Thermoresistance of Mycobacteria

An investigation was made into the thermoresistance of some pathogenic species of mycobacteria in water and in liquid serum medium. A total of 105 strains of 7 species of mycobacteria (Mycobacterium bOfJis, Mycobacterium afJium, Mycobacterium intracellulare, Mycobacterium gordonae, Mycobacterium kansani, Mycobacterium smegmatis, Mycobacterium phlei) were examined using a method of glass capillary tubes. They were exposed to 60C, 65 c, 70C and 75 c for 10, 20 and 40 seconds, 2, 4, 8, 16, 30 and 60 minutes and 2, 4, 6 and 8 hours. The lowest thermoresistance was shown by M. bofJis strains: they were devitalized by exposure to 60C for as few as 16 minutes and by exposure to 70C and 75 c within 10 seconds. The highest thermoresistance was shown by M. phlei strains: they were devitalized by exposure to 75C for 20 seconds.