Multiple serovars of Mycobacterium avium complex in patients with AIDS.

Mycobacterium avium complex (MAC) was isolated and serotyped from 127 samples from 43 HIV-infected patients with disseminated disease in Sweden. Thirteen different serovars were observed. Serovar 6 was the most common, followed by 4, 9 and 11. Serovar 8 was rare. In 22 of the patients the same serovar was found in blood and at other sites. Clinical symptoms and outcome were compared in patients with different serovars. Analysis of patient records revealed no association between clinical picture and any specific serovar. The median survival time after MAC infection was 7 months. Somewhat shorter survival was observed in patients with serovar 4 than in those with serovar 6.