The Treatment of Mycobacterium Avium-Intracellulare Complex Disease

Abstract

Unlike the isolation of Mycobacterium tuberculosis from sputum in man, the finding of M. avium-intracellulare from the same source creates a clinical dilemma. This organism (actually a complex of organisms that are closely related morphologically, serologically, and biochemically) is found commonly in man's environment but seldom as a cause of disease. Infection without disease must be frequent, since delayed hypersensitivity reactions to purified protein derivatives of this complex occur with a high incidence in areas in which the organisms predominate. Colonization of the respiratory tract undoubtedly occurs. Factors such as rate of infection or colonization and incidence of disease remain speculative. It is certain, however, that disease does occur. It presents with a wide spectrum of clinical characteristics from the nonprogressive, asymptomatic to the acute, disseminated, often fatal form. In general, the organism is considered less virulent and the disease more likely asymptomatic and more slowly progressive than that of tuberculosis. It should be remembered, however, that tuberculosis also has a broad clinical spectrum, and our knowledge of the complex inter-relationships of organism and host is limited, particularly for M. avium-intracellulare. It is easier to be complacent about this disease, since the ogre of contagiousness does not compel our attention as it does with tuberculosis. Unfortunately, this attitude is further enhanced by uncertain expectations of treatment. However, the majority of patients with disease are responsive to currently available therapy. DIAGNOSTIC CONSIDERATIONS