.00445-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa isolates from chronic lung infections often overproduce alginate, giving rise to the mucoid phenotype. Isolation of mucoid strains from chronic lung infections correlates with a poor patient outcome. The most common mutation that causes the mucoid phenotype is called mucA22 and results in a truncated form of the anti-sigma factor MucA that is continuously subjected to proteolysis. When a functional MucA is absent, the cognate sigma factor, AlgT, is no longer sequestered and continuously transcribes the alginate biosynthesis operon, leading to alginate overproduction. In this work, we report that in the absence of wild-type MucA, providing exogenous AlgT is toxic. This is intriguing, since mucoid strains endogenously possess high levels of AlgT. Furthermore, we show that suppressors of toxic AlgT production have mutations in mucP, a protease involved in MucA degradation, and provide the first atomistic model of MucP. Based on our findings, we speculate that mutations in mucP stabilize the truncated form of MucA22, rendering it functional and therefore able to reduce toxicity by properly sequestering AlgT.IMPORTANCE Pseudomonas aeruginosa is an opportunistic bacterial pathogen capable of causing chronic lung infections. Phenotypes important for the long-term persistence and adaption to this unique lung ecosystem are largely regulated by the AlgT sigma factor. Chronic infection isolates often contain mutations in the anti-sigma factor mucA, resulting in uncontrolled AlgT and continuous production of alginate in addition to the expression of ∼300 additional genes. Here, we report that in the absence of wild-type MucA, AlgT overproduction is lethal and that suppressors of toxic AlgT production have mutations in the MucA protease, MucP. Since AlgT contributes to the establishment of chronic infections, understanding how AlgT is regulated will provide vital information on how P. aeruginosa is capable of causing long-term infections.
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18
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Henriksen K, Rørbo N, Rybtke ML, Martinet MG, Tolker-Nielsen T, Høiby N, Middelboe M, Ciofu O. P. aeruginosa flow-cell biofilms are enhanced by repeated phage treatments but can be eradicated by phage-ciprofloxacin combination. Pathog Dis 2020; 77:5368070. [PMID: 30821815 DOI: 10.1093/femspd/ftz011] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/28/2019] [Indexed: 02/06/2023] Open
Abstract
Phage therapy has shown promising results in the treatment of Pseudomonas aeruginosa biofilm infections in animal studies and case reports. The aim of this study was to quantify effects of phage treatments on P. aeruginosa biofilm production and structure. Confocal scanning microscopy was used to follow the interaction between a cocktail of three virulent phages and P. aeruginosa flow-cell biofilms. The role of (i) biofilm age, (ii) repeated phage treatments, (iii) alginate production and (iv) the combination with sub-MIC levels of ciprofloxacin was investigated. Single phage treatment in the early biofilm stages significantly reduced P. aeruginosa PAO1 biovolume (85%-98% reduction). Repeated phage treatments increased the biovolume from 18.25 (untreated biofilm) to 22.24 and 31.07 µm3/µm2 for biofilms treated with phages twice and thrice, respectively. Alginate protected against the phage treatment as the live biovolume remained unaffected by the phage treatment in the mucoid biofilm (20.11 µm3/µm2 in untreated and 21.74 µm3/µm2 in phage-treated biofilm) but decreased in the PAO1 biofilm from 27.35 to 0.89 µm3/µm2. We show that the combination of phages with antibiotics at sub-MIC levels caused a ∼6 log units reduction in the abundance of P. aeruginosa cells in biofilms and that phage treatment increased the size of microcolonies in flow-cell system.
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Affiliation(s)
- Karoline Henriksen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark
| | - Nanna Rørbo
- Department of Biology, Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Morten Levin Rybtke
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark
| | - Mark Grevsen Martinet
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark
| | - Niels Høiby
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark.,Department of Clinical Microbiology, University Hospital, Rigshospitalet, Henrik Harpestrengs Vej 4A, 2100 , Copenhagen, Denmark
| | - Mathias Middelboe
- Department of Biology, Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark
| | - Oana Ciofu
- Department of Immunology and Microbiology, Costerton Biofilm Center, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 N, Copenhagen, Denmark
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19
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Malhotra S, Hayes D, Wozniak DJ. Cystic Fibrosis and Pseudomonas aeruginosa: the Host-Microbe Interface. Clin Microbiol Rev 2019; 32:e00138-18. [PMID: 31142499 PMCID: PMC6589863 DOI: 10.1128/cmr.00138-18] [Citation(s) in RCA: 256] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In human pathophysiology, the clash between microbial infection and host immunity contributes to multiple diseases. Cystic fibrosis (CF) is a classical example of this phenomenon, wherein a dysfunctional, hyperinflammatory immune response combined with chronic pulmonary infections wreak havoc upon the airway, leading to a disease course of substantial morbidity and shortened life span. Pseudomonas aeruginosa is an opportunistic pathogen that commonly infects the CF lung, promoting an accelerated decline of pulmonary function. Importantly, P. aeruginosa exhibits significant resistance to innate immune effectors and to antibiotics, in part, by expressing specific virulence factors (e.g., antioxidants and exopolysaccharides) and by acquiring adaptive mutations during chronic infection. In an effort to review our current understanding of the host-pathogen interface driving CF pulmonary disease, we discuss (i) the progression of disease within the primitive CF lung, specifically focusing on the role of host versus bacterial factors; (ii) critical, neutrophil-derived innate immune effectors that are implicated in CF pulmonary disease, including reactive oxygen species (ROS) and antimicrobial peptides (e.g., LL-37); (iii) P. aeruginosa virulence factors and adaptive mutations that enable evasion of the host response; and (iv) ongoing work examining the distribution and colocalization of host and bacterial factors within distinct anatomical niches of the CF lung.
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Affiliation(s)
- Sankalp Malhotra
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
- The Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Don Hayes
- The Ohio State University College of Medicine, Columbus, Ohio, USA
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
- Section of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA
| | - Daniel J Wozniak
- The Ohio State University College of Medicine, Columbus, Ohio, USA
- Section of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
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20
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Malhotra S, Hayes D, Wozniak DJ. Mucoid Pseudomonas aeruginosa and regional inflammation in the cystic fibrosis lung. J Cyst Fibros 2019; 18:796-803. [PMID: 31036488 DOI: 10.1016/j.jcf.2019.04.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa is the prominent bacterial pathogen in the cystic fibrosis (CF) lung and contributes to significant morbidity and mortality. Though P. aeruginosa strains initially colonizing the CF lung have a nonmucoid colony morphology, they often mutate into mucoid variants that are associated with clinical deterioration. Both nonmucoid and mucoid P. aeruginosa variants are often co-isolated on microbiological cultures of sputum collected from CF patients. With regional variation in bronchiectasis, tissue damage, inflammation, and microbial colonization, lobar distribution of nonmucoid and mucoid P. aeruginosa variants may impact local microenvironments in the CF lung, but this has not been well-studied. METHODS We prospectively collected lobe-specific bronchoalveolar lavage (BAL) fluid from a CF patient cohort (n = 14) using a standardized bronchoscopic protocol where collection was performed in 6 lobar regions. The lobar BAL specimens were plated on P. aeruginosa-selective media and proinflammatory cytokines (IL-1, TNF, IL-6 and IL-8) were measured via cytokine array. Correlations between infecting P. aeruginosa variants (nonmucoid, mucoid, or mixed-variant populations), the lobar regions in which these variants were found, and regional proinflammatory cytokine concentrations were measured. RESULTS P. aeruginosa mucoid and nonmucoid variants were homogenously distributed throughout the CF lung. However, infection with mucoid variants (found within single- or mixed-variant populations) was associated with significantly greater regional inflammation. The upper and lower lobes of the CF lung did not exhibit differences in inflammatory cytokine concentrations. CONCLUSIONS Mucoid P. aeruginosa infection is a microbial determinant of regional inflammation within the CF lung.
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Affiliation(s)
- Sankalp Malhotra
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA; The Ohio State University College of Medicine, Columbus, OH, USA
| | - Don Hayes
- The Ohio State University College of Medicine, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA; Section. of Pulmonary Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA; The Ohio State University College of Medicine, Columbus, OH, USA; Department of Microbiology, The Ohio State University, Columbus, OH, USA.
