A retrospective study of the prevalence of cpa, cpby cpe, and cpb2 toxin genes among Clostridium perfringens field isolates obtained from pigs with gastrointestinal diseases using PCR genotyping

摘要

Clostridium perjringens plays an important role in causing gastrointestinal (GI) diseases in pigs. The virulence of this pathogen comes from its ability to produce toxins. The C. perfringens isolates of pig origin have been found to be able to produceat least four different toxins (i.e., the alpha toxin, beta toxin, enterotoxin, and beta 2 toxin). The knowledge about the prevalence of these four toxin genes among the field strains of C. perfringens is very limited. In this study, a total of 113 field strains were isolated from pigs with GI diseases and examined with PCR genotyping. Of these, 46.0% were PCR positive for the cpb2 gene, 18.6% were positive for the cpe gene, 98.2% were positive for the cpa gene, and 31.0% were positive for the cpb gene. Of the 113 field isolates, 69.0% were type A, 29.2% were type C, and 1.8% were untypeable due to missing the cpa gene. The isolates that only carried the cpa gene (29.2%) and those that carried both cpa and cpb2 genes (29.2%) were most prevalent and were followed by those that carried both cpa and cpb genes (11.5%). Only a small portion of the 113 isolates carried both cpe and cpb2 genes (7.1%). Based on the results obtained by PCR genotyping, a subtyping system was established to help distinguish the difference due to the presence of cpe and cpb2 genes among field strains that are traditionally classified as type A or type C.