Growth of Mycobacterium lepraemurium Maintained in Cultures of Rat Fibroblasts

Abstract

Hitherto only limited multiplication of Mycobacterium lepraemurium has been obtained in cell cultures; in cultures of rat fibroblasts (strain 14pf) used by Garbutt, Rees and Barr (1958) growth of bacilli was limited to one or two generations. The present work shows that more continuous intracellular growth of _M. lepraemurium can be achieved in cultures of rat iibroblasts by repeatedly subculturing the infected cells. The results suggest that multiplication of the bacteria is maintained only when a high proportion (50-75%) of the infected cells are transferred at each subculture. In one experiment, continued for 156 days, the increase in the number of bacteria was equivalent to 8 generations and the bacteria recovered from the cells were still infectious for mice. Quantitative electron microscopy also was used to follow the viability of bacteria from the cell cultures.