Detection of Clostridium perfringens enterotoxin in stool specimens and culture supernatants by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay was developed to detect and quantitate Clostridium perfringens enterotoxin A in culture supernatants and in stool specimens from cases of diarrhea in which high numbers of enterotoxin-producing Clostridium perfringens were isolated. To analyze for enterotoxin A, polyvinyl chloride microtiter plates were coated with dilute immune whole rabbit serum. Enterotoxin A standards and samples were allowed to react with sensitized wells. The presence of the immobilized antigen in the wells was detected by the binding of immune rabbit immunoglobulin conjugated with peroxidase. Nanograms of enterotoxin were detectable. Four enterotoxin-positive and seven enterotoxin-negative cultures grown in Duncan-Strong medium gave expected results. Eighteen of 23 diarrheal stool specimens obtained after a food-poisoning outbreak at a state hospital were found to contain microgram quantities of enterotoxin per gram of stool, whereas five control diarrheal specimens contained less than 0.6 ng enterotoxin per gram of stool. These results indicate that the enzyme-linked immunosorbent assay technique is useful for differentiating enterotoxigenic strains and for diagnosing diarrhea caused by enterotoxigenic Clostridium perfringens.