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Schwarz C, Bend J, Hebestreit H, Hogardt M, Hügel C, Illing S, Mainz JG, Rietschel E, Schmidt S, Schulte-Hubbert B, Sitter H, Wielpütz MO, Hammermann J, Baumann I, Brunsmann F, Dieninghoff D, Eber E, Ellemunter H, Eschenhagen P, Evers C, Gruber S, Koitschev A, Ley-Zaporozhan J, Düesberg U, Mentzel HJ, Nüßlein T, Ringshausen FC, Sedlacek L, Smaczny C, Sommerburg O, Sutharsan S, Vonberg RP, Weber AK, Zerlik J. [CF Lung Disease - a German S3 Guideline: Pseudomonas aeruginosa]. Pneumologie 2024; 78:367-399. [PMID: 38350639 DOI: 10.1055/a-2182-1907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
Cystic Fibrosis (CF) is the most common autosomal recessive genetic multisystemic disease. In Germany, it affects at least 8000 people. The disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene leading to dysfunction of CFTR, a transmembrane chloride channel. This defect causes insufficient hydration of the airway epithelial lining fluid which leads to reduction of the mucociliary clearance.Even if highly effective, CFTR modulator therapy has been available for some years and people with CF are getting much older than before, recurrent and chronic infections of the airways as well as pulmonary exacerbations still occur. In adult CF life, Pseudomonas aeruginosa (PA) is the most relevant pathogen in colonisation and chronic infection of the lung, leading to further loss of lung function. There are many possibilities to treat PA-infection.This is a S3-clinical guideline which implements a definition for chronic PA-infection and demonstrates evidence-based diagnostic methods and medical treatment in order to give guidance for individual treatment options.
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Affiliation(s)
- Carsten Schwarz
- Klinikum Westbrandenburg GmbH, Standort Potsdam, Deutschland
| | - Jutta Bend
- Mukoviszidose Institut gGmbH, Bonn, Deutschland
| | | | - Michael Hogardt
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main, Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Frankfurt, Deutschland
| | - Christian Hügel
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main, Deutschland
| | | | - Jochen G Mainz
- Klinikum Westbrandenburg, Standort Brandenburg an der Havel, Universitätsklinikum der Medizinischen Hochschule Brandenburg (MHB), Brandenburg an der Havel, Deutschland
| | - Ernst Rietschel
- Medizinische Fakultät der Universität zu Köln, Mukoviszidose-Zentrum, Klinik und Poliklinik für Kinder- und Jugendmedizin, Köln, Deutschland
| | - Sebastian Schmidt
- Ernst-Moritz-Arndt Universität Greifswald, Kinderpoliklinik, Allgemeine Pädiatrie, Greifswald, Deutschland
| | | | - Helmut Sitter
- Philipps-Universität Marburg, Institut für theoretische Medizin, Marburg, Deutschland
| | - Marc Oliver Wielpütz
- Universitätsklinikum Heidelberg, Klinik für Diagnostische und Interventionelle Radiologie, Heidelberg, Deutschland
| | - Jutta Hammermann
- Universitäts-Mukoviszidose-Zentrum "Christiane Herzog", Dresden, Deutschland
| | - Ingo Baumann
- Universität Heidelberg, Hals-Nasen-Ohrenklinik, Heidelberg, Deutschland
| | - Frank Brunsmann
- Allianz Chronischer Seltener Erkrankungen (ACHSE) e. V., Deutschland (Patient*innenvertreter)
| | | | - Ernst Eber
- Medizinische Universität Graz, Univ. Klinik für Kinder- und Jugendheilkunde, Klinische Abteilung für Pädiatrische Pulmonologie und Allergologie, Graz, Österreich
| | - Helmut Ellemunter
- Tirolkliniken GmbH, Department für Kinderheilkunde, Pädiatrie III, Innsbruck, Österreich
| | | | | | - Saskia Gruber
- Medizinische Universität Wien, Universitätsklinik für Kinder- und Jugendheilkunde, Wien, Österreich
| | - Assen Koitschev
- Klinikum Stuttgart - Standort Olgahospital, Klinik für Hals-Nasen-Ohrenkrankheiten, Stuttgart, Deutschland
| | - Julia Ley-Zaporozhan
- Klinik und Poliklinik für Radiologie, Kinderradiologie, LMU München, Deutschland
| | | | - Hans-Joachim Mentzel
- Universitätsklinikum Jena, Sektion Kinderradiologie, Institut für Diagnostische und Interventionelle Radiologie, Jena, Deutschland
| | - Thomas Nüßlein
- Gemeinschaftsklinikum Mittelrhein, Klinik für Kinder- und Jugendmedizin Koblenz und Mayen, Koblenz, Deutschland
| | - Felix C Ringshausen
- Medizinische Hochschule Hannover, Klinik für Pneumologie und Infektiologie und Deutsches Zentrum für Lungenforschung (DZL), Hannover, Deutschland
| | - Ludwig Sedlacek
- Medizinische Hochschule Hannover, Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Hannover, Deutschland
| | - Christina Smaczny
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt am Main, Deutschland
| | - Olaf Sommerburg
- Universitätsklinikum Heidelberg, Sektion Pädiatrische Pneumologie, Allergologie und Mukoviszidose-Zentrum, Heidelberg, Deutschland
| | | | - Ralf-Peter Vonberg
- Medizinische Hochschule Hannover, Institut für Medizinische Mikrobiologie und Krankenhaushygiene, Hannover, Deutschland
| | | | - Jovita Zerlik
- Altonaer Kinderkrankenhaus gGmbH, Abteilung Physiotherapie, Hamburg, Deutschland
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2
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Granton E, Brown L, Defaye M, Moazen P, Almblad H, Randall TE, Rich JD, Geppert A, Abdullah NS, Hassanabad MF, Hiroki CH, Farias R, Nguyen AP, Schubert C, Lou Y, Andonegui G, Iftinca M, Raju D, Vargas MA, Howell PL, Füzesi T, Bains J, Kurrasch D, Harrison JJ, Altier C, Yipp BG. Biofilm exopolysaccharides alter sensory-neuron-mediated sickness during lung infection. Cell 2024; 187:1874-1888.e14. [PMID: 38518773 DOI: 10.1016/j.cell.2024.03.001] [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: 06/09/2023] [Revised: 01/04/2024] [Accepted: 03/01/2024] [Indexed: 03/24/2024]
Abstract
Infections of the lung cause observable sickness thought to be secondary to inflammation. Signs of sickness are crucial to alert others via behavioral-immune responses to limit contact with contagious individuals. Gram-negative bacteria produce exopolysaccharide (EPS) that provides microbial protection; however, the impact of EPS on sickness remains uncertain. Using genome-engineered Pseudomonas aeruginosa (P. aeruginosa) strains, we compared EPS-producers versus non-producers and a virulent Escherichia coli (E. coli) lung infection model in male and female mice. EPS-negative P. aeruginosa and virulent E. coli infection caused severe sickness, behavioral alterations, inflammation, and hypothermia mediated by TLR4 detection of the exposed lipopolysaccharide (LPS) in lung TRPV1+ sensory neurons. However, inflammation did not account for sickness. Stimulation of lung nociceptors induced acute stress responses in the paraventricular hypothalamic nuclei by activating corticotropin-releasing hormone neurons responsible for sickness behavior and hypothermia. Thus, EPS-producing biofilm pathogens evade initiating a lung-brain sensory neuronal response that results in sickness.
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Affiliation(s)
- Elise Granton
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Luke Brown
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Manon Defaye
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Inflammation Research Network, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Parisa Moazen
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Henrik Almblad
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Trevor E Randall
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Jacquelyn D Rich
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Andrew Geppert
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Nasser S Abdullah
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Inflammation Research Network, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Mortaza F Hassanabad
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Carlos H Hiroki
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Raquel Farias
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Angela P Nguyen
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Courtney Schubert
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Yuefei Lou
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Graciela Andonegui
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Mircea Iftinca
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Inflammation Research Network, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Deepa Raju
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - Mario A Vargas
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, The Hospital for Sick Children, Toronto, ON, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Tamás Füzesi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Cumming School of Medicine Optogenetics Core Facility, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jaideep Bains
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Krembil Research Institute, University Health Network, Toronto, ON, Canada.
| | - Deborah Kurrasch
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada; Department of Medical Genetics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - Joe Jonathan Harrison
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
| | - Christophe Altier
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Inflammation Research Network, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
| | - Bryan G Yipp
- Department of Critical Care, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
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3
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Trottier MC, de Oliveira Pereira T, Groleau MC, Hoffman LR, Dandekar AA, Déziel E. The end of the reign of a "master regulator''? A defect in function of the LasR quorum sensing regulator is a common feature of Pseudomonas aeruginosa isolates. mBio 2024; 15:e0237623. [PMID: 38315035 PMCID: PMC10936206 DOI: 10.1128/mbio.02376-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024] Open
Abstract
Pseudomonas aeruginosa, a bacterium causing infections in immunocompromised individuals, regulates several of its virulence functions using three interlinked quorum sensing (QS) systems (las, rhl, and pqs). Despite its presumed importance in regulating virulence, dysfunction of the las system regulator LasR occurs frequently in strains isolated from various environments, including clinical infections. This newfound abundance of LasR-defective strains calls into question existing hypotheses regarding their selection. Indeed, current assumptions concerning factors driving the emergence of LasR-deficient isolates and the role of LasR in the QS hierarchy must be reconsidered. Here, we propose that LasR is not the primary master regulator of QS in all P. aeruginosa genetic backgrounds, even though it remains ecologically significant. We also revisit and complement current knowledge on the ecology of LasR-dependent QS in P. aeruginosa, discuss the hypotheses explaining the putative adaptive benefits of selecting against LasR function, and consider the implications of this renewed understanding.
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Affiliation(s)
- Mylène C. Trottier
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Thays de Oliveira Pereira
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
| | - Lucas R. Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, Washington, USA
| | - Ajai A. Dandekar
- Departments of Medicine and Microbiology, University of Washington, Seattle, Washington, USA
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique (INRS), Laval, Québec, Canada
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4
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Ledger EL, Smith DJ, Teh JJ, Wood ME, Whibley PE, Morrison M, Goldberg JB, Reid DW, Wells TJ. Impact of CFTR Modulation on Pseudomonas aeruginosa Infection in People With Cystic Fibrosis. J Infect Dis 2024:jiae051. [PMID: 38442240 DOI: 10.1093/infdis/jiae051] [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: 11/22/2023] [Accepted: 01/29/2024] [Indexed: 03/07/2024] Open
Abstract
BACKGROUND Pseudomonas aeruginosa is a multidrug-resistant pathogen causing recalcitrant pulmonary infections in people with cystic fibrosis (pwCF). Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been developed that partially correct the defective chloride channel driving disease. Despite the many clinical benefits, studies in adults have demonstrated that while P. aeruginosa sputum load decreases, chronic infection persists. Here, we investigate how P. aeruginosa in pwCF may change in the altered lung environment after CFTR modulation. METHODS P. aeruginosa strains (n = 105) were isolated from the sputum of 11 chronically colonized pwCF at baseline and up to 21 months posttreatment with elexacaftor-tezacaftor-ivacaftor or tezacaftor-ivacaftor. Phenotypic characterization and comparative genomics were performed. RESULTS Clonal lineages of P. aeruginosa persisted after therapy, with no evidence of displacement by alternative strains. We identified commonly mutated genes among patient isolates that may be positively selected for in the CFTR-modulated lung. However, classic chronic P. aeruginosa phenotypes such as mucoid morphology were sustained, and isolates remained just as resistant to clinically relevant antibiotics. CONCLUSIONS Despite the clinical benefits of CFTR modulators, clonal lineages of P. aeruginosa persist that may prove just as difficult to manage in the future, especially in pwCF with advanced lung disease.
