Genomic analysis and multidrug resistance of monophasic Salmonella enterica serovar Typhimurium isolates from Henan
10.3760/cma.j.cn114452-20241231-00722
- VernacularTitle:河南省单相鼠伤寒沙门菌的耐药性及基因组特征分析
- Author:
Lingling WU
1
;
Haoyu QI
1
;
Yanfen LI
1
;
Yongli LI
1
;
Jin XU
1
;
Xingguang LIAO
1
;
Xiuli ZHANG
1
;
Zhiwei HAN
1
Author Information
1. 河南省疾病预防控制中心，郑州 450016
- Publication Type:Journal Article
- Keywords:
Salmonella typhimurium;
Whole genome sequencing;
Drug resistance
- From:
Chinese Journal of Laboratory Medicine
2025;48(11):1452-1460
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the multidrug resistance and genomic characteristics of Monophasic variant of Salmonella enterica serovar Typhimurium (monophasic Salmonella enterica serovar Typhimurium) isolates from clinical patients and food sources in Henan province. Method:A total of 91 monophasic S.Typhimurium strains isolated from clinical and food sources in Henan from 2021 to 2023 were analyzed for antimicrobial sensitivity and underwent whole genome sequencing. Multilocus sequence typing(MLST), multidrug resistance genes and plasmid types were identified using the sequencing data. Phylogenetic tree based on core genome multilocus sequence typing (cgMLST) and single nucleotide polymorphism (SNP) sites was constructed to analyze the genetic evolutionary relationship by comparing with international popular strains in public databases. The Chi-square test was used to compare drug resistance rates. Results:No significant difference was observed in the drug resistance rates between the clinical strains and food strains in Henan [82.19%(60/73) and 11/18, χ2=2.614, P=0.106]. The overall multidrug resistance (MDR) rate was 78.02%(71/91). Most strains were resistant to ampicillin, tetracycline chloramphenicol, β-lactam and sulfonamides. Resistance genes carried by the isolates varied, as well as the drug-resistant phenotypes. MLST showed that 91 strains of S.Typhimurium belonged to ST34 and carried aminoglycoside acetyltransferase gene aac(6′)-Iaa and mobile genetic elements such as plasmids IncQ1 and IncHI2/IncHI2A. The results of cgMLST typing phylogenetic trees showed that food and clinical isolates from the same region in Henan were identified as the same cgST type and clustered in the same branch, which indicated the risk for cross-infection between animal and human. The phylogenetic tree of monophasic S.Typhimurium constructed based on SNP sites showed that the majority of monophasic S.Typhimurium strains in Henan were close to the strains from other provinces in China, other strains were close to the strains from Europe and Southeast Asia, suggesting the possibility of cross regional transmission of the strains. Pork was identified as the main food source. Conclusion:The prevalent ST type of monophasic S.Typhimurium isolated from Henan was ST34, which carried multiple antibiotic resistance genes and widespread drug resistance phenotypes. Most of the monophasic S.Typhimurium isolates in Henan showed a specific phylogenetic lineage with the foreign epidemic strains, indicating the possibility of dissemination of strains between humans and food.
