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Antibiotic Efflux

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https://www.readbyqxmd.com/read/28224989/mechanisms-of-envelope-permeability-and-antibiotic-influx-and-efflux-in-gram-negative-bacteria
#1
Muriel Masi, Matthieu Réfregiers, Klaas M Pos, Jean-Marie Pagès
No abstract text is available yet for this article.
February 22, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28223380/vitamin-k3-induces-the-expression-of-the-stenotrophomonas-maltophilia-smevwx-multidrug-efflux-pump
#2
P Blanco, F Corona, M B Sánchez, J L Martínez
Stenotrophomonas maltophilia is an opportunistic pathogen, with increasing prevalence, able to cause infections in immunocompromised patients or in those with a previous pathology. The treatment of the infections caused by this bacterium is often complicated due to the several intrinsic antibiotic resistance mechanisms that it presents. Multidrug efflux pumps are among the best studied mechanisms of S. maltophilia antibiotic resistance. Some of these efflux pumps have a basal expression level but, in general, their expression is often low and only reaches high levels when the local regulator is mutated or bacteria are in the presence of an effector...
February 21, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28210464/evaluation-of-efflux-pumps-gene-expression-in-resistant-pseudomonas-aeruginosa-isolates-in-an-iranian-referral-hospital
#3
Babak Pourakbari, Sahar Yaslianifard, Somaye Yaslianifard, Shima Mahmoudi, Sepideh Keshavarz-Valian, Setareh Mamishi
BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa (PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of P. aeruginosa, MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of P. aeruginosa. MATERIALS AND METHODS: In this study, 45 P...
August 2016: Iranian Journal of Microbiology
https://www.readbyqxmd.com/read/28207789/carbapenem-resistance-and-pathogenicity-of-bovine-acinetobacter-indicus-like-isolates
#4
Peter Klotz, Stephan Göttig, Ursula Leidner, Torsten Semmler, Sandra Scheufen, Christa Ewers
The objective of this study was to characterize blaOXA-23 harbouring Acinetobacter indicus-like strains from cattle including genomic and phylogenetic analyses, antimicrobial susceptibility testing and evaluation of pathogenicity in vitro and in vivo. Nasal and rectal swabs (n = 45) from cattle in Germany were screened for carbapenem-non-susceptible Acinetobacter spp. Thereby, two carbapenem resistant Acinetobacter spp. from the nasal cavities of two calves could be isolated. MALDI-TOF mass spectrometry and 16S rDNA sequencing identified these isolates as A...
2017: PloS One
https://www.readbyqxmd.com/read/28193667/whole-genome-sequencing-of-a-large-panel-of-contemporary-neisseria-gonorrhoeae-clinical-isolates-indicates-that-a-wild-type-mtra-gene-is-common-implications-for-inducible-antimicrobial-resistance
#5
Eshaw Vidyaprakash, A Jeanine Abrams, William M Shafer, David L Trees
Previous studies (1) have shown that the expression of the mtrCDE efflux pump operon is inducible at the transcriptional level in gonococci during incubation in sub-lethal concentrations of the nonionic detergent Triton X-100, which along with antibiotics, bile salts, progesterone and antimicrobial peptides, is a substrate of the MtrCDE efflux pump (2).….
February 13, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28169223/insights-into-the-ion-coupling-mechanism-in-the-mate-transporter-norm-vc
#6
Alexander Krah, Ulrich Zachariae
Bacteria have developed a variety of different mechanisms to defend themselves from compounds that are toxic to them, such as antibiotics. One of these defence mechanisms is the expulsion of drugs or other noxious compounds by multidrug efflux pumps. Multidrug and toxic compound extrusion (MATE) transporters are efflux pumps that extrude metabolic waste and a variety of antibiotics out of the cell, using an ion gradient as energy source. They function via an alternative-access mechanism. When ions bind in the outward facing conformation, a large conformational change to the inward facing conformation is induced, from which the ion is released and the extruded chemical compound is bound...
