Screening for nosocomial legionellosis by culture of the water supply and targeting of high-risk patients for specialized laboratory testing

Abstract

Pneumonia caused by Legionella is a wellestablished nosocomial infection. The first known nosocomial outbreak occurred in 1965, when 57 cases of nosocomial pneumonia occurred at St. Elizabeth’s Hospital in Washington, D.C.’ The etiologic agent was never identified. Twelve years later, following the discovery of Legionella pneumophila in 1977, antibody assays of stored frozen sera of St. Elizabeth patients established that the outbreak was caused by L. pneumophila. Since that time, numerous outbreaks of nosocomial legionellosis have been reported.2F3 The source of the organism remained a mystery until Tobin et a1.4 isolated the organism from hospital shower heads. Since the discovery that Legionella could colonize water-distribution systems, the water-distribution system has