title: Epidemic Legionnaires' disease two decades later: old sources, new diagnostic methods.
abstract: In July 1995 we investigated a pneumonia outbreak in a Pennsylvania town. We conducted epidemiological and molecular microbiological studies to determine the outbreak source and interrupt transmission of disease. Legionnaires' disease (LD) was quickly identified by urine antigen testing, and a newly developed immunohistochemical stain confirmed nosocomial transmission to a hospital inpatient. LD was confirmed in 22 patients. Case-patients were more likely than controls to have been within 1,000 feet of the hospital (matched odds ratio, 21.0; 95% confidence interval, 2.9-368) during the 2 weeks prior to illness. Legionella pneumophila serogroup 1 (Lp-1) was isolated from hospital cooling towers (CTs) and rooftop air samples but not from hospital potable water or community CTs. Hospital CT and air Lp-1 isolates matched all five patient isolates by monoclonal antibody, arbitrarily primed polymerase chain reaction, and pulsed-field gel electrophoresis subtyping. Strategies to prevent LD must include minimizing transmission from CTs.
authors.affiliation: Epidemic Intelligence Service, Division of Bacterial and Mycotic Diseases, National Center for Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Fiore
authors.forename: J P
authors.initials: JP
authors.lastname: Nuorti
authors.forename: O S
authors.initials: OS
authors.lastname: Levine
authors.forename: A
authors.initials: A
authors.lastname: Marx
authors.forename: A C
authors.initials: AC
authors.lastname: Weltman
authors.forename: S
authors.initials: S
authors.lastname: Yeager
authors.forename: R F
authors.initials: RF
authors.lastname: Benson
authors.forename: J
authors.initials: J
authors.lastname: Pruckler
authors.forename: P H
authors.initials: PH
authors.lastname: Edelstein
authors.forename: P
authors.initials: P
authors.lastname: Greer
authors.forename: S R
authors.initials: SR
authors.lastname: Zaki
authors.forename: B S
authors.initials: BS
authors.lastname: Fields
authors.forename: J C
authors.initials: JC
authors.lastname: Butler
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004196:Disease Outbreaks; D005260:Female; D006272:Health Facility Environment; D006801:Humans; D007877:Legionnaires' Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged