Adaptive evolution of Pseudomonas aeruginosa ST299 population colonizing a hospital copper water network over a 2.5-year period

Background. Descriptions of genomic characters and dynamics related to Pseudomonas aeruginosa (PA) adaptation and survival in hospital water networks remain scarce but necessary for sustainable water management in hospitals. Methods. A new copper water network in an intensive care unit (ICU) was chronically colonized by a genotype sequence type (ST) 299 of PA and sporadically by a genotype ST2685. Sixty-eight ST299-PA and four ST2685-PA strains from ICU-water samples collected over 29 months and 4 months, respectively, were studied for genomic adaptation to copper water network. PFGE and whole-genome sequencing allowing SNP, comparative genomics, resistome, virulome and pangenome analyses were performed. In order to understand the adaptive phenomena linked to the colonization niche, 16 isolates of ST299-PA colonizing a cystic fibrosis (CF) patient during 16 months were included. Results and discussion. The 68 ST299-PA ICU-water differed by