Laboratory of Microbiology and Infectious Diseases, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
J Antimicrob Chemother. 2010 Jul;65(7):1372-6. doi: 10.1093/jac/dkq160. Epub 2010 May 22.
TolC is a major outer membrane channel and it plays an important role in the excretion of a wide range of molecules, including antibiotics. A recent study has shown that Salmonella enterica serovar Typhimurium has nine functional drug efflux pumps; however, the TolC dependency of these efflux pumps remains to be studied in detail. The aim of this study was to investigate the TolC dependency of multidrug efflux pumps in this organism.
All genes encoding the drug efflux systems were cloned into the pUC118 vector. Constructed plasmids were transformed into DeltaacrB and DeltatolC mutants of S. enterica serovar Typhimurium ATCC 14028s, and then the drug susceptibilities of these transformants were determined.
Plasmids carrying the acrAB, acrD, acrEF, mdsAB, mdtABC, emrAB or macAB genes did not confer resistance to the tolC mutant, whereas they conferred drug resistance to the acrB mutant. Only three plasmids carrying mdsABC, mdfA or mdtK conferred resistance to the tolC mutant.
TolC is required for the function of seven drug efflux systems (AcrAB, AcrD, AcrEF, MdsAB, MdtABC, EmrAB and MacAB) in S. enterica serovar Typhimurium.
TolC 是主要的外膜通道，在排泄包括抗生素在内的各种分子中发挥重要作用。最近的一项研究表明，鼠伤寒沙门氏菌有 9 个功能正常的药物外排泵；然而，这些外排泵对 TolC 的依赖性仍需详细研究。本研究旨在探讨该菌中多药外排泵对 TolC 的依赖性。
将编码药物外排系统的所有基因克隆到 pUC118 载体中。构建的质粒转化为鼠伤寒沙门氏菌 ATCC 14028s 的 DeltaacrB 和 DeltatolC 突变体，然后测定这些转化体的药物敏感性。
携带 acrAB、acrD、acrEF、mdsAB、md tABC、emrAB 或 macAB 基因的质粒不能赋予 tolC 突变体抗性，但能赋予 acrB 突变体抗性。只有携带 mdsABC、mdfA 或 mdtK 的三个质粒赋予 tolC 突变体抗性。
TolC 是鼠伤寒沙门氏菌 7 种药物外排系统（AcrAB、AcrD、AcrEF、MdsAB、MdtABC、EmrAB 和 MacAB）功能所必需的。
