PREVALENCE OF ASYMPTOMATIC NASOPHARYNGEAL CARRIAGE OF CHLAMYDIA-PNEUMONIAE IN SUBJECTIVELY HEALTHY-ADULTS - ASSESSMENT BY POLYMERASE CHAIN REACTION-ENZYME IMMUNOASSAY AND CULTURE

Although Chlamydia pneumoniae is a well-described and common respirato ry tract pathogen, up to 90% of infections with this organism are thou ght to be asymptomatic, Because asymptomatic infection with C. pneumon iae has not been studied in a systematic manner, we conducted a prospe ctive study of healthy adults to establish the prevalence of asymptoma tic infection, Nasopharyngeal swab specimens were obtained from 104 su bjectively healthy people and evaluated by culture and polymerase chai n reaction-enzyme immunoassay (PCR-EIA) for the presence of the organi sm, Serum obtained from 103 of these individuals was tested by microim munofluorescence for the titer of specific antibody to C. pneumoniae, For two individuals, C, pneumoniae was identified in nasopharyngeal sp ecimens by culture and/or PCR-EIA; one of these individuals had an IgG titer of 1:256, whereas the other had no detectable antibody, Of the remaining 101 individuals with negative culture and PCR-EIA results, 1 9 fulfilled presently accepted serological criteria for acute infectio n; i.e., the IgM titer was greater than or equal to 1:16, the IgG tite r was greater than or equal to 1:512, or both, On the basis of our fin dings, we conclude that asymptomatic upper airway infection and carria ge with C, pneumoniae occur among subjectively healthy persons; we als o propose that such individuals may represent a reservoir for this org anism in the community, Further, this study demonstrates that currentl y available diagnostic tests for C. pneumoniae may be unable to accura tely distinguish between infection responsible for respiratory tract d isease and that representing carriage.