Substrate specificity of the OqxAB multidrug resistance pump in Escherichia coli and selected enteric bacteria
Substrate specificity of the OqxAB multidrug resistance pump in Escherichia coli and selected enteric bacteria
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DOI：
10.1093/jac/dkm167
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发表时间：
2007-07-01
影响因子：
5.2
通讯作者：
Sorensen, Soren Johannes
中科院分区：
文献类型：
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作者：
Hansen, Lars Hestbjerg;Jensen, Lars Bogo;Sorensen, Soren Johannes
目的：研究从猪源大肠杆菌中分离到的质粒编码多药联苯泵OqxAB对所选抗生素、洗涤剂和消毒剂的底物特异性。水平转移到肠杆菌科食源性病原体的能力也进行了调查。方法：除存在oqxAB操纵子外，采用两种等基因大肠杆菌菌株的肉汤稀释法测定所选底物的mic。构建了编码OqxAB的质粒衍生物（pOLA52），并对其向鼠伤寒沙门菌、肺炎克雷伯菌、克卢韦拉菌和绿色肠杆菌的水平转移进行了研究。用肉汤稀释法研究了OqxAB泵的存在对所选化合物的敏感性的影响。结果：OqxAB泵在大肠杆菌中赋予抗菌素耐药性或降低对多种底物的敏感性。这些包括动物生长促进剂、抗菌剂、消毒剂和洗涤剂。pOLA52可以很容易地转移到肠杆菌病原体。转偶联物对氯霉素、环丙沙星和喹啉的敏感性降低。结论：质粒编码的OqxAB泵具有广泛的底物特异性，可以在肠杆菌科细菌之间转移，从而降低了对多种底物的敏感性。这些结果可能表明不同物种对外膜蛋白存在一定的依赖性。
Objectives: A plasmid-encoded multidrug eff lux pump, OqxAB, identified in Escherichia coli of porcine origin, was tested for substrate specificity against selected antibiotics, detergents and disinfectants. The ability of horizontal transfer to food-borne pathogens of the Enterobacteriaceae family was also investigated.Methods: The MICs of selected substrates were determined with a broth dilution assay using two isogenic E. coli strains, except for the presence of the oqxAB operon. A derivative of the plasmid encoding OqxAB (pOLA52) was constructed and horizontal transfer to Salmonella Typhimurium, Klebsiella pneumoniae, Kluyvera sp. and Enterobacter aerogrenes was investigated. The effect of the presence of the OqxAB pump on susceptibility for selected compounds was investigated using broth dilution assays.Results: The OqxAB pump conferred antimicrobial resistance or reduced susceptibility towards a variety of substrates in E. coli. These included animal growth promoters, antimicrobials, disinfectants and detergents. pOLA52 could readily be transferred to enterobacterial pathogens. Transconjugants showed reduced susceptibility towards chloramphenicol, ciprofloxacin and olaquindox.Conclusions: The plasmid-encoded OqxAB pump has a wide substrate specificity and can be transferred between Enterobacteriaceae conferring reduced susceptibility to a multitude of substrates. These results could indicate some dependence on the outer membrane proteins present in the different species.