Researchers in Japan have identified dishwashers as a reservoir for strains of Legionella bacteria that contaminated two tap water sources in a hospital, according to a presentation at ICAAC 2014.

Legionella bacteria were found in the hospital staff areas during an annual water inspection in 2011, leading the investigators to conduct two studies to determine whether contamination was a widespread problem.

They conducted a retrospective descriptive study of 5 years of medical records of patients hospitalized from 2006 to 2011. They also conducted an environmental building inspection to identify other areas of contamination in the water system.

Five of the 17 faucets and seven of the 14 dishwasher connectors were contaminated with Legionella species. None of the contaminated faucetswere from inpatient areas. Isolates from three of the faucets and all of the dishwashers were identified as L. pneumophila SG6. The five contaminated faucets were connected to the same hot water pipelines as the seven dishwashers. The L. pneumophila SG6 strains isolated from the faucets and dishwashers were identified using PCR.