Background: Multidrug-resistant efflux pumps are one of the most significant methods by which bacteria can evade effects numerous antimicrobials. The aim this study was to determine prevalence multidrug-resistant MDR, extremely drug-resistant XDR, and pan-drug-resistant PDR K. pneumoniae phenotypes in clinical isolates, as well examine detection pump genes ompK35, ompK36, tolC, acrAB strains.&#...

AcrAB-TolC is the major multidrug efflux system in Enterobacteriaceae recognizing structurally unrelated molecules including antibiotics, dyes, and detergents. Additionally, in Escherichia coli it mediates resistance to bile salts. In the plant pathogen Erwinia amylovora AcrAB-TolC is required for virulence and phytoalexin resistance. Exchange analysis of AcrAB-TolC was conducted by complementi...

Two regulons, soxRS and marRAB, are associated with resistance to quinolones or multiple antibiotic in Salmonella enterica serovar Typhimurium. These regulons are activated by nitric oxide and redox-cycling drugs, such as paraquat and cause on activation of the acrAB-encoded efflux pump. In this study, we investigated the effect of nitric oxide (NO) alone and in combination with ofloxacin, cipr...

Multidrug resistant (MDR) bacteria are an increasing health problem with the shortage of new active antibiotic agents. Among effective mechanisms that contribute to the spread of MDR Gram-negative bacteria are drug efflux pumps that expel clinically important antibiotic classes out of the cell. Drug pumps are attractive targets to restore the susceptibility toward the expelled antibiotics by im...

OBJECTIVES Starting from the observation that Escherichia coli tolC mutations severely reduced the high-level resistance to tetracycline afforded by Tn10- and plasmid-encoded Tet(A) pumps, we studied the mechanism of this susceptibility. METHODS The MIC of tetracycline for MC4100 tolC::Tn10 and several tolC mutants carrying the Tn10 in other sites on the chromosome (thr::Tn10) was determined....

Escherichia coli K-12 strains are normally tolerant to n-hexane and susceptible to cyclohexane. Constitutive expression of marA of the multiple antibiotic resistance (mar) locus or of the soxS or robA gene product produced tolerance to cyclohexane. Inactivation of the mar locus or the robA locus, but not the soxRS locus, increased organic solvent susceptibility in the wild type and Mar mutants ...

OBJECTIVES The transcriptional activator RamA regulates production of the multidrug resistance efflux AcrAB-TolC system in several Enterobacteriaceae. This study investigated factors that lead to increased expression of ramA. METHODS In order to monitor changes in ramA expression, the promoter region of ramA was fused to a gfp gene encoding an unstable green fluorescence protein (GFP) on the ...

26 Control of membrane permeability is a key step in regulating the intracellular 27 concentration of antibiotics. Efflux pumps confer innate resistance to a wide 28 range of toxic compounds such as antibiotics, dyes, detergents and 29 disinfectants in members of the Enterobacteriaceae. The AcrAB-TolC efflux 30 pump is involved in multidrug resistance in E. cloacae. However, the underlying 31 m...

The ability of bacterial pathogens to infect and cause disease is dependent upon their ability to resist antimicrobial components produced by their host, such as bile acids, fatty acids and other detergent-like molecules, and products of the innate immune system (e.g. cationic antimicrobial peptides). Bacterial resistance to the antimicrobial effects of such compounds is often mediated by activ...