Diagnosis of Legionnaires' Disease from Transtracheal Aspirate by Direct Fluorescent-Antibody Staining and Isolation of the Bacterium

Abstract

LEGIONNAIRES' disease, an acute infection caused by a newly described gram-negative bacterium, is most commonly recognized as severe pneumonia associated with a high mortality rate.1 Diagnosis is difficult during the acute illness because clinical findings are similar to those of other atypical pneumonias,2 the organism is difficult to isolate and serum antibody titers may not be diagnostic until after the third week of illness.3 Furthermore, the indirect fluorescent-antibody test, which is the standard serologic method for diagnosis, has shown lack of specificity. Fourfold rises in antibody titers against the agent of Legionnaires' disease have been found in cases of plague, . . .