Pseudomonas aeruginosa is an opportunistic, nosocomial pathogen for which antibiotic resistance and biofilm development is common. Quorum sensing communication is known to be a major controlling factor in virulence gene expression, biofilm development, antibiotic resistance factors, and specifically MexAB-OprM multi-drug efflux pump expression in P.aeruginosa. MexAB-OprM efflux pumps contribute...

Retrospective analysis of 189 nonredundant strains of Pseudomonas aeruginosa sequentially recovered from the sputum samples of 46 cystic fibrosis (CF) patients over a 10-year period (1998 to 2007) revealed that 53 out of 189 (28%) samples were hypersusceptible to the beta-lactam antibiotic ticarcillin (MIC < or = 4 microg/ml) (phenotype dubbed Tic(hs)). As evidenced by trans-complementation and...

The use of radiopharmaceuticals for the diagnosis of infection is increasing due to their ability to distinguish between septic and aseptic inflammation. The aim of this study was to analyze the intracellular accumulation of technetium-99m-ciprofloxacin in strains of Staphylococcus aureus and Pseudomonas aeruginosa harboring an overexpression of NorA and MexAB-OprM, respectively.

OBJECTIVES The objectives of this study were to compare the antibiotic susceptibility of Pseudomonas aeruginosa strains with increased efflux pump expression in vitro and in vivo and to use these same strains to evaluate the efficacy of combinations of antibiotics with putative efflux pump inhibitors in vivo. METHODS A collection of P. aeruginosa strains that overexpress three efflux pumps (M...

Fluorescein-di-β-D-galactopyranoside (FDG), a fluorogenic compound, is hydrolyzed by β-galactosidase in the cytoplasm of Escherichia coli to produce a fluorescent dye, fluorescein. We found that both FDG and fluorescein were substrates of efflux pumps, and have developed a new method to evaluate efflux-inhibitory activities in E. coli using FDG and a microfluidic channel device. We used E. coli...

background and objectives: pseudomonas aeruginosa (pa) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. among all the resistance-nodulation-division (rnd) pumps of p. aeruginosa, mexab-oprm is the first efflux pump found to target multiple classes of antibiotics. this study was aimed to evaluate the expression level of genes expre...

Mutations in mexR yield a multidrug resistance phenotype in nalB mutants of Pseudomonas aeruginosa as a result of derepression of the mexAB-oprM multidrug efflux operon. MexR produced by several nalB strains carried single amino acid changes that compromised MexR stability or its ability to dimerize. Changes at residues L95 and R21, however, produced a stable MexR protein capable of dimerizatio...

We describe an original activity assay for membrane transport that uses the proton motive force-dependent efflux pump MexAB from Pseudomonas aeruginosa. This pump is co-reconstituted into proteoliposomes together with bacteriorhodopsin (BR), a light-activated proton pump. In this system, upon illumination with visible light, the photo-induced proton gradient created by the BR is shown to be cou...

There are errors in the second and eighth authors’ names. Their names should read: Anamika Ghose and Atanu Chakravarty. The corrected citation is: Choudhury D, Ghose A, Dhar Chanda D, Das Talukdar A, Dutta Choudhury M, Paul D, et al. (2016) Premature Termination of MexR Leads to Overexpression of MexAB-OprM Efflux Pump in Pseudomonas aeruginosa in a Tertiary Referral Hospital in India. PLoS ONE...