CHLAMYDIA-PNEUMONIAE PNEUMONIA IN HOSPITALIZED-PATIENTS - CLINICAL CHARACTERISTICS AND DIAGNOSTIC-VALUE OF POLYMERASE CHAIN-REACTION DETECTION IN BAL

Study objective: To evaluate the incidence and clinical characteristic s of Chlamydia pneumoniae infection as detected by polymerase chain re action (PCR) and culture of BAL in hospitalized patients with pneumoni a, HN-infected persons, and control subjects. Design: Prospective, com parative clinical study. Setting: University hospital medical center. Patients: Fifty-seven hospitalized patients with acute lower respirato ry tract infection (group 1); 47 HIV-positive patients (group 2); 100 patients with noninfectious bronchopulmonary disorders (group 3). Inte rventions: BAL was performed in all patients at hospital admission for diagnostic purposes, In addition to semiquantitative bacterial and fu ngal culture, isolation and detection of C pneumoniae were performed b y cell culture and PCR of the lavage fluid. Measurements and results: C pneumoniae was detected in 16% of group 1, 13% of HIV-positive perso ns, and 0% of control subjects. The sensitivity of chlamydial culture was much lower as compared with PCR (4 vs 15 cases). In contrast to gr oup 1, in the HN-positive patients, acute respiratory symptoms were no t always present, and in 3 of 6 cases, copathogens were found in the B AL. BAL differential cell counts disclosed a significant lymphocyte el evation mostly due to the CD8 subset (group 1: 15% vs 5%; group II: 18 .5% vs 4%; C pneumoniae positive vs negative cases, respectively). Con clusions: C pneumoniae is frequently detected in the BAL of hospitaliz ed patients with pneumonia as sole pathogen. PCR detection is highly s pecific and far more sensitive than cell culture. Asymptomatic carriag e seems to be uncommon in immunocompetent patients, but does occur in HIV-positive patients. A lymphocytic alveolitis is frequently found by BAL cytologic study and may represent a T-cell response to chlamydial infection in the lower respiratory tract.