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Affiliation(s)
- Emma L Ledger
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Daniel J Smith
- Northside Clinical Unit, The University of Queensland, Brisbane, Australia
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Brisbane, Australia
| | - Jing Jie Teh
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Michelle E Wood
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Brisbane, Australia
| | - Page E Whibley
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Brisbane, Australia
| | - Mark Morrison
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, Australia
- Australian Infectious Diseases Research Centre, Brisbane, Australia
| | - Joanna B Goldberg
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David W Reid
- Northside Clinical Unit, The University of Queensland, Brisbane, Australia
- Australian Infectious Diseases Research Centre, Brisbane, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Timothy J Wells
- Frazer Institute, Faculty of Medicine, The University of Queensland, Brisbane, Australia
- Australian Infectious Diseases Research Centre, Brisbane, Australia
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5
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Cholon DM, Greenwald MA, Higgs MG, Quinney NL, Boyles SE, Meinig SL, Minges JT, Chaubal A, Tarran R, Ribeiro CMP, Wolfgang MC, Gentzsch M. A Novel Co-Culture Model Reveals Enhanced CFTR Rescue in Primary Cystic Fibrosis Airway Epithelial Cultures with Persistent Pseudomonas aeruginosa Infection. Cells 2023; 12:2618. [PMID: 37998353 PMCID: PMC10670530 DOI: 10.3390/cells12222618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 10/31/2023] [Accepted: 11/06/2023] [Indexed: 11/25/2023] Open
Abstract
People with cystic fibrosis (pwCF) suffer from chronic and recurring bacterial lung infections that begin very early in life and contribute to progressive lung failure. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which encodes an ion channel important for maintaining the proper hydration of pulmonary surfaces. When CFTR function is ablated or impaired, airways develop thickened, adherent mucus that contributes to a vicious cycle of infection and inflammation. Therapeutics for pwCF, called CFTR modulators, target the CFTR defect directly, restoring airway surface hydration and mucociliary clearance. However, even with CFTR modulator therapy, bacterial infections persist. To develop a relevant model of diseased airway epithelium, we established a primary human airway epithelium culture system with persistent Pseudomonas aeruginosa infection. We used this model to examine the effects of CFTR modulators on CFTR maturation, CFTR function, and bacterial persistence. We found that the presence of P. aeruginosa increased CFTR mRNA, protein, and function. We also found that CFTR modulators caused a decrease in P. aeruginosa burden. These results demonstrate the importance of including live bacteria to accurately model the CF lung, and that understanding the effects of infection on CFTR rescue by CFTR modulators is critical to evaluating and optimizing drug therapies for all pwCF.
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Affiliation(s)
- Deborah M. Cholon
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Matthew A. Greenwald
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew G. Higgs
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Nancy L. Quinney
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Susan E. Boyles
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Suzanne L. Meinig
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Pharmaceutical Product Development (PPD), Thermo Fisher Scientific, Morrisville, NC 27560, USA
| | - John T. Minges
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Ashlesha Chaubal
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
| | - Robert Tarran
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Division of Genetic, Department of Internal Medicine, Environmental and Inhalational Disease, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Carla M. P. Ribeiro
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Division of Pulmonary Diseases, Department of Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Matthew C. Wolfgang
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Martina Gentzsch
- Marsico Lung Institute and Cystic Fibrosis Research Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA; (D.M.C.); (M.A.G.)
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
- Division of Pediatric Pulmonology, Department of Pediatrics, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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6
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Ribeiro CMP, Higgs MG, Muhlebach MS, Wolfgang MC, Borgatti M, Lampronti I, Cabrini G. Revisiting Host-Pathogen Interactions in Cystic Fibrosis Lungs in the Era of CFTR Modulators. Int J Mol Sci 2023; 24:ijms24055010. [PMID: 36902441 PMCID: PMC10003689 DOI: 10.3390/ijms24055010] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/25/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, a new series of therapeutics that correct and potentiate some classes of mutations of the CFTR, have provided a great therapeutic advantage to people with cystic fibrosis (pwCF). The main hindrances of the present CFTR modulators are related to their limitations in reducing chronic lung bacterial infection and inflammation, the main causes of pulmonary tissue damage and progressive respiratory insufficiency, particularly in adults with CF. Here, the most debated issues of the pulmonary bacterial infection and inflammatory processes in pwCF are revisited. Special attention is given to the mechanisms favoring the bacterial infection of pwCF, the progressive adaptation of Pseudomonas aeruginosa and its interplay with Staphylococcus aureus, the cross-talk among bacteria, the bronchial epithelial cells and the phagocytes of the host immune defenses. The most recent findings of the effect of CFTR modulators on bacterial infection and the inflammatory process are also presented to provide critical hints towards the identification of relevant therapeutic targets to overcome the respiratory pathology of pwCF.
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Affiliation(s)
- Carla M. P. Ribeiro
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: (C.M.P.R.); (G.C.)
| | - Matthew G. Higgs
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Marianne S. Muhlebach
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Pediatrics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Matthew C. Wolfgang
- Marsico Lung Institute/Cystic Fibrosis Research Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Monica Borgatti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Ilaria Lampronti
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
| | - Giulio Cabrini
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
- Innthera4CF, Center on Innovative Therapies for Cystic Fibrosis, University of Ferrara, 44121 Ferrara, Italy
- Correspondence: (C.M.P.R.); (G.C.)
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7
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Morris AJ, Yau YCW, Park S, Eisha S, McDonald N, Parsek MR, Howell PL, Hoffman LR, Nguyen D, DiGiandomenico A, Rooney AM, Coburn B, Grana-Miraglia L, Wang P, Guttman DS, Wozniak DJ, Waters VJ. Pseudomonas aeruginosa aggregation and Psl expression in sputum is associated with antibiotic eradication failure in children with cystic fibrosis. Sci Rep 2022; 12:21444. [PMID: 36509824 PMCID: PMC9744911 DOI: 10.1038/s41598-022-25889-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
We previously demonstrated that P. aeruginosa isolates that persisted in children with cystic fibrosis (CF) despite inhaled tobramycin treatment had increased anti-Psl antibody binding in vitro compared to those successfully eradicated. We aimed to validate these findings by directly visualizing P. aeruginosa in CF sputum. This was a prospective observational study of children with CF with new-onset P. aeruginosa infection who underwent inhaled tobramycin eradication treatment. Using microbial identification passive clarity technique (MiPACT), P. aeruginosa was visualized in sputum samples obtained before treatment and classified as persistent or eradicated based on outcomes. Pre-treatment isolates were also grown as biofilms in vitro. Of 11 patients enrolled, 4 developed persistent infection and 7 eradicated infection. P. aeruginosa biovolume and the number as well as size of P. aeruginosa aggregates were greater in the sputum of those with persistent compared with eradicated infections (p < 0.01). The amount of Psl antibody binding in sputum was also greater overall (p < 0.05) in samples with increased P. aeruginosa biovolume. When visualized in sputum, P. aeruginosa had a greater biovolume, with more expressed Psl, and formed more numerous, larger aggregates in CF children who failed eradication therapy compared to those who successfully cleared their infection.
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Affiliation(s)
- Amanda J Morris
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Yvonne C W Yau
- Division of Microbiology, Department of Pediatric Laboratory Medicine, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Subin Park
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Shafinaz Eisha
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Nancy McDonald
- Division of Respiratory Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - P Lynne Howell
- Program in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Lucas R Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, WA, USA
| | - Dao Nguyen
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Antonio DiGiandomenico
- Vaccines and Immune Therapies, Biopharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Ashley M Rooney
- Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Bryan Coburn
- Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Lucia Grana-Miraglia
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Pauline Wang
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - David S Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Daniel J Wozniak
- Departments of Microbial Infection and Immunity, Microbiology, Ohio State University, Columbus, OH, USA
| | - Valerie J Waters
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.
- Division of Infectious Diseases, Department of Pediatrics, Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
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8
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Blanchard AC, Waters VJ. Opportunistic Pathogens in Cystic Fibrosis: Epidemiology and Pathogenesis of Lung Infection. J Pediatric Infect Dis Soc 2022; 11:S3-S12. [PMID: 36069904 DOI: 10.1093/jpids/piac052] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022]
Abstract
Cystic fibrosis (CF) is one of the most common life-shortening genetic diseases in Caucasians. Due to abnormal accumulation of mucus, respiratory failure caused by chronic infections is the leading cause of mortality in this patient population. The microbiology of these respiratory infections includes a distinct set of opportunistic pathogens, including Pseudomonas aeruginosa, Burkholderia spp., Achromobacter spp., Stenotrophomonas maltophilia, anaerobes, nontuberculous mycobacteria, and fungi. In recent years, culture-independent methods have shown the polymicrobial nature of lung infections, and the dynamics of microbial communities. The unique environment of the CF airway predisposes to infections caused by opportunistic pathogens. In this review, we will highlight how the epidemiology and role in disease of these pathogens in CF differ from that in individuals with other medical conditions. Infectious diseases (ID) physicians should be aware of these differences and the specific characteristics of infections associated with CF.
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Affiliation(s)
- Ana C Blanchard
- Department of Pediatrics, Division of Infectious Diseases, CHU Sainte-Justine, Université de Montréal, 3175 Chemin de la Côte-Sainte-Catherine, Montreal, Quebec, H3T 1C5, Canada
| | - Valerie J Waters
- Department of Pediatrics, Division of Infectious Diseases, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
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9
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Greenwald MA, Wolfgang MC. The changing landscape of the cystic fibrosis lung environment: From the perspective of Pseudomonas aeruginosa. Curr Opin Pharmacol 2022; 65:102262. [DOI: 10.1016/j.coph.2022.102262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 02/03/2023]
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10
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Schumann AR, Sue AD, Roach DR. Hypoxia Increases the Tempo of Phage Resistance and Mutational Bottlenecking of Pseudomonas aeruginosa. Front Microbiol 2022; 13:905343. [PMID: 35979493 PMCID: PMC9376454 DOI: 10.3389/fmicb.2022.905343] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 06/16/2022] [Indexed: 11/23/2022] Open
Abstract
Viruses that infect bacteria (i.e., phages) are abundant and widespread in the human body, and new anti-infective approaches such as phage therapy are essential for the future of effective medicine. Our understanding of microenvironmental factors such as tissue oxygen availability at the site of phage-bacteria interaction remains limited, and it is unknown whether evolved resistance is sculpted differentially under normoxia vs. hypoxia. We, therefore, analyzed the phage-bacteria interaction landscape via adsorption, one-step, time-kill dynamics, and genetic evolution under both normoxia and hypoxia. This revealed that adsorption of phages to Pseudomonas aeruginosa decreased under 14% environmental oxygen (i.e., hypoxia), but phage time-kill and one-step growth kinetics were not further influenced. Tracking the adaptation of P. aeruginosa to phages uncovered a higher frequency of phage resistance and constrained types of spontaneous mutation under hypoxia. Given the interest in developing phage therapies, developing our understanding of the phage-pathogen interaction under microenvironmental conditions resembling those in the body offers insight into possible strategies to overcome multidrug-resistant (MDR) bacteria.
