Chen Xiang, Zhang Weiqiu, Yin Jiajun, Zhang Ning, Chen Chen, Yang Su, Jiao Xin'an
Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
Wei Sheng Wu Xue Bao. 2013 Oct 4;53(10):1080-6.
To investigate the prevalence and transmission of plasmid-mediated quinolone resistance qnrS gene among Escherichia coli isolates in a poultry farm and its environment.
E. coli isolates from fecal samples in a poultry farm and its environment from February to June 2010 were screened for the prevalence and dynamic changes of qnrS gene. Susceptibility testing, conjugant experiments, and pulsed field gel electrophoresis of qnrS-positive isolates were also performed.
A total of 379 isolates were randomly obtained from feces samples of chickens, ducks and geese in a poultry farm and its environment. The qnrS positive strains were detected in all sources of isolates and two alleles of qnrS were prevalent on this farm. The positive rate of qnrS gene in environmental strains was 29.2%, which was significantly higher than that in the avian strains (13.4%). Chicken can quickly acquire qnrS gene after they live on this farm. Transconjugants of the qnrS gene can elevate ciprofloxacin Minimun inhibitory concentrations (MICs) by 16 - 32 fold compared with the recipient. Various determinants for resistance to other antimicrobial agents were also transferred with the qnrS plasmid. The Xba I PFGE analysis of the qnrS positive strains showed that the dissemination of qnrS was not mainly due to the clonal dissemination of positive strains. However, qnrS-positive strains with indistinguishable PFGE patterns were found in ducks and environment.
Both horizontal gene transfer and clonal spread could be responsible for the dissemination of the qnrS gene in the poultry farm and its environment, but it is mainly disseminated by horizontal transmission.
调查某家禽养殖场及其环境中大肠杆菌分离株中质粒介导的喹诺酮耐药qnrS基因的流行情况和传播方式。
对2010年2月至6月某家禽养殖场及其环境中粪便样本分离得到的大肠杆菌进行qnrS基因流行情况及动态变化的筛查。对qnrS阳性分离株还进行了药敏试验、接合试验和脉冲场凝胶电泳分析。
从某家禽养殖场及其环境中鸡、鸭、鹅粪便样本中随机获得379株分离株。在所有分离株来源中均检测到qnrS阳性菌株，且该养殖场存在两种qnrS等位基因。环境菌株中qnrS基因阳性率为29.2%，显著高于禽类菌株（13.4%）。鸡在该养殖场饲养后可迅速获得qnrS基因。qnrS基因的接合子与受体相比可使环丙沙星最低抑菌浓度（MIC）升高16 - 32倍。qnrS质粒还可携带对其他抗菌药物的多种耐药决定子。对qnrS阳性菌株的Xba I PFGE分析表明，qnrS的传播并非主要由于阳性菌株的克隆传播。然而，在鸭和环境中发现了PFGE图谱无法区分的qnrS阳性菌株。
水平基因转移和克隆传播均可能导致qnrS基因在家禽养殖场及其环境中的传播，但主要通过水平传播。
