OUTBREAK OF CHLAMYDIA-PNEUMONIAE INFECTION IN FORMER INJECTION-DRUG USERS

In a retrospective analysis of lower respiratory tract infections in a n ex-injection-drag users community, we found an outbreak (April to Ju ly 1991) of Chlamydia pneumoniae infection. The epidemic occurred in a group of 26 community members (23 men and 3 women, mean age, 28.9 - 3 years) living and working together, who underwent acute and convalesc ent serologic tests for Mycoplasma pneumoniae, Legionella pneumophila, cytomegalovirus, adenovirus, Coxiella burnetii, and Chlamydia pneumon iae. All subjects were submitted to chest radiograph, while sputum and blood cultures were performed in symptomatic patients. Antibodies to C pneumoniae were determined by a microimmunofluorescence test. Among all subjects studied (13 HIV-1 positive and 13 HIV-1 negative), 11 (8 HIV-positive and 3 HIV-negative) developed pneumonia, 2 (1 HIV-positiv e and 1 HIV-negative) developed pharyngitis, and 2 (1 HIV-positive and 1 HIV-negative) developed flu-like syndromes sustained by C pneumonia e; in 4 subjects (2 HIV-positive and 2 HIV-negative) suffering from fl u-like syndrome, no causal agents were found. Seven subjects (one HIV- positive and six HIV-negative) remained asymptomatic without any evide nce of infection. The prevalence of antibodies to C pneumoniae in HIV- 1-positive e subjects observed in a sample of community members was si gnificantly higher than in HIV-negative subjects. C pneumoniae seems t o be involved in respiratory tract infections in HIV-1-infected subjec ts. Our data suggest that C pneumoniae should be included in the diagn ostic approach of respiratory infections in HIV-infected subjects.