Nosocomial Legionnaires' disease.

Legionella is being recognized as an increasingly important cause of community-acquired nosocomial pneumonia. Cases of nosocomial pneumonia caused by Legionella particularly occur in hospitals with a water supply colonized with various Legionella species. The recognition of Legionella as a significant nosocomial pathogen depends on the recognition of its association with the aquatic environment of water systems in hospitals. The diagnosis and treatment of legionnaires' disease is discussed, as well as infection control measures needed to prevent the spread of legionnaires' disease in the hospital.