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Affiliation(s)
- Ashley R. Schumann
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Andrew D. Sue
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Dwayne R. Roach
- Department of Biology, San Diego State University, San Diego, CA, United States
- Viral Information Institute, San Diego State University, San Diego, CA, United States
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11
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Jensen PØ, Nielsen BU, Kolpen M, Pressler T, Faurholt-Jepsen D, Mathiesen IHM. Increased sputum lactate during oral glucose tolerance test in cystic fibrosis. APMIS 2022; 130:535-539. [PMID: 35635299 PMCID: PMC9545947 DOI: 10.1111/apm.13233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 11/28/2022]
Abstract
Blood glucose levels exceeding 8 mM are shown to increase glucose levels in airway surface in cystic fibrosis (CF). Moreover, high levels of endobronchial glucose are proposed to increase the growth of common CF bacteria and feed the neutrophil‐driven inflammation. In the infected airways, glucose may be metabolized by glycolysis to lactate by both bacteria and neutrophils. Therefore, we aimed to investigate whether increased blood glucose may fuel the glycolytic pathways of the lung inflammation by determining sputum glucose and lactate during an oral glucose tolerance test (OGTT). Sputum from 27 CF patients was collected during an OGTT. Sputum was collected at fasting and one and two hours following the intake of 75 g of glucose. Only participants able to expectorate more than one sputum sample were included. Glucose levels in venous blood and lactate and glucose content in sputum were analyzed using a regular blood gas analyzer. We collected 62 sputum samples: 20 at baseline, 22 after 1 h, and 20 after 2 h. Lactate and glucose were detectable in 30 (48.4%) and 43 (69.4%) sputum samples, respectively. The sputum lactate increased significantly at 2 h in the OGTT (p = 0.024), but sputum glucose was not changed. As expected, plasma glucose level significantly increased during the OGTT (p < 0.001). In CF patients, sputum lactate increased during an OGTT, while the sputum glucose did not reflect the increased plasma glucose. The increase in sputum lactate suggests that glucose spills over from plasma to sputum where glucose may enhance the inflammation by fueling the anaerobic metabolism in neutrophils or bacteria.
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Affiliation(s)
- Peter Østrup Jensen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark.,Costerton Biofilm Center, Institute of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Bibi Uhre Nielsen
- Cystic Fibrosis Centre Copenhagen, Rigshospitalet, Copenhagen, Denmark
| | - Mette Kolpen
- Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark
| | - Tacjana Pressler
- Cystic Fibrosis Centre Copenhagen, Rigshospitalet, Copenhagen, Denmark
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12
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Peres-Emidio EC, Freitas GJC, Costa MC, Gouveia-Eufrasio L, Silva LMV, Santos APN, Carmo PHF, Brito CB, Arifa RDN, Bastos RW, Ribeiro NQ, Oliveira LVN, Silva MF, Paixão TA, Saliba AM, Fagundes CT, Souza DG, Santos DA. Pseudomonas aeruginosa Infection Modulates the Immune Response and Increases Mice Resistance to Cryptococcus gattii. Front Cell Infect Microbiol 2022; 12:811474. [PMID: 35548467 PMCID: PMC9083911 DOI: 10.3389/fcimb.2022.811474] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/22/2022] [Indexed: 11/30/2022] Open
Abstract
Cryptococcosis is an invasive mycosis caused by Cryptococcus spp. that affects the lungs and the central nervous system (CNS). Due to the severity of the disease, it may occur concomitantly with other pathogens, as a coinfection. Pseudomonas aeruginosa (Pa), an opportunistic pathogen, can also cause pneumonia. In this work, we studied the interaction of C. gattii (Cg) and Pa, both in vitro and in vivo. Pa reduced growth of Cg by the secretion of inhibitory molecules in vitro. Macrophages previously stimulated with Pa presented increased fungicidal activity. In vivo, previous Pa infection reduced morbidity and delayed the lethality due to cryptococcosis. This phenotype was correlated with the decreased fungal burden in the lungs and brain, showing a delay of Cg translocation to the CNS. Also, there was increased production of IL-1β, CXCL-1, and IL-10, together with the influx of iNOS-positive macrophages and neutrophils to the lungs. Altogether, Pa turned the lung into a hostile environment to the growth of a secondary pathogen, making it difficult for the fungus to translocate to the CNS. Further, iNOS inhibition reverted the Pa protective phenotype, suggesting its
important role in the coinfection. Altogether, the primary Pa infection leads to balanced pro-inflammatory and anti-inflammatory responses during Cg infection. This response provided better control of cryptococcosis and was decisive for the mild evolution of the disease and prolonged survival of coinfected mice in a mechanism dependent on iNOS.
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Affiliation(s)
- Eluzia C. Peres-Emidio
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Gustavo J. C. Freitas
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marliete C. Costa
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ludmila Gouveia-Eufrasio
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lívia M. V. Silva
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Anderson P. N. Santos
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Paulo H. F. Carmo
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Camila B. Brito
- Departamento de Microbiologia/Laboratorio de Interação Microorganismo-Hospedeiro, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Raquel D. N. Arifa
- Departamento de Microbiologia/Laboratorio de Interação Microorganismo-Hospedeiro, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Rafael W. Bastos
- Faculdade de Ciencias Farmaceuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- Centro de Biociencias, Universidade Federal do Rio Grande do Norte, Natal, Brazil
| | - Noelly Q. Ribeiro
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lorena V. N. Oliveira
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Monique F. Silva
- Departamento de Patologia/Laboratorio de Patologia Celular e Molecular, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Tatiane A. Paixão
- Departamento de Patologia/Laboratorio de Patologia Celular e Molecular, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Alessandra M. Saliba
- Departamento de Microbiologia e Imunologia, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Caio T. Fagundes
- Departamento de Microbiologia/Laboratorio de Interação Microorganismo-Hospedeiro, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniele G. Souza
- Departamento de Microbiologia/Laboratorio de Interação Microorganismo-Hospedeiro, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniel A. Santos
- Departamento de Microbiologia/Laboratorio de Micologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- *Correspondence: Daniel A. Santos, ;
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13
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Genetic and Transcriptomic Characteristics of RhlR-Dependent Quorum Sensing in Cystic Fibrosis Isolates of Pseudomonas aeruginosa. mSystems 2022; 7:e0011322. [PMID: 35471121 PMCID: PMC9040856 DOI: 10.1128/msystems.00113-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested in determining whether there were reproducible genetic characteristics of these isolates and whether there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. We did not identify a common genetic mechanism to explain the switch from Las- to Rhl-dominated QS. We describe a core RhlR regulon encompassing 20 genes encoding 7 products. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infections and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understand QS beyond what has been described in laboratory strains. IMPORTANCE The bacterial pathogen Pseudomonas aeruginosa can cause chronic infections that are resistant to treatment in immunocompromised individuals. Over the course of these infections, the original infecting organism adapts to the host environment. P. aeruginosa uses a cell-cell signaling mechanism termed quorum sensing (QS) to regulate virulence factors and cooperative behaviors. The key QS regulator in laboratory strains, LasR, is frequently mutated in infection-adapted isolates, leaving another transcription factor, RhlR, in control of QS gene regulation. Such isolates provide an opportunity to understand Rhl-QS regulation without the confounding effects of LasR, as well as the scope of QS in the context of within-host evolution. We show that a core group of virulence genes is regulated by RhlR in a variety of infection-adapted LasR-null isolates. Our results reveal commonalities in infection-adapted QS gene regulation and key QS factors that may serve as therapeutic targets in the future.
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14
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The Effect of CFTR Modulators on Airway Infection in Cystic Fibrosis. Int J Mol Sci 2022; 23:ijms23073513. [PMID: 35408875 PMCID: PMC8998472 DOI: 10.3390/ijms23073513] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 02/08/2023] Open
Abstract
The advent of Cystic fibrosis transmembrane receptor (CFTR) modulators in 2012 was a critical event in the history of cystic fibrosis (CF) treatment. Unlike traditional therapies that target downstream effects of CFTR dysfunction, CFTR modulators aim to correct the underlying defect at the protein level. These genotype-specific therapies are now available for an increasing number of CF patients, transforming the way we view the condition from a life-limiting disease to one that can be effectively managed. Several studies have demonstrated the vast improvement CFTR modulators have on normalization of sweat chloride, CFTR function, clinical endpoints, and frequency of pulmonary exacerbation. However, their impact on other aspects of the disease, such as pathogenic burden and airway infection, remain under explored. Frequent airway infections as a result of increased susceptibility and impaired innate immune response are a serious problem within CF, often leading to accelerated decline in lung function and disease progression. Current evidence suggests that CFTR modulators are unable to eradicate pathogenic organisms in those with already established lung disease. However, this may not be the case for those with relatively low levels of disease progression and conserved microbial diversity, such as young patients. Furthermore, it remains unknown whether the restorative effects exerted by CFTR modulators extend to immune cells, such as phagocytes, which have the potential to modulate the response of people with CF (pwCF) to infection. Throughout this review, we look at the potential impact of CFTR modulators on airway infection in CF and their ability to shape impaired pulmonary defences to pathogens.
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15
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Balmuri SR, Phandanouvong-Lozano V, House SD, Yang JC, Niepa TH. Mucoid Coating Provides a Growth Advantage to Pseudomonas aeruginosa at Oil–Water Interfaces. ACS APPLIED BIO MATERIALS 2022; 5:1868-1878. [DOI: 10.1021/acsabm.1c01198] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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16
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Groleau MC, Taillefer H, Vincent AT, Constant P, Déziel E. Pseudomonas aeruginosa isolates defective in function of the LasR quorum sensing regulator are frequent in diverse environmental niches. Environ Microbiol 2021; 24:1062-1075. [PMID: 34488244 DOI: 10.1111/1462-2920.15745] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/24/2021] [Indexed: 01/12/2023]
Abstract
The saprophyte Pseudomonas aeruginosa is a versatile opportunistic pathogen causing infections in immunocompromised individuals. To facilitate its adaptation to a large variety of niches, this bacterium exploits population density-dependent gene regulation systems called quorum sensing (QS). In P. aeruginosa, three distinct but interrelated QS systems (las, rhl and pqs) regulate the production of many survival and virulence functions. In prototypical strains, the las system, through its transcriptional regulator LasR, is important for the full activation of the rhl and pqs systems. Still, LasR-deficient isolates have been reported, mostly sampled from the lungs of people with cystic fibrosis, where they are considered selected by the chronic infection environment. In this study, we show that a defect in LasR activity appears to be an actually widespread mechanism of adaptation in this bacterium. Indeed, we found abundant LasR-defective isolates sampled from hydrocarbon-contaminated soils, hospital sink drains and meat/fish market environments, using an approach based on phenotypic profiling, supported by gene sequencing. Interestingly, several LasR-defective isolates maintain an active rhl system or are deficient in pqs system signalling. The high prevalence of a LasR-defective phenotype among environmental P. aeruginosa isolates questions the role of QS in niche adaptation.
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Affiliation(s)
- Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Hélène Taillefer
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Antony T Vincent
- Département des sciences animales, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Quebec City, Quebec, Canada
| | - Philippe Constant
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), Laval, Quebec, Canada
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17
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Morris AJ, Jackson L, Cw Yau Y, Reichhardt C, Beaudoin T, Uwumarenogie S, Guttman KM, Lynne Howell P, Parsek MR, Hoffman LR, Nguyen D, DiGiandomenico A, Guttman DS, Wozniak DJ, Waters VJ. The role of Psl in the failure to eradicate Pseudomonas aeruginosa biofilms in children with cystic fibrosis. NPJ Biofilms Microbiomes 2021; 7:63. [PMID: 34349133 PMCID: PMC8338932 DOI: 10.1038/s41522-021-00234-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/01/2021] [Indexed: 11/09/2022] Open
Abstract
The exopolysaccharide Psl contributes to biofilm structure and antibiotic tolerance and may play a role in the failure to eradicate Pseudomonas aeruginosa from cystic fibrosis (CF) airways. The study objective was to determine whether there were any differences in Psl in P. aeruginosa isolates that were successfully eradicated compared to those that persisted, despite inhaled tobramycin treatment, in children with CF. Initial P. aeruginosa isolates were collected from children with CF undergoing eradication treatment, grown as biofilms and labeled with 3 anti-Psl monoclonal antibodies (Cam003/Psl0096, WapR001, WapR016) before confocal microscopy visualization. When grown as biofilms, P. aeruginosa isolates from children who failed antibiotic eradication therapy, had significantly increased Psl0096 binding compared to isolates from those who cleared P. aeruginosa. This was confirmed in P. aeruginosa isolates from the SickKids Eradication Cohort as well as the Early Pseudomonas Infection Control (EPIC) trial. Increased anti-Psl antibody binding was associated with bacterial aggregation and tobramycin tolerance. The biofilm matrix represents a potential therapeutic target to improve P. aeruginosa eradication treatment.
