[Acute upper respiratory tract infections associated with Chlamydia pneumoniae]

From March 1990 to January 1991, a total of 46 outpatients with acute upper respiratory infections (URTI) were studied to determine the etiological role of Chlamydia pneumoniae. Sera from 40 patients were tested by micro-IF method for evidence of recent or past infections of this organism, and swab specimens from tonsilar crypt from 26 were cultured. Sera from 20 patients without any evidence of acute infectious disease were selected as controls. The seroprevalence of antibodies to C. pneumoniae was 52.5% in patients group and 30.0% in the control group. No statistical difference was found in seroprevalence between patients and controls. Serological evidence of acute infections with C. pneumoniae was found in 7 (17.5%) patients with acute URTI, but was not found in any of the control group. Of 26 patients, three (11.5%) had C. pneumoniae isolated from a tonsilar crypt swab specimen. Therefore ten of the 46 patients with acute URTI were associated with C. pneumoniae. It is suggested that C. pneumoniae is a common pathogen in acute upper respiratory infections without any evidence of lower respiratory tract symptoms.