PREVENTING DISSEMINATED MYCOBACTERIUM-AVIUM COMPLEX DISEASE IN PATIENTS INFECTED WITH HUMAN-IMMUNODEFICIENCY-VIRUS

Disseminated Mycobacterium avium complex (MAC) infection is an importa nt late-stage complication of infection with the human immunodeficienc y virus, Since MAC is widely dispersed in the environment, the source of infection for patients with disseminated MAC generally cannot be de termined, Therefore, specific recommendations for avoiding exposure ar e not supported at this time, Routine screening of stools and sputum t o detect MAC colonization as a means of targeting prophylaxis for diss eminated disease is also not recommended at present, Two randomized, p lacebo-controlled trials have demonstrated that prophylactic use of ri fabutin in persons with low CD4 lymphocyte counts results in a 50% dec rease in MAC bacteremia as well as a reduction in some signs, symptoms , and laboratory abnormalities associated with MAC disease, Thus a pro phylactic daily dose of rifabutin (300 mg) should be considered for ad ults who have had a previous AIDS-defining opportunistic illness and w ho have a CD4 lymphocyte count of <75/mu L. Many experts would conside r prophylaxis appropriate only when the CD4 lymphocyte count is <50/mu L, particularly when there has not been a previous AIDS-defining oppo rtunistic infection, Clinicians should be aware of drug interactions a nd potential adverse effects associated with the use of rifabutin. Pre liminary reports of randomized, placebo-controlled trials suggest that chemoprophylaxis with clarithromycin is also effective in the prevent ion of disseminated MAC disease, and evaluation of other agents is und er way. Prophylaxis for disseminated MAC infection in children has not been evaluated but is presumed to be as effective as that in adults, Decisions regarding initiation of MAC chemoprophylaxis should be indiv idualized.