A study of alleged leprosy bacillus strain HI-75

Subcultures of strain HI-75 of Skinsnes leprosy bacillus received in Antwerp and London have been studied bacteriologically and compared. Both contained moderately large acid-fast bacilli readily subcultured and maintained on ordinary mycobacteriologic media. These organisms were found to be a variety of Mycobacterium marianum (syn. serofulaceum) and were considered likely to be a laboratory contaminant. The earlier subculture studied also contained numbers of a much smaller mycobacterium (of a similar size to M. leprae) which appeared to be dead and which did not grow on the ordinary media. Skin tests and immunodiffusion analyses performed with extracts of the earlier subculture failed to demonstrate the presence of the specific antigens of leprosy bacilli. Similar studies on other cultures of Skinsnes bacillus must be performed to confirm or refute its identity as M. leprae.