Nosocomial Legionnaires' disease.

The first proved outbreak of nosocomial Legionnaires' disease occurred in a psychiatric hospital in Washington D.C. in 1965, but the diagnosis was not established until determination of serum antibodies against Legionella pneumophila by the indirect fluorescent antibody (IFA) test was undertaken, using the bacterial antigen isolated from patients with Legionnaires' disease in the 1976 outbreak in Philadelphia. The second nosocomial outbreak of Legionnaires' disease occurred in three immunocompromised patients who received renal transplantation at the University of Kansas Medical Center and died of extensive lobar pneumonia in 1975. The direct fluorescent antibody (DFA) test revealed L. pneumophila in the lungs of all three patients after the Legionnaires' disease agent was identified. The lack of prospective surveys using sensitive diagnostic procedures by various types has limited our knowledge on the extent of the problem caused by legionella. In fact, nosocomial Legionnaires' disease is a worldwide problem, and control of this disease requires thorough cooperation of physicians, epidemiologists, microbiologists and expert engineers.