Antimicrobial resistance of human pathogenic bacteria is an emerging problem for global public health. This resistance is often associated with the overproduction of membrane transport proteins that are capable to pump chemotherapeutics, antibiotics, detergents, dyes and organic solvents out of the cell. In Gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa, tripartite m...

The deployment of multidrug efflux pumps is a powerful defence mechanism for Gram-negative bacterial cells when exposed to antimicrobial agents. The major multidrug efflux transport system in Escherichia coli, AcrAB-TolC, is a tripartite system using the proton-motive force as an energy source. The polyspecific substrate-binding module AcrB uses various pathways to sequester drugs from the peri...

Membrane transporters of the RND superfamily confer multidrug resistance to pathogenic bacteria, and are essential for cholesterol metabolism and embryonic development in humans. We use high-resolution X-ray crystallography and computational methods to delineate the mechanism of the homotrimeric RND-type proton/drug antiporter AcrB, the active component of the major efflux system AcrAB-TolC in ...

BACKGROUND & OBJECTIVES There is a worldwide emergence of fluoroquinolone resistance in Shigella species. To understand the molecular mechanisms associated with fluoroquinolone resistance, naturally occurring fluoroquinolone-resistant strains and laboratory-induced spontaneous mutants of Shigella spp. were used and the relative contributions of acrAB-tolC efflux pumps, gyrase and topoisomerase ...

Genes acrAB encode a multidrug efflux pump in Escherichia coli. We have previously reported that transcription of acrAB is increased under general stress conditions (i.e. 4% ethanol, 0.5 M NaCl, and the stationary phase in Luria-Bertani medium). In this study, lacZ transcriptional fusions and an in vitro gel mobility shift assay have been utilized to study the mechanisms governing the regulatio...

Transposon mutagenesis of a clinical isolate of Morganella morganii, G1492 (tigecycline MIC of 4 microg/ml), yielded two insertion knockout mutants for which tigecycline MICs were 0.03 microg/ml. Transposon insertions mapped to acrA, which is constitutively overexpressed in G1492, suggesting a role of the AcrAB efflux pump in decreased susceptibility to tigecycline in M. morganii.

In over eighty years, despite successive antibiotics discoveries, the rapid advent of multidrug resistance among bacterial pathogens has jolted our misapprehension success them. Resistance is spreading faster than discovery new antibiotics/antimicrobials. Therefore, search for better antimicrobials/additives becomes prudent. A water-soluble curcumin derivative (Curaq) was synthesised, employing...

Sir, Tigecycline is a therapeutic option for multidrug-resistant Acinetobacter baumannii and Klebsiella pneumoniae infections. Recently, tigecycline-non-susceptible A. baumannii and K. pneumoniae have been reported in patients receiving tigecycline. Despite several reports concerning in vitro and in vivo susceptibility of bacterial pathogens to tigecycline, there is a paucity of data regarding ...