THE ACTIVITY OF RIFABUTIN AGAINST MYCOBACTERIUM-LEPRAE IN ARMADILLOS

The activity of rifabutin (LM 427) against Mycobacterium leprae was ev aluated in armadillos inoculated earlier with human-derived M. leprae. Rifabutin was administered daily at a dose of 6 mg/kg body weight/day . The effect of rifabutin on M. leprae harvested from armadillos was d etermined by measuring the intracellular levels of ATP (an indicator o f metabolic activity) of M. leprae and also their ability to multiply in the mouse footpads and in vitro in DH medium. Within 2 weeks of ini tiating the treatment, ATP levels declined to 21% of the original (pre -treatment level) and these M. leprae failed to multiply in the footpa ds of mice as well as in the in vitro culture system. This suggests th at rifabutin was able to kill all M. leprae within 2 weeks. After 8 we eks the treatment was terminated and results showed that M. leprae fro m the treated armadillos remained non-viable in the mouse footpad syst em as well as in the in vitro system, indicating bactericidal action o f rifabutin. The results suggest that rifabutin can be a substitute fo r rifampin in the leprosy multi-drug therapy regimen. (C) 1998 Elsevie r Science B.V.