[Importance of Chlamydia pneumoniae as a new respiratory pathogen].

The incidence of Chlamydia pneumoniae as a cause of respiratory tract infection was evaluated in a one-year prospective study in 142 patients with community-acquired pneumonia. An indirect immunofluorescence method which detects antibodies in acute and convalescent serum samples was used. Serological evidence of current infection was a four-fold rise in IgG antibody titer or a positive IgM fraction. C. pneumoniae was the causative pathogen in nine patients. This result is similar to those obtained in other studies and suggests that C. pneumoniae is a common etiological agent of community-acquired pneumonia in the studied area.