羊源A型产气荚膜梭菌的鉴定和耐药性分析OA

To identify the pathogen and its characteristics responsible for the death of goats in a sheep farm in Wancheng District,Nanyang City,Henan Province,liver and lung samples from diseased goats were collected for bacterial isolation and culture.The isolated strains were identified by 16S rDNA gene sequencing and phylogenetic analysis.Toxin genes were detected by PCR for typing.Multilocus sequence typing(MLST),whole-genome sequencing,phylogenetic and SNP analysis were performed.Virulence genes and antimicrobial resistance genes were predicted using the VFDB and CARD databases.The Kirby-Bauer(K-B)disk diffusion method was used to test the strain's susceptibility to 12 antimicrobial agents,and a mouse infection test was conducted to evaluate pathogenicity.One strain of Clostridium perfringens type A was isolated and named WC202409.Phylogenetic analysis revealed that the strain is closely related to the Russian strain QDAF01.SNP analysis showed minimal variation between WC202409 and Chinese strains 1718G,QHY-2,XZ-D1,and ZWCP079.VFDB analysis annotated 11 virulence factors and 16 C.perfringens-related genes,while CARD predicted 14 resistance genes associated with six classes of antibiotics.Antimicrobial susceptibility testing showed resistance to tetracycline,cefazolin,oxacillin,penicillin G,streptomycin,and florfenicol,but susceptibility to cefotaxime,enrofloxacin,ceftriaxone,and imipenem.In the mouse infection test,all mice died within 5 days,with obvious pathological lesions confirmed to be caused by WC202409.The results indicate that strain WC202409 was the causative agent of disease in the affected goat flock,exhibits multidrug resistance,and is highly pathogenic.The strain may have originated from transboundary livestock trade.These findings provide valuable reference for the prevention and control of C.perfringens infection and for vaccine development and pathogen research.