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Affiliation(s)
- Amanda J Morris
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Lindsay Jackson
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Yvonne Cw Yau
- Division of Microbiology, Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | | | - Trevor Beaudoin
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Stephanie Uwumarenogie
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Kevin M Guttman
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - P Lynne Howell
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, ON, Canada.,Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Matthew R Parsek
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Lucas R Hoffman
- Departments of Pediatrics and Microbiology, University of Washington, Seattle, WA, USA
| | - Dao Nguyen
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Antonio DiGiandomenico
- Discovery Microbiome, Microbial Sciences, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, USA
| | - David S Guttman
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Daniel J Wozniak
- Departments of Microbial Infection and Immunity, Microbiology, Ohio State University, Columbus, OH, USA
| | - Valerie J Waters
- Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada. .,Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada. .,Department of Pediatrics, University of Toronto, Toronto, ON, Canada.
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18
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Pseudomonas aeruginosa Consumption of Airway Metabolites Promotes Lung Infection. Pathogens 2021; 10:pathogens10080957. [PMID: 34451421 PMCID: PMC8401524 DOI: 10.3390/pathogens10080957] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/03/2022] Open
Abstract
Prevailing dogma indicates that the lung of cystic fibrosis (CF) individuals is infected by multiple pathogens due to the abundant accumulation of mucus, which traps most of inhaled organisms. However, this hypothesis does not explain how specific opportunists, like Pseudomonas aeruginosa, are selected in the CF lung to cause chronic disease. This strongly suggests that other factors than mucus are accrued in the human airway and might predispose to bacterial disease, especially by P. aeruginosa. In this review we discuss the role of macrophage metabolites, like succinate and itaconate, in P. aeruginosa pneumonia. We analyze how dysfunction of the CF transmembrane conductance regulator (CFTR) favors release of these metabolites into the infected airway, and how P. aeruginosa exploits these elements to induce transcriptomic and metabolic changes that increase its capacity to cause intractable disease. We describe the host and pathogen pathways associated with succinate and itaconate catabolism, mechanisms of bacterial adaptation to these determinants, and suggest how both experimental settings and future therapies should consider macrophage metabolites abundance to better study P. aeruginosa pathogenesis.
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Kwong K, Benedetti A, Yau Y, Waters V, Nguyen D. Failed eradication therapy of new onset Pseudomonas aeruginosa infections in cystic fibrosis children is associated with bacterial resistance to neutrophil functions. J Infect Dis 2021; 225:1886-1895. [PMID: 33606875 PMCID: PMC9159338 DOI: 10.1093/infdis/jiab102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/12/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Antibiotics, such as inhaled tobramycin are used to eradicate new onset Pseudomonas aeruginosa (PA) infections in cystic fibrosis (CF) patients but frequently fail due to reasons poorly understood. We hypothesized that PA isolates' resistance to neutrophil antibacterial functions was associated with failed eradication in patients harboring those strains. METHODS We analyzed all PA isolates from a cohort of 39 CF children with new onset PA infections undergoing tobramycin eradication therapy, where N=30 patients had eradicated and N=9 patients had persistent infection. We characterized several bacterial phenotypes and measured the isolates' susceptibility to neutrophil antibacterial functions using in vitro assays of phagocytosis and intracellular bacterial killing. RESULTS PA isolates from persistent infections were more resistant to neutrophil functions, with lower phagocytosis and intracellular bacterial killing compared to those from eradicated infections. In multivariable analyses, in vitro neutrophil responses were positively associated with twitching motility, and negatively with mucoidy. In vitro neutrophil phagocytosis was a predictor of persistent infection following tobramycin even after adjustment for clinical risk factors. CONCLUSIONS PA isolates from new onset CF infection show strain-specific susceptibility to neutrophil antibacterial functions, and infection with PA isolates resistant to neutrophil phagocytosis is an independent risk factor for failed tobramycin eradication.
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Affiliation(s)
- K Kwong
- Department of Microbiology and Immunology, McGill University, Montreal, CA.,Meakins Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, CA
| | - A Benedetti
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montréal, CA.,Centre for Health Outcome Research, Research Institute of the McGill University Health Centre, Montreal, CA
| | - Y Yau
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, CA.,Division of Microbiology, Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, CA
| | - V Waters
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, CA.,Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, CA
| | - D Nguyen
- Department of Microbiology and Immunology, McGill University, Montreal, CA.,Meakins Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, CA.,Department of Medicine, McGill University, Montreal, CA
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20
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Wolter DJ, Scott A, Armbruster CR, Whittington D, Edgar JS, Qin X, Buccat AM, McNamara S, Blackledge M, Waalkes A, Salipante SJ, Ernst RK, Hoffman LR. Repeated isolation of an antibiotic-dependent and temperature-sensitive mutant of Pseudomonas aeruginosa from a cystic fibrosis patient. J Antimicrob Chemother 2021; 76:616-625. [PMID: 33259594 DOI: 10.1093/jac/dkaa482] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/02/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Bacteria adapt to survive and grow in different environments. Genetic mutations that promote bacterial survival under harsh conditions can also restrict growth. The causes and consequences of these adaptations have important implications for diagnosis, pathogenesis, and therapy. OBJECTIVES We describe the isolation and characterization of an antibiotic-dependent, temperature-sensitive Pseudomonas aeruginosa mutant chronically infecting the respiratory tract of a cystic fibrosis (CF) patient, underscoring the clinical challenges bacterial adaptations can present. METHODS Respiratory samples collected from a CF patient during routine care were cultured for standard pathogens. P. aeruginosa isolates recovered from samples were analysed for in vitro growth characteristics, antibiotic susceptibility, clonality, and membrane phospholipid and lipid A composition. Genetic mutations were identified by whole genome sequencing. RESULTS P. aeruginosa isolates collected over 5 years from respiratory samples of a CF patient frequently harboured a mutation in phosphatidylserine decarboxylase (psd), encoding an enzyme responsible for phospholipid synthesis. This mutant could only grow at 37°C when in the presence of supplemented magnesium, glycerol, or, surprisingly, the antibiotic sulfamethoxazole, which the source patient had repeatedly received. Of concern, this mutant was not detectable on standard selective medium at 37°C. This growth defect correlated with alterations in membrane phospholipid and lipid A content. CONCLUSIONS A P. aeruginosa mutant chronically infecting a CF patient exhibited dependence on sulphonamides and would likely evade detection using standard clinical laboratory methods. The diagnostic and therapeutic challenges presented by this mutant highlight the complex interplay between bacterial adaptation, antibiotics, and laboratory practices, during chronic bacterial infections.
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Affiliation(s)
- Daniel J Wolter
- Department of Pediatrics, University of Washington, Seattle, WA, USA.,Seattle Children's Hospital, Seattle, WA, USA
| | - Alison Scott
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | | | - Dale Whittington
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - John S Edgar
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - Xuan Qin
- Seattle Children's Hospital, Seattle, WA, USA
| | | | | | | | - Adam Waalkes
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Stephen J Salipante
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
| | - Robert K Ernst
- Department of Microbial Pathogenesis, University of Maryland, Baltimore, MD, USA
| | - Lucas R Hoffman
- Department of Pediatrics, University of Washington, Seattle, WA, USA.,Seattle Children's Hospital, Seattle, WA, USA.,Department of Microbiology, University of Washington, Seattle, WA, USA
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21
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Lasko MJ, Huse HK, Nicolau DP, Kuti JL. Contemporary analysis of ETEST for antibiotic susceptibility and minimum inhibitory concentration agreement against Pseudomonas aeruginosa from patients with cystic fibrosis. Ann Clin Microbiol Antimicrob 2021; 20:9. [PMID: 33468149 PMCID: PMC7816365 DOI: 10.1186/s12941-021-00415-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023] Open
Abstract
Objectives Cystic fibrosis (CF) acute pulmonary exacerbations are often caused by Pseudomonas aeruginosa, including multi-drug resistant strains. Optimal antibiotic therapy is required to return lung function and should be guided by in vitro susceptibility results. There are sparse data describing ETEST performance for CF isolates using contemporary isolates, methods and interpretation, as well as novel antibiotics, such as ceftazidime–avibactam and ceftolozane–tazobactam. Methods Pseudomonas aeruginosa (n = 105) isolated during pulmonary exacerbation from patients with CF were acquired from 3 US hospitals. Minimum inhibitory concentrations (MICs) were assessed by reference broth microdilution (BMD) and ETEST for aztreonam, cefepime, ceftazidime, ceftazidime–avibactam, ceftolozane–tazobactam, ciprofloxacin, levofloxacin, meropenem, piperacillin–tazobactam, and tobramycin. Broth microdilution was conducted in concordance with the Clinical and Laboratory Standards Institute M100. ETEST methodology reflected package insert recommendations. Performance of ETEST strips was evaluated using the Food and Drug Administration (FDA) and Susceptibility Testing Manufacturers Association (STMA) guidance. Results Of the 105 P. aeruginosa included, 46% had a mucoid phenotype. ETEST MICs typically read 0–1 dilution higher than BMD for all drugs. Categorical agreement and essential agreement ranged from 64 to 93% and 63 to 86%, respectively. The majority of observed errors were minor. A single very major error occurred with ceftazidime (4.2%). For ceftazidime–vibactam, 2 very major errors were observed and both were within essential agreement. Major errors occurred for aztreonam (3.3%), cefepime (9.4%), ceftazidime–avibactam (5.3%, adjusted 2.1%), ceftolozane–tazobactam (1%), meropenem (3.3%), piperacillin–tazobactam (2.9%), and tobramycin (1.5%). Conclusions ETEST methods performed conservatively for most antibiotics against this challenging collection of P. aeruginosa from patients with CF.
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Affiliation(s)
- Maxwell J Lasko
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, 06102, CT, USA
| | - Holly K Huse
- Department of Clinical Microbiology, Huntington Hospital, Pasadena, CA, USA.,Department of Clinical Microbiology, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, 06102, CT, USA.,Division of Infectious Diseases, Hartford Hospital, Hartford, CT, USA
| | - Joseph L Kuti
- Center for Anti-Infective Research and Development, Hartford Hospital, 80 Seymour Street, Hartford, 06102, CT, USA.
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22
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Jackson L, Waters V. Factors influencing the acquisition and eradication of early Pseudomonas aeruginosa infection in cystic fibrosis. J Cyst Fibros 2020; 20:8-16. [PMID: 33172756 DOI: 10.1016/j.jcf.2020.10.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/02/2020] [Accepted: 10/27/2020] [Indexed: 12/21/2022]
Abstract
In recent years considerable improvements have been made in increasing the life expectancy of patients with cystic fibrosis. New highly effective modulator therapies targeting the underlying defect in the cystic fibrosis transmembrane conductance regulator protein are expected to enhance lifespan even further. However, chronic Pseudomonas aeruginosa pulmonary infections continue to threaten CF patient lung health and mortality rates. Early and aggressive antibiotic eradication therapies targeting P. aeruginosa are standard practice, but these eradication therapies fail in 10-40% of patients. The reasons for P. aeruginosa eradication failure remain unclear. Thus, this review summarizes the evidence to date for pseudomonal acquisition and eradication failure in the cystic fibrosis lung. A complex combination of host and bacterial factors are responsible for initial establishment of P. aeruginosa pulmonary infections. Moreover, host and pseudomonal factors, polymicrobial interactions, and antimicrobial limitations in relation to P. aeruginosa eradication therapy failure are summarized.
