Antimicrobial resistance and genomic investigation of Salmonella isolated from retail foods in Guizhou, China

Li Zhou; Qian Ye; Qian Zhou; Jian Wang; Guanqiao Li; Jingshu Xiang; Jingyu Huang; Yuanyuan Zhao; Tianli Zheng; Haojiang Zuo; Shijun Li

doi:10.3389/fmicb.2024.1345045

Antimicrobial resistance and genomic investigation of Salmonella isolated from retail foods in Guizhou, China

Front Microbiol. 2024 Mar 6:15:1345045. doi: 10.3389/fmicb.2024.1345045. eCollection 2024.

Authors

Li Zhou^#¹, Qian Ye^#², Qian Zhou¹, Jian Wang^{2

3}, Guanqiao Li⁴, Jingshu Xiang¹, Jingyu Huang¹, Yuanyuan Zhao², Tianli Zheng², Haojiang Zuo^{2

3}, Shijun Li¹

Affiliations

¹ Guizhou Provincial Centre for Disease Control and Prevention, Guiyang, China.
² West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.
³ Food Safety Monitoring and Risk Assessment Key Laboratory of Sichuan Province, Chengdu, China.
⁴ Institute of Bioinformatics, Chongqing University of Posts and Telecommunications, Chongqing, China.

^# Contributed equally.

Abstract

Introduction: Salmonella is a major foodborne pathogen worldwide that causes severe morbidity and mortality. It is mainly caused by consuming contaminated food, with retail food considered the primary source.

Methods: In Guizhou, China, 102 Salmonella strains isolated from 2016 to 2021 underwent phenotypic antimicrobial resistance testing and whole-genome sequencing (WGS) to understand Salmonella diversity, including serotypes, sequencing types (STs), antimicrobial genes, virulence genes, plasmid types, multi-locus sequence types (MLST), and core genome MLST (cgMLST).

Results and discussion: S.Typhimurium was the dominant serotype, and O:4(B) was the leading serogroup. The most prevalent genotype was ST40. Phenotypic antimicrobial resistance identified 66.7% of the sampled isolates as multi-drug resistant (MDR). S.Enteritidis (n = 7), S.Typhimurium (n = 1), S.Indiana (n = 1), S.Kentucky (n = 1), S.Uganda (n = 1), all of which were MDR, were resistant to Colistin. Resistance rates varied significantly across different strains and food types, particularly meat products exhibiting higher resistance. Notably, significant increases in resistance were observed from 2016 to 2021 for the following: ≥ 1 resistant (P = 0.001), MDR (P = 0.001), ampicillin (P = 0.001), tetracycline (P < 0.001), chloramphenicol (P = 0.030), and trimethoprim/sulfamethoxazole (P = 0.003). The marked escalation in drug resistance over the recent years, coupled with the varying resistance rates among food sources, underscores the growing public health concern. Our findings highlight the need for a coordinated approach to effectively monitor and respond to Salmonella infections in Guizhou, China.

Keywords: Guizhou province; Salmonella; multi-drug resistance; retail foods; whole genome sequencing.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was funded by the Guizhou Provincial Science and Technology Support Program Project (2021-435 to LZ), Guizhou Provincial Health Commission Science and Technology Fund Project (gzwkj 2023-492 to QZ), Guizhou Province Infectious Disease Prevention and Control Talent Base Scientific Research Team (RCJD2105 to SL, RCJD2102 to SL), Sichuan/Tibet/Yibin/Chengdu Science and Technology Bureau Funding (N.O. 2022ZDZX0017/XZ202301ZY0049G/2021NY006/2019-YF05-01247-SN to HZ).