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21
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Klockgether J, Cramer N, Fischer S, Wiehlmann L, Tümmler B. Long-Term Microevolution of Pseudomonas aeruginosa Differs between Mildly and Severely Affected Cystic Fibrosis Lungs. Am J Respir Cell Mol Biol 2019; 59:246-256. [PMID: 29470920 DOI: 10.1165/rcmb.2017-0356oc] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Chronic airway infections with Pseudomonas aeruginosa determine morbidity in most individuals with cystic fibrosis (CF). P. aeruginosa may persist for decades in CF lungs, which provides a rare opportunity to study the long-term within-host evolution of a bacterial airway pathogen. In this work, we sought to resolve the genetic adaptation of P. aeruginosa in CF lungs from the onset of colonization until the patient's death or permanent replacement by another P. aeruginosa clone. We followed the microevolution of the first persisting P. aeruginosa clone by whole-genome sequencing of serial isolates from highly divergent clinical courses of airway infection, i.e., a fatal outcome because of respiratory insufficiency within less than 15 years, or a rather normal daily life 25-35 years after acquisition of P. aeruginosa. Nonneutral mutations predominantly emerged in P. aeruginosa genes relevant for protection against and communication with signals from the lung environment, i.e., antibiotic resistance, cell wall components, and two-component systems. Drastic and loss-of-function mutations preferentially happened during the severe courses of infection, and the bacterial lineages of the mild courses more proficiently incorporated extra metabolic genes into their accessory genome. P. aeruginosa followed different evolutionary paths depending on whether the bacterium had taken up residence in a patient with CF and normal or already compromised lung function.
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Affiliation(s)
- Jens Klockgether
- 1 Clinical Research Group "Molecular Pathology of Cystic Fibrosis," Clinic for Pediatric Pneumology, Allergology and Neonatology, and
| | - Nina Cramer
- 1 Clinical Research Group "Molecular Pathology of Cystic Fibrosis," Clinic for Pediatric Pneumology, Allergology and Neonatology, and
| | - Sebastian Fischer
- 1 Clinical Research Group "Molecular Pathology of Cystic Fibrosis," Clinic for Pediatric Pneumology, Allergology and Neonatology, and
| | - Lutz Wiehlmann
- 1 Clinical Research Group "Molecular Pathology of Cystic Fibrosis," Clinic for Pediatric Pneumology, Allergology and Neonatology, and.,2 Research Core Unit Genomics, Hannover Medical School, Hannover, Germany; and
| | - Burkhard Tümmler
- 1 Clinical Research Group "Molecular Pathology of Cystic Fibrosis," Clinic for Pediatric Pneumology, Allergology and Neonatology, and.,3 Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Centre for Lung Research, Hannover, Germany
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22
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Hyperbaric oxygen treatment increases killing of aggregating Pseudomonas aeruginosa isolates from cystic fibrosis patients. J Cyst Fibros 2019; 18:657-664. [PMID: 30711384 DOI: 10.1016/j.jcf.2019.01.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/10/2019] [Accepted: 01/15/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa is a major pathogen of the chronic lung infections in cystic fibrosis (CF) patients. These persistent bacterial infections are characterized by bacterial aggregates with biofilm-like properties and are treated with nebulized or intravenous tobramycin in combination with other antibiotics. However, the chronic infections are close to impossible to eradicate due to reasons that are far from fully understood. Recent work has shown that re‑oxygenation of hypoxic aggregates by hyperbaric oxygen (O2) treatment (HBOT: 100% O2 at 2.8 bar) will increase killing of aggregating bacteria by antibiotics. This is relevant for treatment of infected CF patients where bacterial aggregates are found in the endobronchial secretions that are depleted of O2 by the metabolism of polymorphonuclear leukocytes (PMNs). The main objective of this study was to investigate the effect of HBOT as an adjuvant to tobramycin treatment of aggregates formed by P. aeruginosa isolates from CF patients. METHODS The effect was tested using a model with bacterial aggregates embedded in agarose. O2 profiling was used to confirm re‑oxygenation of aggregates. RESULTS We found that HBOT was able to significantly enhance the effect of tobramycin against aggregates of all the P. aeruginosa isolates in vitro. The effect was attributed to increased O2 levels leading to increased growth and thus increased uptake of and killing by tobramycin. CONCLUSIONS Re‑oxygenation may in the future be a clinical possibility as adjuvant to enhance killing by antibiotics in cystic fibrosis lung infections.
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23
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Candido Caçador N, Paulino da Costa Capizzani C, Gomes Monteiro Marin Torres LA, Galetti R, Ciofu O, da Costa Darini AL, Høiby N. Adaptation of Pseudomonas aeruginosa to the chronic phenotype by mutations in the algTmucABD operon in isolates from Brazilian cystic fibrosis patients. PLoS One 2018; 13:e0208013. [PMID: 30496246 PMCID: PMC6264809 DOI: 10.1371/journal.pone.0208013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 11/09/2018] [Indexed: 01/15/2023] Open
Abstract
Chronic lung infection by Pseudomonas aeruginosa is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. This is associated with the conversion of the non-mucoid to the mucoid phenotype. However, there is little information about the occurrence of alginate-producing P. aeruginosa in CF patients outside Europe and North America. The aim of the present study was to investigate mutations in the algTmucABD operon in mucoid and non-mucoid isolates from Brazilian CF patients. Twenty-seven mucoid and 37 non-mucoid isolates from 40 CF patients chronically infected by P. aeruginosa attending a CF reference center in Brazil were evaluated by sequence analysis. Mutations in mucA were observed in 93% of the mucoid isolates and 54% of the non-mucoid isolates. Among these non-mucoid isolates, 55% were considered revertants, since they also had mutations in algT (algU). Most isolates associated with moderate alginate production presented point mutations in mucB and/or mucD. We identified 30 mutations not previously described in the operon. In conclusion, mutations in mucA were the main mechanism of conversion to mucoidy, and most of the non-mucoid isolates were revertants, but the mechanism of revertance is not fully explained by changes in algT.
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Affiliation(s)
- Natália Candido Caçador
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (NCC); (ALCD)
| | | | | | - Renata Galetti
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Oana Ciofu
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Ana Lúcia da Costa Darini
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail: (NCC); (ALCD)
| | - Niels Høiby
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, University Hospital, Rigshospitalet, Copenhagen, Denmark
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24
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Chevalier S, Bouffartigues E, Bazire A, Tahrioui A, Duchesne R, Tortuel D, Maillot O, Clamens T, Orange N, Feuilloley MGJ, Lesouhaitier O, Dufour A, Cornelis P. Extracytoplasmic function sigma factors in Pseudomonas aeruginosa. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:706-721. [PMID: 29729420 DOI: 10.1016/j.bbagrm.2018.04.008] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/06/2018] [Accepted: 04/30/2018] [Indexed: 01/26/2023]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa, like all members of the genus Pseudomonas, has the capacity to thrive in very different environments, ranging from water, plant roots, to animals, including humans to whom it can cause severe infections. This remarkable adaptability is reflected in the number of transcriptional regulators, including sigma factors in this bacterium. Among those, the 19 to 21 extracytoplasmic sigma factors (ECFσ) are endowed with different regulons and functions, including the iron starvation σ (PvdS, FpvI, HasI, FecI, FecI2 and others), the cell wall stress ECFσ AlgU, SigX and SbrI, and the unorthodox σVreI involved in the expression of virulence. Recently published data show that these ECFσ have separate regulons although presenting some cross-talk. We will present evidence that these different ECFσ are involved in the expression of different phenotypes, ranging from cell-wall stress response, production of extracellular polysaccharides, formation of biofilms, to iron acquisition.
