Genetic characterization of a Salmonella enterica serovar Typhimurium isolated from an infant with concurrent resistance to ceftriaxone, ciprofloxacin and azithromycin

Meiling Liu; Kunpeng Zhu; Xinge Li; Yiran Han; Chaojie Yang; Hongbo Liu; Xinyin Du; Xuebin Xu; Haiyan Yang; Hongbin Song; Shaofu Qiu; Ying Xiang

doi:10.1016/j.jgar.2023.09.016

Genetic characterization of a Salmonella enterica serovar Typhimurium isolated from an infant with concurrent resistance to ceftriaxone, ciprofloxacin and azithromycin

J Glob Antimicrob Resist. 2023 Dec:35:252-256. doi: 10.1016/j.jgar.2023.09.016. Epub 2023 Sep 30.

Authors

Meiling Liu¹, Kunpeng Zhu², Xinge Li³, Yiran Han², Chaojie Yang⁴, Hongbo Liu⁴, Xinyin Du⁴, Xuebin Xu⁵, Haiyan Yang², Hongbin Song⁴, Shaofu Qiu⁴, Ying Xiang⁶

Affiliations

¹ Chinese PLA Center for Disease Control and Prevention, Beijing, China; Shaoyang Disease Control and Prevention Center, Shaoyang, China.
² Department of Epidemiology, School of Public Health, Zhengzhou University, Zhengzhou, China.
³ Chinese PLA Center for Disease Control and Prevention, Beijing, China; China Medical University, Shenyang, China.
⁴ Chinese PLA Center for Disease Control and Prevention, Beijing, China.
⁵ Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China.
⁶ Chinese PLA Center for Disease Control and Prevention, Beijing, China. Electronic address: icicle928@126.com.

PMID: 37778506
DOI: 10.1016/j.jgar.2023.09.016

Abstract

Objectives: To investigate the resistance mechanism of a Salmonella Typhimurium (S. Typhimurium) isolated from a faecal sample of an infant, which exhibited concurrent resistance to ceftriaxone, ciprofloxacin and azithromycin.

Methods: Antimicrobial susceptibility testing was performed by broth microdilution in two kinds of drug-sensitive plates. Antimicrobial resistance (AMR) genes were identified by whole genome sequencing and bioinformatics analysis. Genotyping of the strain was performed by multilocus sequence typing (MLST). Plasmid DNA was sequenced and analysed using plasmid bioinformatics tools.

Results: The SH11G993 strain was resistant to 28 antibiotics and carried 54 AMR genes. MLST results showed that the strain belonged to a rare genotype. The plasmid profile and plasmid sequencing showed that the strain carried two resistance plasmids. The pSH11G993-1 carried 14 AMR genes (especially co-harboured bla_CMY-2, mphA and ermB) and a variety of insertion sequences, belonging to the IncC. The pSH11G993-2 carried 3 AMR genes and 9 virulence genes, belonging to the IncFIB-FII, forming a novel resistance and virulence co-harbouring plasmid.

Conclusions: Our findings highlight that continuously monitor the changes in antibiotic resistance patterns and research on the resistance mechanisms in potential human pathogens are imperative.

Keywords: Multidrug-resistant; Plasmid; Resistance gene; Salmonella Typhimurium.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents / pharmacology
Anti-Bacterial Agents / therapeutic use
Azithromycin* / pharmacology
Ceftriaxone / pharmacology
Ciprofloxacin / pharmacology
Drug Resistance, Multiple, Bacterial / genetics
Humans
Infant
Multilocus Sequence Typing
Salmonella typhimurium* / genetics
Serogroup

Substances

Azithromycin
Ceftriaxone
Ciprofloxacin
Anti-Bacterial Agents