What’s In Your Water? Legionella Outbreak at Academic Medical Center

Reviewed by Clare Marlin, MS, RN; CIC Brain Innovation Center, Shirley Ryan AbilityLab, Chicago, IL

The authors present the investigation and case study of a 2018 Legionella pneumonia outbreak among 13 identified cases at their hospital, which had an existing copper-silver ionization system in place for water disinfection at the time of the outbreak. A comprehensive review of electronic charts, as well as collaboration with the CDC’s Legionella Team and the state’s Department of Public Health, revealed hot potable water was the most likely outbreak source and smoking, steroid use, and showering during the hospital stay were identified as risk factors for acquiring Legionella pneumonia during this outbreak. Within the month before the outbreak, the hospital water system had been modified causing an increased mixing of water flow between two circuits supplying water to outbreak-impacted hospital floors and the copper-silver ionization system flow was changed. The outbreak was mitigated with multiple responses including the installation of point-of-use water filters, serial culturing of potable water for Legionella, and the development of a multidisciplinary water management committee.


Kessler, M. et al. Hospital-acquired Legionella pneumonia outbreak at an academic medical center: Lessons learned. American Journal of Infection Control 2021; 49:1014-1020.
Electronic link: https://www.ajicjournal.org/article/S0196-6553(21)00091-2/fulltext 

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