Disseminated "Mycobacterium genavense" infection in patients with AIDS

We describe 18 patients with advanced HIV infection, most of whom had a chronic illness characterised by fever, diarrhoea, and massive loss of weight. Biopsy and necropsy samples revealed abundant acid-fast microorganisms in intestines, liver, spleen, lymph nodes, and many other tissues, which did not grow on solid media, although limited growth was observed in liquid blood cultures. Using primers complementary to bacterial 16S rRNA we amplified DNA sequences from tissue and leucocyte extracts and from blood-culture bottles. The sequences obtained were unique and suggest that the microorganism is a new member of the genus Mycobacterium, for which we propose the name "Mycobacterium genavense". Disseminated infection with "M genavense" should be considered in the differential diagnosis of HIV-infected patients with extreme immunosuppression, wasting, and fever.