Viability of M. leprae while undergoing laboratory procedures

Studies were carried out to assess whether various methodological procedures adopted while conducting experiments, or, maintaining M. leprae under different conditions affected the number of organisms made available or their viability. Results of mouse foot-pad experiments showed that bacilli survived for one day at 37 degrees C, 7 days at 20 degrees to 30 degrees C and for 90 days in lyophilized conditions. Repeated daily exposure of the material preserved in refrigerator at +4 degrees C, to room temperatures showed that bacilli survived for only up to five days; whereas, with single exposure they survived up to 14 days. M. leprae were found to lose infectivity after 30 minutes of exposure to various disinfectants and ultra violet light. Centrifugation at high speed did not affect the viability of M. leprae.