Lack of association between hypermutation and antibiotic resistance development in Pseudomonas aeruginosa isolates from intensive care unit patients.

Hypermutation is a common feature of Pseudomonas aeruginosa isolates from chronically infected cystic fibrosis patients that is linked with antibiotic resistance development. In this work, using a large collection of sequential P. aeruginosa isolates from ICU patients, we found that despite the fact that mutational antibiotic resistance development is a frequent outcome, the prevalence of hypermutable strains is low (found in isolates from only 1 of 103 patients) and there is no evidence of coselection of the hypermutable and antibiotic resistance phenotypes.