PCR identification of the plasmid-borne enterotoxin gene (cpe) in Clostridium perfringens strains isolated from food poisoning outbreaks.

It is generally accepted that Clostridium perfringens strains associated with food poisoning carry their enterotoxin gene, cpe, on the chromosome, while C. perfringens strains isolated from non-food-borne diseases, such as antibiotic-associated diarrhea and sporadic diarrhea, carry cpe on the plasmid. However, we recently encountered a food poisoning outbreak caused by C. perfringens bearing a plasmid cpe. We therefore investigated a total of 31 clinical and non-clinical C. perfringens strains to locate the cpe gene by PCR. The cpe of nine heat-sensitive (100 degrees C for 10min) strains isolated from three outbreaks of food poisoning were located on the plasmid, while those of six heat-resistant strains from other food poisoning outbreaks were located on the chromosome. Moreover, the cpe of 5 heat-sensitive strains isolated from healthy human feces and those of 11 heat-sensitive soil strains were also located on the plasmid. These findings indicate that heat-sensitive, cpe-plasmid-borne C. perfringens strains should not be disregarded as causative agents of food poisoning.