keyword
MENU ▼
Read by QxMD icon Read
search

Antibiotic Efflux

keyword
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#1
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...
January 18, 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
#2
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
#3
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
#4
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
#5
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
#6
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
https://www.readbyqxmd.com/read/28074055/effects-of-two-6-quinolinyl-chalcones-on-the-integrity-of-plasma-membrane-of-paracoccidioides-brasiliensis
#7
Nívea P de Sá, Patrícia S Cisalpino, Luciana C Tavares, Leandro Espíndola, Beatriz M Borelli, Paulo Js Barbeira, Gabriele de Matos Cardoso Perdigão, Elaine M Souza-Fagundes, Carlos A Rosa, Moacir G Pizzolatti, Susana Johann
Paracoccidioidomycosis is the most prevalent systemic mycosis in Latin America, yet few therapeutic options exist. Our aim was to search for new compounds with high efficacy, low toxicity, shorter treatment time and affordable cost. We studied two synthetic 6-quinolinyl chalcones, 3b and 3e, to determine their effects on VERO cells, antifungal activity, survival curve, interaction with other drugs and phenotypic effects against several isolates of Paracoccidioides spp. In this study, we verified that the compounds were not toxic, exhibited superior in vitro activity compared with that shown by trimethoprim-sulfamethoxazole, and after 5 days of treatment, decreased the fungal cell viability by approximately 70%...
January 11, 2017: Journal of Antibiotics
https://www.readbyqxmd.com/read/28062292/use-of-carvacrol-thymol-and-eugenol-for-biofilm-eradication-and-resistance-modifying-susceptibility-of-salmonella-enterica-serovar-typhimurium-strains-to-nalidixic-acid
#8
Hanene Miladi, Tarek Zmantar, Bochra Kouidhi, Yassine Chaabouni, Kacem Mahdouani, Amina Bakhrouf, Kamel Chaieb
The Aims of the study was to evaluate the antibacterial susceptibility and the biofilm eradication of three natural compounds carvacrol (CAR), thymol (TH) and eugenol (EUG), alone or in combination with nalidixic acid (NA) against twelve Salmonella Typhimurium strains. The minimum inhibitory concentration (MIC) and the minimum biofilm eradication concentration (BEC50) of the tested compounds (CAR, TH and EUG) and their combinations with NA were evaluated. In order to assess whether these bacteria had active efflux pumps, ethidium bromide (EtBr) accumulation assays was achieved using spectrophotometric accumulation assays...
January 3, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28060821/customized-regulation-of-diverse-stress-response-genes-by-the-multiple-antibiotic-resistance-activator-mara
#9
Nicholas A Rossi, Mary J Dunlop
Stress response networks frequently have a single upstream regulator that controls many downstream genes. However, the downstream targets are often diverse, therefore it remains unclear how their expression is specialized when under the command of a common regulator. To address this, we focused on a stress response network where the multiple antibiotic resistance activator MarA from Escherichia coli regulates diverse targets ranging from small RNAs to efflux pumps. Using single-cell experiments and computational modeling, we showed that each downstream gene studied has distinct activation, noise, and information transmission properties...
January 6, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28044273/rnd-efflux-pump-mediated-antibiotic-resistance-in-gram-negative-bacteria-escherichia-coli-and-pseudomonas-aeruginosa-a-major-issue-worldwide
#10
REVIEW
Minakshi Puzari, Pankaj Chetia
Therapeutic failures against diseases due to resistant Gram-negative bacteria have become a major threat nowadays as confirmed by surveillance reports across the world. One of the methods of development of multidrug resistance in Escherichia coli and Pseudomonas aeruginosa is by means of RND efflux pumps. Inhibition of these pumps might help to combat the antibiotic resistance problem, for which the structure and regulation of the pumps have to be known. Moreover, judicious antibiotic use is needed to control the situation...
February 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28040182/effects-of-exposure-to-quaternary-ammonium-based-biocides-on-antimicrobial-susceptibility-and-tolerance-to-physical-stresses-in-bacteria-from-organic-foods
#11
Rebeca Gadea, Miguel Ángel Fernández Fuentes, Rubén Pérez Pulido, Antonio Gálvez, Elena Ortega
In the present study, a collection of 76 biocide-sensitive bacterial strains isolated from organically produced food were adapted by repeated exposure to increasing concentrations of the quaternary ammonium compounds (QACs) benzalkonium chloride (BC) and hexadecylpyridinium chloride (HDP). The sensitivity of both wildtype strains and their corresponding QAC-adapted strains to other biocides and to antibiotics was studied. QAC tolerance increased in 88.2% of strains for BC and in 30.3% of strains for HDP, with increases in minimum inhibitory concentrations between 2 and over 100 fold...