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Affiliation(s)
- Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France.
| | - Emeline Bouffartigues
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alexis Bazire
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Ali Tahrioui
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Rachel Duchesne
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Damien Tortuel
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Maillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Thomas Clamens
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Nicole Orange
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
| | - Alain Dufour
- IUEM, Université de Bretagne-Sud (UBL), Laboratoire de Biotechnologie et Chimie Marines EA 3884, Lorient, France
| | - Pierre Cornelis
- Laboratory of Microbiology Signals and Microenvironment LMSM EA 4312, Normandy University, University of Rouen, 27000 Evreux, France
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25
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Malhotra S, Limoli DH, English AE, Parsek MR, Wozniak DJ. Mixed Communities of Mucoid and Nonmucoid Pseudomonas aeruginosa Exhibit Enhanced Resistance to Host Antimicrobials. mBio 2018; 9:e00275-18. [PMID: 29588399 PMCID: PMC5874919 DOI: 10.1128/mbio.00275-18] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 02/08/2018] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa causes chronic pulmonary infections in patients with cystic fibrosis (CF). P. aeruginosa mucoid conversion, defined by overproduction of the exopolysaccharide alginate, correlates with accelerated decline in CF patient lung function. Recalcitrance of the mucoid phenotype to clearance by antibiotics and the immune response is well documented. However, despite advantages conferred by mucoidy, mucoid variants often revert to a nonmucoid phenotype both in vitro and in vivo Mixed populations of mucoid isolates and nonmucoid revertants are recovered from CF lungs, suggesting a selective benefit for coexistence of these variants. In this study, cocultures of mucoid and nonmucoid variants exhibited enhanced resistance to two host antimicrobials: LL-37, a cationic antimicrobial peptide, and hydrogen peroxide (H2O2). Alginate production by mucoid isolates protected nonmucoid variants in consortia from LL-37, as addition of alginate exogenously to nonmucoid variants abrogated LL-37 killing. Conversely, nonmucoid revertants shielded mucoid variants from H2O2 stress via catalase (KatA) production, which was transcriptionally repressed by AlgT and AlgR, central regulators of alginate biosynthesis. Furthermore, extracellular release of KatA by nonmucoid revertants was dependent on lys, encoding an endolysin implicated in autolysis and extracellular DNA (eDNA) release. Overall, these data provide a rationale to study interactions of P. aeruginosa mucoid and nonmucoid variants as contributors to evasion of innate immunity and persistence within the CF lung.IMPORTANCEP. aeruginosa mucoid conversion within lungs of cystic fibrosis (CF) patients is a hallmark of chronic infection and predictive of poor prognosis. The selective benefit of mixed populations of mucoid and nonmucoid variants, often isolated from chronically infected CF patients, has not been explored. Here, we show that mixed-variant communities of P. aeruginosa demonstrate advantages in evasion of innate antimicrobials via production of shared goods: alginate and catalase. These data argue for therapeutically targeting multiple constituents (both mucoid and nonmucoid variants) within diversified P. aeruginosa communities in vivo, as these variants can differentially shield one another from components of the host response.
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Affiliation(s)
- Sankalp Malhotra
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Dominique H Limoli
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth, Hanover, New Hampshire, USA
| | - Anthony E English
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
- Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
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26
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Yang J, Toyofuku M, Sakai R, Nomura N. Influence of the alginate production on cell-to-cell communication in Pseudomonas aeruginosa PAO1. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:239-249. [PMID: 28120378 DOI: 10.1111/1758-2229.12521] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/13/2017] [Accepted: 01/18/2017] [Indexed: 06/06/2023]
Abstract
Many bacteria communicate with each other through signalling molecules, a process known as cell-to-cell communication. During this process, it is important for the signalling molecules to: (1) reach the target cells; and (2) to be received by the cognate receptor. Barriers such as the presence of extracellular matrix may prevent signals from reaching their targets; however, the influence of the extracellular matrix on cell-to-cell communication has scarcely been studied. Here, we demonstrate that the overproduction of an extracellular matrix, alginate, in a Pseudomonas aeruginosa mucoid variant, alters cell-to-cell communication by interfering with the response to quinolone signals while having no effect on N-acyl-L-homoserine lactones. The inhibition of quinolone signalling by alginate is limited to the alginate overproducer and has no effect on neighbour cells that do not produce alginate. Our study indicates that alginate overproduction affects the cell-to-cell communication of the mucoid variant, which may results in different downstream behaviours when it emerges in the presence of the wild-type (WT).
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Affiliation(s)
- Jiayue Yang
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
| | - Masanori Toyofuku
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
- Department of Plant and Microbial Biology, University of Zurich, Zürich, 8008, Switzerland
| | - Ryosuke Sakai
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
| | - Nobuhiko Nomura
- Department of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
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27
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Høiby N, Bjarnsholt T, Moser C, Jensen PØ, Kolpen M, Qvist T, Aanaes K, Pressler T, Skov M, Ciofu O. Diagnosis of biofilm infections in cystic fibrosis patients. APMIS 2017; 125:339-343. [PMID: 28407432 DOI: 10.1111/apm.12689] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/03/2017] [Indexed: 12/22/2022]
Abstract
Chronic Pseudomonas aeruginosa biofilm lung infection in cystic fibrosis patients is the best described biofilm infection in medicine. The initial focus can be the paranasal sinuses and then follows repeated colonization and infection of the lungs by aspiration. The matrix of the biofilms is dominated by alginate and the pathogenesis of tissue damage is immune complex-mediated chronic inflammation dominated by polymorphonuclear leukocytes and their products (DNA, oxygen radicals and proteases). The P. aeruginosa biofilm infection can be diagnosed by microscopy of lung tissue, sputum and mucus from the paranasal sinuses, where aggregates of the bacteria are found surrounded by the abundant alginate matrix. Specific PNA-FISH probes can be used to identify P. aeruginosa and other pathogens in situ in the biofilms. Growth of mucoid colonies from the locations mentioned above is also diagnostic for biofilm infection. Rise of specific anti-P. aeruginosa antibodies is likewise diagnostic, IgG in serum in case of lung infection, sIgA in saliva or nasal secretions in case of paranasal sinus infection. Similar approaches have been developed to diagnose chronic biofilm infections in cystic fibrosis caused by other pathogens e.g., Stenotrophomonas, Burkholderia multivorans, Achromobacter xylosoxidans and Mycobacterium abscessus complex.
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Affiliation(s)
- Niels Høiby
- Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark.,Costerton Biofilm Center, Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bjarnsholt
- Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark.,Costerton Biofilm Center, Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Claus Moser
- Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Peter Østrup Jensen
- Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark.,Costerton Biofilm Center, Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, University of Copenhagen, Copenhagen, Denmark.,Costerton Biofilm Center, Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Tavs Qvist
- Copenhagen Cystic Fibrosis Centre, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Aanaes
- Department of Otorhinology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Tanja Pressler
- Copenhagen Cystic Fibrosis Centre, University of Copenhagen, Copenhagen, Denmark
| | - Marianne Skov
- Copenhagen Cystic Fibrosis Centre, University of Copenhagen, Copenhagen, Denmark
| | - Oana Ciofu
- Costerton Biofilm Center, Institute for Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
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28
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Moore JE, Mastoridis P. Clinical implications of Pseudomonas aeruginosa location in the lungs of patients with cystic fibrosis. J Clin Pharm Ther 2017; 42:259-267. [PMID: 28374433 DOI: 10.1111/jcpt.12521] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/05/2017] [Indexed: 12/18/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Pseudomonas aeruginosa is the leading cause of lung infection in patients with cystic fibrosis (CF) and is associated with significant morbidity and mortality. Antibiotics are regarded as the foundational pharmacological treatment for the suppressive management of chronic P. aeruginosa infections and to eradicate the first infection by P. aeruginosa. Inhalation remains a preferred route for drug administration, providing direct access to the site of infection while minimizing systemic side effects. Effective suppressive management of P. aeruginosa infections, however, requires an understanding of the location of the bacteria in the lungs and consideration of the factors that could limit access of the inhaled antibiotic to the infected area. This review provides a systematic assessment of the scientific literature to gain insight into the location of P. aeruginosa in the lungs of patients with CF and its clinical implications. The characteristics of antibiotic inhalation systems are also discussed in this context. METHODS We reviewed evidence-based literature from both human and animal studies in which P. aeruginosa lung location was reported. Relevant publications were identified through a screening strategy and summarized by reported P. aeruginosa location. RESULTS AND DISCUSSION Most areas of the conductive and respiratory zones of the lungs are susceptible to P. aeruginosa colonization. Deposition of an inhaled antibiotic is dependent on the device and formulation characteristics, as well as the ability of the patient to generate sufficient inhaled volume. As patients with CF often experience a decline in lung function, the challenge is to ensure that the inhaled antibiotic can be delivered throughout the bronchial tree. WHAT IS NEW AND CONCLUSION An effective drug delivery system that can target P. aeruginosa in both the respiratory and conductive zones is required. The chosen inhalation device should also offer a drug formulation that can be quickly and effectively delivered to specific lung locations, with minimal inspiratory effort from the patient.
