Aquatic reservoir-associated outbreaks of multi-drug-resistant bacteria: a hospital outbreak report of Pseudomonas aeruginosa in perspective from the Dutch national surveillance databases

A hospital outbreak of Pseudomonas aeruginosa producing Verona integron-encoded metallo-β-lactamase type 2 (CRPA-VIM, ST111) was traced to contaminated ICU sinks. Initial detection occurred in December 2023 (3 patients), with a new cluster in March–April 2024 (5 patients). Whole-genome sequencing linked cases to a decommissioned sink and confirmed that sinks, not patient-to-patient transmission, were the source. Despite multiple interventions—enhanced cleaning, hygiene retraining, faucet modifications, and splash-reducing inlets—transmission persisted until all ICU water fixtures were removed.

National surveillance showed the outbreak strain was unique to the hospital, with 3–5 similar waterborne outbreaks reported annually in Dutch hospitals.

Conclusion: ICU sinks served as reservoirs for CRPA-VIM transmission. Effective control required removing all water fixtures, highlighting the need for continuous patient–environment surveillance and hospital designs that minimize contamination risks from drains and sinks.