TREATMENT OF DISSEMINATED MYCOBACTERIUM GENAVENSE INFECTION IN A MURINE MODEL WITH CIPROFLOXACIN, AMIKACIN, ETHAMBUTOL, CLARITHROMYCIN AND RIFABUTIN

Mycobacterium genavense is a recently described agent which can induce disseminated infections in patients with AIDS. Up to now, no standard approach to treatment has been defined and patients have been treated empirically with antibiotics used for treating infections caused by o ther nontuberculous mycobacteria. In this study, we compared the effec tiveness of ciprofloxacin, amikacin, ethambutol, clarithromycin and ri fabutin in the treatment of an animal model of M. genavense infection in C57BL/6 mice. Antimycobacterial treatment was started 4 weeks after an intravenous bacterial challenge and was continued for 30 days. Tre ated and control mice were killed at days 15 and 30 of treatment and t he number of viable bacteria in their spleens was counted. Treatment w ith clarithromycin (50 mg/kg/day sc) and rifabutin (20 mg/kg/day po) w as found to decrease the bacterial counts in the spleens significantly as early as 15 days after the onset of treatment (P < 0.01). The effe ct of treatment was more pronounced after 30 days of treatment (P < 0. 001). Amikacin (25 mg/kg/day sc) and ethambutol (50 mg/kg/day sc) were found to decrease significantly the cfu in the spleens only after 30 days of treatment (P < 0.01). Ciprofloxacin (25 mg/kg/day sc) was inef fective in the experimental conditions used here.