UMR_MD1, U-1261, Aix-Marseille Univ, INSERM, IRBA, MCT, Marseille, France.
DISCO beamline, Synchrotron Soleil, Saint-Aubin, France.
Commun Biol. 2022 Oct 6;5(1):1062. doi: 10.1038/s42003-022-04024-1.
Sufficient concentration of antibiotics close to their target is key for antimicrobial action. Among the tools exploited by bacteria to reduce the internal concentration of antibiotics, multidrug efflux pumps stand out for their ability to capture and expel many unrelated compounds out of the cell. Determining the specificities and efflux efficiency of these pumps towards their substrates would provide quantitative insights into the development of antibacterial strategies. In this light, we developed a competition efflux assay on whole cells, that allows measuring the efficacy of extrusion of clinically used quinolones in populations and individual bacteria. Experiments reveal the efficient competitive action of some quinolones that restore an active concentration of other fluoroquinolones. Computational methods show how quinolones interact with the multidrug efflux transporter AcrB. Combining experiments and computations unveils a key molecular mechanism acting in vivo to detoxify bacterial cells. The developed assay can be generalized to the study of other efflux pumps.
足够浓度的抗生素接近其靶标是抗菌作用的关键。在细菌用来降低抗生素内部浓度的工具中，多药外排泵因其能够捕获和排出细胞内许多不相关的化合物而引人注目。确定这些泵对其底物的特异性和外排效率将为制定抗菌策略提供定量见解。有鉴于此，我们在全细胞上开发了一种竞争外排测定法，该方法可用于测量临床上使用的喹诺酮类药物在群体和单个细菌中的外排效率。实验揭示了一些喹诺酮类药物的有效竞争作用，这些药物恢复了其他氟喹诺酮类药物的有效浓度。计算方法显示了喹诺酮类药物如何与多药外排转运蛋白 AcrB 相互作用。实验和计算的结合揭示了一种在体内起作用的关键分子机制，用于解毒细菌细胞。开发的测定法可推广到其他外排泵的研究。
