Assessing the role of environment in Pseudomonas aeruginosa healthcare-associated bloodstream infections: a one-year prospective survey.

Abstract

Objective: To prospectively investigate the role of hospital environment in Pseudomonas aeruginosa (Pa) nosocomial bloodstream infections (BSIs) during one year in a tertiary-care hospital.

Methods: Clinical records of patients presenting Pa-BSIs after >48h of hospitalization were investigated to confirm the nosocomial character of BSIs and identify the way of entry and risk factors. 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.

Results: 53 episodes of BSIs in 49 patients were considered as nosocomial, mostly involving men (73%), with an average age of 62.4, immunosuppressed in over 40% of cases, and after previous antibiotic therapy in almost 92% of cases. BSIs occurred after 27 days of hospitalization on average. The main routes of entry were urinary (30%, on indwelling catheters for 2/3 of cases) and cutaneous (17%, catheter-related in almost 80% of cases). Pa was found in 16/49 investigations, representing 34 positive samples, including 54% of sink traps, 23% of water and 20% of tap aerators. An epidemiological link was established between environmental and clinical strains only for 8 patients representing 15% of nosocomial BSIs.

Conclusion: The hospital environment usually considered as the main source of Pa healthcare-associated infections was identified as responsible of nosocomial BSIs for only 15% of patients. Since the implementation of water and hospital environment management, one can hypothesize that Pa has become a community-acquired pathogen with a nosocomial expression in infection.