Emergence of chromosomally located blaCTX-M-14b and qnrS1 in Salmonella enterica serotype Kentucky ST198 in China
Yiying She, Yixiang Jiang, Miaomiao Luo, Xiangke Duan, Li Xie, Chao Yang, Liangcai Xu, Yulin Fu, Ziquan Lv, Rui Cai, Yinghui Li, Yaqun Qiu, Lulu Hu, Xiaolu Shi, Lei Wang, Shuang Wu, Qiongcheng Chen, Min Jiang, Qinghua Hu
Abstract
Highly fluoroquinolone-resistant Salmonella enterica serotype Kentucky (S. Kentucky) has been widespread in recent years, largely associated with the spread of the ST (sequence type) 198, which often leads to multi-drug resistance (MDR). The genomic epidemiology research of S. Kentucky in China is rare and needs to be conducted. We analyzed the genomic epidemiology and antimicrobial characteristics of S. Kentucky ST198 collected from foodborne disease surveillance in Shenzhen, China, during 2010–2021, using whole genome sequencing and antibiotic sensitivity test, and 158 global S. Kentucky genomes ST198 were included to compare. Among the 8,559 Salmonella isolates, 43 S. Kentucky ST198 isolates were detected, during 2010–2021. The global S. Kentucky ST198 evolutionary tree was divided into 5 clades, and Shenzhen isolates were distributed in clades 198.1, 198.2-1, and 198.2-2, mainly clustered with Chinese strains. Strains in clade 198.2 dominated in Shenzhen and all of them showed MDR. Nine strains showed high resistance to ceftriaxone, which was associated with the blaCTX-M-14b in clade 198.2-1. And blaCTX-M-14b was demonstrated to be located on the chromosome. Fifteen strains showed high resistance to ciprofloxacin, which was associated with the carriage of qnrS1 in clade 198.2-2. QnrS1 was first located in the IncHI2 plasmid, then transferred into the chromosome. Here, we reported the genomic and resistance characterization of the S. Kentucky ST198 in Shenzhen, China. Of particular concern, we first identified a clade 198.2-1 carrying blaCTX-M-14b, and chromosomally located qnrS1 in clade 198.2-2 of S. Kentucky ST198 in China, highlighting the necessity of surveillance of clade 198.2.