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Affiliation(s)
- J E Moore
- Northern Ireland Public Health Laboratory, Department of Bacteriology, Belfast City Hospital, Belfast, UK
| | - P Mastoridis
- Respiratory Department, Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
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29
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Limoli DH, Whitfield GB, Kitao T, Ivey ML, Davis MR, Grahl N, Hogan DA, Rahme LG, Howell PL, O'Toole GA, Goldberg JB. Pseudomonas aeruginosa Alginate Overproduction Promotes Coexistence with Staphylococcus aureus in a Model of Cystic Fibrosis Respiratory Infection. mBio 2017; 8:e00186-17. [PMID: 28325763 PMCID: PMC5362032 DOI: 10.1128/mbio.00186-17] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 02/22/2017] [Indexed: 01/30/2023] Open
Abstract
While complex intra- and interspecies microbial community dynamics are apparent during chronic infections and likely alter patient health outcomes, our understanding of these interactions is currently limited. For example, Pseudomonas aeruginosa and Staphylococcus aureus are often found to coinfect the lungs of patients with cystic fibrosis (CF), yet these organisms compete under laboratory conditions. Recent observations that coinfection correlates with decreased health outcomes necessitate we develop a greater understanding of these interbacterial interactions. In this study, we tested the hypothesis that P. aeruginosa and/or S. aureus adopts phenotypes that allow coexistence during infection. We compared competitive interactions of P. aeruginosa and S. aureus isolates from mono- or coinfected CF patients employing in vitro coculture models. P. aeruginosa isolates from monoinfected patients were more competitive toward S. aureus than P. aeruginosa isolates from coinfected patients. We also observed that the least competitive P. aeruginosa isolates possessed a mucoid phenotype. Mucoidy occurs upon constitutive activation of the sigma factor AlgT/U, which regulates synthesis of the polysaccharide alginate and dozens of other secreted factors, including some previously described to kill S. aureus Here, we show that production of alginate in mucoid strains is sufficient to inhibit anti-S. aureus activity independent of activation of the AlgT regulon. Alginate reduces production of siderophores, 2-heptyl-4-hydroxyquinolone-N-oxide (HQNO), and rhamnolipids-each required for efficient killing of S. aureus These studies demonstrate alginate overproduction may be an important factor driving P. aeruginosa coinfection with S. aureusIMPORTANCE Numerous deep-sequencing studies have revealed the microbial communities present during respiratory infections in cystic fibrosis (CF) patients are diverse, complex, and dynamic. We now face the challenge of determining the influence of these community dynamics on patient health outcomes and identifying candidate targets to modulate these interactions. We make progress toward this goal by determining that the polysaccharide alginate produced by mucoid strains of P. aeruginosa is sufficient to inhibit multiple secreted antimicrobial agents produced by this organism. Importantly, these secreted factors are required to outcompete S. aureus, when the microbes are grown in coculture; thus we propose a mechanism whereby mucoid P. aeruginosa can coexist with S. aureus Finally, the approach used here can serve as a platform to investigate the interactions among other CF pathogens.
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Affiliation(s)
- Dominique H Limoli
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Tomoe Kitao
- Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children Boston, Boston, Massachusetts, USA
| | - Melissa L Ivey
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Michael R Davis
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Nora Grahl
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Deborah A Hogan
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Laurence G Rahme
- Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
- Department of Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Shriners Hospitals for Children Boston, Boston, Massachusetts, USA
| | - P Lynne Howell
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - George A O'Toole
- Department of Microbiology & Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Joanna B Goldberg
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, USA
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30
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Waite RD, Qureshi MR, Whiley RA. Modulation of behaviour and virulence of a high alginate expressing Pseudomonas aeruginosa strain from cystic fibrosis by oral commensal bacterium Streptococcus anginosus. PLoS One 2017; 12:e0173741. [PMID: 28301571 PMCID: PMC5354419 DOI: 10.1371/journal.pone.0173741] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/24/2017] [Indexed: 12/16/2022] Open
Abstract
Cystic fibrosis (CF) airways harbour complex and dynamic polymicrobial communities that include many oral bacteria. Despite increased knowledge of CF airway microbiomes the interaction between established CF pathogens and other resident microbes and resulting impact on disease progression is poorly understood. Previous studies have demonstrated that oral commensal streptococci of the Anginosus group (AGS) can establish chronic pulmonary infections and become numerically dominant in CF sputa indicating that they play an important role in CF microbiome dynamics. In this study a strain of Pseudomonas aeruginosa (DWW2) of the mucoid alginate overproducing phenotype associated with chronic CF airway infection and a strain of the oral commensal AGS species Streptococcus anginosus (3a) from CF sputum were investigated for their ability to co-exist and their responses to biofilm co-culture. Bacteria in biofilms were quantified, pyocyanin expression by DWW2 was measured and the effect of AGS strain 3a on reversion of DWW2 to a non-mucoidal phenotype investigated. The virulence of DWW2, 3a and colony variant phenotypes of DWW2 in mono- and co-culture were compared in a Galleria mellonella infection model. Co-culture biofilms were formed in normoxic, hypercapnic (10% CO2) and anoxic atmospheres with the streptococcus increasing in number in co-culture, indicating that these bacteria would be able to co-exist and thrive within the heterogeneous microenvironments of the CF airway. The streptococcus caused increased pyocyanin expression by DWW2 and colony variants by stimulating reversion of the mucoid phenotype to the high pyocyanin expressing non-mucoid phenotype. The latter was highly virulent in the infection model with greater virulence when in co-culture with the streptococcus. The results of this study demonstrate that the oral commensal S. anginosus benefits from interaction with P. aeruginosa of the CF associated mucoid phenotype and modulates the behaviour of the pseudomonad in ways that may be clinically relevant.
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Affiliation(s)
- Richard D. Waite
- Centre for Immunobiology, Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Muhammad R. Qureshi
- Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Robert A. Whiley
- Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
- * E-mail:
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31
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Sommer LM, Alanin MC, Marvig RL, Nielsen KG, Høiby N, von Buchwald C, Molin S, Johansen HK. Bacterial evolution in PCD and CF patients follows the same mutational steps. Sci Rep 2016; 6:28732. [PMID: 27349973 PMCID: PMC4923847 DOI: 10.1038/srep28732] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/08/2016] [Indexed: 11/25/2022] Open
Abstract
Infections with Pseudomonas aeruginosa increase morbidity in primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) patients. Both diseases are associated with a defect of the mucociliary clearance; in PCD caused by non-functional cilia, in CF by changed mucus. Whole genome sequencing of P. aeruginosa isolates from CF patients has shown that persistence of clonal lineages in the airways is facilitated by genetic adaptation. It is unknown whether this also applies to P. aeruginosa airway infections in PCD. We compared within-host evolution of P. aeruginosa in PCD and CF patients. P. aeruginosa isolates from 12 PCD patients were whole genome sequenced and phenotypically characterised. Ten out of 12 PCD patients were infected with persisting clone types. We identified convergent evolution in eight genes, which are also important for persistent infections in CF airways: genes related to antibiotic resistance, quorum sensing, motility, type III secretion and mucoidity. We document phenotypic and genotypic parallelism in the evolution of P. aeruginosa across infected patients with different genetic disorders. The parallel changes and convergent adaptation and evolution may be caused by similar selective forces such as the intensive antibiotic treatment and the inflammatory response, which drive the evolutionary processes.
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Affiliation(s)
- Lea M Sommer
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Mikkel Christian Alanin
- Department of Otorhinolaryngology - Head and Neck Surgery and Audiology, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Rasmus L Marvig
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Denmark.,Center for Genomic Medicine, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Kim Gjerum Nielsen
- Danish PCD Centre, Paediatric Pulmonary Service, Department of Paediatrics and Adolescent Medicine, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Niels Høiby
- Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Denmark.,Institute of Immunology and Microbiology, University of Copenhagen, Denmark
| | - Christian von Buchwald
- Department of Otorhinolaryngology - Head and Neck Surgery and Audiology, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Søren Molin
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.,Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Helle Krogh Johansen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark.,Department of Clinical Microbiology, Copenhagen University Hospital, Rigshospitalet, Denmark
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32
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Schmidt A, Hammerbacher AS, Bastian M, Nieken KJ, Klockgether J, Merighi M, Lapouge K, Poschgan C, Kölle J, Acharya KR, Ulrich M, Tümmler B, Unden G, Kaever V, Lory S, Haas D, Schwarz S, Döring G. Oxygen-dependent regulation of c-di-GMP synthesis by SadC controls alginate production in Pseudomonas aeruginosa. Environ Microbiol 2016; 18:3390-3402. [PMID: 26743546 DOI: 10.1111/1462-2920.13208] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/18/2015] [Accepted: 12/24/2015] [Indexed: 12/31/2022]
Abstract
Pseudomonas aeruginosa produces increased levels of alginate in response to oxygen-deprived conditions. The regulatory pathway(s) that links oxygen limitation to increased synthesis of alginate has remained elusive. In the present study, using immunofluorescence microscopy, we show that anaerobiosis-induced alginate production by planktonic PAO1 requires the diguanylate cyclase (DGC) SadC, previously identified as a regulator of surface-associated lifestyles. Furthermore, we found that the gene products of PA4330 and PA4331, located in a predicted operon with sadC, have a major impact on alginate production: deletion of PA4330 (odaA, for oxygen-dependent alginate synthesis activator) caused an alginate production defect under anaerobic conditions, whereas a PA4331 (odaI, for oxygen-dependent alginate synthesis inhibitor) deletion mutant produced alginate also in the presence of oxygen, which would normally inhibit alginate synthesis. Based on their sequence, OdaA and OdaI have predicted hydratase and dioxygenase reductase activities, respectively. Enzymatic assays using purified protein showed that unlike OdaA, which did not significantly affect DGC activity of SadC, OdaI inhibited c-di-GMP production by SadC. Our data indicate that SadC, OdaA and OdaI are components of a novel response pathway of P. aeruginosa that regulates alginate synthesis in an oxygen-dependent manner.
