Serological, clinical and radiological findings in adults with bronchopulmonary infections caused by Chlamydia trachomatis.

We report here four cases of lower respiratory tract infection caused by Chlamydia trachomatis. Three of them had clinical and radiological findings of atypical pneumonia, while one presented with an acute exacerbation of chronic obstructive pulmonary disease (COPD). None of the patients had signs of ocular or genitourinary infections. All patients had specific IgM, IgA and IgG antibodies for C. trachomatis during the acute infection, and were seronegative for C. psittaci. No specific clinical or radiological patterns were found. Two of the patients with pneumonia were laboratory workers who were exposed to the L2 (434 bu) serovar of C. trachomatis. They had a striking seroconversion and were followed up serologically for up to 30 weeks after onset of illness.