Outbreak of foodborne illness caused by Salmonella Braenderup ST2443 in China: Epidemiological and pathogenic insights

IF 4.8 3区医学 Q1 INFECTIOUS DISEASES

Journal of Infection and Public Health Pub Date : 2026-02-01 Epub Date: 2025-11-17 DOI:10.1016/j.jiph.2025.103053

Yezhen Fang , Xiaoyan Wang , Hua Yu , Rui Tian , Yiyi Wang , Pan Zhao , Shiwang Huang , Xiaoting Hua

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引用次数: 0

Abstract

Background

Salmonella outbreaks, particularly those caused by Salmonella Braenderup (S. Braenderup), represent a significant public health challenge due to their potential for widespread food contamination. While S. Braenderup outbreaks are reported globally, research on this serotype in China remains limited, leading to gaps in understanding its epidemiological patterns, pathogenic characteristics, and molecular features. This study investigates a foodborne outbreak in Hangzhou, China, in July 2023 to elucidate the transmission dynamics and molecular features of the causative strain.

Methods

A detailed epidemiological investigation was conducted, with rectal swabs, fecal samples, food, and environmental samples collected. Rapid pathogen detection, isolation, serotyping, and whole-genome sequencing (WGS) were performed to identify the infection source and characterize the outbreak strain. Epidemiological and genomic data were analyzed to determine the genetic relationships among isolates.

Results

Ten S. Braenderup strains, identified by the antigenic formula 6,7:e,h:e,n,z15, were isolated from patient feces, rectal swabs of restaurant employees, and food samples. All outbreak strains were classified as ST2443. WGS revealed two distinct phylogenetic clusters, with intragroup single nucleotide polymorphism (SNP) distances ranging from 2 to 503, indicating both recent common ancestry and substantial genomic diversity among the isolates. Notably, two food isolates (SCGL31 and SCGL35) exhibited close genomic relatedness to a patient isolate (SCGL39), supporting a direct link between foodborne transmission and clinical infection. The outbreak source was traced to contaminated food and infected restaurant employees. Virulence profiling identified key determinants, including invA, SPI-1 to SPI-5, and fimbrial genes. All strains demonstrated resistance to nalidixic acid. Although no acquired resistance genes were detected, a gyrA D87Y mutation associated with quinolone resistance was present.

Conclusion

This study provides the first detailed characterization of a foodborne outbreak in China caused by S. Braenderup ST2443. The findings highlight the value of WGS in outbreak investigation and underscore the necessity of stringent hygiene protocols and ongoing genomic surveillance to mitigate future risks.

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中国由沙门氏菌ST2443引起的食源性疾病暴发：流行病学和病原学见解

沙门氏菌暴发，特别是由布氏沙门氏菌（S. Braenderup）引起的暴发，由于其可能造成广泛的食品污染，是一项重大的公共卫生挑战。虽然全球都报道了布氏沙门氏菌的暴发，但在中国对该血清型的研究仍然有限，导致对其流行病学模式、致病特征和分子特征的了解存在空白。本研究调查了2023年7月在中国杭州发生的食源性暴发，以阐明致病菌株的传播动力学和分子特征。方法进行详细的流行病学调查，收集直肠拭子、粪便、食物和环境样本。采用快速病原体检测、分离、血清分型和全基因组测序（WGS）确定感染源和暴发菌株特征。对流行病学和基因组学数据进行分析，以确定分离株之间的遗传关系。结果从患者粪便、餐馆工作人员直肠拭子和食品样品中分离到勃氏链球菌，抗原式分别为6、7:e、h:e、n、z15。所有爆发菌株都被归类为ST2443。WGS显示了两个不同的系统发育集群，群内单核苷酸多态性（SNP）距离在2到503之间，表明分离物之间有共同的祖先和大量的基因组多样性。值得注意的是，两种食物分离株（SCGL31和SCGL35）与一种患者分离株（SCGL39）表现出密切的基因组相关性，支持食源性传播与临床感染之间的直接联系。疫情源头可追溯至受污染的食物和受感染的餐厅员工。毒力分析确定了关键决定因素，包括invA、SPI-1至SPI-5和毛膜基因。所有菌株均表现出对萘啶酸的抗性。虽然没有检测到获得性耐药基因，但存在与喹诺酮类药物耐药相关的gyrA D87Y突变。结论本研究首次详细描述了由S. Braenderup ST2443引起的中国食源性暴发。这些发现突出了WGS在疫情调查中的价值，并强调了严格的卫生协议和持续的基因组监测以减轻未来风险的必要性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Infection and Public Health PUBLIC, ENVIRONMENTAL & OCCUPATIONAL HEALTH -INFECTIOUS DISEASES

CiteScore

13.10

自引率

1.50%

发文量

203

审稿时长

96 days

期刊介绍： The Journal of Infection and Public Health, first official journal of the Saudi Arabian Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences and the Saudi Association for Public Health, aims to be the foremost scientific, peer-reviewed journal encompassing infection prevention and control, microbiology, infectious diseases, public health and the application of healthcare epidemiology to the evaluation of health outcomes. The point of view of the journal is that infection and public health are closely intertwined and that advances in one area will have positive consequences on the other. The journal will be useful to all health professionals who are partners in the management of patients with communicable diseases, keeping them up to date. The journal is proud to have an international and diverse editorial board that will assist and facilitate the publication of articles that reflect a global view on infection control and public health, as well as emphasizing our focus on supporting the needs of public health practitioners. It is our aim to improve healthcare by reducing risk of infection and related adverse outcomes by critical review, selection, and dissemination of new and relevant information in the field of infection control, public health and infectious diseases in all healthcare settings and the community.