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Affiliation(s)
- Lindsay Jackson
- Translational Medicine, Hospital for Sick Children, Toronto, Canada.
| | - Valerie Waters
- Translational Medicine, Hospital for Sick Children, Toronto, Canada; Infectious Diseases, Department of Pediatrics, Hospital for Sick Children, Toronto, Canada
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Pseudomonas aeruginosa Volatilome Characteristics and Adaptations in Chronic Cystic Fibrosis Lung Infections. mSphere 2020; 5:5/5/e00843-20. [PMID: 33028687 PMCID: PMC7568651 DOI: 10.1128/msphere.00843-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa is a leading cause of chronic lung infections in cystic fibrosis (CF), which are correlated with lung function decline. Significant clinical efforts are therefore aimed at detecting infections and tracking them for phenotypic changes, such as mucoidy and antibiotic resistance. Both the detection and tracking of lung infections rely on sputum cultures, but due to improvements in CF therapies, sputum production is declining, although risks for lung infections persist. Therefore, we are working toward the development of breath-based diagnostics for CF lung infections. In this study, we characterized of the volatile metabolomes of 81 P. aeruginosa clinical isolates collected from 17 CF patients over a duration of at least 5 years of a chronic lung infection. We found that the volatilome of P. aeruginosa adapts over time and is correlated with infection phenotype changes, suggesting that it may be possible to track chronic CF lung infections with a breath test. Pseudomonas aeruginosa chronic lung infections in individuals with cystic fibrosis (CF) significantly reduce quality of life and increase morbidity and mortality. Tracking these infections is critical for monitoring patient health and informing treatments. We are working toward the development of novel breath-based biomarkers to track chronic P. aeruginosa lung infections in situ. Using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC–TOF-MS), we characterized the in vitro volatile metabolomes (“volatilomes”) of 81 P. aeruginosa isolates collected from 17 CF patients over at least a 5-year period of their chronic lung infections. We detected 539 volatiles produced by the P. aeruginosa isolates, 69 of which were core volatiles that were highly conserved. We found that each early infection isolate has a unique volatilome, and as infection progresses, the volatilomes of isolates from the same patient become increasingly dissimilar, to the point that these intrapatient isolates are no more similar to one another than to isolates from other patients. We observed that the size and chemical diversity of P. aeruginosa volatilomes do not change over the course of chronic infections; however, the relative abundances of core hydrocarbons, alcohols, and aldehydes do change and are correlated with changes in phenotypes associated with chronic infections. This study indicates that it may be feasible to track P. aeruginosa chronic lung infections by measuring changes to the infection volatilome and lays the groundwork for exploring the translatability of this approach to direct measurement using patient breath. IMPORTANCEPseudomonas aeruginosa is a leading cause of chronic lung infections in cystic fibrosis (CF), which are correlated with lung function decline. Significant clinical efforts are therefore aimed at detecting infections and tracking them for phenotypic changes, such as mucoidy and antibiotic resistance. Both the detection and tracking of lung infections rely on sputum cultures, but due to improvements in CF therapies, sputum production is declining, although risks for lung infections persist. Therefore, we are working toward the development of breath-based diagnostics for CF lung infections. In this study, we characterized of the volatile metabolomes of 81 P. aeruginosa clinical isolates collected from 17 CF patients over a duration of at least 5 years of a chronic lung infection. We found that the volatilome of P. aeruginosa adapts over time and is correlated with infection phenotype changes, suggesting that it may be possible to track chronic CF lung infections with a breath test.
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24
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Nazik H, Sass G, Déziel E, Stevens DA. Aspergillus Is Inhibited by Pseudomonas aeruginosa Volatiles. J Fungi (Basel) 2020; 6:jof6030118. [PMID: 32722412 PMCID: PMC7557479 DOI: 10.3390/jof6030118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/09/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022] Open
Abstract
Background: Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) compete with each other for nutrients and survival in natural environments, and have been extensively studied because of their intermicrobial interactions in the human microbiome. These are the principal microbes infecting immunocompromised patients and persons with cystic fibrosis, particularly the airways. These intermicrobial studies have largely been conducted in liquid medium or on agar, and thus focus on soluble or diffusible microbial products. Several key inhibitory molecules were defined in such studies. Methods: in the present report, we examine several methodologies which can be conveniently used to study the interaction of microbial volatiles, including capture methods and kinetics. Results: Pa volatiles inhibit Af, and the inhibitory mechanism appears to be the incorporation of the inhibitory molecules into the substrate nourishing the Af, rather than directly onto Af structures. We define by mass spectroscopy some specific volatile Pa products that can inhibit Af. Some of these molecules are selected for interest by the study of gene deletion mutants, producing a few Pa strains that were impaired in inhibition. We presumed the volatiles of these latter strains could be excluded from the search for inhibitors. Conclusion: the Pa inhibition of Af via a gaseous phase could be critical components in their competition, particularly in airways, where more direct contact may not be extensive.
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Affiliation(s)
- Hasan Nazik
- California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
| | - Gabriele Sass
- California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
| | - Eric Déziel
- Institut National de la Recherche Scientifique, Institut Armand-Frappier, Laval, QC H7V 1B7, Canada;
| | - David A. Stevens
- California Institute for Medical Research, San Jose, CA 95128, USA; (H.N.); (G.S.)
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Correspondence: ; Tel.: +1-408-998-4554
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25
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Pip serves as an intermediate in RpoS-modulated phz2 expression and pyocyanin production in Pseudomonas aeruginosa. Microb Pathog 2020; 147:104409. [PMID: 32707314 DOI: 10.1016/j.micpath.2020.104409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/17/2020] [Accepted: 07/17/2020] [Indexed: 11/22/2022]
Abstract
Pyocyanin, a main virulence factor that is produced by Pseudomonas aeruginosa, plays an important role in pathogen-host interaction during infection. Two copies of phenazine-biosynthetic operons on genome, phz1 (phzA1B1C1D1E1F1G1) and phz2 (phzA2B2C2D2E2F2G2), contribute to phenazine biosynthesis. In our previous study, we found that RpoS positively regulates expression of the phz2 operon and pyocyanin biosynthesis in P. aeruginosa PAO1. In this work, when a TetR-family regulator gene, pip, was knocked out, we found that pyocyanin production was dramatically reduced, indicating that Pip positively regulates pyocyanin biosynthesis. With further phenazines quantification and β-galactosidase assay, we confirmed that Pip positively regulates phz2 expression, but does not regulate phz1 expression. In addition, while the rpoS gene was deleted, expression of pip was down-regulated. Expression of rpoS in the wild-type PAO1 strain, however, was similar to that in the Pip-deficient mutant PAΔpip, suggesting that expression of pip could positively be regulated by RpoS, whereas rpoS could not be regulated by Pip. Taken together, we drew a conclusion that Pip might serve as an intermediate in RpoS-modulated expression of the phz2 operon and pyocyanin biosynthesis in P. aeruginosa.
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26
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Pel Polysaccharide Biosynthesis Requires an Inner Membrane Complex Comprised of PelD, PelE, PelF, and PelG. J Bacteriol 2020; 202:JB.00684-19. [PMID: 31988082 DOI: 10.1128/jb.00684-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 01/17/2020] [Indexed: 12/31/2022] Open
Abstract
The Pel polysaccharide is a structural component of the extracellular matrix of Pseudomonas aeruginosa biofilms. Recent analyses suggest that Pel production proceeds via a synthase-dependent polysaccharide secretion pathway, which in Gram-negative bacteria is defined by an outer membrane β-barrel porin, a periplasmic tetratricopeptide repeat-containing scaffold protein, and an inner membrane-embedded synthase. Polymerization is catalyzed by the glycosyltransferase domain of the synthase component of these systems, which is allosterically regulated by cyclic 3',5'-dimeric GMP (c-di-GMP). However, while the outer membrane and periplasmic components of the Pel system have been characterized, the inner membrane complex required for Pel polymerization has yet to be defined. To address this, we examined over 500 pel gene clusters from diverse species of Proteobacteria This analysis identified an invariant set of four syntenic genes, three of which, pelD, pelE, and pelG, are predicted to reside within the inner membrane, while the fourth, pelF, encodes a glycosyltransferase domain. Using a combination of gene deletion analysis, subcellular fractionation, coimmunoprecipitation, and bacterial two-hybrid assays, we provide evidence for the existence of an inner membrane complex of PelD, PelE, and PelG. Furthermore, we show that this complex interacts with PelF in order to facilitate its localization to the inner membrane. Mutations that abolish c-di-GMP binding to the known receptor domain of PelD had no effect on complex formation, suggesting that c-di-GMP binding stimulates Pel production through quaternary structural rearrangements. Together, these data provide the first experimental evidence of an inner membrane complex involved in Pel polysaccharide production.IMPORTANCE The exopolysaccharide Pel plays an important role in bacterial cell-cell interactions, surface adhesion, and protection against certain antibiotics. We identified invariant pelDEFG gene clusters in over 500 diverse proteobacterial species. Using Pseudomonas aeruginosa, we demonstrate that PelD, PelE, PelF, and PelG form a complex at the inner membrane and propose that this complex represents the previously unidentified Pel polysaccharide synthase, which is responsible for Pel polymerization and transport across the cytoplasmic membrane. We show that the formation of this complex is independent of cyclic 3',5'-dimeric GMP (c-di-GMP) binding to the receptor PelD. Collectively, these data establish the widespread Pel apparatus as a member of the synthase-dependent pathway of polysaccharide biosynthetic systems and broaden the architectural diversity of already-established bacterial polysaccharide synthases.
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27
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Taccetti G, Denton M, Hayes K, Drevinek P, Sermet-Gaudelus I, Bilton D, Campana S, Dolce D, Ferroni A, Héry-Arnaud G, Martin-Gomez MT, Nash E, Pereira L, Pressler T, Tümmler B. A critical review of definitions used to describe Pseudomonas aeruginosa microbiological status in patients with cystic fibrosis for application in clinical trials. J Cyst Fibros 2020; 19:52-67. [DOI: 10.1016/j.jcf.2019.08.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/23/2019] [Accepted: 08/15/2019] [Indexed: 01/23/2023]
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Abstract
Although survival of individuals with cystic fibrosis (CF) has been continuously improving for the past 40 years, respiratory failure secondary to recurrent pulmonary infections remains the leading cause of mortality in this patient population. Certain pathogens such as Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and species of the Burkholderia cepacia complex continue to be associated with poorer clinical outcomes including accelerated lung function decline and increased mortality. In addition, other organisms such as anaerobes, viruses, and fungi are increasingly recognized as potential contributors to disease progression. Culture-independent molecular methods are also being used for diagnostic purposes and to examine the interaction of microorganisms in the CF airway. Given the importance of CF airway infections, ongoing initiatives to promote understanding of the epidemiology, clinical course, and treatment options for these infections are needed.
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Affiliation(s)
- Ana C Blanchard
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Valerie J Waters
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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29
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Clark ST, Guttman DS, Hwang DM. Diversification of Pseudomonas aeruginosa within the cystic fibrosis lung and its effects on antibiotic resistance. FEMS Microbiol Lett 2019; 365:4834010. [PMID: 29401362 DOI: 10.1093/femsle/fny026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/30/2018] [Indexed: 12/13/2022] Open
Abstract
The evolution and diversification of bacterial pathogens within human hosts represent potential barriers to the diagnosis and treatment of life-threatening infections. Tremendous genetic and phenotypic diversity is characteristic of host adaptation in strains of Pseudomonas aeruginosa that infect the airways of individuals with chronic lung diseases and prove to be extremely difficult to eradicate. In this MiniReview, we examine recent advances in understanding within-host diversity and antimicrobial resistance in P. aeruginosa populations from the lower airways of individuals with the fatal genetic disease cystic fibrosis and the potential impacts that this diversity may have on detecting and interpreting antimicrobial susceptibility within these populations.
