Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific

The potential for siderophore mutants of Pseudomonas aeruginosa to attenuate virulence during infection, and the possibility of exploiting this for clinical ends, have attracted much discussion. This has largely been based on the results of in vitro experiments conducted in iron-limited growth mediu...

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Main Authors: Harrison, Freya, McNally, Alan, da Silva, Ana C., Heeb, Stephan, Diggle, Stephen P.
Format: Article
Published: Nature Publishing Group 2017
Online Access:https://eprints.nottingham.ac.uk/46934/
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author Harrison, Freya
McNally, Alan
da Silva, Ana C.
Heeb, Stephan
Diggle, Stephen P.
author_facet Harrison, Freya
McNally, Alan
da Silva, Ana C.
Heeb, Stephan
Diggle, Stephen P.
author_sort Harrison, Freya
building Nottingham Research Data Repository
collection Online Access
description The potential for siderophore mutants of Pseudomonas aeruginosa to attenuate virulence during infection, and the possibility of exploiting this for clinical ends, have attracted much discussion. This has largely been based on the results of in vitro experiments conducted in iron-limited growth medium, in which siderophore mutants act as social ‘cheats:’ increasing in frequency at the expense of the wild type to result in low-productivity, low-virulence populations dominated by mutants. We show that insights from in vitro experiments cannot necessarily be transferred to infection contexts. First, most published experiments use an undefined siderophore mutant. Whole-genome sequencing of this strain revealed a range of mutations affecting phenotypes other than siderophore production. Second, iron-limited medium provides a very different environment from that encountered in chronic infections. We conducted cheating assays using defined siderophore deletion mutants, in conditions designed to model infected fluids and tissue in cystic fibrosis lung infection and non-healing wounds. Depending on the environment, siderophore loss led to cheating, simple fitness defects, or no fitness effect at all. Our results show that it is crucial to develop defined in vitro models in order to predict whether siderophores are social, cheatable and suitable for clinical exploitation in specific infection contexts.
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spelling nottingham-469342020-05-04T18:54:54Z https://eprints.nottingham.ac.uk/46934/ Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific Harrison, Freya McNally, Alan da Silva, Ana C. Heeb, Stephan Diggle, Stephen P. The potential for siderophore mutants of Pseudomonas aeruginosa to attenuate virulence during infection, and the possibility of exploiting this for clinical ends, have attracted much discussion. This has largely been based on the results of in vitro experiments conducted in iron-limited growth medium, in which siderophore mutants act as social ‘cheats:’ increasing in frequency at the expense of the wild type to result in low-productivity, low-virulence populations dominated by mutants. We show that insights from in vitro experiments cannot necessarily be transferred to infection contexts. First, most published experiments use an undefined siderophore mutant. Whole-genome sequencing of this strain revealed a range of mutations affecting phenotypes other than siderophore production. Second, iron-limited medium provides a very different environment from that encountered in chronic infections. We conducted cheating assays using defined siderophore deletion mutants, in conditions designed to model infected fluids and tissue in cystic fibrosis lung infection and non-healing wounds. Depending on the environment, siderophore loss led to cheating, simple fitness defects, or no fitness effect at all. Our results show that it is crucial to develop defined in vitro models in order to predict whether siderophores are social, cheatable and suitable for clinical exploitation in specific infection contexts. Nature Publishing Group 2017-07-11 Article PeerReviewed Harrison, Freya, McNally, Alan, da Silva, Ana C., Heeb, Stephan and Diggle, Stephen P. (2017) Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific. ISME Journal . ISSN 1751-7362 (In Press) https://www.nature.com/ismej/journal/vaop/ncurrent/full/ismej2017103a.html doi:10.1038/ismej.2017.103 doi:10.1038/ismej.2017.103
spellingShingle Harrison, Freya
McNally, Alan
da Silva, Ana C.
Heeb, Stephan
Diggle, Stephen P.
Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title_full Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title_fullStr Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title_full_unstemmed Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title_short Optimised chronic infection models demonstrate that siderophore ‘cheating’ in Pseudomonas aeruginosa is context specific
title_sort optimised chronic infection models demonstrate that siderophore ‘cheating’ in pseudomonas aeruginosa is context specific
url https://eprints.nottingham.ac.uk/46934/
https://eprints.nottingham.ac.uk/46934/
https://eprints.nottingham.ac.uk/46934/