Toxinotyping of Clostridium perfringens Strains Recovered from U.S. Turkeys with Necrotic Enteritis

Necrotic enteritis (NE) is a serious disease of chickens and turkeys that causes significant economic losses to the poultry industry. On the basis of studies in chickens, Clostridium perfringens type G is considered by many to be the cause of NE in poultry. However, studies on isolates from Finnish and Italian turkeys with NE revealed that the vast majority were C. perfringens type A, and very few were C. perfringens type G. We therefore examined 74 C. perfringens isolates from U.S. turkeys with NE; 98% were type A and only 1% was type G. This result confirms that different C. perfringens types are involved in NE in turkeys when compared with chickens. We also examined the turkey isolates for other toxin genes associated with enteritis in various animal species, namely tpeL, cpb2, cpe, netE, netF, and netG. The tpeL gene, which has been associated with enhanced virulence of C. perfringens in chickens, was only found in 1% of turkey NE isolates. The cpe gene, which encodes C. perfringens enterotoxin (a major cause of food poisoning and non-foodborne C. perfringens-mediated diarrhea in humans) was also found in only 1% of our turkey NE isolates. Although cpb2, which encodes for the beta2 toxin, was found in 73% of our NE isolates, it has also been found in similar percentages of isolates from turkeys with normal intestine. The netE, netF, and netG genes were not detected among our C. perfringens isolates from turkeys.