title: Fluctuations in phenotypes and genotypes within populations of Pseudomonas aeruginosa in the cystic fibrosis lung during pulmonary exacerbations.
abstract: Chronic respiratory infection by Pseudomonas aeruginosa contributes significantly to the morbidity and mortality associated with cystic fibrosis (CF). Using a series of phenotypic and genotypic tests on collections of 40 isolates per sputum sample, we analysed fluctuations within sputum populations of the P. aeruginosa Liverpool epidemic strain (LES) during pulmonary exacerbations. For each of three patients, three sequential sputum samples were analysed: (1) on presentation with exacerbation at the Regional Adult Cystic Fibrosis Unit, Liverpool; (2) a few days into intravenous antibiotic treatment; (3) when the patient had recovered. Fluctuations were observed in morphotype distribution, the production of virulence-associated quorum-sensing-dependent exoproducts (the phenazine compound pyocyanin and the elastase LasA), antibiotic susceptibility profiles and levels of auxotrophy. PCR assays were used to screen isolates for the presence of novel regions of the LES genome (islands and prophages) and to detect free phages. In one patient there was an increase in the prevalence of the LESGI-5 genomic island during the sampling period from 10 to 97.5 % carriage. LES phages 2-4 were detected in either the majority or all sputum samples tested, indicating widespread phage activity during the sampling period. The results of this study are indicative that significant fluctuations occur within P. aeruginosa populations during short periods of pulmonary exacerbation and intravenous antibiotic therapy.
authors.affiliation: Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK.|Biomedical Research Centre, Royal Liverpool UniversityHospital, Liverpool L69 3GA, UK.
authors.forename: Joanne L
authors.initials: JL
authors.lastname: Fothergill
authors.affiliation: Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK.
authors.forename: Eilidh
authors.initials: E
authors.lastname: Mowat
authors.affiliation: Regional Adult Cystic Fibrosis Unit, Liverpool Heartand Chest Hospital, Liverpool L14 3PE, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Ledson
authors.affiliation: Regional Adult Cystic Fibrosis Unit, Liverpool Heartand Chest Hospital, Liverpool L14 3PE, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Walshaw
authors.affiliation: Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK.|Biomedical Research Centre, Royal Liverpool UniversityHospital, Liverpool L69 3GA, UK.
authors.forename: Craig
authors.initials: C
authors.lastname: Winstanley
mesh_terms: D000328:Adult; D001435:Bacteriophages / Q000302:isolation & purification; D002939:Ciprofloxacin / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005838:Genotype; D006801:Humans; D008168:Lung / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D011550:Pseudomonas aeruginosa / Q000145:classification* / Q000187:drug effects / Q000821:virology; D013183:Sputum / Q000382:microbiology
chemical_list: D002939:Ciprofloxacin