The incidence of Chlamydia pneumoniae in community-acquired pneumonia in children was studied prospectively in 112 children aged 1 mo to 14 y. Diagnosis of C. pneumoniae was performed by polymerase chain reaction (PCR) on nasopharyngeal aspirates and serology by the microimmunofluorescence test on a single serum specimen. Three (2.7%) cases of pneumonia due to this agent were diagnosed by both PCR and serology. C. pneumoniae was not found in any of 62 children below 5 y of age. In the age group 5-8 y, only 1/30 (3%) was found positive, and in the age group 9-14 y, C. pneumoniae was diagnosed in 2/20 (10%) children.
Conclusion: Although the number of enrolled patients is small, and the diagnostic techniques used may have some limitations, the results of this study suggest that C. pneumoniae.plays a minor role in the aetiology of pneumonia in children less than 9 y of age in our country. However, it should be considered as a potential agent in pneumonia in older children.