Effect of lysozyme on Mycobacterium leprae

Because large amounts of lysozyme are present in phagocytes, it was selected, as one of the bactericidal substances, to study the in vitro effects on M. leprae. The results obtained led the author to conclude that M. leprae is not susceptible to lysozyme as many other atypical as well as attenuated pathogenic mycobacteria. This resistance of M. leprae to lysozyme was seen up to a level of 100-500 micrograms per ml, while levels of 1000 micrograms and more had very significant effect; the ATP content of such treated M. leprae declined to 30% of the original levels in 5 days of incubation at 37 degrees C, with optimum pH of 6.0, and these M. leprae after such exposure to lysozyme failed to multiply in the foot pads of mice. The interpretation of these results, though not definitive, have been discussed.