Symposium on microbiology update: old friends and new enemies. Clostridium perfringens.

In the United States and Canada, Clostridium perfringens remains a leading cause of bacterial food poisoning in humans. It has been primarily associated with meat and poultry products prepared in food service establishments. Fecal spore levels of 10(6) or more per g are considered indicative of a food poisoning outbreak. However, elevated spore levels of this organism are frequently seen in healthy elderly individuals, an observation that complicates investigations of suspected outbreaks. Recent studies with this population indicate that fecal enterotoxin levels are a valuable and effective assay for confirming outbreaks due to this organism. With regard to the toxin itself, a membrane protein of 50 000-70,000 molecular weight has been isolated as a possible enterotoxin-receptor site. It is the subsequent action of the toxin on membrane structure that results in the loss of ions and fluid associated with illness. In addition, the enterotoxin gene has been cloned in E. coli and sequenced. Using toxin-specific DNA probes, only 6% of non-symptomatic farm animals were found to possess the enterotoxin gene, disproving the hypothesis that all strains of this organism can produce the toxin.