Nosocomial Legionnaires' Disease Caused by Aerosolized Tap Water from Respiratory Devices

Abstract

Five cases of nosocomial Legionnaires'' disease which occurred over a 5-mo. period were retrospectively investigated. Chart review showed that during the 2-10 day incubation period before the onset of illness, all of the patients inhaled aerosolized tap water from jet nebulizers (4 patients) or from a portable room humidifier (1 patient) and all received high dosages of corticosteroids on ACTH. Exposure to both factors was highly significant (P < 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 Cl level was < 0.05 ppm. Thus, Legionnaires'' disease may be caused by contaminated tap water in such devices represents a previously unrecognized hazard to which corticosteroid-treated patients should not be exposed.