Toxinotypes of Clostridium perfringens isolated from sick and healthy avian species

Currently, the factors/toxins responsible for Clostridium perfringens-associated avian enteritis are not well understood. To assess whether specific C perfringens' toxinotypes are associated with avian enteritis, the isolates of C perfringens from 31 cases of avian necrotic or ulcerative enteritis submitted between 1997 and 2005 were selected for retrospective analysis using multiplex PCR. C perfringens was isolated from chickens, turkeys, quail, and psittacines. The toxinotypes of isolates from diseased birds were compared against the toxinotype of 19 C perfringens isolates from avian cases with no evidence of clostridial enteritis. All C. perfringens isolates were classified as type A regardless of species or disease history. Although many isolates (from all avian groups) had the gene encoding the C. perfirngens beta2 toxin, only 54% produced the toxin in vitro when measured using Western blot analysis. Surprisingly, a large number of healthy birds (90%) carried CPB2-producing isolates, whereas over half of the cpb2-positive isolates from diseased birds failed to produce CPB2. These data from this investigation do not suggest a causal relationship between beta2 toxin and necrotic enteritis in birds.