Infrequency of pulmonary microbial colonisation prior to respiratory disease in HIV-infected individuals

To determine whether organisms are present in the HIV-infected lung prior t o clinical respiratory disease, a cross-sectional bronchoscopic comparative analysis of 39 asymptomatic HIV-positive subjects and 31 healthy controls with 2-year prospective bronchoscopic monitoring of the HIV study group was performed. Pathological examination of bronchoalveolar lavage (BAL) fluid using standard microbiological techniques was undertaken. Organisms were re covered from similar numbers of HIV-positive and control subjects (7 of 39 and 3 of 31) and comprised predominantly scanty growths of bacteria. Five s ubjects developed respiratory disease during follow-up. Repeat BAL was perf ormed in 11 asymptomatic HIV-positive patients; no relationship was found b etween the organisms isolated at the two procedures. The findings suggest t hat the asymptomatic HIV-positive lung is not a frequent site of either mic robial colonisation or subclinical infection. This has implications for the understanding of the pathogenesis of HIV-related pulmonary disease.