May 2017: Food Microbiology
https://www.readbyqxmd.com/read/28034542/shifts-in-microbial-community-structure-and-function-in-surface-waters-impacted-by-unconventional-oil-and-gas-wastewater-revealed-by-metagenomics
#12
N L Fahrenfeld, Hannah Delos Reyes, Alessia Eramo, Denise M Akob, Adam C Mumford, Isabelle M Cozzarelli
Unconventional oil and gas (UOG) production produces large quantities of wastewater with complex geochemistry and largely uncharacterized impacts on surface waters. In this study, we assessed shifts in microbial community structure and function in sediments and waters upstream and downstream from a UOG wastewater disposal facility. To do this, quantitative PCR for 16S rRNA and antibiotic resistance genes along with metagenomic sequencing were performed. Elevated conductivity and markers of UOG wastewater characterized sites sampled downstream from the disposal facility compared to background sites...
December 26, 2016: Science of the Total Environment
https://www.readbyqxmd.com/read/28034459/calcium-induces-tobramycin-resistance-in-pseudomonas-aeruginosa-by-regulating-rnd-efflux-pumps
#13
Sharmily Khanam, Manita Guragain, Dirk L Lenaburg, Ryan Kubat, Marianna A Patrauchan
Pseudomonas aeruginosa is an opportunistic multidrug resistant pathogen causing severe chronic infections. Our previous studies showed that elevated calcium (Ca(2+)) enhances production of several virulence factors and plant infectivity of the pathogen. Here we show that Ca(2+) increases resistance of P. aeruginosa PAO1 to tobramycin, antibiotic commonly used to treat Pseudomonas infections. LC-MS/MS-based comparative analysis of the membrane proteomes of P aeruginosa grown at elevated versus not added Ca(2+), determined that the abundances of two RND (resistance-nodulation-cell division) efflux pumps, MexAB-OprM and MexVW-OprM, were increased in the presence of elevated Ca(2+)...
November 20, 2016: Cell Calcium
https://www.readbyqxmd.com/read/28025037/impact-of-azithromycin-on-the-clinical-and-antimicrobial-effectiveness-of-tobramycin-in-the-treatment-of-cystic-fibrosis
#14
Dave P Nichols, Carrie L Happoldt, Preston E Bratcher, Silvia M Caceres, James F Chmiel, Kenneth C Malcolm, Milene T Saavedra, Lisa Saiman, Jennifer L Taylor-Cousar, Jerry A Nick
BACKGROUND: Concomitant use of oral azithromycin and inhaled tobramycin occurs in approximately half of US cystic fibrosis (CF) patients. Recent data suggest that this combination may be antagonistic. METHODS: Test the hypothesis that azithromycin reduces the clinical benefits of tobramycin by analyses of clinical trial data, in vitro modeling of P. aeruginosa antibiotic killing, and regulation of the MexXY efflux pump. RESULTS: Ongoing administration of azithromycin associates with reduced ability of inhaled tobramycin, as compared with aztreonam, to improve lung function and quality of life in a completed clinical trial...
December 23, 2016: Journal of Cystic Fibrosis: Official Journal of the European Cystic Fibrosis Society
https://www.readbyqxmd.com/read/28011349/elevated-prevalence-of-multidrug-resistant-acinetobacter-baumannii-with-extensive-genetic-diversity-in-the-largest-burn-centre-of-northeast-iran
#15
Nazanin Sarhaddi, Saman Soleimanpour, Hadi Farsiani, Arman Mosavat, Samaneh Dolatabadi, Himen Salimizand, Saeid Amel Jamehdar
OBJECTIVES: The emergence and spread of multidrug-resistant (MDR) Acinetobacter baumannii isolates is now frequently associated with nosocomial infections. The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst A. baumannii isolated from a burn centre at a teaching hospital in Iran. METHODS: A total of 54 A. baumannii isolates were collected from burn wound infections of hospitalised patients. Antimicrobial susceptibility of the isolates was determined, and genotyping analysis was performed by repetitive extragenic palindromic PCR (rep-PCR)...
