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MdeA S. aureus

Mary K Phillips-Jones, Stephen E Harding
In this review, we discuss mechanisms of resistance identified in bacterial agents Staphylococcus aureus and the enterococci towards two priority classes of antibiotics-the fluoroquinolones and the glycopeptides. Members of both classes interact with a number of components in the cells of these bacteria, so the cellular targets are also considered. Fluoroquinolone resistance mechanisms include efflux pumps (MepA, NorA, NorB, NorC, MdeA, LmrS or SdrM in S. aureus and EfmA or EfrAB in the enterococci) for removal of fluoroquinolone from the intracellular environment of bacterial cells and/or protection of the gyrase and topoisomerase IV target sites in Enterococcus faecalis by Qnr-like proteins...
April 2018: Biophysical Reviews
Geng-Hsi Wu, Shan-Hui Hsu
Cationic polymers are often used as antimicrobial materials and transfection reagents. Water-based process could reduce environmental pollution and prevent the risk of solvent residue in the final product. In this study, waterborne biodegradable cationic polyurethane (WCPU) was synthesized by reacting polycaprolactone (PCL diol), isophorone diisocyanate (IPDI), and N-methyldiethanolamine (N-MDEA) under 75°C. An aqueous dispersion of WCPU nanoparticles (NPs) could be acquired by vigorous stirring under acidic condition...
October 1, 2016: Colloids and Surfaces. B, Biointerfaces
Bryan D Schindler, Pauline L Jacinto, Joseph Adrian L Buensalido, Susan M Seo, Glenn W Kaatz
Increased expression of genes encoding multidrug resistance efflux pumps (MDR-EPs) contributes to antimicrobial agent and biocide resistance in Staphylococcus aureus. Previously identified associations between norA overexpression and spa type t002 meticillin-resistant S. aureus (MRSA), and a similar yet weaker association between mepA overexpression and type t008 meticillin-susceptible S. aureus (MSSA), in clinical isolates are suggestive of clonal dissemination. It is also possible that related strains are prone to mutations resulting in overexpression of specific MDR-EP genes...
May 2015: International Journal of Antimicrobial Agents
Wen-Shuai Liu, Chun-Hua Wang, Ju-Feng Sun, Gui-Ge Hou, Yu-Peng Wang, Rong-Jun Qu
Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R = -benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E. coli, S. aureus, B. subtilis, especially C12QAS with the best antibacterial ability (100% to E...
January 2015: Chemical Biology & Drug Design
Jihoon Woo, Juhee Ahn
This study was designed to evaluate the combined effect of probiotic Lactobacillus rhamnosus and bacteriophage SA11 on the control of antibiotic-sensitive Staphylococcus aureus (ASSA) and antibiotic-resistant S. aureus (ARSA) under the simulated intestinal conditions. The survivability of ASSA and ARSA were determined in the simulated phosphate-buffered saline (PBS)-, trypticase soy broth (TSB)-, and milk-based gastric juices adjusted to pH 2.0, 3.0, and 5.0 at 37 °C for 30 min. The inhibitory effect of bacteriophage SA11 and probiotic on the growth of ASSA and ARSA was evaluated in the simulated intestinal juices at 37 °C for 20 h...
October 2014: Archives of Microbiology
Xinlong He, Juhee Ahn
This study was designed to evaluate gene expression patterns of the planktonic and biofilm cells of Staphylococcus aureus and Salmonella Typhimurium in trypticase soy broth adjusted to pH 5.5 and pH 7.3. The planktonic and biofilm cells of multiple antibiotic-resistant S. aureus (S. aureus(R) ) and S. Typhimurium (S. Typhimurium(R) ) were more resistant to β-lactams than those of antibiotic-susceptible S. aureus (S. aureus(S) ) and S. Typhimurium (S. Typhimurium(S) ) at pH 5.5 and pH 7.3. The relative gene expression levels of norB, norC, and mdeA genes were increased by 7...
