BACKGROUND One of the most important resistance mechanisms in bacteria is the increased expression of multidrug efflux pumps. To combat efflux-related resistance, the development of new efflux pump inhibitors is essential. MATERIALS AND METHODS Ten phosphorus ylides were compared based on their MDR-reverting activity in multidrug efflux pump system consisting of the subunits acridine-resistan...

AcrAB-TolC is a major efflux pump in Escherichia coli. It was reported that tolC is overexpressed and involves in improving the organic solvent tolerance level in Escherichia coli marR mutants that are resistant to several antibiotics, such as ciprofloxacin. Low and intermediate levels resistance did not improve organic solvent tolerance. Thus, in this descriptive-experimental study it was deci...

The AcrAB/TolC efflux pump-mediated drug resistance in gram-negative bacteria might be controlled by pump inhibitors (EPIs). This study was planned to discover a compound from plants that can used as an EPI. Forty isolates of K. pneumoniae and 33 different were collected. methanolic extracts parts prepared. Chloramphenicol, tetracycline, Ciprofloxacin for the sensitivity assay. Plant tested EPI...

Growth of Escherichia coli is inhibited upon exposure to a large volume of a harmful solvent, and there is an inverse correlation between the degree of inhibition and the log P(OW) of the solvent, where P(OW) is the partition coefficient measured for the partition equilibrium established between the n-octanol and water phases. The AcrAB-TolC efflux pump system is involved in maintaining intrins...

Erwinia amylovora causes fire blight on several plant species such as apple and pear, which produce diverse phytoalexins as defence mechanisms. An evolutionary successful pathogen thus must develop resistance mechanisms towards these toxic compounds. The E. amylovora outer membrane protein, TolC, might mediate phytoalexin resistance through its interaction with the multidrug efflux pump, AcrAB....

Many laboratory strains of Escherichia coli are resistant to methotrexate (MTX), a folate analogue that binds dihydrofolate reductase (DHFR). Mutations that inactivate either tolC or acrA confer MTX sensitivity. Further, overexpression of a fusion protein with DHFR activity reverses this sensitivity by titrating out intracellular MTX. These results suggest that MTX accumulates in cells where mu...

The AcrAB-TolC efflux pump plays an intrinsic role in resistance to hydrophobic solvents in Escherichia coli. E. coli OST5500 is hypersensitive to solvents due to inactivation of the acrB gene by insertion of IS30. Suppressor mutants showing high solvent resistance were isolated from OST5500. These mutants produced high levels of AcrE and AcrF proteins, which were not produced in OST5500, and i...

The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps in Pseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump compone...

As a representative fluoroquinolone antibacterial, ciprofloxacin is frequently used to treat infections caused by bacteria such as E. coli. It is much meaningful to explore ciprofloxacin susceptibility and investigate a possible mechanism of drug susceptibility changes in E. coli ATCC25922 exposed to the environmental stress of simulated microgravity. The subculture of E. coli lasted for 7 days...