Heat resistance and alpha-toxigenicity of Clostridium perfringens strains in normal intestines of Japanese.

Heat-resistant strains of Clostridium perfringens were isolated from normal feces samples of Japanese people more frequently than from European people. However, the predominant number of the C. perfringens cells in the human intestines were sensitive to the heat at 100 C for 10 min. This proved to be true of the feces samples which were demonstrated to carry the organism resistant to 100 C for 60 min. Further studies indicated that the more the number of the organism in the intestines, the higher was the recovery ratio of the heat-resistant strains. Concomitant estimation for α-toxigenicity of those strains isolated from unheated feces samples revealed that the α-toxigenicity ranged mainly between 0.05 and 0.9 α-antitoxin equivalents.