December 2011: FEMS Microbiology Letters
Zahid Mehmood Mirza, Ashwani Kumar, Nitin Pal Kalia, Afzal Zargar, Inshad Ali Khan
Piperine, a trans-trans-isomer of 1-piperoyl-piperidine, was tested in combination with mupirocin for antimicrobial activity against Staphylococcus aureus strains including meticillin-resistant S. aureus. The combination markedly reduced the MIC of mupirocin and also lowered the mutation frequency. Enhanced accumulation and efflux of ethidium bromide from wild-type and mutant (Mup(r)-1) strains in the presence of piperine indicated that inhibition of efflux could be a possible mechanism of potentiation of mupirocin activity by piperine...
October 2011: Journal of Medical Microbiology
Emmanuel Frempong-Manso, Jose L Raygada, Carmen E DeMarco, Susan M Seo, Glenn W Kaatz
Overexpression of efflux pump genes conferring multidrug resistance (MDR) in Staphylococcus aureus results in reduced susceptibility to select biocides, dyes and fluoroquinolones. Reserpine is commonly used as an inhibitor of MDR efflux pumps and previous work from our laboratory using a reserpine-based screen to identify clinical isolates with an efflux phenotype revealed that nearly one-half overexpressed norA-B-C, mepA or mdeA. The accuracy of reserpine in predicting efflux pump gene overexpression in clinical strains was examined in detail...
April 2009: International Journal of Antimicrobial Agents
Aurélie A Huet, Jose L Raygada, Kabir Mendiratta, Susan M Seo, Glenn W Kaatz
Biocides and dyes are commonly employed in hospital and laboratory settings. Many of these agents are substrates for multiple-drug resistance (MDR)-conferring efflux pumps of both Gram-positive and Gram-negative organisms. Several such pumps have been identified in Staphylococcus aureus, and mutants overexpressing the NorA and MepA MDR pumps following exposure to fluoroquinolones have been identified. The effect of exposure to low concentrations of biocides and dyes on the expression of specific pump genes has not been evaluated...
October 2008: Microbiology
Azmi Johari Saiful, Mohtar Mastura, Suhaili Zarizal, Mohamed Isa Mazurah, Mustafa Shuhaimi, Abdul Manaf Ali
Efflux-mediated resistance has been recognized as an important contributor of antibiotic resistance in bacteria, especially in methicillin-resistant Staphylococcus aureus (MRSA) isolates. This study was carried out to detect and analyze efflux genes (norA and mdeA) and active efflux activity in a collection of Malaysian MRSA and methicillin-sensitive S. aureus (MSSA) clinical isolates. Nineteen isolates including three ATCC S. aureus reference strains were subjected to PCR detection and DNA sequence analysis for norA and mdeA and active efflux detection using modified minimum inhibitory concentration (MIC) assay...
August 2008: Journal of Basic Microbiology
Youichi Yamada, Sumiko Shiota, Tohru Mizushima, Teruo Kuroda, Tomofusa Tsuchiya
A DNA fragment conferring drug resistance was cloned from the chromosomal DNA of Staphylococcus aureus N315 using a drug hypersensitive Escherichia coli KAM32 as the host. Although E. coli KAM32 cells were sensitive to many antimicrobial agents, transformed cells harboring a recombinant plasmid carrying the DNA region became resistant to several structurally unrelated antimicrobial agents, such as tetraphenylphosphonium chloride, Hoechst 33342 and norfloxacin. These results suggest that the cloned DNA fragment carries a gene(s) encoding a multidrug efflux pump...
April 2006: Biological & Pharmaceutical Bulletin
Jianzhong Huang, Paul W O'Toole, Wei Shen, Heather Amrine-Madsen, Xinhe Jiang, Neethan Lobo, Leslie M Palmer, LeRoy Voelker, Frank Fan, Michael N Gwynn, Damien McDevitt
Antibiotic efflux is an important mechanism of resistance in pathogenic bacteria. Here we describe the identification and characterization of a novel chromosomally encoded multidrug resistance efflux protein in Staphylococcus aureus, MdeA (multidrug efflux A). MdeA was identified from screening an S. aureus open reading frame expression library for resistance to antibiotic compounds. When overexpressed, MdeA confers resistance on S. aureus to a range of quaternary ammonium compounds and antibiotics, but not fluoroquinolones...
March 2004: Antimicrobial Agents and Chemotherapy
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