Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China; Key Laboratory for Prevention and Control of Major Ruminant Diseases, Ministry of Agriculture and Rural Affairs, Yangling, China.
Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China.
Vet Microbiol. 2024 Jul;294:110105. doi: 10.1016/j.vetmic.2024.110105. Epub 2024 May 6.
C. perfringens type D strains are the leading cause of enterotoxaemia in ruminants such as goats, sheep, and cattle. However, there has been no prior research on the genomic characteristics of C. perfringens type D strains from various regions in China. Here, we investigated the antibiotic resistance, genomic characteristics, and phylogenetic relationship of C. perfringens type D isolates recovered from goat farms in Shaanxi, Gansu, and Ningxia provinces. The antibiotic resistance test indicated that the isolates displayed high minimum inhibitory concentration (MIC) values to sulfafurazole, whereas the other antibiotics tested, such as penicillin, enrofloxacin, and florfenicol, worked well on them. Additionally, only tetracycline resistance genes [tetA(P) and tetB(P)] were identified from the isolates. A collective of 13 toxin genes, including etx and cpe were detected among the isolates. Sequence comparison revealed that the etx and cpe genes shared high sequence identities, and they could coexist on a pCW3-like plasmid, representing a potential risk to both animal breeding and public health. Phylogenetic analysis using core genome multi-locus sequence typing (cgMLST) and core genome single nucleotide polymorphisms (SNPs) revealed the close genetic relationship and potential regional/transregional transmission of the C. perfringens type D isolates in Shaanxi and Gansu provinces. Furthermore, pan-genomic analysis suggested the functional differences at the protein-coding gene level, although isolates from the same source shared a close genetic relationship. In conclusion, this study indicated the antibiotic resistance, virulence markers, potential transregional transmission, and genomic diversity of C. perfringens type D strains from various regions in China, which could provide references for the prevention of C. perfringens foodborne diseases and further research.
C 型产气荚膜梭菌 D 型菌株是山羊、绵羊和牛等反刍动物肠毒血症的主要病原体。然而，目前还没有关于中国不同地区 C 型产气荚膜梭菌 D 型菌株的基因组特征的研究。在这里，我们研究了从陕西、甘肃和宁夏的山羊养殖场分离到的 C 型产气荚膜梭菌 D 型分离株的抗生素耐药性、基因组特征和系统发育关系。抗生素耐药性试验表明，分离株对磺胺嘧啶的最低抑菌浓度（MIC）值较高，而其他测试的抗生素，如青霉素、恩诺沙星和氟苯尼考，对它们有效。此外，仅从分离株中鉴定出四环素耐药基因 [tetA(P) 和 tetB(P)]。在分离株中检测到包括 etx 和 cpe 在内的 13 种毒素基因。序列比较表明，etx 和 cpe 基因具有高度的序列同一性，它们可以共存于 pCW3 样质粒上，这代表了对动物养殖和公共卫生的潜在风险。使用核心基因组多位点序列分型（cgMLST）和核心基因组单核苷酸多态性（SNP）的系统发育分析表明，陕西和甘肃两省的 C 型产气荚膜梭菌 D 型分离株具有密切的遗传关系和潜在的区域/跨区域传播。此外，泛基因组分析表明，尽管来自同一来源的分离株具有密切的遗传关系，但在蛋白质编码基因水平上存在功能差异。总之，本研究表明了中国不同地区 C 型产气荚膜梭菌 D 型菌株的抗生素耐药性、毒力标志物、潜在的跨区域传播和基因组多样性，可为预防 C 型产气荚膜梭菌食源性疾病和进一步研究提供参考。
