Acid-alcohol fast bacilli in sputa of HIV-infected patients

We identified 34 HIV-infected patients with sputum smear positive for acid-alcohol fast bacilli (AAFB) to determine any factors predictive of subsequent species identification. There were 20 cases of Mycobacterium tuberculosis (MTB), 9 cases of Mycobacterium avium-intracellulare (MAI), 3 cases of Mycobacterium kansasii and one each of Mycobacterium malmoense and Mycobacterium fortuitum. Factors associated with isolation of MAI were lower CD4 cell count, a higher incidence of previous AIDS diagnosis, a history of dyspnoea and a normal chest X-ray. The organism was isolated from blood cultures in 58% of patients with MTB and 78% of patients with MAI infection. Disseminated disease was diagnosed in 45% of MTB patients and 33% of MAI patients.