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Affiliation(s)
- Annika Schmidt
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany
| | - Anna Silke Hammerbacher
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany.,Bristol-Myers Squibb, Munich, Germany
| | - Mike Bastian
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany.,Birken AG, Niefern-Öschelbronn, Germany
| | - Karen Jule Nieken
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany
| | - Jens Klockgether
- Clinical Research Group, 'Molecular Pathology' of Cystic Fibrosis and Pseudomonas Genomics, Hannover Medical School, 30625, Hannover, Germany.,Hannover and Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), German Center for Lung Research, Hannover, Germany
| | - Massimo Merighi
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA, 02115, USA.,Ginkgo Bioworks, Boston, Massachusetts, USA
| | - Karine Lapouge
- Departement of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland.,Biochemistry Center (BZH), University of Heidelberg, 69120, Heidelberg, Germany
| | - Claudia Poschgan
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany
| | - Julia Kölle
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany.,University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - K Ravi Acharya
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, England
| | - Martina Ulrich
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany
| | - Burkhard Tümmler
- Clinical Research Group, 'Molecular Pathology' of Cystic Fibrosis and Pseudomonas Genomics, Hannover Medical School, 30625, Hannover, Germany.,Hannover and Biomedical Research in Endstage and Obstructive Lung Disease (BREATH), German Center for Lung Research, Hannover, Germany
| | - Gottfried Unden
- Institute for Microbiology and Wine Research, Johannes Gutenberg University Mainz, 55099, Mainz, Germany
| | - Volkhard Kaever
- Research Core Unit Metabolomics and Institute of Pharmacology, Hannover Medical School, 30625, Hannover, Germany
| | - Stephen Lory
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Dieter Haas
- Departement of Fundamental Microbiology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Sandra Schwarz
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany.
| | - Gerd Döring
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), University of Tübingen, 72076, Tübingen, Germany
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Flores-Kim J, Darwin AJ. Regulation of bacterial virulence gene expression by cell envelope stress responses. Virulence 2015; 5:835-51. [PMID: 25603429 DOI: 10.4161/21505594.2014.965580] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The bacterial cytoplasm lies within a multilayered envelope that must be protected from internal and external hazards. This protection is provided by cell envelope stress responses (ESRs), which detect threats and reprogram gene expression to ensure survival. Pathogens frequently need these ESRs to survive inside the host, where their envelopes face dangerous environmental changes and attack from antimicrobial molecules. In addition, some virulence genes have become integrated into ESR regulons. This might be because these genes can protect the cell envelope from damage by host molecules, or it might help ESRs to reduce stress by moderating the assembly of virulence factors within the envelope. Alternatively, it could simply be a mechanism to coordinate the induction of virulence gene expression with entry into the host. Here, we briefly describe some of the bacterial ESRs, followed by examples where they control virulence gene expression in both Gram-negative and Gram-positive pathogens.
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Key Words
- BFP, bundle-forming pilus
- CAMP, cationic antimicrobial peptide
- CF, cystic fibrosis
- ECF, extracytoplasmic function
- EPEC, enteropathogenic E. coli
- ESR, envelope stress response
- HMV, hypermucoviscosity
- IM, inner membrane
- LPS, lipopolysaccharide
- LTA, lipoteichoic acids
- OM, outer membrane
- OMP, outer membrane protein
- PG, phosphatidylglycerol
- T(2/3/4)SS, type II/III/IV secretion system
- UPEC, uropathogenic E. coli
- WTA, wall teichoic acids
- antimicrobial peptide
- bacterial pathogens
- cell envelope
- gene regulation
- peptidoglycan
- phospholipid
- stress response
- teichoic acid
- virulence gene
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Affiliation(s)
- Josué Flores-Kim
- a Department of Microbiology ; New York University School of Medicine ; New York , NY USA
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Jørgensen KM, Wassermann T, Johansen HK, Christiansen LE, Molin S, Høiby N, Ciofu O. Diversity of metabolic profiles of cystic fibrosis Pseudomonas aeruginosa during the early stages of lung infection. MICROBIOLOGY-SGM 2015; 161:1447-62. [PMID: 25873584 DOI: 10.1099/mic.0.000093] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Pseudomonas aeruginosa is the dominant pathogen infecting the airways of cystic fibrosis (CF) patients. During the intermittent colonization phase, P. aeruginosa resembles environmental strains but later evolves to the chronic adapted phenotype characterized by resistance to antibiotics and mutations in the global regulator genes mucA, lasR and rpoN. Our aim was to understand the metabolic changes occurring over time and between niches of the CF airways. By applying Phenotype MicroArrays, we investigated changes in the carbon and nitrogen catabolism of subsequently clonally related mucoid and non-mucoid (NM) lung and sinus P. aeruginosa isolates from 10 CF patients (five intermittently colonized/five chronically infected). We found the most pronounced catabolic changes for the early/late NM isolate comparisons, with respiratory reduction seen for all chronically infecting isolates and two intermittently colonizing isolates. Fewer differences were observed between sinus and lung isolates, showing a higher degree of isolate similarity between these two niches. Modest respiratory changes were seen for the early isolate/PAO1 comparisons, indicating colonization with environmental isolates. Assignment of metabolic pathways via the KEGG database showed a prevalence of substrates involved in the metabolism of Ala, Asp and Glu, d-Ala, and Arg and Pro. In conclusion, extensive heterogeneity in the metabolic profiles of the P. aeruginosa isolates was observed from the initial stages of the infection, showing a rapid diversification of the bacteria in the heterogeneous environment of the lung. Metabolic reduction seems to be a common trait and therefore an adaptive phenotype, though it can be reached via multiple metabolic pathways.
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Affiliation(s)
- Karin Meinike Jørgensen
- 1 Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Denmark
| | - Tina Wassermann
- 2 Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Helle Krogh Johansen
- 2 Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark 3 The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark
| | - Lasse Engbo Christiansen
- 4 Department of Informatics and Mathematical Modelling, Technical University of Denmark, Denmark
| | - Søren Molin
- 3 The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark 5 Center for Systems Biology, Technical University of Denmark, Denmark
| | - Niels Høiby
- 1 Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Denmark 2 Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Oana Ciofu
- 1 Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Denmark
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35
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Tolker-Nielsen T. Pseudomonas aeruginosa biofilm infections: from molecular biofilm biology to new treatment possibilities. APMIS 2015:1-51. [PMID: 25399808 DOI: 10.1111/apm.12335] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bacteria in natural, industrial and clinical settings predominantly live in biofilms, i.e., sessile structured microbial communities encased in self-produced extracellular matrix material. One of the most important characteristics of microbial biofilms is that the resident bacteria display a remarkable increased tolerance toward antimicrobial attack. Biofilms formed by opportunistic pathogenic bacteria are involved in devastating persistent medical device-associated infections, and chronic infections in individuals who are immune-compromised or otherwise impaired in the host defense. Because the use of conventional antimicrobial compounds in many cases cannot eradicate biofilms, there is an urgent need to develop alternative measures to combat biofilm infections. The present review is focussed on the important opportunistic pathogen and biofilm model organism Pseudomonas aeruginosa. Initially, biofilm infections where P. aeruginosa plays an important role are described. Subsequently, current insights into the molecular mechanisms involved in P. aeruginosa biofilm formation and the associated antimicrobial tolerance are reviewed. And finally, based on our knowledge about molecular biofilm biology, a number of therapeutic strategies for combat of P. aeruginosa biofilm infections are presented.
