High Prevalence of Plasmid-Mediated Quinolone Resistance Determinants qnr, aac(6′)-Ib-cr, and qepA among Ceftiofur-Resistant Enterobacteriaceae Isolates from Companion and Food-Producing Animals
High Prevalence of Plasmid-Mediated Quinolone Resistance Determinants qnr, aac(6′)-Ib-cr, and qepA among Ceftiofur-Resistant Enterobacteriaceae Isolates from Companion and Food-Producing Animals
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DOI：
10.1128/aac.00886-08
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发表时间：
2009-02-01
影响因子：
4.9
通讯作者：
Wang, Minggui
中科院分区：
文献类型：
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作者：
Ma, Junying;Zeng, Zhenling;Wang, Minggui
已发现三种质粒介导的喹诺酮抗性 (PMQR) 决定簇，并已证明它们广泛分布于临床分离株中：qnr 基因、aac(6')-Ib-cr 和 qepA。关于这些决定因素在动物菌株中的流行率的数据很少。通过 PCR 扩增和 DNA 测序确定动物分离株中是否存在 PMQR 基因。检测菌株中超广谱β-内酰胺酶（ESBL）和AmpC β-内酰胺酶的产生，并确定其基因型。分析了所选质粒中 PMQR 决定簇的遗传环境。所有头孢噻呋耐药（MIC≥8μg/ml）肠杆菌科菌株均选自2003年11月至2007年4月期间中国广东省的36只伴侣动物和65只食用动物，其中包括89株大肠埃希菌菌株、9株肺炎克雷伯菌菌株和其他3个属的菌株。总共 68.3% (69/101) 的分离株产生 ESBL 和/或 AmpC β-内酰胺酶，主要是 CTX-M 和 CMY 类型。在 101 株菌株中，PMQR 决定簇存在于 35 株（34.7%）菌株中，其中 qnr、aac(6')-Ib-cr 和 qepA 单独或组合检测到，分别在 8 株（7.9%）、19 株（18.8%）和 16 株（15.8%）中检测到。检测到的qnr基因包括1个qnrB4基因、4个qnrB6基因和3个qnrS1基因。 5 株菌株对 aac(6')-Ib-cr 和 qepA 均呈阳性，而 1 株菌株对 qnrS1、aac(6')-Ib-cr 和 qepA 呈阳性。 qnrB6 的两侧是 ISCR1 的两个拷贝，下游有一个插入的 dfr 基因，上游有 sul1 和 qacE Delta 1 基因。在另一个质粒中，aac(6')-Ib-cr 位于 intI1 后面，arr-3 位于下游。 PMQR 决定簇在从中国动物中分离出的头孢噻呋耐药肠杆菌科菌株中非常普遍。这是首次报道伴侣动物分离株中存在 PMQR 决定因素。
Three kinds of plasmid-mediated quinolone resistance (PMQR) determinants have been discovered and have been shown to be widely distributed among clinical isolates: qnr genes, aac(6')-Ib-cr, and qepA. Few data on the prevalence of these determinants in strains from animals are available. The presence of PMQR genes in isolates from animals was determined by PCR amplification and DNA sequencing. The production of extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases in the strains was detected, and their genotypes were determined. The genetic environment of PMQR determinants in selected plasmids was analyzed. All samples of ceftiofur-resistant (MICs >= 8 mu g/ml) isolates of the family Enterobacteriaceae were selected from 36 companion animals and 65 food-producing animals in Guangdong Province, China, between November 2003 and April 2007, including 89 Escherichia coli isolates, 9 Klebsiella pneumoniae isolates, and isolates of three other genera. A total of 68.3% (69/101) of the isolates produced ESBLs and/or AmpC beta-lactamases, mainly those of the CTX-M and CMY types. Of the 101 strains, PMQR determinants were present in 35 (34.7%) isolates, with qnr, aac(6')-Ib-cr, and qepA detected alone or in combination in 8 (7.9%), 19 (18.8%), and 16 (15.8%) strains, respectively. The qnr genes detected included one qnrB4 gene, four qnrB6 genes, and three qnrS1 genes. Five strains were positive for both aac(6')-Ib-cr and qepA, while one strain was positive for qnrS1, aac(6')-Ib-cr, and qepA. qnrB6 was flanked by two copies of ISCR1 with an intervening dfr gene downstream and sul1 and qacE Delta 1 genes upstream. In another plasmid, aac(6')-Ib-cr followed intI1 and arr-3 was downstream. PMQR determinants are highly prevalent in ceftiofur-resistant Enterobacteriaceae strains isolated from animals in China. This is the first report of the occurrence of PMQR determinants among isolates from companion animals.