Evolutionary diversification of Pseudomonas aeruginosa in an artificial sputum model

BMC Microbiology

Research Article

Michael A. Brockhurst¹  Emily V. Davies²  Craig Winstanley²  Chloe E. James³ 

[1] Department of Biology, University of York, YO10 5DD, York, UK;Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, L69 7BE, Liverpool, UK;Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, L69 7BE, Liverpool, UK;School of Environment and Life Sciences, University of Salford, M5 4WT, Manchester, UK;

关键词: Pseudomonas aeruginosa;    Bacteriophage;    Cystic fibrosis;    Evolution;    Motility;    Biofilm;    Antimicrobial resistance;   

DOI  :  10.1186/s12866-016-0916-z

 received in 2016-08-04, accepted in 2016-12-15,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundDuring chronic lung infections of cystic fibrosis patients Pseudomonas aeruginosa populations undergo extensive evolutionary diversification. However, the selective drivers of this evolutionary process are poorly understood. To test the effects of temperate phages on diversification in P. aeruginosa biofilms we experimentally evolved populations of P. aeruginosa for approximately 240 generations in artificial sputum medium with or without a community of three temperate phages.ResultsAnalysis of end-point populations using a suite of phenotypic tests revealed extensive phenotypic diversification within populations, but no significant differences between the populations evolved with or without phages. The most common phenotypic variant observed was loss of all three types of motility (swimming, swarming and twitching) and resistance to all three phages. Despite the absence of selective pressure, some members of the population evolved antibiotic resistance. The frequency of antibiotic resistant isolates varied according to population and the antibiotic tested. However, resistance to ceftazidime and tazobactam-piperacillin was observed more frequently than resistance to other antibiotics, and was associated with higher prevelence of isolates exhibiting a hypermutable phenotype and increased beta-lactamase production.ConclusionsWe observed considerable within-population phenotypic diversity in P. aeruginosa populations evolving in the artificial sputum medium biofilm model. Replicate populations evolved both in the presence and absence of phages converged upon similar sets of phenotypes. The evolved phenotypes, including antimicrobial resistance, were similar to those observed amongst clinical isolates from cystic fibrosis infections.

【 授权许可】

CC BY   
© The Author(s). 2017