Enumeration of Mycobacterium lepraemurium by the Microspot Method

ABSTRACT Known numbers of Mycobacterium lepraemurium were inoculated into the foot‐pads of 10 mice. Thirty minutes after inoculation, the bacteria were harvested from each mouse and counted by the microspot method. The per cent of the original inoculum recovered ranged from 82.5 to 105.4 among the 10 mice. The difference between the number of bacilli inoculated into a mouse and the number recovered was analyzed statistically. Of the 10 samples, this difference was not significant in 7, and significant in the remaining 3. The facility with which M. lepraemurium can be counted by the microspot method should eliminate much of the laboriousness from experimental leprosy research.