SPECIES DISTRIBUTION IN HUMAN IMMUNODEFICIENCY VIRUS-RELATED MYCOBACTERIAL INFECTIONS - IMPLICATIONS FOR SELECTION OF INITIAL TREATMENT

Management of mycobacterial infection is species specific; however, tr eatment is prompted by positive smears or cultures, often several week s before species identification. The objective of this study was to de termine the species distribution of mycobacterial isolates from variou s body sites in patients infected with human immunodeficiency virus (H IV). All mycobacterial isolates recovered at St. Paul's Hospital (Vanc ouver, British Columbia, Canada) from April 1989 to March 1993 were re viewed. Among 357 HIV-positive patients with mycobacterial infections, 64% (96) of the sputum isolates were Mycobacterium avium complex (MAC ), 18% were Mycobacterium tuberculosis, and 17% were Mycobacterium kan sasii. Lymph node involvement (25 patients) was due to either MAC (72% ) or M. tuberculosis (24%). Two hundred ninety-eight episodes of mycob acteremia were due to MAC (98%), M. tuberculosis (1%), and M. kansasii (1%). Similarly, cultures of 84 bone marrow biopsy specimens (99%), 1 9 intestinal biopsy specimens (100%), and 30 stool specimens (97%) yie lded predominantly MAC. These results have implications for initial th erapy, particularly in areas where rapid methods for species identific ation are not readily available. Because of considerable geographic va riation, development of guidelines for selection of initial therapy de pends on regional determination of species distribution in HIV-related mycobacterial infections.