Read by QxMD icon Read

MdeA efflux

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
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
María del Carmen Casado Muñoz, Nabil Benomar, Leyre Lavilla Lerma, Antonio Gálvez, Hikmate Abriouel
Antimicrobial resistance of Lactobacillus pentosus (n=59) and Leuconostoc pseudomesenteroides (n=13) isolated from Aloreña green table olives (which are naturally-fermented olives from Málaga, Spain) to 15 antibiotics was evaluated. Most Lb. pentosus (95%) and all Lc. pseudomesenteroides were resistant to at least three antibiotics. Principal component analysis determined that the prevalence of antibiotic resistance in LAB throughout the fermentation process was highly dependent on the fermenter where the fermentation took place...
February 17, 2014: International Journal of Food Microbiology
Miguel Angel Fernández-Fuentes, Hikmate Abriouel, Elena Ortega Morente, Rubén Pérez Pulido, Antonio Gálvez
Bacterial biocide resistance is becoming a matter of concern. In the present study, a collection of biocide-resistant, Gram-positive bacteria from organic foods (including 11 isolates from genus Bacillus, 25 from Enterococcus and 10 from Staphylococcus) were analyzed for genes associated to biocide resistance efflux pumps and antibiotic resistance. The only qac-genes detected were qacA/B (one Bacillus cereus isolate) and smr (one B. cereus and two Staphylococcus saprophyticus isolates). Efflux pump genes efrA and efrB genes were detected in Staphylococcus (60% of isolates), Bacillus (54...
February 17, 2014: International Journal of Food Microbiology
Weiwei Jiang, Bin Li, Xinchuan Zheng, Xin Liu, Xichun Pan, Rongxin Qing, Yanyan Cen, Jiang Zheng, Hong Zhou
Methicillin-resistant Staphylococcus aureus (MRSA) has now emerged as a predominant and serious pathogen because of its resistance to a large group of antibiotics, leading to high morbidity and mortality. Therefore, to develop new agents against resistance is urgently required. Previously, artesunate (AS) was found to enhance the antibacterial effect of β-lactams against MRSA. In this study, AS was first found to increase the accumulation of antibiotics (daunorubicin and oxacillin) within MRSA by laser confocal microscopy and liquid chromatography-tandem MS method, suggesting the increased antibiotics accumulation might be related to the enhancement of AS on antibiotics...
June 2013: Journal of Antibiotics
Do Kyun Kim, Kyoung Hoon Kim, Eun Ji Cho, Seoung-Je Joo, Jung-Min Chung, Byoung Yil Son, Jong Hwa Yum, Young-Man Kim, Hyun-Ju Kwon, Byung-Woo Kim, Tae Hoon Kim, Eun-Woo Lee
Multidrug resistance, especially multidrug efflux mechanisms that extrude structurally unrelated cytotoxic compounds from the cell by multidrug transporters, is a serious problem and one of the main reasons for the failure of therapeutic treatment of infections by pathogenic microorganisms as well as of cancer cells. Streptococcus mutans is considered one of the primary causative agents of dental caries and periodontal disease, which comprise the most common oral diseases. A fragment of chromosomal DNA from S...
March 2013: Journal of Microbiology and Biotechnology
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
Andrew Crowe, Susanna Diep
The purpose of this study was to investigate possible efflux mechanisms involved in amphetamine derivative transport such as for 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyethylamphetamine (MDEA), para-methoxyamphetamine (p-MA), dexamphetamine and pseudoephedrine, especially across pH gradients that exist in intestinal or kidney transport. This was determined using our Caco-2 subclone, CLEFF9. Transport of the amphetamine derivatives was evaluated at pH 7.4 and pH 6/7.4+/-efflux inhibitors...
September 11, 2008: European Journal of Pharmacology
Carmen E DeMarco, Laurel A Cushing, Emmanuel Frempong-Manso, Susan M Seo, Tinevimbo A A Jaravaza, Glenn W Kaatz
Efflux is an important resistance mechanism in Staphylococcus aureus, but its frequency in patients with bacteremia is unknown. Nonreplicate bloodstream isolates were collected over an 8-month period, and MICs of four common efflux pump substrates, with and without the broad-spectrum efflux pump inhibitor reserpine, were determined (n = 232). A reserpine-associated fourfold decrease in MIC was considered indicative of efflux. Strains exhibiting efflux of at least two of the four substrates were identified ("effluxing strains" [n = 114])...
September 2007: Antimicrobial Agents and Chemotherapy
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"