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Affiliation(s)
- Tim Tolker-Nielsen
- Costerton Biofilm Center, Department of International Health, Immunology and Microbiology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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36
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Convergent evolution and adaptation of Pseudomonas aeruginosa within patients with cystic fibrosis. Nat Genet 2014; 47:57-64. [DOI: 10.1038/ng.3148] [Citation(s) in RCA: 404] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 10/27/2014] [Indexed: 12/30/2022]
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Chew SC, Kundukad B, Seviour T, van der Maarel JRC, Yang L, Rice SA, Doyle P, Kjelleberg S. Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides. mBio 2014; 5:e01536-14. [PMID: 25096883 PMCID: PMC4128364 DOI: 10.1128/mbio.01536-14] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 12/24/2022] Open
Abstract
Biofilms are densely populated communities of microbial cells protected and held together by a matrix of extracellular polymeric substances. The structure and rheological properties of the matrix at the microscale influence the retention and transport of molecules and cells in the biofilm, thereby dictating population and community behavior. Despite its importance, quantitative descriptions of the matrix microstructure and microrheology are limited. Here, particle-tracking microrheology in combination with genetic approaches was used to spatially and temporally study the rheological contributions of the major exopolysaccharides Pel and Psl in Pseudomonas aeruginosa biofilms. Psl increased the elasticity and effective cross-linking within the matrix, which strengthened its scaffold and appeared to facilitate the formation of microcolonies. Conversely, Pel reduced effective cross-linking within the matrix. Without Psl, the matrix becomes more viscous, which facilitates biofilm spreading. The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces. This suggests that there are regulatory mechanisms to control production of the exopolysaccharides that serve to remodel the matrix of developing biofilms. The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus. Pel was required for close association of the two species in mixed-species microcolonies. In contrast, Psl was important for P. aeruginosa to form single-species biofilms on top of S. aureus biofilms. Our results demonstrate that Pel and Psl have distinct physical properties and functional roles during biofilm formation. Importance: Most bacteria grow as biofilms in the environment or in association with eukaryotic hosts. Removal of biofilms that form on surfaces is a challenge in clinical and industrial settings. One of the defining features of a biofilm is its extracellular matrix. The matrix has a heterogeneous structure and is formed from a secretion of various biopolymers, including proteins, extracellular DNA, and polysaccharides. It is generally known to interact with biofilm cells, thus affecting cell physiology and cell-cell communication. Despite the fact that the matrix may comprise up to 90% of the biofilm dry weight, how the matrix properties affect biofilm structure, maturation, and interspecies interactions remain largely unexplored. This study reveals that bacteria can use specific extracellular polymers to modulate the physical properties of their microenvironment. This in turn impacts biofilm structure, differentiation, and interspecies interactions.
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Affiliation(s)
| | - Binu Kundukad
- BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
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Okkotsu Y, Little AS, Schurr MJ. The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes. Front Cell Infect Microbiol 2014; 4:82. [PMID: 24999454 PMCID: PMC4064291 DOI: 10.3389/fcimb.2014.00082] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/02/2014] [Indexed: 01/28/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections.
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Affiliation(s)
- Yuta Okkotsu
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Alexander S Little
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
| | - Michael J Schurr
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
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Alhede M, Bjarnsholt T, Givskov M, Alhede M. Pseudomonas aeruginosa biofilms: mechanisms of immune evasion. ADVANCES IN APPLIED MICROBIOLOGY 2014; 86:1-40. [PMID: 24377853 DOI: 10.1016/b978-0-12-800262-9.00001-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The opportunistic gram-negative bacterium Pseudomonas aeruginosa is implicated in many chronic infections and is readily isolated from chronic wounds, medical devices, and the lungs of cystic fibrosis patients. P. aeruginosa is believed to persist in the host organism due to its capacity to form biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes (PMNs). In this chapter, the interplay between P. aeruginosa and the PMNs in chronic infections is discussed with focus on the role of rhamnolipids and extracellular DNA.
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Affiliation(s)
- Maria Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.
| | - Thomas Bjarnsholt
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Michael Givskov
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Morten Alhede
- Department of International Health, Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark; Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
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40
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Silva IN, Tavares AC, Ferreira AS, Moreira LM. Stress conditions triggering mucoid morphotype variation in Burkholderia species and effect on virulence in Galleria mellonella and biofilm formation in vitro. PLoS One 2013; 8:e82522. [PMID: 24358195 PMCID: PMC3865030 DOI: 10.1371/journal.pone.0082522] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/24/2013] [Indexed: 11/18/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) bacteria are opportunistic pathogens causing chronic respiratory infections particularly among cystic fibrosis patients. During these chronic infections, mucoid-to-nonmucoid morphotype variation occurs, with the two morphotypes exhibiting different phenotypic properties. Here we show that in vitro, the mucoid clinical isolate Burkholderia multivorans D2095 gives rise to stable nonmucoid variants in response to prolonged stationary phase, presence of antibiotics, and osmotic and oxidative stresses. Furthermore, in vitro colony morphotype variation within other members of the Burkholderia genus occurred in Bcc and non-Bcc strains, irrespectively of their clinical or environmental origin. Survival to starvation and iron limitation was comparable for the mucoid parental isolate and the respective nonmucoid variant, while susceptibility to antibiotics and to oxidative stress was increased in the nonmucoid variants. Acute infection of Galleria mellonella larvae showed that, in general, the nonmucoid variants were less virulent than the respective parental mucoid isolate, suggesting a role for the exopolysaccharide in virulence. In addition, most of the tested nonmucoid variants produced more biofilm biomass than their respective mucoid parental isolate. As biofilms are often associated with increased persistence of pathogens in the CF lungs and are an indicative of different cell-to-cell interactions, it is possible that the nonmucoid variants are better adapted to persist in this host environment.
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Affiliation(s)
- Inês N. Silva
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Andreia C. Tavares
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Ana S. Ferreira
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
| | - Leonilde M. Moreira
- Department of Bioengineering, Instituto Superior Técnico, Lisbon University, Lisbon, Portugal
- Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisbon, Portugal
- * E-mail:
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41
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Moyano AJ, Feliziani S, Di Rienzo JA, Smania AM. Simple sequence repeats together with mismatch repair deficiency can bias mutagenic pathways in Pseudomonas aeruginosa during chronic lung infection. PLoS One 2013; 8:e80514. [PMID: 24278287 PMCID: PMC3837008 DOI: 10.1371/journal.pone.0080514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/04/2013] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that chronically infects the airways of cystic fibrosis (CF) patients and undergoes a process of genetic adaptation based on mutagenesis. We evaluated the role of mononucleotide G:C and A:T simple sequence repeats (SSRs) in this adaptive process. An in silico survey of the genome sequences of 7 P. aeruginosa strains showed that mononucleotide G:C SSRs but not A:T SSRs were greatly under-represented in coding regions, suggesting a strong counterselection process for G:C SSRs with lengths >5 bp but not for A:T SSRs. A meta-analysis of published whole genome sequence data for a P. aeruginosa strain from a CF patient with chronic airway infection showed that G:C SSRs but not A:T SSRs were frequently mutated during the infection process through the insertion or deletion of one or more SSR subunits. The mutation tendency of G:C SSRs was length-dependent and increased exponentially as a function of SSR length. When this strain naturally became a stable Mismatch Repair System (MRS)-deficient mutator, the degree of increase of G:C SSRs mutations (5-fold) was much higher than that of other types of mutation (2.2-fold or less). Sequence analysis of several mutated genes reported for two different collections, both containing mutator and non-mutator strains of P. aeruginosa from CF chronic infections, showed that the proportion of G:C SSR mutations was significantly higher in mutators than in non-mutators, whereas no such difference was observed for A:T SSR mutations. Our findings, taken together, provide genome-scale evidences that under a MRS-deficient background, long G:C SSRs are able to stochastically bias mutagenic pathways by making the genes in which they are harbored more prone to mutation. The combination of MRS deficiency and virulence-related genes that contain long G:C SSRs is therefore a matter of concern in P. aeruginosa CF chronic infection.
