BioProject

Although previous studies have characterised the evolution and adaptation of Pseudomonas aeruginosa populations during chronic lung infections of cystic fibrosis (CF) patients, less in known in relation to P. More...

Although previous studies have characterised the evolution and adaptation of Pseudomonas aeruginosa populations during chronic lung infections of cystic fibrosis (CF) patients, less in known in relation to P. aeruginosa infections in non-CF bronchiectasis (BE). We used whole genome sequencing of isolates from BE patients to (i) assess the diversity of P. aeruginosa and the prevalence of multi-lineage infections, (ii) seek evidence for cross-infection or common source acquisition and (iii) characterize P. aeruginosa adaptations.In a cross sectional analysis, 189 isolates, obtained from the sputa of 93 patients attending 16 adult UK BE centres, were whole genome sequenced to determine genetic relationships between isolates, and identify common adaptations. Measurements and Main Results: Of 23 patients where multiple isolates were examined, there were six examples of multi-lineage infections. Pairwise comparisons indicated that, in some cases, the number of nucleotide variants occurring between isolates from different patients was comparable to the variations observed between isolates from individual patient sputum samples. Loss of function mutations and deletions were common in genes associated with phenotypes such as virulence, motility, iron scavenging and biofilm production. During infections of BE patients, P. aeruginosa populations adapt by accumulating loss of function mutations, leading to switches in phenotypes including the mode of iron acquisition and the production of biofilm-associated polysaccharides. The within-population diversification observed during P. aeruginosa infections of BE patients, suggests that larger scale longitudinal surveillance studies will be required to capture cross infection or common source acquisition events at an early stage. Less...