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Ruhluel D, Fisher L, Barton TE, Leighton H, Kumar S, Morillo PA, O'Brien S, Fothergill JL, Neill DR. Secondary messenger signalling influences Pseudomonas aeruginosa adaptation to sinus and lung environments. ISME J 2024:wrae065. [PMID: 38647527 DOI: 10.1093/ismejo/wrae065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 03/08/2024] [Accepted: 04/18/2024] [Indexed: 04/25/2024]
Abstract
Pseudomonas aeruginosa is a cause of chronic respiratory tract infections in people with cystic fibrosis (CF), non-CF bronchiectasis and chronic obstructive pulmonary disease. Prolonged infection allows accumulation of mutations and horizontal gene transfer, increasing the likelihood of adaptive phenotypic traits. Adaptation is proposed to arise first in bacterial populations colonising upper airway environments. Here, we model this process using an experimental evolution approach. P. aeruginosa PAO1, which is not airway adapted, was serially passaged, separately, in media chemically reflective of upper or lower airway environments. To explore whether the CF environment selects for unique traits, we separately passaged PAO1 in airway-mimicking media with or without CF-specific factors. Our findings demonstrated that all airway environments - sinus and lungs, under CF and non-CF conditions - selected for loss of twitching motility, increased resistance to multiple antibiotic classes and a hyper-biofilm phenotype. These traits conferred increased airway colonisation potential in an in vivo model. CF-like conditions exerted stronger selective pressures, leading to emergence of more pronounced phenotypes. Loss of twitching was associated with mutations in type IV pili genes. Type IV pili mediate surface attachment, twitching and induction of cAMP signalling. We additionally identified multiple evolutionary routes to increased biofilm formation involving regulation of cyclic-di-GMP signalling. These included loss of function mutations in bifA and dipA phosphodiesterase genes and activating mutations in the siaA phosphatase. These data highlight that airway environments select for traits associated with sessile lifestyles and suggest upper airway niches support emergence of phenotypes that promote establishment of lung infection.
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Affiliation(s)
- Dilem Ruhluel
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool
| | - Lewis Fisher
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Thomas E Barton
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Hollie Leighton
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool
| | - Sumit Kumar
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Paula Amores Morillo
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- Department of Clinical Infection, Microbiology and Immunology, University of Liverpool, Ronald Ross Building, 8 West Derby Street, Liverpool
| | - Daniel R Neill
- Division of Molecular Microbiology, University of Dundee, Dow Street, Dundee, United Kingdom
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/18/2022] [Indexed: 11/25/2023] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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Ruhluel D, O'Brien S, Fothergill JL, Neill DR. Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health. F1000Res 2022; 11:1007. [PMID: 36519007 PMCID: PMC9718992 DOI: 10.12688/f1000research.125074.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/18/2022] [Indexed: 12/05/2022] Open
Abstract
The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.
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Affiliation(s)
- Dilem Ruhluel
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Siobhan O'Brien
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin, 2, Ireland
| | - Joanne L Fothergill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
| | - Daniel R Neill
- University of Liverpool, Institute of Infection, Veterinary and Ecological Sciences,, Liverpool, L69 7BE, UK
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