Identification of enterotoxigenic Clostridium perfringens type A in mixed cultures

Three known enterotoxigenic Clostridium perfringens type A strains were mixed in various combinations with three nonenterotoxigenic strains and three lots of animal intestinal contents. They were grown as mixed cultures and tested for the presence of enterotoxin by the fluorescent antibody, reversed passive hemagglutination and immunodiffusion techniques. The fluorescent antibody and reversed passive hemagglutination tests detected enterotoxin in all 16 cultures prepared but the immunodiffusion test failed on two cultures. Attempts to reisolate the enterotoxigenic strains from the mixed cultures was successful in 12 cases when two of five isolated colonies were selected.