Epidemic Legionnaires' disease two decades later: old sources, new diagnostic methods.
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.
Fiore
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AE
Epidemic Intelligence Service, Division of Bacterial and Mycotic Diseases, National Center for Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Nuorti
J P
JP
Levine
O S
OS
Marx
A
A
Weltman
A C
AC
Yeager
S
S
Benson
R F
RF
Pruckler
J
J
Edelstein
P H
PH
Greer
P
P
Zaki
S R
SR
Fields
B S
BS
Butler
J C
JC
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