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Affiliation(s)
- Shawn T Clark
- Toronto General Hospital Research Institute, University Health Network, 101 College Street, PMCRT - MaRS Centre, Toronto, Ontario M5G 1L7, Canada
| | - David S Guttman
- Department of Cell & Systems Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada.,Centre for the Analysis of Genome Evolution & Function, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada
| | - David M Hwang
- Toronto General Hospital Research Institute, University Health Network, 101 College Street, PMCRT - MaRS Centre, Toronto, Ontario M5G 1L7, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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30
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Abstract
The opportunistic bacterial pathogen Pseudomonas aeruginosa has a layered acyl-homoserine lactone (AHL) quorum-sensing (QS) system, which controls production of a variety of extracellular metabolites and enzymes. The LasRI system activates genes including those coding for the extracellular protease elastase and for the second AHL QS system, RhlRI. Growth of P. aeruginosa on casein requires elastase production and LasR-mutant social cheats emerge in populations growing on casein. P. aeruginosa colonizes the lungs of individuals with the genetic disease cystic fibrosis (CF), and LasR mutants can be isolated from the colonized lungs; however, unlike laboratory-generated LasR mutants, many of these CF isolates have functioning RhlR-RhlI systems. We show that one such mutant can use the RhlR-RhlI system to activate expression of elastase and grow on casein. We carried out social-evolution experiments by growing this isolate on caseinate and, as with wild-type P. aeruginosa, elastase-negative mutants emerge as cheats, but these are not RhlR mutants; rather, they are mutants that do not produce the non-AHL Pseudomonas quinolone signal (PQS). Furthermore, we generated a RhlRI mutant and showed it had a fitness defect when growing together with the parent. Apparently, RhlR QS and PQS collude to support growth on caseinate in the absence of a functional LasR. Our findings provide a plausible explanation as to why P. aeruginosa LasR mutants, but not RhlR mutants, are common in CF lungs.
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31
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Standardized clinical criteria and sweat test combined as a tool to diagnose Cystic Fibrosis. Heliyon 2018; 4:e01050. [PMID: 30582056 PMCID: PMC6299035 DOI: 10.1016/j.heliyon.2018.e01050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/29/2018] [Accepted: 12/11/2018] [Indexed: 11/23/2022] Open
Abstract
Context CF is under-diagnosed in Ecuador; one out of every 11,252 live births born in Ecuador could have CF. Aim To analyze the clinical findings, based on previously established criteria, with the results of the sweat test, in circumstances where we do not have the routine molecular study. Methods Epidemiological, observational, analytic, cross-sectional study. It analyzed 180 patients clinically suspected of CF. Inclusion criteria: children of both sexes older than 30 days and younger than 12 years, who meet at least three clinical criteria suggestive for CF, outpatient and referred by a specialist physician who made a preliminary diagnosis. This is a pilot study. Results The combination of criteria pneumonia, chronic cough and chronic obstructive bronchial syndrome is the most frequent, with not a significant relationship with a positive sweat test. On the contrary, a significant relationship was found between the clinical combinations of pneumonia with cough and rhinosinusitis; pneumonia with cough; presence of Pseudomonas aeruginosa; and pneumonia with digital cough and clubbing, so it is recommended to perform the test in all these associations. The most frequent clinical criterion for the reference and performance of the electrolyte test in sweat is pneumonia to repeat for two or more episodes. Conclusion Clinical combinations of pneumonia with cough and rhinosinusitis; pneumonia with cough; presence of Pseudomonas aeruginosa; and pneumonia with digital cough and clubbing are pathognomonic for CF and indication for the sweat test. The predictive performance in CF diagnosis, defined as compatible clinical presence plus high values of chloride in sweat test, was 91.1%.
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32
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Dittrich AM. [Chronic Pseudomonas aeruginosa airway colonization in cystic fibrosis patients : Prevention concepts]. Internist (Berl) 2018; 58:1133-1141. [PMID: 28963697 DOI: 10.1007/s00108-017-0327-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pseudomonas aeruginosa (PsA) is a hallmark pathogen of the lung disease in cystic fibrosis (CF) patients. Chronic PsA colonization is a central factor in the course of CF lung disease. PsA contributes considerably to morbidity and mortality, and also has a significant impact on quality of life and the costs of CF treatment. Prevention of chronic colonization has therefore been a major goal in the treatment of CF patients for many years now. In the present article, studies are presented which suggest that prevention of chronic colonization can be achieved. Approaches to prevent chronic PsA colonization are critically evaluated and recommendations for preventative approaches are generated from this discussion.
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Affiliation(s)
- A-M Dittrich
- Klinik für pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland.
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33
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Sousa AM, Monteiro R, Pereira MO. Unveiling the early events of Pseudomonas aeruginosa adaptation in cystic fibrosis airway environment using a long-term in vitro maintenance. Int J Med Microbiol 2018; 308:1053-1064. [PMID: 30377031 DOI: 10.1016/j.ijmm.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/16/2018] [Accepted: 10/10/2018] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa chronic infections are the major cause of high morbidity and mortality in cystic fibrosis (CF) patients due to the use of sophisticated mechanisms of adaptation, including clonal diversification into specialized CF-adapted phenotypes. In contrast to chronic infections, very little is known about what occurs after CF lungs colonization and at early infection stages. This study aims to investigate the early events of P. aeruginosa adaptation to CF environment, in particular, to inspect the occurrence of clonal diversification at early stages of infection development and its impact on antibiotherapy effectiveness. To mimic CF early infections, three P. aeruginosa strains were long-term grown in artificial sputum (ASM) over 10 days and phenotypic diversity verified through colony morphology characterization. Biofilm sub- and inhibitory concentrations of ciprofloxacin were applied to non- and diversified populations to evaluate antibiotic effectiveness on P. aeruginosa eradication. Our results demonstrated that clonal diversification might occur after ASM colonization and growth. However, this phenotypic diversification did not compromise ciprofloxacin efficacy in P. aeruginosa eradication since a biofilm minimal inhibitory dosage would be applied. The expected absence of mutators in P. aeruginosa populations led us to speculate that clonal diversification in the absence of ciprofloxacin treatments could be driven by niche specialization. Yet, biofilm sub-inhibitory concentrations of ciprofloxacin seemed to overlap niche specialization as "fitter" variants emerged, such as mucoid, small colony and pinpoint variants, known to be highly resistant to antibiotics. The pathogenic potential of all emergent colony morphotypes-associated bacteria, distinct from the wild-morphotypes, revealed that P. aeruginosa evolved to a non-swimming phenotype. Impaired swimming motility seemed to be one of the first evolutionary steps of P. aeruginosa in CF lungs that could pave the way for further adaptation steps including biofilm formation and progress to chronic infection. Based on our findings, impaired swimming motility seemed to be a candidate to disease marker of P. aeruginosa infection development. Despite our in vitro CF model represents a step forward towards in vivo scenario simulation and provided valuable insights about the early events, more and distinct P. aeruginosa strains should be studied to strengthen our results.
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Affiliation(s)
- Ana Margarida Sousa
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Rosana Monteiro
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria Olívia Pereira
- CEB - Centre of Biological Engineering, LIBRO - Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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Waters V, Grimwood K. Defining chronic Pseudomonas aeruginosa infection in cystic fibrosis. J Cyst Fibros 2018; 17:292-293. [PMID: 29602718 DOI: 10.1016/j.jcf.2018.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Valerie Waters
- Division of Infectious Diseases, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Canada.
| | - Keith Grimwood
- Menzies Health Institute Queensland, Griffith University, Australia; Departments of Infectious Diseases and Paediatrics, Gold Coast Health, Gold Coast, Australia.
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Early detection using qPCR of Pseudomonas aeruginosa infection in children with cystic fibrosis undergoing eradication treatment. J Cyst Fibros 2018. [PMID: 29525410 DOI: 10.1016/j.jcf.2018.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Infection with Pseudomonas aeruginosa (Pa) with a chronic phenotype is associated with antibiotic eradication therapy (AET) failure. Our objective was to determine whether higher levels of Pa (detected using qPCR) prior to culture positivity were associated with AET failure in pediatric CF patients. METHODS Pa-specific qPCR was performed on stored sputa prior to culture positivity in pediatric CF patients with new-onset culture-positive Pa infections undergoing AET with a 28-day course of tobramycin-inhaled solution (TIS). DNA concentrations were compared in patients in whom AET was successful (Eradicated) to those with persistently positive sputum cultures (Persistent). RESULTS Forty-seven patients were included. AET was successful in 32 cases (68%), but failed in 15 cases (32%). Median sputum Pa-specific DNA concentration preceding the positive sputum culture was 2.2 × 10-6 μg/mL in Eradicated cases compared to 3 × 10-5 μg/mL in Persistent cases (p = 0.14). There was no significant difference in DNA concentration in the last sputum sample prior to culture positivity, nor in maximal DNA values. There was also no difference in sputum Pa DNA concentrations in patients who had a mucoid (compared to non-mucoid) Pa infection. CONCLUSIONS Pediatric CF patients with new-onset Pa infections have detectable Pa-specific DNA in the year preceding a positive culture, however, there is no significant difference in Pa DNA concentrations between patients in whom AET is successful compared to those in whom it fails. Therefore, early molecular detection of Pa may not lead to improved eradication success rates.
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Dhand R. The Rationale and Evidence for Use of Inhaled Antibiotics to Control Pseudomonas aeruginosa Infection in Non-cystic Fibrosis Bronchiectasis. J Aerosol Med Pulm Drug Deliv 2017; 31:121-138. [PMID: 29077527 PMCID: PMC5994662 DOI: 10.1089/jamp.2017.1415] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Non-cystic fibrosis bronchiectasis (NCFBE) is a chronic inflammatory lung disease characterized by irreversible dilation of the bronchi, symptoms of persistent cough and expectoration, and recurrent infective exacerbations. The prevalence of NCFBE is on the increase in the United States and Europe, but no licensed therapies are currently available for its treatment. Although there are many similarities between NCFBE and cystic fibrosis (CF) in terms of respiratory symptoms, airway microbiology, and disease progression, there are key differences, for example, in response to treatment, suggesting differences in pathogenesis. This review discusses possible reasons underlying differences in response to inhaled antibiotics in people with CF and NCFBE. Pseudomonas aeruginosa infections are associated with the most severe forms of bronchiectasis. Suboptimal levels of antibiotics in the lung increase the mutation frequency of P. aeruginosa and lead to the development of mucoid strains characterized by formation of a protective polysaccharide biofilm. Mucoid strains of P. aeruginosa are associated with a chronic infection stage, requiring long-term antibiotic therapy. Inhaled antibiotics provide targeted delivery to the lung with minimal systemic toxicity and adverse events compared with oral/intravenous routes of administration, and they could be alternative treatment options to help address some of the treatment challenges in the management of severe cases of NCFBE. This review provides an overview of completed and ongoing trials that evaluated inhaled antibiotic therapy for NCFBE. Recently, several investigators conducted phase 3 randomized controlled trials with inhaled aztreonam and ciprofloxacin in patients with NCFBE. While the aztreonam trial results were not associated with significant clinical benefit in NCFBE, initial results reported from the inhaled ciprofloxacin (dry powder for inhalation and liposome-encapsulated/dual-release formulations) trials hold promise. A more targeted approach could identify specific populations of NCFBE patients who benefit from inhaled antibiotics.
