Evaluation of two PCR-based procedures for typing Clostridium perfringens.

Two polymerase chain reaction (PCR)-based procedures for typing Clostridium, perfringens, which affects most domestic animals, were compared and evaluated for efficiency as substitute to the guinea-pig intradermal test routinely used in our laboratory, namely a multiplex PCR and a protocol based on the individual amplification of gene sequences specific for each toxin. Reference isolates of C. perfringens types A, B, C and D as well as cultures from clinical specimens were tested. The sensitivity and specificity of the PCR was confirmed on reference isolates. There was similarity in results on 43 of the 46 samples typed by all 3 methods. Clear results were obtained by PCR on 5 clinical samples that showed either equivocal or weak skin reactions in guinea-pigs. The multiplex PCR protocol, in combination with the evaluation of bacterial growth, is a better alternative to in vivo toxin typing, since C. perfringens can only be incriminated as cause of a disease when it is present in large numbers in the intestine.