Prevalence and diversity of toxigenic Clostridium perfringens and Clostridium difficile among swine herds in the midwest

Abstract

Clostridium perfringens and Clostridium difficile are associated with scours in the neonatal piglet and are an economic concern in swine production. The objective of this study was to characterize the prevalence and diversity of C. perfringens and C. difficile isolates obtained from scouring neonatal piglets in a large integrated production system, as well as in smaller independently owned regional farms. Rectal swabs were collected from 333 pigs at 11 sites in an integrated swine production system and from an additional 180 pigs at 16 regional farms located throughout the Midwest. C. perfringens was isolated from 89.8% of the pigs swabbed at the integrated sites, and C. difficile was isolated from 57.7% of these pigs. Of the pigs from the regional farms sampled, 95.6% were positive for isolation of C. perfringens and 27.2% were positive for C. difficile. Toxigenic isolates were typed using random amplified polymorphic DNA (RAPD) PCR, and were placed in four dendrograms for C. perfringens and C. difficile populations isolated from the integrated sites and regional farms. Diversity indices showed that there was greater diversity in C. difficile populations and in populations isolated from the regional farms. A subset of isolates from the C. difficile dendrograms were further toxinotyped by amplification of the pathogenicity locus and subsequent digestion by HincII, AccI, and EcoRI. Of the 45 isolates typed, 44 were determined to be toxinotype V. The results of this study illustrate the diversity of C. perfringens and C. difficile isolates and the prevalence of these pathogens in swine production sites.

FIG. 1.

Dendrograms of toxigenic C. perfringens (A) and C. difficile (B) isolates from the 11 integrated sites and toxigenic C. perfringens (C) and C. difficile (D) isolates from the 16 regional farms. Isolates from each of the sites studied are indicated by a different color. The dendrograms were constructed using the Dice coefficient and UPGMA. The vertical red line in each dendrogram indicates a similarity coefficient of 80% and is used to indicate unique clusters.

FIG. 2.

Restriction enzyme patterns of PCR fragments A3 and B1 from four representative C. difficile isolates examined in this study. Toxinotypes of the isolates were determined by comparison to previously described reference strains (27, 28, 30). Lanes 1 to 3, toxinotype V; lane 4, toxinotype I; lane 5, toxinotype 0 (positive-control strain ATCC 9689); lane 6, negative control.