[Etiology of pneumonia in chilean HIV-infected adult patients].

OBJECTIVES: To establish the etiology of pneumonia and to compare the yield of diagnostic techniques for diagnosis of Pneumocystis jiroveci and Mycobacterium tuberculosis infections in HIV-1-infected patients. PATIENTS AND METHODS: Subjects underwent sputum induction and bronchoalveolar lavage (BAL). Gram, Ziehl-Neelsen, silver stain (SS) and immunofluorescense staining (IF) for P. jiroveci, fluorescent stain for mycobacteria, PCR for P. jiroveci and M. tuberculosis, aerobic, fungal and mycobacterial cultures, respiratory viruses and CMV cultures were performed on the sputum and BAL. IgM for Mycoplasma pneumoniae and Chlamydophyla pneumoniae, and Legionella pneumophila urinary antigen were also obtained.
RESULTS: Sixty patients were included. An etiologic diagnosis was made in 97%. Pneumocystis jiroveci was the most frequent etiology (58%) followed by Streptococcus pneumoniae (12%), and Mycobacterium avium complex (12%). Mycobacterium tuberculosis was found in 5%.
CONCLUSIONS: The comparison of diagnostic methods for P. jiroveci showed a higher sensitivity of IF and SS in BAL than in sputum, however PCR was equally sensitive in both samples. With this approach a precise etiologic diagnosis was reached in the great majority of patients. The most common etiology was P. jiroveci. IF in BAL remains the gold standard for diagnosis of P. jiroveci pneumonia.