Retrospective analysis of clinical and environmental genotyping reveals persistence of Pseudomonas aeruginosa in the water infrastructure of a large tertiary children's hospital in England.

BACKGROUND

Pseudomonas aeruginosa is a major cause of healthcare-associated infections in paediatric settings, where its persistence in hospital water infrastructure poses a particular risk to neonates and immunocompromised children.

AIM: The aim of the present study was to investigate the long-term survival and transmission risk of P. aeruginosa in a large tertiary children's hospital in England.

METHODS

Environmental P. aeruginosa isolates from taps, sinks, showers, and baths in augmented care units built in accordance with NHS Health Technical Memorandum 04-01 were referred to the UK Health Security Agency (UKHSA) for characterisation. Clinical isolates referred to UKHSA were classified as invasive (blood, cerebrospinal fluid, and bronchoalveolar lavage) or non-invasive (respiratory tract, urine, ear, abdomen, and rectal swabs). Variable-number tandem repeat (VNTR) profiles and metadata of isolates were extracted from UKHSA reports, de-identified, deduplicated, and analysed to define genotypes by identical VNTR profiles.

FINDINGS: This retrospective study analysed 404 P. aeruginosa referral isolates, identifying 56 VNTR clusters (each with ≥2 isolates), of which 19 (34%) contained 1-3 invasive isolates (5-50%). Thirty-nine clusters demonstrated persistence spanning one to more than eight years. The largest cluster (N = 20) persisted for over eight years (July 2016-December 2024), comprising 17 environmental, one invasive, and two non-invasive isolates. In nine clusters, environmental isolates were detected before genetically matching clinical isolates.

CONCLUSION

These findings demonstrate long-term persistence of certain P. aeruginosa genotypes within hospital water infrastructure and temporal overlap between environmental and clinical isolates, supporting continuous water surveillance and data-driven optimisation of water safety measures to reduce transmission risk in healthcare settings.