Disseminated infection with Mycobacterium genavense: a challenge to physicians and mycobacteriologists

In the present study we compared the clinical presentations of patients wit h a clinical diagnosis of AIDS and disseminated Mycobacterium genavense inf ection (n = 12) with those of patients with AIDS and disseminated M, avium complex (MAC) infection (n = 24). Abdominal pain was seen more frequently i n the group of patients infected with M genavense than in patients infected with MAC (P = 0.003), Analysis of microbiological data revealed that stool specimens from patients infected with M, genavense were more often smear p ositive than stool specimens from patients infected with MAC (P = 0.00002), However, M, genavense could be cultured on solid media from only 15.4% of the stool specimens, whereas MAC could be cultured from 71.4% of the specim ens. Bone marrow and liver biopsy specimens yielded growth of M genavense w ithin a reasonably short time, allowing species identification by DNA techn ology. Microbiological data clearly demonstrated the importance of acidic l iquid medium for primary culture, the avoidance of pretreatment and the use of additives in culture, and the necessity for prolonged incubation if M, genavense is suspected. Susceptibility testing showed that M, genavense is sensitive to rifamycins, fluoroquinolones, and macrolides, whereas it is re sistant to isoniazid, Susceptibility to ethambutol and clofazimine could no t be evaluated. The mean survival times of patients in the two groups were similar.