DIAGNOSIS OF CHLAMYDIA-PNEUMONIAE INFECTION IN PATIENTS WITH COMMUNITY-ACQUIRED PNEUMONIA BY POLYMERASE CHAIN-REACTION ENZYME-IMMUNOASSAY

We conducted a prospective study of 385 patients who had community-acq uired pneumonia with use of a modified polymerase chain reaction (PCR) assay that detects amplified DNA by enzyme immunoassay (EIA). We used PCR-EIA to improve detection of Chlamydia pneumoniae infection and to differentiate C. pneumoniae infection from other chlamydial infection s. Cultures of throat swab specimens from four patients yielded Chlamy dia species (C. pneumoniae, one patient; Chlamydia species, two patien ts; and C. psittaci, one patient). C. pneumoniae was repeatedly detect ed by PCR-EIA for thirteen (3.4%) of these 385 patients. Six of these 13 patients were infected with the human immunodeficiency virus. Ten ( 76.9%) of the patients who were positive by PCR-EIA had IgG titers of greater than or equal to 1:16, and two (15.4%) of the 13 patients had Ige titers of <1:16; no sera was available in one case. Other pathogen s were recovered in eight (61.5%) of the 13 cases in which C. pneumoni ae was detected by PCR-EIA. In addition, for 46 (11.9%) of the 385 pat ients the titers of antibody were considered diagnostic of C. pneumoni ae infection; however, as 36 of the 46 patients were infected with the human immunodeficiency virus (which may have affected their serologic al response to C. pneumoniae), interpretation of these titers was prob lematic. As PCR-EIA was more sensitive than was culture for detecting C. pneumoniae infection in this study, this method may be a valuable t ool for the prompt diagnosis of this infection.