Incidence of community-acquired pneumonia caused by Chlamydia pneumoniae in Italian patients.

The incidence of Chlamydia pneumoniae as a cause of community-acquired pneumonia was evaluated in a one-year prospective study in 108 patients with community-acquired pneumonia. The bacteriological diagnosis was based on culture of sputum or bronchial aspirate and examination of acute and convalescent phase sera for Mycoplasma pneumoniae, Legionella pneumophila and Chlamydia pneumoniae. A definitive microbiological diagnosis was obtained in 58 (54%) patients. Chlamydia pneumoniae was the causative agent in 14 patients (13%) on the basis of positive serological tests; in 10 of the 14 patients Chlamydia pneumoniae was also detected by means of an indirect immunofluorescence test using pharyngeal swab specimens. In conclusion, Chlamydia pneumoniae seems to be a common etiological agent of community-acquired pneumonia, as increasingly reported in the last six to seven years.