Therapeutic Activity of Bacitracin in Rabbit Syphilis, and Its Synergistic Action with Penicillin.

Abstract

Bacitracin is effective in the treatment of rabbit syphilis. An intramus. dose of 2,300 U./kg. repeated once daily for 4 days cured approx. 1/2 the animals tested. A striking synergism was noted in the therapeutic effect of penicillin and bacitracin. As little as 1 mg./kg. of penicillin (approx. l/40th of the CD50 dosage of penicillin alone) and 1,280 U./kg of bacitracin (approx. l/7th of the CD50 value) were curative if used in conjunction.