Mycobacteremia in AIDS patients. Results of a prospective study

The importance of blood cultures in diagnosing disseminated mycobacteriosis in AIDS patients was evaluated. Blood samples were screened for mycobacteria by culture and microscopic techniques. Mycobacteremia was proven in 20/136 (14.7%) AIDS patients, the agent being M. avium-M. intracellulare (MAI) in 16 cases and M. tuberculosis in four cases. The rate of cases with positive blood samples in disseminated MAI infection was 59.3% (16/27 cases) and in disseminated tuberculosis 57.1% (4/7 cases). To detect mycobacteria buffy-coat was slightly superior to lysated cell pellets, obtained by a lysis-centrifugation technique. In 4/16 cases with MAI bacteremia, the agent was proven by positive blood smears for acid-fast bacilli only; in these four patients MAI was demonstrated at other body sites. These results illustrate the diagnostic role of blood culture and its use in early diagnosis of disseminated mycobacteriosis, with microscopic examination of blood smears being an important adjunct.