Regional distribution, toxinotyping, and antimicrobial resistance profiles of Clostridium perfringens in sheep from Northwestern China

Clostridium perfringens , a Gram-positive, anaerobic, spore-forming bacterium, is an important zoonotic pathogen. The prevalence and toxin gene profiles of C. perfringens isolates derived from sheep in northwestern China remain insufficiently characterized. This study aimed to characterize the prevalence, toxin gene profiles, and antimicrobial resistance of C. perfringens isolates recovered from caecal samples of sheep in five provinces in northwestern China (Ningxia, Gansu, Inner Mongolia, Xinjiang, and Qinghai). Based on MALDI-TOF MS and species-specific PCR, 47 C. perfringens strains (29.01%) were recovered from 162 sheep caecal samples. Among them, type D was the predominant genotype ( n = 26), followed by type B ( n = 13) and type A ( n = 8). The toxin genes cpa , cpb , etx , and cpb2 were detected in 47, 13, 39, and 40 strains, respectively, whereas i.a. and netB were not detected in any strain. With respect to antimicrobial resistance, based on disk diffusion results, all isolates were classified as susceptible to amoxicillin, cefotaxime, ceftriaxone, vancomycin, and florfenicol. Variable resistance was observed to other antimicrobial agents. Resistance patterns varied among regions and were associated mainly with the sul3 , tetA , tetB , and ermQ genes; the β-lactamase gene blaOXA was not detected. This study provides baseline data on the prevalence, toxin gene profiles, and antimicrobial resistance of C. perfringens in sheep from five northwestern Chinese provinces, and supports continued regional surveillance.