Growth Curves and Generation Times of Four Strains of Mycobacterium lepraemurium in the Foot-pad of the dd and C₃H Strains of Mice

Abstract

Comparisons of growth curves and generation times of four strains of M, lepraemurium, Kurume No. 42, Hawaii, Kumamoto and Fukuoka No. 1, inoculated into the foot-pads of the dd and C₃H strains of mice were made, and the results obtained were as follows; one step growth curve was observed in the foot-pad of the dd mouse in the case of all strains of M. lepraemurium tested. On the other hand, in the case of the C₃H mouse, one step growth curve of Kumamoto and Hawaiian strains, and the two-step growth curve of Kurume No. 42 and Fukuoka No. 1 strains were observed.
The Kurume No. 42 and Fukuoka No. 1 strains had approximately 4 days' generation time. The Hawaiian strain and Kumamoto strain had 6-8 days and 4 days, respectively, when the bacilli were inoculated into the foot-pad of the dd mouse. When the bacilli of Hawaiian strain and Kumamoto strain were inoculated into the C₃H mouse foot-pad, the generation time of the former was approximately 4 days and that of the latter was 10 days. In conclusion, there might be two types of M. lepraemurium; the one would be the M. lepraemurium whose growth should be modified by the strain of mice employed, and the other would have a characteristic growth rate which should not be influenced by the type of mice used.