Isolation of Chlamydia pneumoniae and Antibodies to the Agent in Patients with Acute Bronchitis

Isolation of Chlamydia pneumoniae and serologic tests were performed on 85 children and adults patients with acute bronchitis admitted to the Kitasato Institute Hospital from January 1989 to May 1991. C. pneumoniae was isolated from sputa or tonsillar swabs in 11 of 57 (19%) patients examined. Of these, 10 patients were tested serologically and 9 (90%) had 16 or higher titer of IgG antibody. A total of 68 patients were tested serologically, and 17 (25%) revealed positive; 14 had a fourfold rise or more in the titer of IgG antibody, or IgM titer of 16 or more, and 3 had IgG antibody with a titer of 512 or greater. In 34 patients, sera were tested for evidence of acute infections not only with C. pneumoniae, but also with Mycoplasma pneumoniae, influenza A virus, influenza B virus, adenovirus, respiratory syncytial virus, coxackie A9 virus, parainfluenza virus type I, II, and III. Two of the 34 patients were associated with influenza A virus, 4 with influenza B virus, whereas 6 were associated with C. pneumoniae. The data available suggest that C. pneumoniae cause bronchitis much more than has been suspected, and also confirm earlier suggestions that the agent played an important role in respiratory tract infections. Chlamydia trachomatis was recovered from sputa and tonsillar swabs in 6 adults patients with acute bronchitis. Studies are needed for a better understanding of the epidemiology and clinical relevance of this microorganism to lower respiratory tract diseases in adults.