show Abstracthide AbstractTo conduct systematic prospective clinical and environmental investigations of Pseudomonas aeruginosa (Pa) nosocomial bloodstream infections (BSIs) during one year in a tertiary-care hospital. Patients presenting Pa-positive blood culture after >48h of hospitalization were included. Environmental investigations were performed to track Pa source/reservoir along the pathway of cares. Clinical and environmental strains were compared by whole-genome sequencing to identify the path of contamination from hospital environment to patients.