Five cases of nosocomial Legionnaires' disease which occurred over a five-month period were retrospectively investigated. Chart review showed that during the two- to 10-day incubation period before the onset of illness, all of the patients inhaled aerosolized tap water from jet nebulizers (four patients) or from a portable room humidifier (one patient), and all received high dosages of corticosteroids or adrenocorticotropic hormone. Exposure to both factors was highly significant (P less than 0.000001) when compared with the rate of exposure in 69 control patients. Environmental cultures yielded Legionella pneumophila from tap water and from reservoirs of tap water-filled respiratory devices. The yield was highest from hot tap water, in which the free chlorine level was less than 0.05 parts per million. Thus, Legionnaires' disease may be caused by contaminated aerosols from respiratory devices, and the use of contaminated tap water in such devices represents a previously unrecognized hazard to which corticosteroid-treated patients should not be exposed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.