AcrAB-TolC is the paradigm resistance-nodulation-division (RND) multidrug resistance efflux system in Gram-negative bacteria, with AcrB being the pump protein in this complex. We constructed a nonfunctional AcrB mutant by replacing D408, a highly conserved residue essential for proton translocation. Western blotting confirmed that the AcrB D408A mutant had the same native level of expression of...

Due to the limited information of the contribution of various antibiotic resistance mechanisms in clinical Burkholderia cepacia complex isolates, Antibiotic resistance mechanisms, including integron analysis, identification of quinolone resistance-determining region mutations, measurement of efflux pump activity, and sequence analysis of efflux pump regulators, were investigated in 66 clinical ...

INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) is a persistent problem in community and health care settings. Fluoroquinolones are among the drugs of choice used to treat MRSA infections. This study aims to identify different mechanisms of fluoroquinolne resistance in local MRSA random sampling isolates in Cairo, Egypt. METHODOLOGY A total of 94 clinical isolates of S. aureus...

Fungi transcriptionally upregulate expression of azole efflux pumps and ergosterol biosynthesis pathway genes when exposed to antifungal agents that target ergosterol biosynthesis. To date, these transcriptional responses have been shown to be dependent on the presence of the azoles and/or depletion of ergosterol. Using an inducible promoter to regulate Neurospora crassa erg11, which encodes th...

Title of Dissertation: CHARACTERIZATION AND MOLECULAR MECHANISMS OF ANTIMICROBIAL RESISTANCE IN FOODBORNE PATHOGENS Sheng Chen, Doctor of Philosophy, 2004 Dissertation directed by: Associate Professor Jianghong Meng Department of Nutrition and Food Science The emergence of antimicrobial resistance bacteria in both the medical and agricultural fields has become a serious problem worldwide. The u...

AIM To evaluate the role of biofilm formation on the resistance of Helicobacter pylori (H. pylori) to commonly prescribed antibiotics, the expression rates of resistance genes in biofilm-forming and planktonic cells were compared. METHODS A collection of 33 H. pylori isolates from children and adult patients with chronic infection were taken for the present study. The isolates were screened f...

The authors previously described srpABC, an operon involved in proton-dependent solvent efflux in the solvent-tolerant Pseudomonas putida S12. Recently, it was shown that organic solvents and not antibiotics induce this operon. In the present study, the authors characterize a new efflux pump, designated ArpABC, on the basis of two isolated chloramphenicol-sensitive transposon mutants. The arpAB...

Efflux mediated multidrug resistance (MDR) is a major problem in the treatment of bacterial, fungal and protozoal infections in addition to cancer chemotherapy. Among other well known mechanisms, efflux pumps are significant contributors to chemo-resistance. Efflux mediated resistance generally occurs through up-regulation of genes responsible for the expression of transporter proteins extrudin...

Thirty-one A. baumannii isolates were obtained from Shar and Burn hospitals in Sulaimani City, KRG-Iraq. Bacterial identification was confirmed by detecting both 16S rRNA blaOXA-51 genes. The detection of carbapenem resistant carried out using Kirby- Bauer, RAPDEC Carba NP combined disc assays. A high rate drug resistance observed, as 74.2% the multidrug-resistant (MDR) 38.7% extensively drug-r...

Induction of the membrane-associated organic solvent efflux system SrpABC of Pseudomonas putida S12 was examined by cloning a 312-bp DNA fragment, containing the srp promoter, in the broad-host-range reporter vector pKRZ-1. Compounds that are capable of inducing expression of the srpABC genes include aromatic and aliphatic solvents and alcohols. General stress conditions such as pH, temperature...