Biochemical and molecular identification of Clostridium perfringens toxinotypes associated with suspected enterotoxemia in sheep

Abstract

Enterotoxemia caused by Clostridium perfringens toxinotypes is an often fatal disease of sheep in all ages, with a substantial economic loss to the sheep industry. This study was conducted to isolate C. perfringens from suspected cases of enterotoxemia in sheep at central part of Qassim Region, Saudi Arabia; and to determine the prevalent toxinotype by detecting alpha (cpA), beta (cpB) and epsilon (etX) toxin genes; a step might help in the control of the disease locally. A total of 93 samples were collected from sheep suspected to have enterotoxemia (50 rectal swabs from live animals and 43 intestinal contents from recently died animals); in addition to 20 samples from apparently healthy ones (10 rectal swabs from live animals and 10 intestinal content samples from one of the local abattoirs) during the first half of 2020. Samples were subjected to bacteriological examination, biochemical analysis of isolates by VITEK 2, and molecular toxinotyping of isolates by LightCycler® real-time PCR (RT-PCR). A total of 40 C. perfringens-suspected isolates were obtained from samples of the suspected enterotoxemia cases and no isolate was obtained from samples of apparently healthy animals. The results revealed that only 14 isolates were confirmed by VITEK 2 as C. perfringens, with excellent identification, probability bettween 95% and 97%. Toxinotyping showed that all of the isolates possessed both cpA and etX toxin genes, while cpB toxin gene was not detected in any of the isolates. This finding indicated that C. perfringens type D is the only toxinotype found in the central part of Qassim Region at the time of this study. Only 15% (14/93) of suspected cases were confirmed to be due to C. perfringens infection, a result highlighted the importance of clinical and laboratory differential diagnosis of enterotoxemia in sheep.