Clostridium perfringens toxin types from wild-caught Atlantic cod (Gadus morhua L.), determined by PCR and ELISA

Ninety-five fecal samples from Atlantic cod (Gadus morhua L.), caught along the northern Norwegian coast, were examined bacteriologically for occurrence of C. perfringens. Isolates were examined by polymerase chain reaction (PCR) for genes encoding the four lethal toxins (alpha, beta, epsilon, and iota) for classification into toxin types and for genes encoding enterotoxin and the novel beta2 toxin for further subclassification. In addition, a commercial enzyme-linked immunosorbent assay (ELISA) kit for detection of C. perfringens alpha, beta, and epsilon toxin was used. Clostridium perfringens could be isolated in 37 fecal samples (38.9%) from cod. All isolates were C. perfringens toxin type A (alpha toxin positive) as determined by PCR and also ELISA. In addition, in isolates from two cod (2.1%) the gene encoding for beta2 toxin was found (A, beta2) by PCR. Genes encoding for beta, epsilon, and iota toxins and enterotoxin were not found. This is the first detection of C. perfringens alpha and beta2 toxin in cod and of beta2 toxin in fish in general. The origin of this bacterium in cod is discussed.