Mycobacterial diseases and the compromised host.

Tuberculosis due to Mycobacterium tuberculosis and other mycobacteria should be considered in the diagnostic approach to febrile immunocompromised patients. In patients with AIDS, organisms of the Mycobacterium avium complex (MAC) are the most common bacterial causes of disseminated infection. Effective means of both treating and preventing disseminated MAC infections have been developed that use regimens including the new macrolides, aminoglycosides, and rifamycins. Antimicrobial agents active against M. tuberculosis are not usually active against MAC organisms, and the converse may also be true. With the advent of more cases of drug-resistant tuberculosis, however, the urgency regarding development of new therapeutic approaches for tuberculosis is widely appreciated. Research into the pathogenesis and treatment of infections due to M. tuberculosis and MAC, which has been much neglected, is likely to provide new knowledge that will benefit the clinical approach to all mycobacterial diseases.