Plasmid-encoded multidrug efflux pump conferring resistance to olaquindox in Escherichia coli
Plasmid-encoded multidrug efflux pump conferring resistance to olaquindox in Escherichia coli
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DOI：
10.1128/aac.48.9.3332-3337.2004
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发表时间：
2004-09-01
影响因子：
4.9
通讯作者：
Sorensen, SJ
中科院分区：
文献类型：
--
作者：
Hansen, LH;Johannesen, E;Sorensen, SJ
我们在这里报告的第一个基因编码的耐药机制，猪生长促进剂喹乙醇。从分离自大肠杆菌的接合质粒中亚克隆了与喹乙醇抗性相关的遗传元件并进行了测序。该亚克隆片段含有两个开放阅读框oqxA和oqxB，它们与来自不同物种的几个抗性-增殖-细胞分裂家族外排系统同源。将推定的蛋白质序列与实验验证的和推定的外排泵进行比对。我们发现oqxA和oqxB在E.杆菌含有oqxAB基因的质粒在大肠杆菌中产生了对喹乙醇的高抗性（>128 μ g/ ml）。而含有对照质粒的菌株显示出对药物的低抗性（8 μ g/ml）。oqxAB编码的泵还赋予对氯霉素的高（>64 μ g/ml）抗性。我们证明，亚克隆片段赋予H+依赖的乙锭流出能力，以E。coliN 43菌株。此外，我们表明，外排系统是依赖于宿主TolC外膜蛋白表达时，在E。杆菌
We report here the first gene-encoded resistance mechanism to the swine growth enhancer olaquindox. The genetic elements involved in resistance to olaquindox were subcloned and sequenced from a conjugative plasmid isolated from Escherichia coli. The subcloned fragment contained two open reading frames, oqxA and oqxB, that are homologous to several resistance-nodulation-cell-division family efflux systems from different species. The putative protein sequences were aligned to both experimentally verified and putative efflux pumps. We show that oqxA and oqxB are expressed in E. coli. Plasmids containing the oqxAB genes yielded high (>128 mug/ ml) resistance to olaquindox in E. coli, whereas strains containing the control plasmid showed low resistance to the drug (8 mug/ml). The oqxAB-encoded pump also conferred high (>64 mug/ml) resistance to chloramphenicol. We demonstrate that the subcloned fragment conferred H+-dependent ethidium efflux abilities to E. coli strain N43. In addition, we show that the efflux system is dependent on the host TolC outer membrane protein when expressed in E. coli.