A retrospective bacteriological study of mycobacterial infections in patients with acquired immune deficiency syndrome (AIDS).

The main species of mycobacteria isolated in 51 patients with acquired immune deficiency syndrome (AIDS) admitted to the Clinical Hospital of UNICAMP (Teaching Hospital) in 1996, were studied retrospectively by recording the isolation site and signs of pathogenesis. Of these isolates, 31 (55%) were M.tuberculosis and 20 (45%) M.avium complex. Strains of M.tuberculosis isolated in 1996, 1997, and 1998, originating from 42 patients who had AIDS, were tested for susceptibility to isoniazid and rifampicin. Of these, 34 (81%) were susceptible to both drugs tested, 4 (10%) were resistant to isoniazid and susceptible to rifampicin, 2 (5%) were susceptible to isoniazid and resistant to rifampicin, and 2 (5%) were resistant to both rifampicin and isoniazid. We conclude that, in Brazil, M. avium complex infections in AIDS are more common than has been previously suggested; i.e., almost as frequent as M.tuberculosis infections. Approximately 20% of M.tuberculosis strains showed resistance to rifampicin and/or isoniazid. Further distribution of information regarding how to treat the disease in AIDS patients is needed.