In late 2016 a female resident at a residential psychiatric facility, was diagnosed with Legionella pneumophila serogroup 1. The diagnosis was based on a positive urine antigen test result and symptoms were consistent with legionnaire’s disease. No sputum sample was collected. Legionella is a bacteria that is common in water systems and can cause Legionnaires’ disease and Pontiac fever when susceptible individuals inhale contaminated aerosolized water droplets. Legionella diagnoses have been increasing nationally and in Washington State. The Washington State Department of Health visited the facility on December 16, 2016 to conduct an investigation. Prior to the visit investigators learned that the hospital’s water system was supplied by two private, untreated wells. The facility has a connection to treated city water that they used to flush the campus water system approximately five weeks before the case was diagnosed.
METHODS:
Healthcare acquired Legionnaires’ disease investigations are highly interdisciplinary requiring expertise in epidemiology, environmental health, laboratory science, and facilities management. Communicable disease epidemiologists conducted a chart review and found that the patient had not left the ward during the entire exposure period. Based on the chart review environmental health staff sampled the recirculating on demand hot water interchangers that supplied the building, the shower that the patient used, and the cold water from the sink in the patient’s room following CDC’s legionella water sampling guidelines.
RESULTS:
Legionella pneumophila serotypes 2-15 was found in both water interchangers and in the bulk water sample of the shower used by the patient, but not in the swabs or cold water samples. Due to the patient’s limited mobility and absence of other potential exposure sources, it is highly likely that the patient was exposed to Legionella bacteria in the shower, however, because there was no sputum sample we will never know for certain.
CONCLUSIONS:
The patient had very little mobility and the facility had very few potential exposure sources which greatly reduced the complexity of the environmental investigation. In an abundance of caution we advised the hospital to stop showering patients in that building and switch to bottled water for patients and staff until the water system was cleared for use. We also recommended that the facility hire a consultant to assist them in an immediate heat flush and other long term legionella controls that included a legionella management plan following CDC’s guidance.