A pair of semisolid media facilitate detection of spore and enterotoxin of Clostridium perfringens

Abstract We devised a pair of sporulation media, peptone-bile-theophylline (PBT) and peptone-bile-theophylline-strach (PBTS), for Clostridium perfringens and 33 out of 36 strains tested sporulated to a level making direct microscopic observation feasible. Of 33 spore-positive strains, 16 sporulated well, i.e., percentage of sporulation of most strains was several percent or more, in both sporulation media, but nine sporulated well only in the PBTS, while conversely, eight sporulated only in the PBT medium. Of 33 sporepositive strains, 20 produced a higher amount of enterotoxin, i.e., 512 ng/ml or more, in media which caused good sporulation. However, the amount of enterotoxin in cultures of 13 spore-positive and three non-sporulating strains was 32 ng/ml or less. In Duncan and Strong medium, which has been used widely for detection of spore enterotoxin of C. perfringens , only eight strains sporulated to the level detectable by direct microscopic counts. We conclude that use of PBT and PBTS media will produce more satisfactory results when attempting to determine the causative organism o f clinical food poisoning.