The infection hazard of contaminated nebulizers.

Ineffectual disinfection of inhalation equipment between therapy sessions of different patients has been reported to produce serious outbreaks of infection. The role of properly disinfected equipment that becomes colonized during use was assessed. In the Vancouver General Hospital gram-negative bacilli in the nebulizer water were demonstrated in 10.5% of nebulizers being used for periods of 24 to 72 hours. In at least 15% of patients exposed to contaminated nebulizers the organism was recovered from the respiratory tract 48 hours after removal of the equipment. Only one out of 85 patients exposed to contaminated nebulizers developed pneumonia, and in this instance a clear history of aspiration of vomitus was present. The low incidence of pneumonia may be related to the high percentage of nebulizers contaminated by organisms of low virulence and might be much greater in hospitals where more highly pathogenic organisms are commonly found as nebulizer contaminants. Fifteen patients with pneumonia prior to exposure to a contaminated nebulizer failed to show any evidence of superinfection.