Zhang Xiyan, Zhu Jinlu, Kerdsin Anusak, Wang Jianping, Wang Mingliu, Yang Hui, Kang Weiming, Lu Xiaojing, Wang Yan, Sun Hui, Gottschalk Marcelo, Zheng Han, Xu Jianguo, Wu Zongfu
National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changping, Beijing, China.
WOAH Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Virulence. 2025 Dec;16(1):2523882. doi: 10.1080/21505594.2025.2523882. Epub 2025 Jun 26.
is a significant pig pathogen and an emerging zoonotic agent. Serotype 5 is becoming an increasing concern among pigs and humans with infection worldwide. This study investigated the population structure, phylogenetic relationship, genomic characteristics, and virulence of serotype 5 population, analyzing 89 isolates, including eight from human cases. The results revealed significant genomic heterogeneity and diverse virulence levels within serotype 5 population. Phylogenetic analysis identified two distinct lineages with notable differences in evolution and genomic traits. Thirty-two representative serotype 5 strains were clustered into four groups: ultra-highly virulent (UV) ( = 1), highly virulent plus (HV) ( = 4), HV ( = 11), and virulent (V) ( = 16). Virulence levels progressively decreased from the UV group to HV, HV, and V groups. The UV, HV, and HV strains induced significantly lethal infection in mice during the early phase of infection. The lethal infection induced by UV and HV strains was time-dependent but dose-independent. Ultra-high bacterial loads, excessive pro-inflammatory cytokines, and severe organ damage were responsible for the sudden death of mice infected with UV strain at the early phase of infection. The capacity to establish infection, induce excessive pro-inflammatory cytokine production, and elevate biomarkers associated with organ damage varied significantly among HV strains. The V strains demonstrated the capacity to induce delayed lethal infection. These findings emphasized the serious public health risk posed by serotype 5 strains. The valuable information for developing effective prevention and control strategies for serotype 5 infections was provided.
是一种重要的猪病原体和新兴的人畜共患病原体。血清型5在全球范围内的猪和人类感染中日益受到关注。本研究调查了血清型5群体的种群结构、系统发育关系、基因组特征和毒力，分析了89株分离株，其中包括8株来自人类病例的分离株。结果显示血清型5群体内存在显著的基因组异质性和不同的毒力水平。系统发育分析确定了两个不同的谱系，在进化和基因组特征上有显著差异。32株代表性血清型5菌株分为四组：超高毒力（UV）（=1）、高毒力加强型（HV）（=4）、HV（=11）和毒力型（V）（=16）。毒力水平从UV组到HV、HV和V组逐渐降低。UV、HV和HV菌株在感染早期对小鼠诱导了显著的致死性感染。UV和HV菌株诱导的致死性感染与时间有关，但与剂量无关。超高细菌载量、过量的促炎细胞因子和严重的器官损伤是感染早期感染UV菌株的小鼠突然死亡的原因。HV菌株在建立感染、诱导过量促炎细胞因子产生以及升高与器官损伤相关的生物标志物方面的能力差异显著。V菌株表现出诱导延迟致死性感染的能力。这些发现强调了血清型5菌株带来的严重公共卫生风险。为制定血清型5感染的有效预防和控制策略提供了有价值的信息。
