DISSEMINATED MYCOBACTERIUM-AVIUM COMPLEX - CORRELATION BETWEEN BLOOD AND TISSUE BURDEN

To determine the relationship between levels of Mycobacterium avium co mplex (MAC) in blood and tissues, histopathologic examination and quan titative MAC cultures were done on blood samples and tissue samples of 7 organs at autopsy of 10 AIDS patients who had been treated for MAC bacteremia, Blood and tissue cultures were negative for MAC for 3 of t he patients and positive for 7. The numbers of MAC colony-forming unit s in the blood and tissues were highly correlated, The highest concent rations of MAC were observed in the reticuloendothelial organs, with a maximum of 6.9 log(10) cfu/g in mesenteric lymph nodes and 6.8 log(10 ) cfu/g in spleen. Histopathologic findings paralleled quantitative cu ltures and were consistent with entry of MAC via lymphatics through th e gastrointestinal tract, followed by hematogenous dissemination.