%A Iino,Ryota %A Nishino,Kunihiko %A Noji,Hiroyuki %A Yamaguchi,Akihito %A Matsumoto,Yoshimi %D 2012 %J Frontiers in Microbiology %C %F %G English %K Escherichia coli,Fluorescein-di-β-D-galactopyranoside,fluorescence microscopy,Microfluidic channel,Phe-Arg-β-naphthylamide,Polymyxin B nonapeptide,Pseudomonas aeruginosa,Pyridopyrimidine %Q %R 10.3389/fmicb.2012.00040 %W %L %M %P %7 %8 2012-February-08 %9 Methods %+ Dr Yoshimi Matsumoto,Osaka University,Institute of Scientific and Industrial Research,8-1 Mihogaoka,Ibaraki,567-0047,Osaka,Japan,yoshimi@sanken.osaka-u.ac.jp %# %! Visualization of efflux pump activity %* %< %T A Microfluidic Device for Simple and Rapid Evaluation of Multidrug Efflux Pump Inhibitors %U https://www.frontiersin.org/articles/10.3389/fmicb.2012.00040 %V 3 %0 JOURNAL ARTICLE %@ 1664-302X %X Recently, multidrug-resistant pathogens have disseminated widely owing essentially to their increased multidrug efflux pump activity. Presently, there is a scarcity of new antibacterial agents, and hence, inhibitors of multidrug efflux pumps belonging to the resistance–nodulation–cell division (RND) family appear useful in the treatment of infections by multidrug-resistant pathogens. Moreover, recent progress in microfabrication technologies has expanded the application of nano/micro-devices to the field of human healthcare, such as the detection of infections and diagnosis of diseases. We developed a microfluidic channel device for a simple and rapid evaluation of bacterial drug efflux activity. By combining the microfluidic device with a fluorogenic compound, fluorescein-di-β-D-galactopyranoside, which is hydrolyzed to a fluorescent dye in the cytoplasm of Escherichia coli, we successfully evaluated the effects of inhibitors on the RND-type multidrug efflux pumps MexAB–OprM and MexXY–OprM from Pseudomonas aeruginosa in E. coli. Our new method successfully detected the MexB-specific inhibitory effect of D13-9001 and revealed an unexpected membrane-permeabilizing effect of Phe-Arg-β-naphthylamide, which has long been used as an efflux pump inhibitor.