December 21, 2016: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28004362/contribution-of-target-alteration-protection-and-efflux-pump-in-achieving-high-ciprofloxacin-resistance-in-enterobacteriaceae
#16
Ram Prosad Chakrabarty, Munawar Sultana, Saadlee Shehreen, Selina Akter, M Anwar Hossain
The study aims at revealing the comprehensive contribution of target alteration, target protection and efflux pump to the development of high level of ciprofloxacin (CIP) resistance in Enterobacteriaceae bacteria of environmental, clinical and poultry origins. Antibiotic susceptibility test was used to detect CIP resistant (CIPR) isolates and MICCIP was determined by broth microdilution method. The presence of qnrS gene was identified by PCR and Southern blot hybridization (SBH) confirmed their location. Checkerboard titration demonstrated the effect of NMP on CIP action...
December 2016: AMB Express
https://www.readbyqxmd.com/read/27999619/comparative-genomics-analyses-revealed-two-virulent-listeria-monocytogenes-strains-isolated-from-ready-to-eat-food
#17
Shu Yong Lim, Kien-Pong Yap, Kwai Lin Thong
BACKGROUND: Listeria monocytogenes is an important foodborne pathogen that causes considerable morbidity in humans with high mortality rates. In this study, we have sequenced the genomes and performed comparative genomics analyses on two strains, LM115 and LM41, isolated from ready-to-eat food in Malaysia. RESULTS: The genome size of LM115 and LM41 was 2,959,041 and 2,963,111 bp, respectively. These two strains shared approximately 90% homologous genes. Comparative genomics and phylogenomic analyses revealed that LM115 and LM41 were more closely related to the reference strains F2365 and EGD-e, respectively...
2016: Gut Pathogens
https://www.readbyqxmd.com/read/27974958/frequency-of-antiseptic-resistance-among-staphylococcus-aureus-and-coagulase-negative-staphylococci-isolated-from-a-university-hospital-in-central-iran
#18
Nona Taheri, Abdollah Ardebili, Alireza Amouzandeh-Nobaveh, Ehsanollah Ghaznavi-Rad
OBJECTIVES: Reduced biocide susceptibility in Staphylococci is associated with various antiseptic resistance genes encoding efflux systems. Our aim was to determine the susceptibility to three disinfectant agents, including benzalkonium chloride (BAC), benzethonium chloride (BZT), and chlorhexidine digluconate (CHDG) among clinical isolates of Staphylococcus aureus and coagulase-negative Staphylococci (CoNS). METHODS: The minimum inhibitory concentration (MIC) of 60 methicillin-resistant S...
November 2016: Oman Medical Journal
https://www.readbyqxmd.com/read/27940264/lincosamides-chemical-structure-biosynthesis-mechanism-of-action-resistance-and-applications
#19
REVIEW
Jaroslav Spížek, Tomáš Řezanka
Lincomycin and its derivatives are antibiotics exhibiting biological activity against bacteria, especially Gram-positive ones, and also protozoans. Lincomycin and its semi-synthetic chlorinated derivative clindamycin are widely used in clinical practice. Both antibiotics are bacteriostatic, inhibiting protein synthesis in sensitive bacteria; however, at higher concentrations, they may be bactericidal. Clindamycin is usually much more active than lincomycin in the treatment of bacterial infections, in particular those caused by anaerobic species; it can also be used for the treatment of important protozoal diseases, e...
December 7, 2016: Biochemical Pharmacology
https://www.readbyqxmd.com/read/27938381/assessment-of-antibiotic-resistance-in-klebsiella-pneumoniae-exposed-to-sequential-in-vitro-antibiotic-treatments
#20
Jeongjin Kim, Ara Jo, Ekachai Chukeatirote, Juhee Ahn
BACKGROUND: Bacteria treated with different classes of antibiotics exhibit changes in susceptibility to successive antibiotic treatments. This study was designed to evaluate the influence of sequential antibiotic treatments on the development of antibiotic resistance in Klebsiella pneumoniae associated with β-lactamase and efflux pump activities. METHODS: The antibiotic susceptibility, β-lactamase activity, and efflux activity were determined in K. pneumoniae grown at 37 °C by adding initial (0 h) and second antibiotics (8 or 12 h)...
December 9, 2016: Annals of Clinical Microbiology and Antimicrobials
keyword
keyword
118006
1
2
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"