Elongation of a Leprosy Bacillus (Mycobacterium lepraemurium) in a Cell-free Medium

Abstract

THE bacillus of human leprosy (Mycobacterium leprae) was one of the first bacteria to be identified as the causative organism of a disease; but it remains to this day among the very few that have failed to grow in any type of culture medium. There is indeed doubt as to whether it has ever even been transmitted to an experimental animal. Much of the laboratory work on leprosy has therefore been concerned with the only other closely related organism, the rat leprosy bacillus (Mycobacterium lepraemurium), which infects rats and mice, causing disease having many of the characteristics of human leprosy; in common with M. leprae it is unusually slow-growing in the body, with at least 10 days elapsing between each generation.