The epidemiology of Clostridium perfringens type A on Ontario swine farms, with special reference to cpb2-positive isolates

In mixed multivariable linear analysis, log10C. perfringens in fecal samples from suckling pigs were higher than that of weanling pigs, grower-finisher pigs, and manure pit samples (P <0.05). In mixed multivariable logistic analysis, the C. perfringens isolates recovered from lactating sows (OR？=？0.069, P <0.001), gestating sows (OR？=？0.020, P <0.001), grower-finishers (OR？=？0.017, P <0.001), and manure pits (OR？=？0.11, P <0.001) were less likely to be positive for the consensus beta2 toxin gene cpb2 compared to the isolates from suckling pigs. The prevalence of cpb2 in the isolates recovered from weanlings did not differ significantly from suckling pigs. C. perfringens isolates that were positive for cpb2 were more likely to carry the atypical cpb2 gene (atyp-cpb2) (OR？=？19, P <0.001) compared to isolates that were negative for cpb2. Multivariable analysis did not identify farm factors affecting the presence of consensus cpb2 and atyp-cpb2 genes.This study provides baseline data on the prevalence of C. perfringens and associated toxin genes in healthy pigs at different stages of production on Ontario swine farms. The study suggests that if C. perfringens type A are involved in neonatal enteritis, there may be strains with specific characteristics that cannot be identified by the existing genotyping system.Clostridium perfringens type A is considered by some to be one of the most common causes of diarrhea in neonatal pigs [1,2]. However, the pathogenic basis of C. perfringens type A diarrhea is unclear, and the current diagnostic methods for this disease are not specific.Clostridium perfringens are ubiquitous Gram-positive anaerobes that can be isolated from many environments, and their spore-forming ability allows them to persist in the swine ecosystem [2]. Currently, C. perfringens are divided into five toxinotypes (A to E) depending on their production of four major toxins. Isolates of any toxinotype may also produce enterotoxin (CPE) and beta2 toxin (CPB2) [3].I