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Affiliation(s)
- Alejandro J. Moyano
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Sofía Feliziani
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Julio A. Di Rienzo
- Estadística y Biometría, Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andrea M. Smania
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
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42
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Hay ID, Ur Rehman Z, Moradali MF, Wang Y, Rehm BHA. Microbial alginate production, modification and its applications. Microb Biotechnol 2013; 6:637-50. [PMID: 24034361 PMCID: PMC3815931 DOI: 10.1111/1751-7915.12076] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/25/2013] [Accepted: 07/06/2013] [Indexed: 11/29/2022] Open
Abstract
Alginate is an important polysaccharide used widely in the food, textile, printing and pharmaceutical industries for its viscosifying, and gelling properties. All commercially produced alginates are isolated from farmed brown seaweeds. These algal alginates suffer from heterogeneity in composition and material properties. Here, we will discuss alginates produced by bacteria; the molecular mechanisms involved in their biosynthesis; and the potential to utilize these bacterially produced or modified alginates for high-value applications where defined material properties are required.
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Affiliation(s)
- Iain D Hay
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand
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43
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Genes required for and effects of alginate overproduction induced by growth of Pseudomonas aeruginosa on Pseudomonas isolation agar supplemented with ammonium metavanadate. J Bacteriol 2013; 195:4020-36. [PMID: 23794622 DOI: 10.1128/jb.00534-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can adapt to changing environments and can secrete an exopolysaccharide known as alginate as a protection response, resulting in a colony morphology and phenotype referred to as mucoid. However, how P. aeruginosa senses its environment and activates alginate overproduction is not fully understood. Previously, we showed that Pseudomonas isolation agar supplemented with ammonium metavanadate (PIAAMV) induces P. aeruginosa to overproduce alginate. Vanadate is a phosphate mimic and causes protein misfolding by disruption of disulfide bonds. Here we used PIAAMV to characterize the pathways involved in inducible alginate production and tested the global effects of P. aeruginosa growth on PIAAMV by a mutant library screen, by transcriptomics, and in a murine acute virulence model. The PA14 nonredundant mutant library was screened on PIAAMV to identify new genes that are required for the inducible alginate stress response. A functionally diverse set of genes encoding products involved in cell envelope biogenesis, peptidoglycan remodeling, uptake of phosphate and iron, phenazine biosynthesis, and other processes were identified as positive regulators of the mucoid phenotype on PIAAMV. Transcriptome analysis of P. aeruginosa cultures growing in the presence of vanadate showed differential expression of genes involved in virulence, envelope biogenesis, and cell stress pathways. In this study, it was observed that growth on PIAAMV attenuates P. aeruginosa in a mouse pneumonia model. Induction of alginate overproduction occurs as a stress response to protect P. aeruginosa, but it may be possible to modulate and inhibit these pathways based on the new genes identified in this study.
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Behrends V, Bell TJ, Liebeke M, Cordes-Blauert A, Ashraf SN, Nair C, Zlosnik JEA, Williams HD, Bundy JG. Metabolite profiling to characterize disease-related bacteria: gluconate excretion by Pseudomonas aeruginosa mutants and clinical isolates from cystic fibrosis patients. J Biol Chem 2013; 288:15098-109. [PMID: 23572517 PMCID: PMC3663530 DOI: 10.1074/jbc.m112.442814] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Metabolic footprinting of supernatants has been proposed as a tool for assigning gene function. We used NMR spectroscopy to measure the exometabolome of 86 single-gene transposon insertion mutant strains (mutants from central carbon metabolism and regulatory mutants) of the opportunistic pathogen Pseudomonas aeruginosa, grown on a medium designed to represent the nutritional content of cystic fibrosis sputum. Functionally related genes had similar metabolic profiles. E.g. for two-component system mutants, the cognate response regulator and sensor kinase genes clustered tightly together. Some strains had metabolic phenotypes (metabotypes) that could be related to the known gene function. E.g. pyruvate dehydrogenase mutants accumulated large amounts of pyruvate in the medium. In other cases, the metabolic phenotypes were not easily interpretable. The rpoN mutant, which lacks the alternative σ factor RpoN (σ54), accumulated high levels of gluconate in the medium. In addition, endometabolome profiling of intracellular metabolites identified a number of systemic metabolic changes. We linked this to indirect regulation of the catabolite repression protein Crc via the non-coding RNA crcZ and found that a crcZ (but not crc) mutant also shared the high-gluconate phenotype. We profiled an additional set of relevant metabolic enzymes and transporters, including Crc targets, and showed that the Crc-regulated edd mutant (gluconate-6-phosphate dehydratase) had similar gluconate levels as the rpoN mutant. Finally, a set of clinical isolates showed patient- and random amplification of polymorphic DNA (RAPD) type-specific differences in gluconate production, which were associated significantly with resistance across four antibiotics (tobramycin, ciprofloxacin, aztreonam, and imipenem), indicating that this has potential clinical relevance.
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Affiliation(s)
- Volker Behrends
- Department of Surgery and Cancer, Imperial College London, London SW7 2AZ, United Kingdom
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45
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Ciofu O, Johansen HK, Aanaes K, Wassermann T, Alhede M, von Buchwald C, Høiby N. P. aeruginosa in the paranasal sinuses and transplanted lungs have similar adaptive mutations as isolates from chronically infected CF lungs. J Cyst Fibros 2013; 12:729-36. [PMID: 23478131 DOI: 10.1016/j.jcf.2013.02.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 02/06/2013] [Accepted: 02/11/2013] [Indexed: 01/02/2023]
Abstract
BACKGROUND Pseudomonas aeruginosa cells are present as biofilms in the paranasal sinuses and the lungs of chronically infected cystic fibrosis (CF) patients. Since different inflammatory responses and selective antibiotic pressures are acting in the sinuses compared with the lungs, we compared the adaptive profiles of mucoid and non-mucoid isolates from the two locations. METHODS We studied the genetic basis of phenotypic diversification and gene expression profiles in sequential lung and sinus P. aeruginosa isolates from four chronically infected CF patients, including pre- and post-lung transplantation isolates. RESULTS The same phenotypes caused by similar mutations and similar gene expression profiles were found in mucoid and non-mucoid isolates from the paranasal sinuses and from the lungs before and after transplantation. CONCLUSION Bilateral exchange of P. aeruginosa isolates between the paranasal sinuses and the lungs occurs in chronically infected patients and extensive sinus surgery before the lung transplantation might prevent infection of the new lung.
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Affiliation(s)
- Oana Ciofu
- Department of International Health, Immunology and Microbiology, Unit of Bacteriology, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
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Jácome PRLDA, Alves LR, Cabral AB, Lopes ACS, Maciel MAV. Phenotypic and molecular characterization of antimicrobial resistance and virulence factors in Pseudomonas aeruginosa clinical isolates from Recife, State of Pernambuco, Brazil. Rev Soc Bras Med Trop 2012; 45:707-12. [DOI: 10.1590/s0037-86822012000600010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 10/23/2012] [Indexed: 11/21/2022] Open
Abstract
INTRODUCTION: The emergence of carbapenem resistance mechanisms in Pseudomonas aeruginosa has been outstanding due to the wide spectrum of antimicrobial degradation of these bacteria, reducing of therapeutic options. METHODS: Sixty-one clinical strains of P. aeruginosa isolated from five public hospitals in Recife, Pernambuco, Brazil, were examined between 2006 and 2010, aiming of evaluating the profiles of virulence, resistance to antimicrobials, presence of metallo-β-lactamase (MBL) genes, and clonal relationship among isolates. RESULTS: A high percentage of virulence factors (34.4% mucoid colonies; 70.5% pyocyanin; 93.4% gelatinase positives; and 72.1% hemolysin positive) and a high percentage of antimicrobial resistance rates (4.9% pan-resistant and 54.1% multi-drug resistant isolates) were observed. Among the 29 isolates resistant to imipenem and/or ceftazidime, 44.8% (13/29) were MBL producers by phenotypic evaluation, and of these, 46.2% (6/13) were positive for the blaSPM-1 gene. The blaIMP and blaVIM genes were not detected. The molecular typing revealed 21 molecular profiles of which seven were detected in distinct hospitals and periods. Among the six positive blaSPM-1 isolates, three presented the same clonal profile and were from the same hospital, whereas the other three presented different clonal profiles. CONCLUSIONS: These results revealed that P. aeruginosa is able to accumulate different resistance and virulence factors, making the treatment of infections difficult. The identification of blaSPM-1 genes and the dissemination of clones in different hospitals, indicate the need for stricter application of infection control measures in hospitals in Recife, Brazil, aiming at reducing costs and damages caused by P. aeruginosa infections.
