Wang Shuang, Yu Xiaolin, Fang Ming, Xie Hengjie, Liu Lu, Liu Ziqing, Wu Guangjian, Chen Yuzhen, Liu Ti, Yang Peng
Infection Disease Control of Institute, Shandong Center for Disease Control and Prevention, Jinan 250014, Shandong Province, China.
Supervision Sampling Department, Shandong Institute for Food and Drug Control, Jinan 250101, Shandong Province, China.
Infect Med (Beijing). 2025 Jun 25;4(3):100195. doi: 10.1016/j.imj.2025.100195. eCollection 2025 Sep.
Paratyphi C is an infrequent etiological agent of enteric fever, with sporadic cases primarily reported in Asia and Africa. Documented outbreaks remain exceedingly rare, and epidemiological data on such events are notably scarce.
This study investigated a paratyphoid fever outbreak caused by Paratyphi C at a secondary school in China in 2023. Comprehensive field epidemiological investigations were conducted, including environmental sampling and the collection of clinical specimens. All outbreak-associated isolates underwent antimicrobial susceptibility testing, whole-genome sequencing, and in-depth bioinformatics analysis. Single-nucleotide polymorphism profiling and core genome multilocus sequence typing were employed to elucidate the genetic relatedness of the isolates.
A total of 11 Paratyphi C strains, characterized by the antigenic formula 6,7:c:1,5, were recovered from a variety of sample sources. Genomic analyses revealed striking homogeneity across all isolates, with uniform multilocus sequence types, identical antimicrobial resistance patterns, and shared virulence-associated genes. Phylogenetic reconstruction demonstrated a tightly clustered lineage, corroborated by highly similar circular genome structures, suggesting a common source of infection.
This investigation offered critical insights into a rare foodborne outbreak caused by Paratyphi C, bridging significant knowledge gaps regarding its epidemiology and genetic characteristics. The findings underscored the global diversity and potential public health threat of Paratyphi C, reinforcing the urgent need to enhance food safety monitoring and improve outbreak preparedness strategies both in China and internationally.
丙型副伤寒杆菌是肠热症的一种罕见病原体，零星病例主要在亚洲和非洲报道。有记录的疫情爆发仍然极为罕见，关于此类事件的流行病学数据也明显匮乏。
本研究调查了2023年中国一所中学由丙型副伤寒杆菌引起的副伤寒热疫情爆发情况。开展了全面的现场流行病学调查，包括环境采样和临床标本采集。对所有与疫情相关的分离株进行了抗菌药物敏感性测试、全基因组测序和深入的生物信息学分析。采用单核苷酸多态性分析和核心基因组多位点序列分型来阐明分离株的遗传相关性。
从各种样本来源共分离出11株丙型副伤寒杆菌菌株，其抗原型为6,7:c:1,5。基因组分析显示所有分离株具有显著的同质性，多位点序列类型一致，抗菌药物耐药模式相同，且具有共同的毒力相关基因。系统发育重建显示出紧密聚类的谱系，高度相似的环状基因组结构也证实了这一点，表明存在共同的感染源。
本调查为丙型副伤寒杆菌引起的罕见食源性疫情爆发提供了关键见解，填补了其流行病学和遗传特征方面的重大知识空白。研究结果强调了丙型副伤寒杆菌的全球多样性和潜在的公共卫生威胁，强化了在中国和国际上加强食品安全监测以及改进疫情应对准备策略的迫切需求。
