Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, Ministry of Agriculture of China, Yangzhou University, Yangzhou 225009, China.
Nantong Center for Disease Control and Prevention, Nantong 226007, China.
Vet Microbiol. 2024 Mar;290:109993. doi: 10.1016/j.vetmic.2024.109993. Epub 2024 Jan 15.
Salmonella enterica serovar Meleagridis (S. Meleagridis) is a non-typhoidal Salmonella serotype commonly found in food and humans. In this study, we investigated 61 Chinese S. Meleagridis isolates from various sources, predominantly from pigs and pig products. Additionally, the serotype was also identified in samples from human infections. Whole-genome sequencing analysis of these isolates, combined with 10 isolates from other countries, demonstrated that the Chinese isolates formed a distinct Cluster C, further divided into two subclusters (Cluster C-1 and Cluster C-2) based on cgMLST analysis. CRISPR typing divided the 61 isolates into three CRISPR types (MCT1, MCT2, MCT3), belonging to Cluster I (96.7%, 59/61) and Cluster II (3.3%, 2/61), which corresponded to Cluster C-2 and Cluster C-1, respectively. Among the 48 identified spacers, the spacer SoeB5 was the only target differentiating MCT1 and MCT2 isolates of Cluster I. MelB12 and MelB13, identified in US and Denmark isolates, were not found among the 61 Chinese isolates. Examination of antimicrobial resistance gene profiles and their genetic contexts uncovered the presence of IncR plasmids in 43 (70.5%, 43/61) isolates within Cluster C, conferring resistance to tetracycline and trimethoprim/sulfamethoxazole. Homology analysis of spacers showed that 12 spacers exhibited similarity to sequences in phages or plasmids. Additionally, five spacers showed homology to sequences in plasmids from other Salmonella serotypes, suggesting their potential role in helping S. Meleagridis resist against Salmonella isolates carrying similar plasmids. The comprehensive analysis of CRISPR, cgMLST, and antimicrobial resistance in S. Meleagridis highlights the pig reservoir as a crucial factor in the evolution and transmission of this serotype to humans.
肠炎沙门氏菌血清型梅里亚吉尔德（S. Meleagridis）是一种常见于食品和人类的非伤寒沙门氏菌血清型。在本研究中，我们调查了来自不同来源的 61 株中国 S. Meleagridis 分离株，主要来自猪和猪产品。此外，该血清型也在人类感染样本中被鉴定出来。对这些分离株进行全基因组测序分析，并结合来自其他国家的 10 株分离株，表明中国分离株形成了一个独特的 C 群，进一步根据 cgMLST 分析分为两个亚群（C-1 群和 C-2 群）。CRISPR 分型将 61 株分离株分为 3 种 CRISPR 型（MCT1、MCT2、MCT3），分别属于 I 群（96.7%，59/61）和 II 群（3.3%，2/61），分别对应于 C-2 群和 C-1 群。在鉴定的 48 个间隔区中，间隔区 SoeB5 是区分 I 群 MCT1 和 MCT2 分离株的唯一靶标。在 61 株中国分离株中未发现美国和丹麦分离株中存在的 MelB12 和 MelB13。对 43 株（70.5%，43/61）C 群内分离株的抗生素耐药基因谱及其遗传背景进行检测，发现有 43 株（70.5%，43/61）分离株携带 IncR 质粒，对四环素和磺胺甲恶唑/甲氧苄啶具有耐药性。间隔区的同源性分析表明，12 个间隔区与噬菌体或质粒中的序列具有相似性。此外，5 个间隔区与其他沙门氏菌血清型质粒中的序列具有同源性，这表明它们在帮助 S. Meleagridis 抵抗携带类似质粒的沙门氏菌分离株方面可能发挥了作用。对 S. Meleagridis 的 CRISPR、cgMLST 和抗生素耐药性的综合分析突出了猪作为该血清型向人类传播和进化的重要因素。
