These organisms occur worldwide, and have been isolated from soil, water, animals, birds and foods. Unlike Mycobacterium tuberculosis , DMAC results from primary infection with the organism, not reactivation. While MAC colonization occurs in many patients, disseminated disease occurs late in HIV disease, contributing to general disability, cachexia and death. Fever may also be cyclical, normal during day.
Alkaline phosphatase is elevated in about one-third of patients.
Patients with Mycobacterium avium cultured from sputum, bronchial wash or stool may only be colonized and should have a blood isolator tube drawn for AFB culture to determine if dissemination has occurred. Order serum alkaline phosphatase, hematocrit and hemoglobin, if not done recently. Positive biopsy specimens will show acid-fast organisms and a weak inflammatory response. Azithromycin and clarithromycin have the advantage of providing some protection against bacterial infections an toxoplasmosis. Additionally, some protease inhibitors are contraindicated with rifabutin, and indinavir requires dosage adjustments.