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Affiliation(s)
- Rajiv Dhand
- Department of Medicine, University of Tennessee Graduate School of Medicine , Knoxville, Tennessee
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Staphylococcus aureus interaction with Pseudomonas aeruginosa biofilm enhances tobramycin resistance. NPJ Biofilms Microbiomes 2017; 3:25. [PMID: 29062489 PMCID: PMC5648753 DOI: 10.1038/s41522-017-0035-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/20/2017] [Accepted: 09/26/2017] [Indexed: 01/18/2023] Open
Abstract
Antimicrobial resistance is a significant threat to the treatment of infectious disease. Multiple mechanisms of resistance to different classes of antibiotics have been identified and well-studied. However, these mechanisms are studied with bacteria in isolation, whereas often, infections have a polymicrobial basis. Using a biofilm slide chamber model, we visualized the formation and development of clinical Pseudomonas aeruginosa biofilms in the presence of secreted Staphylococcus aureus exoproducts, two bacteria that commonly co-infect pediatric patients with cystic fibrosis. We showed that, over time, certain isolates of P. aeruginosa can form different biofilm architecture in the presence of S. aureus exoproducts. We further determined that this interaction was dependent on Psl produced by P. aeruginosa and staphylococcal protein A from S. aureus. Importantly, we identified a mechanism of antibiotic resistance to tobramycin that is dependent on the polymicrobial interactions between these two bacteria. This interaction occurred in isolates of P. aeruginosa recovered from children with cystic fibrosis who failed to clear P. aeruginosa following inhaled tobramycin treatment. The interaction between two different bacterial species can enhance the antibiotic resistance of biofilms. Resistance to antimicrobial therapy is usually studied using individual bacterial species, but many infections involve more than one species. Researchers in Canada, led by Trevor Beaudoin at The Hospital for Sick Children in Toronto, studied the effect of products secreted by Staphylococcus aureus bacteria on biofilms of Pseudomonas aeruginosa. They worked with biofilms that had resisted treatment, isolated from patients with cystic fibrosis. The co-infection altered the biofilm structure and increased its resistance to the antibiotic tobramycin. The effect depended on bacterial aggregation stimulated by the interaction between a large carbohydrate from P. aeruginosa and a protein secreted by S. aureus. The research highlights the need to study bacterial interactions to understand and treat infections involving different bacteria.
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Anand R, Moss RB, Sass G, Banaei N, Clemons KV, Martinez M, Stevens DA. Small Colony Variants of Pseudomonas aeruginosa Display Heterogeneity in Inhibiting Aspergillus fumigatus Biofilm. Mycopathologia 2017; 183:263-272. [DOI: 10.1007/s11046-017-0186-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/28/2017] [Indexed: 11/25/2022]
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Stefani S, Campana S, Cariani L, Carnovale V, Colombo C, Lleo MM, Iula VD, Minicucci L, Morelli P, Pizzamiglio G, Taccetti G. Relevance of multidrug-resistant Pseudomonas aeruginosa infections in cystic fibrosis. Int J Med Microbiol 2017; 307:353-362. [PMID: 28754426 DOI: 10.1016/j.ijmm.2017.07.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 07/13/2017] [Accepted: 07/14/2017] [Indexed: 01/15/2023] Open
Abstract
Multidrug-resistant (MDR) Pseudomonas aeruginosa is an important issue for physicians who take care of patients with cystic fibrosis (CF). Here, we review the latest research on how P. aeruginosa infection causes lung function to decline and how several factors contribute to the emergence of antibiotic resistance in P. aeruginosa strains and influence the course of the infection course. However, many aspects of the practical management of patients with CF infected with MDR P. aeruginosa are still to be established. Less is known about the exact role of susceptibility testing in clinical strategies for dealing with resistant infections, and there is an urgent need to find a tool to assist in choosing the best therapeutic strategy for MDR P. aeruginosa infection. One current perception is that the selection of antibiotic therapy according to antibiogram results is an important component of the decision-making process, but other patient factors, such as previous infection history and antibiotic courses, also need to be evaluated. On the basis of the known issues and the best current data on respiratory infections caused by MDR P. aeruginosa, this review provides practical suggestions to optimize the diagnostic and therapeutic management of patients with CF who are infected with these pathogens.
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Affiliation(s)
- S Stefani
- Department of Biomedical and Biotechnological Sciences, Division of Microbiology, University of Catania, Catania, Italy.
| | - S Campana
- Department of Paediatric Medicine, Cystic Fibrosis Centre, Anna Meyer Children's University Hospital, Florence, Italy
| | - L Cariani
- Cystic Fibrosis Microbiology Laboratory, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - V Carnovale
- Department of Translational Medical Sciences, Cystic Fibrosis Center, University "Federico II", Naples, Italy
| | - C Colombo
- Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - M M Lleo
- Department of Diagnostics and Public Health, University of Verona, Verona, Italy
| | - V D Iula
- Department of Molecular Medicine and Medical Biotechnology, Federico II University Medical School, Naples, Italy
| | - L Minicucci
- Microbiology Laboratory, Cystic Fibrosis Center, G. Gaslini Institute, Genoa, Italy
| | - P Morelli
- Department of Paediatric, Cystic Fibrosis Center, G. Gaslini Institute, Genoa, Italy
| | - G Pizzamiglio
- Respiratory Disease Department, Cystic Fibrosis Center Adult Section, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milano, Milan, Italy
| | - G Taccetti
- Department of Paediatric Medicine, Cystic Fibrosis Centre, Anna Meyer Children's University Hospital, Florence, Italy
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Cogen J, Rosenfeld M. Pseudomonas aeruginosa eradication: Finally moving the needle? J Cyst Fibros 2017; 16:309-310. [DOI: 10.1016/j.jcf.2017.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Anand R, Clemons KV, Stevens DA. Effect of Anaerobiasis or Hypoxia on Pseudomonas aeruginosa Inhibition of Aspergillus fumigatus Biofilm. Arch Microbiol 2017; 199:881-890. [PMID: 28357473 DOI: 10.1007/s00203-017-1362-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 02/26/2017] [Accepted: 03/08/2017] [Indexed: 10/19/2022]
Abstract
Pseudomonas aeruginosa (Pa) and Aspergillus fumigatus (Af) are the major bacterial and fungal pathogens in the airways of cystic fibrosis (CF) patients. This is likely related to their ability to form biofilms. Both microbes have been associated with CF disease progression. The interplay between these two pathogens has been studied under aerobic conditions, though accumulating data indicates that much of the CF airway is hypoxic or anaerobic. We studied the microbial interaction in these latter environments. Pa is an aggressor against Af forming biofilm or as established Af biofilm, whether Pa is cultivated in aerobic, hypoxic, or anaerobic conditions, or tested in aerobic or hypoxic conditions. Pa cells are generally more effective than planktonic or biofilm culture filtrates. Pa growth is less in anaerobic conditions, and filtrates less effective after anaerobic or hypoxic growth, or against hypoxic Af. These, and other comparisons shown, indicate that Pa would be less effective in such environments, as would be the case in a CF mucus plug. These observations would explain why Pa becomes established in CF airways before Af, and why Af may persist during disease progression.
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Affiliation(s)
- Rajesh Anand
- California Institute for Medical Research, 2260 Clove Dr., San Jose, CA, 95128, USA.,Division of Infectious Disease and Geographic Medicine, Department of Medicine, School of Medicine, Stanford University, Stanford, CA, 94305, USA.,Department of Biotechnology, Guru Ghasidas Vishwavidyalaya (A Central University), C.G., Bilaspur, 495009, India
| | - Karl V Clemons
- California Institute for Medical Research, 2260 Clove Dr., San Jose, CA, 95128, USA.,Division of Infectious Disease and Geographic Medicine, Department of Medicine, School of Medicine, Stanford University, Stanford, CA, 94305, USA
| | - David A Stevens
- California Institute for Medical Research, 2260 Clove Dr., San Jose, CA, 95128, USA. .,Division of Infectious Disease and Geographic Medicine, Department of Medicine, School of Medicine, Stanford University, Stanford, CA, 94305, USA.
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Importance of the Exopolysaccharide Matrix in Antimicrobial Tolerance of Pseudomonas aeruginosa Aggregates. Antimicrob Agents Chemother 2017; 61:AAC.02696-16. [PMID: 28137803 DOI: 10.1128/aac.02696-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 01/22/2017] [Indexed: 01/11/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that can infect the lungs of cystic fibrosis (CF) patients and persist in the form of antibiotic-tolerant aggregates in the mucus. It has recently been suggested that such aggregates are formed due to restricted bacterial motility independent of the production of extracellular matrix components, and that they do not rely on an extracellular matrix for antimicrobial tolerance. However, we show here that biofilm matrix overexpression, as displayed by various clinical isolates, significantly protects P. aeruginosa aggregates against antimicrobial treatment. Alginate-overproducing mucA mutant bacteria growing in aggregates showed highly increased antibiotic tolerance compared to wild-type bacteria in aggregates. Deletion of algD in the mucA mutant strain abrogated alginate production and reversed the antibiotic tolerance displayed by the aggregates to a level similar to that observed for aggregates formed by the wild type. The P. aeruginosa ΔwspF and ΔyfiR mutant strains both overproduce Pel and Psl exopolysaccharide, and when these bacteria grew in aggregates, they showed highly increased antibiotic tolerance compared to wild-type bacteria growing in aggregates. However, the ΔwspF and ΔyfiR mutant strains, deficient in Pel/Psl production due to additional ΔpelA ΔpslBCD deletions, formed aggregates that displayed antibiotic tolerance levels close to those of wild-type aggregates. These results suggest that biofilm matrix components, such as alginate, Pel, and Psl, do play a role in the tolerance toward antimicrobials when bacteria grow as aggregates.
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Blanchard AC, Horton E, Stanojevic S, Taylor L, Waters V, Ratjen F. Effectiveness of a stepwise Pseudomonas aeruginosa eradication protocol in children with cystic fibrosis. J Cyst Fibros 2017; 16:395-400. [PMID: 28189634 DOI: 10.1016/j.jcf.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/27/2016] [Accepted: 01/19/2017] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Antibiotic eradication therapy (AET) for initial Pseudomonas aeruginosa (Pa) infection is standard of care in children with cystic fibrosis (CF), but information is limited on treatment for patients who fail initial AET. The aim of this study was to evaluate the effectiveness of a multi-step protocol for AET for new-onset Pa infections in children with CF. METHODS A three-step AET protocol which includes: (step 1) 28days of tobramycin inhalation solution (TIS) for new-onset Pa infection; (step 2) a second course of TIS for patients with positive respiratory tract culture after step 1; (step 3) 14days of intravenous antibiotics followed by 28days of TIS for patients with a subsequent positive culture. We conducted a retrospective review of all pediatric CF patients who underwent the eradication protocol between January 2010 and December 2015. The success rate of each step and of the overall protocol was recorded. RESULTS During the study period, 128 patients had a total of 213 new-onset Pa infections. Of 195 asymptomatic episodes, 150 (76.9%, 95% CI 70.4; 82.6) cleared after step 1 and 12 cleared after step 2 (33.3% (95% CI 18.6; 50.9) stepwise success rate and 87.1% (95% CI 77.1; 88.1) cumulative success rate). Intravenous antibiotics followed by 28days of TIS were administered in 24 episodes; this was successful in 10 episodes (41.7%; 95% CI 22.1; 63.4). The regimen in asymptomatic patients failed in fourteen episodes (7.5%; 95% CI 4.2; 12.3) then considered chronically infected with Pa. Overall, the cumulative success rate of the asymptomatic arm was 88.2% (95% CI 82.8; 92.4). CONCLUSION The first step of the AET protocol led to the greatest eradication success. Subsequent eradication attempts have a success rate below 50%. Prospective studies of eradication protocols for this population are needed to determine the most effective treatment strategy.
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Affiliation(s)
- Ana C Blanchard
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
| | - Eric Horton
- Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
| | - Sanja Stanojevic
- Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
| | - Louise Taylor
- Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
| | - Valerie Waters
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
| | - Felix Ratjen
- Division of Respiratory Medicine, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto M5G 1X8, Canada.
