Lytic activity by temperate phages of Pseudomonas aeruginosa in long-term cystic fibrosis chronic lung infections

James, Chloe E; Davies, Emily V; Fothergill, Joanne L; Walshaw, Martin J; Beale, Colin M; Brockhurst, Michael A; Winstanley, Craig

Abstract

Pseudomonas aeruginosa is the most common bacterial pathogen infecting the lungs of cystic fibrosis (CF) patients. The transmissible Liverpool epidemic strain (LES) harbours multiple inducible prophages (LESϕ2; LESϕ3; LESϕ4; LESϕ5; and LESϕ6), some of which are known to confer a competitive advantage in an in vivo rat model of chronic lung infection. We used quantitative PCR (Q-PCR) to measure the density and dynamics of all five LES phages in the sputa of 10 LES-infected CF patients over a period of 2 years. In all patients, the densities of free-LES phages were positively correlated with the densities of P. aeruginosa, and total free-phage densities consistently exceeded bacterial host densities 10–100-fold. Further, we observed a negative correlation between the phage-to-bacterium ratio and bacterial density, suggesting a role for lysis by temperate phages in regulation of the bacterial population densities. In 9/10 patients, LESϕ2 and LESϕ4 were the most abundant free phages, which reflects the differential in vitro induction properties of the phages. These data indicate that temperate phages of P. aeruginosa retain lytic activity after prolonged periods of chronic infection in the CF lung, and suggest that temperate phage lysis may contribute to regulation of P. aeruginosa density in vivo.

Citation

James, C. E., Davies, E. V., Fothergill, J. L., Walshaw, M. J., Beale, C. M., Brockhurst, M. A., & Winstanley, C. (2015). Lytic activity by temperate phages of Pseudomonas aeruginosa in long-term cystic fibrosis chronic lung infections. ISME Journal, 9(6), 1391-1398. https://doi.org/10.1038/ismej.2014.223

• Journal Article Type: Article
• Acceptance Date: Oct 23, 2014
• Online Publication Date: Dec 2, 2014
• Publication Date: Jun 1, 2015
• Deposit Date: Jan 12, 2015
• Publicly Available Date: Apr 5, 2016
• Journal: The ISME Journal
• Print ISSN: 1751-7362
• Electronic ISSN: 1751-7370
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 9
• Issue: 6
• Pages: 1391-1398
• DOI: https://doi.org/10.1038/ismej.2014.223
• Publisher URL: http://dx.doi.org/10.1038/ismej.2014.223
• Related Public URLs: http://www.nature.com/ismej/index.html