February 7, 2017: Physical Biology
https://www.readbyqxmd.com/read/28160861/antibacterial-activity-of-epigallocatechin-3-gallate-egcg-and-its-synergism-with-%C3%AE-lactam-antibiotics-sensitizing-carbapenem-associated-multidrug-resistant-clinical-isolates-of-acinetobacter-baumannii
#7
Spencer Lee, Ghaida Saleh Al Razqan, Dong H Kwon
BACKGROUND: Infections caused by Acinetobacter baumannii were responsive to conventional antibiotic therapy. However, recently, carbapenem-associated multidrug resistant isolates have been reported worldwide and present a major therapeutic challenge. Epigallocatechin-3-Gallate (EGCG) extracted from green tea exhibits antibacterial activity. PURPOSE: We evaluated the antibacterial activity of EGCG and possible synergism with antibiotics in carbapenem-associated multidrug resistant A...
January 15, 2017: Phytomedicine: International Journal of Phytotherapy and Phytopharmacology
https://www.readbyqxmd.com/read/28157581/survival-of-listeria-monocytogenes-with-different-antibiotic-resistance-patterns-to-food-associated-stresses
#8
Norton Komora, Carolina Bruschi, Rui Magalhães, Vânia Ferreira, Paula Teixeira
The ongoing rise of antibiotic resistant microbial pathogens has become one of the major public health threats worldwide. Despite all the effort and actions taken so far, a proliferation of antibiotic resistant (AR) and multi-antibiotic resistant (MAR) strains is still observed, including in foodborne pathogens. This trend has been also noted recently for isolates of Listeria monocytogenes, a species that, although remaining largely sensitive to clinically relevant antimicrobials, has been reported to develop increased tolerance to antibiotics, particularly in isolates recovered from the food-chain...
January 24, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/28155846/rationalizing-the-permeation-of-polar-antibiotics-into-gram-negative-bacteria
#9
Mariano Andrea Scorciapino, Silvia Acosta-Gutierrez, Dehbia Benkerrou, Tommaso D'Agostino, Giuliano Malloci, Susruta Samanta, Igor Bodrenko, Matteo Ceccarelli
The increasing level of antibiotic resistance in Gram-negative bacteria, together with the lack of new potential drug scaffolds in the pipeline, make the problem of infectious diseases a global challenge for modern medicine. The main reason that Gram-negative bacteria are particularly challenging is the presence of an outer cell-protecting membrane, which is not present in Gram-positive species. Such an asymmetric bilayer is a highly effective barrier for polar molecules. Several protein systems are expressed in the outer membrane to control the internal concentration of both nutrients and noxious species, in particular: (i) water-filled channels that modulate the permeation of polar molecules and ions according to concentration gradients, and (ii) efflux pumps to actively expel toxic compounds...
March 22, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28137939/macrolide-resistance-in-legionella-pneumophila-the-role-of-lpeab-efflux-pump
#10
Clémence Massip, Ghislaine Descours, Christophe Ginevra, Patricia Doublet, Sophie Jarraud, Christophe Gilbert
OBJECTIVES: A previous study on 12 in vitro-selected azithromycin-resistant Legionella pneumophila lineages showed that ribosomal mutations were major macrolide resistance determinants. In addition to these mechanisms that have been well described in many species, mutations upstream of lpeAB operon, homologous to acrAB in Escherichia coli, were identified in two lineages. In this study, we investigated the role of LpeAB and of these mutations in macrolide resistance of L. pneumophila METHODS: The role of LpeAB was studied by testing the antibiotic susceptibility of WT, deleted and complemented L...
January 30, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28129976/evaluation-of-a-series-of-2-napthamide-derivatives-as-inhibitors-of-the-drug-efflux-pump-acrb-for-the-reversal-of-antimicrobial-resistance
#11
Yinhu Wang, Rumana Mowla, Liwei Guo, Abiodun D Ogunniyi, Taufiq Rahman, Miguel A De Barros Lopes, Shutao Ma, Henrietta Venter
Drug efflux pumps confer multidrug resistance to dangerous pathogens which makes these pumps important drug targets. We have synthesised a novel series of compounds based on a 2-naphthamide pharmacore aimed at inhibiting the efflux pumps from Gram-negative bacteria. The archeatypical transporter AcrB from Escherichia coli was used as model efflux pump as AcrB is widely conserved throughout Gram-negative organisms. The compounds were tested for their antibacterial action, ability to potentiate the action of antibiotics and for their ability to inhibit Nile Red efflux by AcrB...
