Mycobacterium genavense. Autopsy findings in three patients.

The authors report on the pathologic findings in three cases of disseminated infection with Mycobacterium genavense, a recently described nontuberculous mycobacterium, in human immunodeficiency virus (HIV)-I-positive patients. The mycobacterium was identified by amplification of a 16S rDNA gene fragment and subsequent sequence determination. The organs mainly involved were the small intestine, spleen, liver, and lymph nodes. In contrast, lungs, myocardium, and kidneys were not involved, or only minimally involved, in this generalizing disease. Histopathologically, infection with Mycobacterium genavense in HIV-positive patients was mostly characterized by masses of foamy histiocytes and, depending on the immunologic reactivity of the host, by ill-formed granulomas, rarely with small foci of necrosis. The pathologic findings and clinical features were similar to those presented by patients who had generalized infection with Mycobacterium avium-intracellulare complex. To obtain more precise information about the specific course of infection with Mycobacterium genavense, scrupulous microbiologic investigations, including molecular biologic techniques, are necessary in cases with mycobacterial infections.