Dr Hannah Poole1, Dr Sara Vogrin1,2, Mr Terry Rout3, Ms Leanne Houston4, A/Prof. Jason Kwong1,5
1Department of Infectious Diseases & Immunology, Austin Health, Australia, 2Department of Medicine, University of Melbourne, Australia, 3Facilities Maintenance & Asset Services, Austin Health, Australia, 4Infection Prevention & Control, Austin Health, Australia, 5Department of Microbiology & Immunology, University of Melbourne, Australia
Biography:
A/Prof Jason Kwong is an Infectious Diseases Physician and Director of Infection Prevention & Control at Austin Health. He is chair of HICSIG within the Australasian Society for Infectious Diseases and is an associate editor for Infection, Disease & Health. His research interests include genomics for surveillance/control of infectious diseases.
Abstract:
Introduction
Healthcare-associated pneumonia due to Legionella is associated with high mortality, particularly in immunocompromised patients. Legionella bacteria can become established and difficult to eradicate from warm water distribution systems in hospitals, where conditions are conducive to Legionella colonisation and growth. We assessed the effect of copper-silver ionisation as a systemic disinfection treatment for a hospital water distribution system colonised with Legionella.
Methods
Following system-wide contamination of a water distribution system of a tertiary cancer hospital with Legionella bacteria, we conducted a retrospective review of Legionella results from sampling of the water system. Any result with ≥10 colony forming units (CFU) of Legionella species was considered positive. An interrupted time series analysis was undertaken to compare incidence before, during, and after the introduction of copper-silver ionisation as a system disinfection treatment.
Results
Between June 2016 and September 2021, the unadjusted overall incidence rate of Legionella in routine surveillance samples across two affected systems was 127 detections per 1000 samples. Following the installation of a copper-silver ionisation dosing in these two water distribution systems and a 12-month implementation period, this fell to 2 per 1000 samples (p < 0.001) through two years of post-implementation surveillance. The incidence of Legionella detected in other water distribution systems of our healthcare facility remained stable across the study period at 45 per 1000 samples. No clinical cases of healthcare-associated Legionellosis were identified.
Conclusions
A significant reduction in Legionella detections through routine surveillance testing of hospital water systems was observed following the introduction of copper-silver ionisation dosing.