Isolation,identification And PFGE Analysis Of Clostridium Perfringens From Some Cattle Farms And Slaughterhouses In Shaanxi

Clostridium perfringens(C.perfringens)is an important zoonotic pathogenand ubiquitous in nature world,causing gas Gangrene and food-borne gastrointestinal diseases,enterotoxemia and necrotic enteritis in animals,leading great perplexity to healthy breeding and food safety.Some cattle farm in shaanxi province In this study,C.perfringens were isolated and serotyped from samples of breeding and milking process were collected from 2 dairy cattle farms,and samples of slaughtering and butchering process were collected from 1 slaughterhouse.Further,total 300 C.perfringens isolated by our laboratory including strains isolated above were analyzed by pulsed field gel electrophoresis(PFGE),in order to investigate the distribution,transimission and the critical control point of contamination.Results obtained as follows:1.The prevalence of 27.91% yielded 252 of C.perfringens type A isolates from 313 samples,including 27.91% from samples of breeding process and 40.76% from milking,85.32% isolates carried atyp.cpb2 gene.The prevalence of 35.92% of C.perfringens isolates from 102 samples,including 38.33% from slaughtering and 30.95% from butchering process,yielded 38 of type A and 37 type D isolates,86.67% isolates carried atyp.cpb2 gene besides 37.33% carried cpe,no cons.cpb2 have been found among all isolates.Type A is the predominant toxinotype in the dairy cattle farms while type A and type B in the slaughterhouse.2.300 isolates from dairy cattle farms and slaughterhouse were analyzed by Pulsed Field Gel Electrophoresis,and similarity of all isolates ranged from 46.4% to 100%,classified into 154 different PFGE genotype while the similarity is greater than 90%,same PFGE were carried by cattle from the same farm and beef cattle from slaughterhouse,and also showed the genetic diversity,and 7 predominant PFGE types in the dairy cattle farms and the slaughterhouse of Shaanxi province.Insides,there were 37 PFGE subtypes with100% similarity,including 30 with same serotoxin-types,indicated when the PFGE type was the same,the same serotoxin-type with 81.1% probability.3.According results of the PFGE analysis,our study traced back and verified that C.perfringens showed feces were the main contamination source of C.perfringens to tools and feed in the breeding process.The contamination of C.perfringens of raw milk mainly from hide and personnel of dairy cattle,following air,tools and personnel introduced raw milk during the milking process.The C.perfringens contamination of beef meat mainly from hide removal in slaughtering process and tools in butching process,and traced back the widespread cross-contamination from the feces of the breeding process with the contamination rate gradually increasing during the whole process.C.perfringens broke through the barriers of bacterial control and contaminated raw milk and beef,which posing a threat to the health of consumers.In conclusion,the pollution situation and dominant serotypes of C.perfringens in cattle farms and abattoirs in some areas of Shaanxi were identified,and the dominant PFGE genotypes of C.perfringens in cattle farms and abattoirs in some areas of Shaanxi were explored with PFGE technology and the key points of pollution control.it providing a scientific basis for the effective prevention and control of contamination and transmission of C.perfringens.