Search for agents causing atypical pneumonia in HIV-positive patients by inhibitor-controlled PCR assays

Pneumonia is one of the most frequent complications in acquired immunodefic iency syndrome-patients with Pneumocystis carinii as the leading cause. The true prevalence of atypical agents such as Chlamydia pneumoniae, C, tracho matis, Legionella pneumophila and Mycoplasma pneumoniae in this population of patients is unknown as the currently used method for diagnosing these ag ents is measurement of antibody levels. However, this method is of limited value in human immunodeficiency virus (HIV)-positive patients who may have a compromised antibody response. To evaluate the prevalence of Chlamydia spp,, Legionella spp. and M, pneumo niae in HIV-infected patients with pulmonary disease, this retrospective st udy has applied inhibitor-controlled polymerase chain reaction analyses on 103 bronchoalveolar lavage (BAL) fluids representing 103 episodes of pneumo nia in 83 HIV-positive patients. L, pneumophila was detected in 1% of the BAL fluids and M, pneumoniae was f ound as a coexisting pathogen in 2% of the samples. Chlamydia spp. could no t be detected in any of the BAL fluids. By culture and staining methods 106 other microorganisms were detected with P, carinii and Streptococcus pneum oniae as the most frequently occurring. Pneumonia due to Chlamydia pneumoniae, Legionella pneumophila or Mycoplasma pneumoniae seems to be rare in Danish human immunodeficiency virus-infecte d patients, but might be considered as a possible cause in cases of treatme nt failure.