Effects of Propionibacterium acnes treatment on the course of Mycobacterium leprae infection in mice.

Studies were carried out to determine the effects of treatment with killed suspensions of Propionibacterium acnes (formerly designated Corynebacterium parvum) on the course of Mycobacterium leprae infection in mice. Systemic (intravenous or intraperitoneal) treatment with P. acnes failed to significantly alter the growth of M. leprae in the mouse footpad. In contrast, injections of P. acnes directly into the infected footpad markedly inhibited the growth of the leprosy bacilli regardless of whether the local treatments were administered before infection or 3 months after infection with M. leprae. The effects of local treatment with P. acnes appeared to be bactericidal and not merely bacteriostatic. Clearance of the organism from the tissues was not enhanced by P. acnes treatment.