January 16, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28128097/high-level-resistance-to-meropenem-in-clinical-isolates-of-pseudomonas-aeruginosa-in-the-absence-of-carbapenemases-role-of-active-efflux-and-porin-alterations
#12
Hussein Chalhoub, Yolanda Sáenz, Hector Rodriguez-Villalobos, Olivier Denis, Barbara C Kahl, Paul M Tulkens, Françoise Van Bambeke
High-level carbapenem resistance is worryingly increasing in clinical isolates and is often attributed to carbapenemase expression. This study aimed to determine the mechanisms leading to high-level meropenem resistance in six carbapenemase-negative Pseudomonas aeruginosa isolated from cystic fibrosis (CF) patients and seven carbapenemase-positive isolates from patients suffering from hospital-acquired pneumonia (HAP). MICs were determined in the absence or presence of l-arginine or glycine-glutamate as competitive substrates for OprD (OccD1) or OpdP (OccD3), respectively, or the efflux pump inhibitor Phe-Arg β-naphthylamide (PAβN)...
December 2016: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28111348/xenobiotic-transporters-and-kidney-injury
#13
REVIEW
Blessy George, Dahea You, Melanie S Joy, Lauren M Aleksunes
Renal proximal tubules are targets for toxicity due in part to the expression of transporters that mediate the secretion and reabsorption of xenobiotics. Alterations in transporter expression and/or function can enhance the accumulation of toxicants and sensitize the kidneys to injury. This can be observed when xenobiotic uptake by carrier proteins is increased or efflux of toxicants and their metabolites is reduced. Nephrotoxic chemicals include environmental contaminants (halogenated hydrocarbon solvents, the herbicide paraquat, the fungal toxin ochratoxin, and heavy metals) as well as pharmaceuticals (certain beta-lactam antibiotics, antiviral drugs, and chemotherapeutic drugs)...
January 20, 2017: Advanced Drug Delivery Reviews
https://www.readbyqxmd.com/read/28109770/modulation-of-the-antibiotic-activity-against-multidrug-resistant-strains-of-coumarins-isolated-from-rutaceae-species
#14
Sara A L Madeiro, Nathalie H P B Borges, Augusto L Souto, Pedro T R de Figueiredo, José P Siqueira-Junior, Josean F Tavares
The first occurrences and dissemination of resistant microorganisms led to the inefficacy of many antibiotics, available in the market nowadays, therefore, the search for new substances with antimicrobial activity from natural sources has gained a great importance. The purpose of this work is to evaluate the antibacterial activity and modulation of drug resistance in Staphylococcus aureus by coumarins such as bergapten, xantotoxin, isopimpinellin and imperatorin obtained from two Rutaceae species (Metrodorea mollis and Pilocarpus spicatus)...
January 19, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#15
Diane Borselli, Marine Blanchet, Jean-Michel Bolla, Aaron Muth, Kristen Skruber, Otto Phanstiel, Jean Michel Brunel
Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump...
February 1, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28096160/determinants-of-antibacterial-spectrum-and-resistance-potential-of-the-elongation-factor-g-inhibitor-argyrin-b-in-key-gram-negative-pathogens
#16
Adriana K Jones, Angela L Woods, Kenneth T Takeoka, Xiaoyu Shen, Jun-Rong Wei, Ruth E Caughlan, Charles R Dean
Argyrins are natural products with antibacterial activity against Gram-negative pathogens such as P. aeruginosa, B. multivorans and S. maltophilia We previously showed that argyrin B targets elongation factor G (FusA). Here we show that Argyrin B activity against P. aeruginosa PAO1 (MIC = 8 μg/mL) was not affected by deletion of the MexAB-OprM, MexXY-OprM, MexCD-OprJ or MexEF-OprN efflux pumps. However, argyrin B induced expression of MexXY causing a slight but reproducible antagonism with the MexXY substrate antibiotic ciprofloxacin...
