PDF(Pubmed)
Abstract：
The prevalence and dissemination of the plasmid-mediated fluoroquinolone (FQ) resistance gene qnr in Salmonella are considered serious public health concerns worldwide. So far, no comprehensive large-scale studies have focused on the prevalence and genetic characteristics of the qnr gene in Salmonella isolated from chickens. Herein, this study aimed to investigate the prevalence, antimicrobial resistance (AMR) patterns, and molecular characteristics of chicken-originated qnr-positive Salmonella strains from chicken farms, slaughterhouses, and markets in 12 provinces of China in 2020-2021. The overall prevalence of the qnr gene was 21.13% (56/265), with the highest prevalence in markets (36.11%, 26/72), followed in farms (17.95%, 21/117), and slaughterhouses (10.53%, 9/76). Only the qnrS and qnrB genes were detected, and the prevalence rate of the qnrS gene (19.25%, 51/265) was higher than that of the qnrB gene (1.89%, 5/265). Whole genome sequencing identified 37 distinct AMR genes and 15 plasmid replicons, and the most frequent mutation in quinolone resistance determining regions was parC (T57S; 91.49%, 43/47). Meanwhile, four different qnrS and two qnrB genetic environments were discovered among 47 qnr-positive Salmonella strains. In total, 21.28% (10/47) of the strains were capable of conjugative transfer, and all were qnrS1-positive strains, with the majority of transferable plasmids being IncHI2 types (n = 4). Overall, the prevalence of qnr-positive Salmonella strains from chickens in China and their carriage of multiple resistance and virulence genes and transferable plasmids is a major concern, which calls for continuous surveillance of qnr-positive Salmonella and the development of measures to control its prevalence and transmission.IMPORTANCESalmonella is a common foodborne pathogen responsible for 155,000 deaths annually worldwide. Fluoroquinolones (FQs) are used as first-line drugs for the treatment of Salmonella infections in several countries and regions. However, the emergence and increasing prevalence of the FQ-resistant gene qnr in Salmonella isolated from chickens have been widely reported. Gaining insight into the genetic mechanisms of AMR genes in chicken could lead to the development of preventive measures to control and reduce the risk of drug resistance. In this study, we identified qnr-positive Salmonellae isolated from chickens in different regions of China and their AMR patterns and genome-wide characteristics, providing a theoretical basis for further control of their prevalence and transmission.
摘要：
沙门氏菌中质粒介导的氟喹诺酮（FQ）抗性基因qnr的流行和传播被认为是全球严重的公共卫生问题。到目前为止,没有全面的大规模研究集中在从鸡中分离的沙门氏菌中qnr基因的流行和遗传特征。在这里，这项研究旨在调查患病率，抗菌素耐药性(AMR)模式，和来自养鸡场的鸡源qnr阳性沙门氏菌菌株的分子特征，屠宰场,2020-2021年中国12个省份的市场。qnr基因的总体患病率为21.13%(56/265),在市场上患病率最高(36.11%，26/72),其次是农场(17.95%，21/117)，和屠宰场(10.53%,9/76)。只检测到qnrS和qnrB基因,qnrS基因的患病率(19.25%，51/265)高于qnrB基因(1.89%,5/265）。全基因组测序鉴定出37个不同的AMR基因和15个质粒复制子，喹诺酮耐药决定区最常见的突变是parC(T57S；91.49%，43/47)。同时,在47株qnr阳性沙门氏菌中发现了四种不同的qnrS和两种qnrB遗传环境。总的来说,21.28%(10/47)的菌株能够接合转移，都是qnrS1阳性菌株,其中大多数可转移质粒是IncHI2型(n=4)。总的来说,中国鸡的qnr阳性沙门菌流行及其携带多个抗性和毒力基因和可转移质粒是一个主要问题，要求对qnr阳性沙门氏菌进行持续监测，并制定控制其流行和传播的措施。重要沙门氏菌是一种常见的食源性病原体，每年在全世界造成155,000人死亡。氟喹诺酮类药物（FQs）在多个国家和地区被用作治疗沙门氏菌感染的一线药物。然而,从鸡中分离的沙门氏菌中FQ抗性基因qnr的出现和患病率的增加已经被广泛报道。深入了解鸡AMR基因的遗传机制可以导致制定预防措施，以控制和降低耐药性的风险。在这项研究中,我们鉴定了从中国不同地区的鸡中分离出的qnr阳性沙门氏菌及其AMR模式和全基因组特征，为进一步控制其流行和传播提供理论依据。
