Growth of Mycobacterium lepraemurium in Cell-Impermeable Diffusion Chambers

Successful growth of Mycobacterium lepraemurium has been achieved by use of a specialized diffusion chamber technique. The cell-impermeable porous chambers were maintained in animals for periods up to 50 days with and without macrophages and LM cells. A generation time of 6 to 8 days was found for the acid-fast bacilli in chambers containing macrophages when maintained in the mouse. Also, cell-free chambers maintained in the mouse gave a generation time of 11 days for M. lepraemurium. There was no doubt that chambers maintained in a susceptible host provided greater yields of bacilli than chambers maintained in a nonsusceptible host such as the guinea pig. In fact, better yields were obtained when the chambers were maintained in monolayer petri plate cultures of mouse peritoneal macrophages than when held in the guinea pig. The most pertinent observation was that living cells are not essential for growth of M. lepraemurium, and the results suggest that multiplication can occur in a cell-free environment within a susceptible host. These studies give evidence that the use of porous chambers has promising possibilities for further investigations on the cultivation of other fastidious mycobacteria.