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Evaluation of quantitative PCR for early diagnosis of Pseudomonas aeruginosa infection in cystic fibrosis: a prospective cohort study. Clin Microbiol Infect 2016; 23:203-207. [PMID: 27903460 DOI: 10.1016/j.cmi.2016.11.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/31/2016] [Accepted: 11/22/2016] [Indexed: 01/29/2023]
Abstract
OBJECTIVES Early detection of Pseudomonas aeruginosa lung positivity is a key element in cystic fibrosis (CF) management. PCR has increased the accuracy of detection of many microorganisms. Clinical relevance of P. aeruginosa quantitative PCR (qPCR) in this context is unclear. Our aim was to determine P. aeruginosa qPCR sensitivity and specificity, and to assess the possible time saved by qPCR in comparison with standard practice (culture). METHODS A multicentre cohort study was conducted over a 3-year period in 96 patients with CF without chronic P. aeruginosa colonization. Sputum samples were collected at each visit. Conventional culture and two-step qPCR (oprL qPCR and gyrB/ecfX qPCR) were performed for 707 samples. The positivity criteria were based on the qPCR results, defined in a previous study as follow: oprL qPCR positivity alone if bacterial density was <730 CFU/mL or oprL qPCR combined with gyrB/ecfX qPCR if bacterial density was ≥730 CFU/mL. RESULTS During follow up, 36 of the 96 patients with CF were diagnosed on culture as colonized with P. aeruginosa. This two-step qPCR displayed a sensitivity of 94.3% (95% CI 79.7%-98.6%), and a specificity of 86.3% (95% CI 83.4%-88.7%). It enabled P. aeruginosa acquisition to be diagnosed earlier in 20 patients, providing a median detection time gain of 8 months (interquartile range 3.7-17.6) for them. CONCLUSIONS Implementing oprL and gyrB/ecfX qPCR in the management of patients with CF allowed earlier detection of first P. aeruginosa lung positivity than culture alone.
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Fischer S, Greipel L, Klockgether J, Dorda M, Wiehlmann L, Cramer N, Tümmler B. Multilocus amplicon sequencing of Pseudomonas aeruginosa cystic fibrosis airways isolates collected prior to and after early antipseudomonal chemotherapy. J Cyst Fibros 2016; 16:346-352. [PMID: 27836448 DOI: 10.1016/j.jcf.2016.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Early antimicrobial chemotherapy can prevent or at least delay chronic cystic fibrosis (CF) airways infections with Pseudomonas aeruginosa. METHODS During a 10-year study period P. aeruginosa was detected for the first time in 54 CF patients regularly seen at the CF centre Hannover. Amplicon sequencing of 34 loci of the P. aeruginosa core genome was performed in baseline and post-treatment isolates of the 15 CF patients who had remained P. aeruginosa - positive after the first round of antipseudomonal chemotherapy. RESULTS Deep sequencing uncovered coexisting alternative nucleotides at in total 33 of 55,284 examined genome positions including six non-synonymous polymorphisms in the lasR gene, a key regulator of quorum sensing. After early treatment 42 of 50 novel nucleotide substitutions had emerged in exopolysaccharide biosynthesis, efflux pump and porin genes. CONCLUSIONS Early treatment selects pathoadaptive mutations in P. aeruginosa that are typical for chronic infections of CF lungs.
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Affiliation(s)
- Sebastian Fischer
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Leonie Greipel
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Jens Klockgether
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Marie Dorda
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Lutz Wiehlmann
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Nina Cramer
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany
| | - Burkhard Tümmler
- Clinical Research Group 'Molecular Pathology of Cystic Fibrosis', Clinic for Paediatric Pneumology, Allergology and Neonatology, OE 6710, Hannover Medical School, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany.
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LasR Variant Cystic Fibrosis Isolates Reveal an Adaptable Quorum-Sensing Hierarchy in Pseudomonas aeruginosa. mBio 2016; 7:mBio.01513-16. [PMID: 27703072 PMCID: PMC5050340 DOI: 10.1128/mbio.01513-16] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Chronic Pseudomonas aeruginosa infections cause significant morbidity in patients with cystic fibrosis (CF). Over years to decades, P. aeruginosa adapts genetically as it establishes chronic lung infections. Nonsynonymous mutations in lasR, the quorum-sensing (QS) master regulator, are common in CF. In laboratory strains of P. aeruginosa, LasR activates transcription of dozens of genes, including that for another QS regulator, RhlR. Despite the frequency with which lasR coding variants have been reported to occur in P. aeruginosa CF isolates, little is known about their consequences for QS. We sequenced lasR from 2,583 P. aeruginosa CF isolates. The lasR sequences of 580 isolates (22%) coded for polypeptides that differed from the conserved LasR polypeptides of well-studied laboratory strains. This collection included 173 unique lasR coding variants, 116 of which were either missense or nonsense mutations. We studied 31 of these variants. About one-sixth of the variant LasR proteins were functional, including 3 with nonsense mutations, and in some LasR-null isolates, genes that are LasR dependent in laboratory strains were nonetheless expressed. Furthermore, about half of the LasR-null isolates retained RhlR activity. Therefore, in some CF isolates the QS hierarchy is altered such that RhlR quorum sensing is independent of LasR regulation. Our analysis challenges the view that QS-silent P. aeruginosa is selected during the course of a chronic CF lung infection. Rather, some lasR sequence variants retain functionality, and many employ an alternate QS strategy involving RhlR. Chronic Pseudomonas aeruginosa infections, such as those in patients with the genetic disease cystic fibrosis, are notable in that mutants with defects in the quorum-sensing transcription factor LasR frequently arise. In laboratory strains of P. aeruginosa, quorum sensing activates transcription of dozens of genes, many of which encode virulence factors, such as secreted proteases and hydrogen cyanide synthases. In well-studied laboratory strains, LasR-null mutants have a quorum-sensing-deficient phenotype. Therefore, the presence of LasR variants in chronic infections has been interpreted to indicate that quorum-sensing-regulated products are not important for those infections. We report that some P. aeruginosa LasR variant clinical isolates are not LasR-null mutants, and others have uncoupled a second quorum-sensing system, the RhlR system, from LasR regulation. In these uncoupled isolates, RhlR independently activates at least some quorum-sensing-dependent genes. Our findings suggest that quorum sensing plays a role in chronic P. aeruginosa infections, despite the emergence of LasR coding variants.
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Abstract
PURPOSE OF REVIEW The current guidelines and recent clinical research in the management of Pseudomonas aeruginosa respiratory infections in cystic fibrosis (CF) are reviewed. Areas where further research is required will also be highlighted. RECENT FINDINGS P. aeruginosa is a key respiratory pathogen in CF. Inhaled tobramycin or colistin is recommended for early eradication to prevent establishment of chronic infection. Other antibiotic options are currently being investigated. The long-term success of eradication strategies is also now being assessed. The use of inhaled antibiotics in the management of chronic P. aeruginosa infection is an area of active investigation. Acute pulmonary exacerbations are still a major cause of morbidity and mortality. Guidelines continue to recommend combination intravenous therapy but further research is required to clarify the advantage of this approach. Multidrug resistance is common and potentially more effective antipseudomonal antibiotics may soon become available. SUMMARY The management of P. aeruginosa respiratory infection in CF remains a challenging area, especially in the setting of multidrug resistance. The role of inhaled antibiotics continues to be expanded. Further research is required in the key areas of eradication and management of chronic infection and acute pulmonary exacerbations to identify those treatments that optimize long-term, clinical benefits.
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Use of a Multiplex Transcript Method for Analysis of Pseudomonas aeruginosa Gene Expression Profiles in the Cystic Fibrosis Lung. Infect Immun 2016; 84:2995-3006. [PMID: 27481238 DOI: 10.1128/iai.00437-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/25/2016] [Indexed: 01/20/2023] Open
Abstract
The discovery of therapies that modulate Pseudomonas aeruginosa virulence or that can eradicate chronic P. aeruginosa lung infections associated with cystic fibrosis (CF) will be advanced by an improved understanding of P. aeruginosa behavior in vivo We demonstrate the use of multiplexed Nanostring technology to monitor relative abundances of P. aeruginosa transcripts across clinical isolates, in serial samples, and for the purposes of comparing microbial physiology in vitro and in vivo The expression of 75 transcripts encoded by genes implicated in CF lung disease was measured in a variety of P. aeruginosa strains as well as RNA serial sputum samples from four P. aeruginosa-colonized subjects with CF collected over 6 months. We present data on reproducibility, the results from different methods of normalization, and demonstrate high concordance between transcript relative abundance data obtained by Nanostring or transcriptome sequencing (RNA-Seq) analysis. Furthermore, we address considerations regarding sequence variation between strains during probe design. Analysis of P. aeruginosa grown in vitro identified transcripts that correlated with the different phenotypes commonly observed in CF clinical isolates. P. aeruginosa transcript profiles in RNA from CF sputum indicated alginate production in vivo, and transcripts involved in quorum-sensing regulation were less abundant in sputum than strains grown in the laboratory. P. aeruginosa gene expression patterns from sputum clustered closely together relative to patterns for laboratory-grown cultures; in contrast, laboratory-grown P. aeruginosa showed much greater transcriptional variation with only loose clustering of strains with different phenotypes. The clustering within and between subjects was surprising in light of differences in inhaled antibiotic and respiratory symptoms, suggesting that the pathways represented by these 75 transcripts are stable in chronic CF P. aeruginosa lung infections.
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Groizeleau J, Rybtke M, Andersen JB, Berthelsen J, Liu Y, Yang L, Nielsen TE, Kaever V, Givskov M, Tolker-Nielsen T. The anti-cancerous drug doxorubicin decreases the c-di-GMP content in Pseudomonas aeruginosa but promotes biofilm formation. MICROBIOLOGY-SGM 2016; 162:1797-1807. [PMID: 27526691 DOI: 10.1099/mic.0.000354] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Current antibiotic treatments are insufficient in eradicating bacterial biofilms, which represent the primary cause of chronic bacterial infections. Thus, there is an urgent need for new strategies to eradicate biofilm infections. The second messenger c-di-GMP is a positive regulator of biofilm formation in many clinically relevant bacteria. It is hypothesized that drugs lowering the intracellular level of c-di-GMP will force biofilm bacteria into a more treatable planktonic lifestyle. To identify compounds capable of lowering c-di-GMP levels in Pseudomonas aeruginosa, we screened 5000 compounds for their potential c-di-GMP-lowering effect using a recently developed c-di-GMP biosensor strain. Our screen identified the anti-cancerous drug doxorubicin as a potent c-di-GMP inhibitor. In addition, the drug decreased the transcription of many biofilm-related genes. However, despite its effect on the c-di-GMP content in P. aeruginosa, doxorubicin was unable to inhibit biofilm formation or disperse established biofilms. On the contrary, the drug was found to promote P. aeruginosa biofilm formation, possibly through release of extracellular DNA from a subpopulation of killed bacteria. Our findings emphasize that lowering of the c-di-GMP content in bacteria might not be sufficient to mediate biofilm inhibition or dispersal.
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Affiliation(s)
- Julie Groizeleau
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Rybtke
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bo Andersen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Berthelsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Yang Liu
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Liang Yang
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Thomas E Nielsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Volkhard Kaever
- Research Core Unit Metabolomics, Hannover Medical School, Hannover, Germany
| | - Michael Givskov
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Tim Tolker-Nielsen
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Colmer-Hamood JA, Dzvova N, Kruczek C, Hamood AN. In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2016; 142:151-91. [PMID: 27571695 DOI: 10.1016/bs.pmbts.2016.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.
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Affiliation(s)
- J A Colmer-Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Medical Education, Texas Tech University Health Sciences Center, Lubbock, TX, United States.
| | - N Dzvova
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - C Kruczek
- Honors College, Texas Tech University, Lubbock, TX, United States
| | - A N Hamood
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX, United States; Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, United States
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