January 17, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28091521/mechanisms-of-intrinsic-resistance-and-acquired-susceptibility-of-pseudomonas-aeruginosa-isolated-from-cystic-fibrosis-patients-to-temocillin-a-revived-antibiotic
#17
Hussein Chalhoub, Daniel Pletzer, Helge Weingart, Yvonne Braun, Michael M Tunney, J Stuart Elborn, Hector Rodriguez-Villalobos, Patrick Plésiat, Barbara C Kahl, Olivier Denis, Mathias Winterhalter, Paul M Tulkens, Françoise Van Bambeke
The β-lactam antibiotic temocillin (6-α-methoxy-ticarcillin) shows stability to most extended spectrum β-lactamases, but is considered inactive against Pseudomonas aeruginosa. Mutations in the MexAB-OprM efflux system, naturally occurring in cystic fibrosis (CF) isolates, have been previously shown to reverse this intrinsic resistance. In the present study, we measured temocillin activity in a large collection (n = 333) of P. aeruginosa CF isolates. 29% of the isolates had MICs ≤ 16 mg/L (proposed clinical breakpoint for temocillin)...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28090273/the-effects-of-berberine-and-palmatine-on-efflux-pumps-inhibition-with-different-gene-patterns-in-pseudomonas-aeruginosa-isolated-from-burn-infections
#18
Seyed Sajjad Aghayan, Hamidreza Kalalian Mogadam, Mozhgan Fazli, Davood Darban-Sarokhalil, Seyed Sajjad Khoramrooz, Fereshteh Jabalameli, Somayeh Yaslianifard, Mehdi Mirzaii
BACKGROUND: Related Multidrug Resistance (MDR) to efflux pumps is a significant problem in treating infections caused by Pseudomonas aeruginosa (P. aeruginosa). Plant compounds have been identified as Pump Inhibitors (EPIs). In the current study, the potential effect of Berberine and Palmatine as EPIs were investigated on efflux pump inhibition through focusing on different gene patterns in P. aeruginosa isolated from burn infections. METHODS: All isolates were collected and identified using the standard biochemical tests...
January 2017: Avicenna Journal of Medical Biotechnology
https://www.readbyqxmd.com/read/28088472/cholesterol-and-ergosterol-affect-the-activity-of-staphylococcus-aureus-antibiotic-efflux-pumps
#19
S R Tintino, C D M Oliveira-Tintino, F F Campina, M S Costa, R P Cruz, R L S Pereira, J C Andrade, E O Sousa, J P Siqueira-Junior, H D M Coutinho, T C Leal-Balbino, V Q Balbino
The aim of this study is to evaluate the effect of ergosterol on steroids and cholesterol efflux pumps in multidrug resistant strains of S. aureus. Were used RN4220 harboring plasmid pUL5054, which carries the gene encoding the MsrA macrolide efflux protein; and IS-58, which possesses the TetK tetracycline efflux protein; 1199B resists hydrophilic fluoroquinolones via a NorA-mediated mechanism and wild strain 1199B. The Minimal Inhibitory Concentration (MIC) was determined and the evaluation of possible inhibition of efflux pumps by reduction of MIC...
January 11, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28087782/mutation-supply-and-relative-fitness-shape-the-genotypes-of-ciprofloxacin-resistant-escherichia-coli
#20
Douglas L Huseby, Franziska Pietsch, Gerrit Brandis, Linnéa Garoff, Angelica Tegehall, Diarmaid Hughes
Ciprofloxacin is an important antibacterial drug targeting Type II topoisomerases, highly active against Gram-negatives including Escherichia coli The evolution of resistance to ciprofloxacin in E. coli always requires multiple genetic changes, usually including mutations affecting two different drug target genes, gyrA and parC Resistant mutants selected in vitro or in vivo can have many different mutations in target genes and efflux regulator genes that contribute to resistance. Among resistant clinical isolates the genotype, gyrA S83L D87N, parC S80I is significantly overrepresented suggesting that it has a selective advantage...
January 12, 2017: Molecular Biology and Evolution
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