Genetic characterization of non-typhoidal Salmonella strains and invasive traits associated with bloodstream infections in China (2017-2022)

Kaichao Chen; Qiaoling Sun; Miaomiao Xie; Xiaoyan Wu; Yangxiao Zhou; Junwen Yang; Gang Li; Juan Wang; Yanyan Hu; Hongwei Zhou; Dejun Liu; Edward Wai Chi Chan; Rong Zhang; Sheng Chen

doi:10.1016/j.jare.2026.05.014

Genetic characterization of non-typhoidal Salmonella strains and invasive traits associated with bloodstream infections in China (2017-2022)

J Adv Res. 2026 May 6:S2090-1232(26)00388-7. doi: 10.1016/j.jare.2026.05.014. Online ahead of print.

Authors

Kaichao Chen¹, Qiaoling Sun², Miaomiao Xie³, Xiaoyan Wu⁴, Yangxiao Zhou⁵, Junwen Yang⁶, Gang Li⁷, Juan Wang⁸, Yanyan Hu⁹, Hongwei Zhou⁹, Dejun Liu¹⁰, Edward Wai Chi Chan³, Rong Zhang¹¹, Sheng Chen¹²

Affiliations

¹ Department of Clinical Laboratory, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang, Hangzhou, China; State Key Lab for Chemical Biology and Drug Discover and the Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
² Department of Clinical Laboratory, The Second Affiliated Hospital of Zhejiang University, School of Medicine, Zhejiang, Hangzhou, China; Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; Key Laboratory of Clinical In Vitro Diagnostic Techniques of Zhejiang Province, Hangzhou, China.
³ State Key Lab for Chemical Biology and Drug Discover and the Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hung Hom, Hong Kong.
⁴ Department of Clinical Laboratory, The Second Affiliated Hospital of Jiaxing University, Jiaxing, Zhejiang, China.
⁵ Department of Clinical Laboratory, Affiliated Dongyang Hospital of Wenzhou Medical University, Dongyang, Zhejiang, China.
⁶ Department of Microbiology Laboratory, Children's Hospital Affiliated of Zhengzhou University (Henan Children's Hospital), Zhengzhou, China.
⁷ Department of Microbiology Laboratory, General Hospital of Ningxia Medical University, Yinchuan, China.
⁸ 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.
⁹ Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
¹⁰ Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University, Beijing, China.
¹¹ Department of Laboratory Medicine, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. Electronic address: zhang-rong@zju.edu.cn.
¹² State Key Lab for Chemical Biology and Drug Discover and the Department of Food Science and Nutrition, Faculty of Science, The Hong Kong Polytechnic University, Hung Hom, Hong Kong. Electronic address: sheng.chen@polyu.edu.hk.

PMID: 42103279
DOI: 10.1016/j.jare.2026.05.014

Abstract

Introduction: Non-typhoidal Salmonella (NTS) is a significant bacterial pathogen causing foodborne diseases, with the potential for severe bloodstream infections (BSI) leading to complications such as sepsis and high mortality rates, particularly in vulnerable populations. The rise of BSI associated NTS strains, notably ST11 S. Enteritidis, has raised public health concerns.

Objectives: This study aimed to investigate the epidemiological and genetic characteristics of Salmonella BSI strains in China, focusing on the adaptation of ST11 S. Enteritidis from animal and food sources to clinical settings, and to analyze correlations between clinical data and genetic profiles.

Methods: A total of 120 non-duplicated NTS strains isolated from bacteremia patients across nine hospitals in China between 2017 and 2022 were investigated using antimicrobial susceptibility testing, whole-genome sequencing and bioinformatics analysis.

Results: The average annual prevalence of bloodstream infections (BSI) due to Salmonella remained stable at 0.77%, based on 31,177 positive blood cultures, with 96.8% of infections caused by NTS strains, primarily Salmonella enterica serovar Enteritidis (41.9%) and Typhimurium variants (16.1%). WGS results revealed significant genetic features, including mutations and multiple copies of the 5S rRNA gene, which were identified as key drivers for host adaptation and systemic dissemination, particularly in immunocompetent adults. Notably, 40% of foodborne strains carried these genetic traits, exhibiting a higher genomic potential for invasiveness compared to animal-derived strains within this specific dataset. Additionally, we demonstrated the resistance levels of BSI Salmonella to first-line antibiotics and identified a novel plasmid that mediates the co-transmission of cefotaxime resistance and virulence factors, complicating treatment options. These factors significantly contribute to the transition of diarrheagenic strains to types with an enhanced potential for bloodstream invasion.

Conclusion: These findings underscore the ongoing public health concern associated with NTS infections and highlight the need for continuous surveillance and effective intervention strategies to manage these emerging threats.

Keywords: 5S rRNA; Bloodstream infection; Plasmid; S. Enteritidis; Salmonella.