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Transcription of the oprF gene of Pseudomonas aeruginosa is dependent mainly on the SigX sigma factor and is sucrose induced. J Bacteriol 2012; 194:4301-11. [PMID: 22685281 DOI: 10.1128/jb.00509-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The OprF porin is the major outer membrane protein of Pseudomonas aeruginosa. OprF is involved in several crucial functions, including cell structure, outer membrane permeability, environmental sensing, and virulence. The oprF gene is preceded by the sigX gene, which encodes the poorly studied extracytoplasmic function (ECF) sigma factor SigX. Three oprF promoters were previously identified. Two intertwined promoters dependent on σ(70) and SigX are located in the sigX-oprF intergenic region, whereas a promoter dependent on the ECF AlgU lies within the sigX gene. An additional promoter was found in the cmpX-sigX intergenic region. In this study, we dissected the contribution of each promoter region and of each sigma factor to oprF transcription using transcriptional fusions. In Luria-Bertani (LB) medium, the oprF-proximal region (sigX-oprF intergenic region) accounted for about 80% of the oprF transcription, whereas the AlgU-dependent promoter had marginal activity. Using the sigX mutant PAOSX, we observed that the SigX-dependent promoter was largely predominant over the σ(70)-dependent promoter. oprF transcription was increased in response to low NaCl or high sucrose concentrations, and this induced transcription was strongly impaired in the absence of SigX. The lack of OprF itself increased oprF transcription. Since these conditions led to cell wall alterations, oprF transcription could be activated by signals triggered by perturbation of the cell envelope.
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Analysis of the Pseudomonas aeruginosa regulon controlled by the sensor kinase KinB and sigma factor RpoN. J Bacteriol 2011; 194:1317-30. [PMID: 22210761 DOI: 10.1128/jb.06105-11] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alginate overproduction by Pseudomonas aeruginosa, also known as mucoidy, is associated with chronic endobronchial infections in cystic fibrosis. Alginate biosynthesis is initiated by the extracytoplasmic function sigma factor (σ(22); AlgU/AlgT). In the wild-type (wt) nonmucoid strains, such as PAO1, AlgU is sequestered to the cytoplasmic membrane by the anti-sigma factor MucA that inhibits alginate production. One mechanism underlying the conversion to mucoidy is mutation of mucA. However, the mucoid conversion can occur in wt mucA strains via the degradation of MucA by activated intramembrane proteases AlgW and/or MucP. Previously, we reported that the deletion of the sensor kinase KinB in PAO1 induces an AlgW-dependent proteolysis of MucA, resulting in alginate overproduction. This type of mucoid induction requires the alternate sigma factor RpoN (σ(54)). To determine the RpoN-dependent KinB regulon, microarray and proteomic analyses were performed on a mucoid kinB mutant and an isogenic nonmucoid kinB rpoN double mutant. In the kinB mutant of PAO1, RpoN controlled the expression of approximately 20% of the genome. In addition to alginate biosynthetic and regulatory genes, KinB and RpoN also control a large number of genes including those involved in carbohydrate metabolism, quorum sensing, iron regulation, rhamnolipid production, and motility. In an acute pneumonia murine infection model, BALB/c mice exhibited increased survival when challenged with the kinB mutant relative to survival with PAO1 challenge. Together, these data strongly suggest that KinB regulates virulence factors important for the development of acute pneumonia and conversion to mucoidy.
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Scanlan PD, Buckling A. Co-evolution with lytic phage selects for the mucoid phenotype of Pseudomonas fluorescens SBW25. ISME JOURNAL 2011; 6:1148-58. [PMID: 22189495 DOI: 10.1038/ismej.2011.174] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The effects of co-evolution with lytic phage on bacterial virulence-related traits are largely unknown. In this study we investigate the incidence of the mucoid phenotype of the bacterium Pseudomonas fluorescens SBW25 in response to co-evolution with the lytic phage phi2 (φ2). The mucoid phenotype of Pseudomonas spp. is due to overproduction of alginate and is a considerable virulence factor contributing to the intractability of infections most notably in cystic fibrosis (CF) lung, but also in pathogenic infections of plants. Our data show that this phenotype can evolve as an adaptive response to phage predation and is favoured under specific abiotic conditions, in particular a homogenous spatial structure and a high rate of nutrient replacement. The mucoid phenotype remains partially sensitive to phage infection, which facilitates 'apparent competition' with phage-sensitive competitors, partially offsetting the costs of alginate production. Although P. fluorescens SBW25 is not a pathogen, several key characteristics typical of Pseudomonas aeruginosa clinical isolates from CF lung were noted, including loss of motility on mucoid conversion and a high rate of spontaneous reversion to the wild-type phenotype. Although the genetic mechanisms of this phenotype remain unknown, they do not include mutations at many of the commonly reported loci implicated in mucoid conversion, including mucA and algU. These data not only further our understanding of the potential role phage have in the ecology and evolution of bacteria virulence in both natural and clinical settings, but also highlight the need to consider both biotic and abiotic variables if bacteriophages are to be used therapeutically.
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Naughton S, Parker D, Seemann T, Thomas T, Turnbull L, Rose B, Bye P, Cordwell S, Whitchurch C, Manos J. Pseudomonas aeruginosa AES-1 exhibits increased virulence gene expression during chronic infection of cystic fibrosis lung. PLoS One 2011; 6:e24526. [PMID: 21935417 PMCID: PMC3174184 DOI: 10.1371/journal.pone.0024526] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/12/2011] [Indexed: 01/26/2023] Open
Abstract
Pseudomonas aeruginosa, the leading cause of morbidity and mortality in people with cystic fibrosis (CF), adapts for survival in the CF lung through both mutation and gene expression changes. Frequent clonal strains such as the Australian Epidemic Strain-1 (AES-1), have increased ability to establish infection in the CF lung and to superimpose and replace infrequent clonal strains. Little is known about the factors underpinning these properties. Analysis has been hampered by lack of expression array templates containing CF-strain specific genes. We sequenced the genome of an acute infection AES-1 isolate from a CF infant (AES-1R) and constructed a non-redundant micro-array (PANarray) comprising AES-1R and seven other sequenced P. aeruginosa genomes. The unclosed AES-1R genome comprised 6.254Mbp and contained 6957 putative genes, including 338 not found in the other seven genomes. The PANarray contained 12,543 gene probe spots; comprising 12,147 P. aeruginosa gene probes, 326 quality-control probes and 70 probes for non-P. aeruginosa genes, including phage and plant genes. We grew AES-1R and its isogenic pair AES-1M, taken from the same patient 10.5 years later and not eradicated in the intervening period, in our validated artificial sputum medium (ASMDM) and used the PANarray to compare gene expression of both in duplicate. 675 genes were differentially expressed between the isogenic pairs, including upregulation of alginate, biofilm, persistence genes and virulence-related genes such as dihydroorotase, uridylate kinase and cardiolipin synthase, in AES-1M. Non-PAO1 genes upregulated in AES-1M included pathogenesis-related (PAGI-5) genes present in strains PACS2 and PA7, and numerous phage genes. Elucidation of these genes' roles could lead to targeted treatment strategies for chronically infected CF patients.
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Affiliation(s)
- Sharna Naughton
- Department of Infectious Diseases and Immunology, University of Sydney, Sydney, Australia
| | - Dane Parker
- Department of Microbiology, Monash University, Melbourne, Australia
| | - Torsten Seemann
- Victorian Bioinformatics Consortium, Monash University, Melbourne, Australia
| | - Torsten Thomas
- School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation, University of New South Wales, Sydney, Australia
| | - Lynne Turnbull
- Department of Microbiology, Monash University, Melbourne, Australia
- The ithree institute, University of Technology, Sydney, Australia
| | - Barbara Rose
- Department of Infectious Diseases and Immunology, University of Sydney, Sydney, Australia
| | - Peter Bye
- Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, Australia
- Sydney Medical School, University of Sydney, Sydney, Australia
| | - Stuart Cordwell
- School of Molecular Biosciences, University of Sydney, Sydney, Australia
| | - Cynthia Whitchurch
- Department of Microbiology, Monash University, Melbourne, Australia
- The ithree institute, University of Technology, Sydney, Australia
| | - Jim Manos
- Department of Infectious Diseases and Immunology, University of Sydney, Sydney, Australia
- * E-mail:
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