A nosocomial outbreak of Legionella pneumophila caused by contaminated transesophageal echocardiography probes

A case-control study of three cases of Legionella pneumophila pneumonia identified transesophageal echocardiography (TEE) as a risk factor. Patient isolates and environmental strains from water used for rinsing TEE probes were identical by pulsed-field gel electrophoresis. This is the first report of endoscopy as a potential source of legionellosis.