An in vitro culture method for screening new drugs against Mycobacterium leprae.

An in vitro culture system has been devised for the maintenance and growth of M. leprae in a cell-free medium. Cells from four-week old cultures could be transferred to fresh medium and normal growth was observed in subcultures. Using this system, the M.I.Cs of dapsone and rifampicin were determined. Dapsone at 25 ng/ml and rifampicin at 300 ng/ml completely inhibited the growth of host-grown as well as in vitro-adapted M. leprae. It was further shown that the effects of both the drugs were bactericidal; this observation was subsequently confirmed using mouse foot-pad technique.