Prophylaxis of mycobacterial infections in immunocompromised patients.

The prophylaxis of tuberculosis is cost-effective in that it prevents hospitalizations and eliminates the need for multidrug treatment of active disease. Isoniazid is recommended for the prophylaxis of tuberculosis in patients with human immunodeficiency virus infection who have a positive tuberculin skin test, who have a history of a positive skin test, who have been in close contact with a person who has active tuberculosis or who are at high risk for tuberculosis because of certain behaviors or situations. Other patients with an altered immune status may also benefit from preventive therapy for tuberculosis. Of the atypical mycobacterial infections, only Mycobacterium avium-intracellulare complex disease (MAC) in AIDS patients has been effectively prevented. Rifabutin is now recommended for adult patients with CD4 counts below 100 per mm3. To prevent the selection of resistant organisms, active tuberculosis must be excluded before prophylactic therapy for tuberculosis or MAC is initiated.