Characterization of quinolone resistance in Salmonella enterica serovar Typhimurium and its monophasic variants from food and patients in China

作者：Yang, Xiaojuan; Yang, Shiyuan; Liu, Shengrong; Liu, Shuxiang; Zhang, Jumei; Guo, Weipeng; Wang, Juan; Song, Zhongjian; Xue, Liang; Chen, Moutong; Wu, Shi; Wei, Xianhu; Wu, Qingping^*

来源：Journal of Global Antimicrobial Resistance, 2023, 35: 216-222.

DOI：10.1016/j.jgar.2023.09.010

• Salmonella enterica serovar Typhimurium
• Salmonella enterica serovar S. 1,4,[5],12:i:-
• Quinolone resistance
• GyrA
• qnrS

Objectives: The study aimed to characterize the quinolone resistance of Salmonella enterica serovar Typhimurium and its monophasic variant (Salmonella enterica serovar 1,4,[5],12:i:-) isolated from food and patients in China.Methods: All of the isolates were assessed for quinolone susceptibility via the broth microdilution method. Then, the isolates were checked for mutations within quinolone resistance-determining regions of gyrA, gyrB, parC, and parE and were examined for plasmid-mediated quinolone resistance genes.Results: High rates of resistance to nalidixic acid in the S. Typhimurium (70.7%) and S. 1,4,[5],12:i:- (41.9%) isolates were observed, and a considerable proportion of isolates with reduced susceptibility to ciprofloxacin and levofloxacin were also detected. The high frequency of mutations in GyrA (60.8%) and a variety of genes (aac[6 ']-Ib-cr [23.2%], oqxAB [19.2%], qnrS [13.6%], and qnrA [3.2%]) conferring quinolone resistance in these Salmonella isolates were noteworthy. Lastly, the isolates carrying qnrS for transferability and transmission of the quinolone resistance were analysed by conjugation. Multiple locus variable-number tandem repeat analysis profiles indicated that some qnrS-positive isolates were clonally related, whilst the other isolates were genetically divergent. This suggested that both clonal spread of resistant strains and horizontal transmission of the plasmid-mediated resistance genes contributed to the dissemination of qnrS-positive Salmonella isolates.Conclusion: This study highlights the prevalence of quinolone-resistant S. Typhimurium and S. 1,4,[5],12:i:- in China, posing a threat to public health.(c) 2023 The Authors.Published by Elsevier Ltd on behalf of International Society for Antimicrobial Chemotherapy.This is an openaccess article under the CCBY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

• 单位
  广东省微生物研究所