Disseminated mycobacterium avium complex infections in South African patients with AIDS.

Abstract

Disseminated Mycobacterium avium complex (MAC) is the most common systemic bacterial infection in patients with acquired immunodeficiency syndrome (AIDS) in developed countries; however, it is reported to be uncommon in Africa. The role of a prior history of tuberculous disease, and the presence of a bacille Calmette-Guerin (BCG) scar, in preventing disseminated MAC is controversial.The aims of the study were to determine the prevalence and clinical features of disseminated MAC in black South African patients with AIDS, and to investigate its interrelationship with Mycobacterium tuberculosis (MTB). All patients diagnosed with disseminated MAC at Chris Hani Baragwanath Hospital from 1997 to 1998 were evaluated retrospectively. Further, one hundred HTV positive black South African patients with CD4 counts of less than 100 cells/mm3 admitted to hospital were subjected to routine Bactec radiometric blood cultures and prospectively followed up. The study showed that the prevalence of disseminated MAC in black South African patients with AIDS is 10%, a prevalence similar to that in developed countries. Furthermore, a prior history of tuberculous disease or the presence of a BCG scar were found not to be protective o f disseminated MAC. The clinical and laboratory manifestations were largely unhelpful in diagnosing the condition.Mycobacteria were cultured from Bactec blood cultures in 29 of the 100 cases. Ten patients in total were diagnosed with disseminated MAC, and 58 with MTB. Of the patients with mycobacterial disease, sputum analysis alone detected disease in 53% of cases, and Bactec blood culture in 45% of cases. Tne two investigations used in combination made the diagnosis in 86% of cases, making this an efficient, cost effective and simple strategy.