Bactericidal activities of HMR 3647, moxifloxacin, and rifapentine againstMycobacterium leprae in mice

Bactericidal activities of HMR 3647 (HMR), moxifloxacin (MXFX), and rifapen tine (RPT) against Mycobacterium leprae, measured by the proportional bacte ricidal technique in the mouse footpad system, were compared with those of the established antileprosy drugs clarithromycin (CLARI), ofloxacin (OFLO), and rifampin (RMP). Administered in five daily doses of 100 mg/kg of body weight, HMR appeared slightly more bactericidal than CLARI. In a single dos e, MXFX at 150 mg/kg was more active than the same dose of OFLO and display ed exactly the same level of activity as RMP at 10 mg/kg; the combination M XFX-minocycline (MINO) (MM) was more bactericidal than the combination OFLO -MINO (OM); RPT at 10 mg/kg was more bactericidal than the same dose of RR; IP and even more active than the combination RMP-OFLO-MINO (ROM); the combi nation RPT-MXFX-MINO (PMM) killed 99.9% of viable M. leprae and was slightl y more bactericidal than RPT alone, indicating that the combination PMM sho wed an additive effect against M. leprae.