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Antibiotic Efflux

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https://www.readbyqxmd.com/read/29468195/transcriptome-profiling-reveals-interplay-of-multifaceted-stress-response-in-escherichia-coli-on-exposure-to-glutathione-and-ciprofloxacin
#1
Manish Goswami, Akkipeddi Venkat Satya Surya Narayana Rao
We have previously reported that supplementation of exogenous glutathione (GSH) promotes ciprofloxacin resistance in Escherichia coli by neutralizing antibiotic-induced oxidative stress and by enhancing the efflux of antibiotic. In the present study, we used a whole-genome microarray as a tool to analyze the system-level transcriptomic changes of E. coli on exposure to GSH and/or ciprofloxacin. The microarray data revealed that GSH supplementation affects redox function, transport, acid shock, and virulence genes of E...
January 2018: MSystems
https://www.readbyqxmd.com/read/29464798/bioactive-compounds-from-the-african-medicinal-plant-cleistochlamys-kirkii-as-resistance-modifiers-in-bacteria
#2
Annamária Kincses, Borisz Varga, Ákos Csonka, Shirley Sancha, Silva Mulhovo, Ana Margarida Madureira, Maria-José U Ferreira, Gabriella Spengler
Cleistochlamys kirkii (Benth) Oliv. (Annonaceae) is a medicinal plant traditionally used in Mozambique to treat infectious diseases. The aim of this study was to find resistance modifiers in C. kirkii for Gram-positive and Gram-negative model bacterial strains. One of the most important resistance mechanisms in bacteria is the efflux pump-related multidrug resistance. Therefore, polycarpol (1), three C-benzylated flavanones (2-4), and acetylmelodorinol (5) were evaluated for their multidrug resistance-reverting activity on methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Escherichia coli AG100 and AG100 A strains overexpressing and lacking the AcrAB-TolC efflux pump system...
February 21, 2018: Phytotherapy Research: PTR
https://www.readbyqxmd.com/read/29463055/antibiotic-resistance-genetic-markers-and-integrons-in-white-soft-cheese-aspects-of-clinical-resistome-and-potentiality-of-horizontal-gene-transfer
#3
Ana Caroline L de Paula, Julliane D Medeiros, Analice C de Azevedo, Jéssica M de Assis Chagas, Vânia L da Silva, Cláudio G Diniz
Antibiotic resistance poses an important threat to global public health and has become a challenge to modern medicine. The occurrence of antibiotic-resistant bacteria in a broad range of foods has led to a growing concern about the impact that food may have as a reservoir of antibiotic resistance genes. Considering Minas Frescal Cheese (MFC)-a typical Brazilian white soft cheese-and its economic and cultural values, in this study, medically relevant antimicrobial-resistance genetic markers (AR genes) were screened, and the occurrence of integrons were evaluated in manufactured MFC using culture-independent approaches...
February 19, 2018: Genes
https://www.readbyqxmd.com/read/29462315/overexpression-of-stenotrophomonas-maltophilia-major-facilitator-superfamily-protein-mfsa-increases-resistance-to-fluoroquinolone-antibiotics
#4
Paiboon Vattanaviboon, Punyawee Dulyayangkul, Skorn Mongkolsuk, Nisanart Charoenlap
Background: Stenotrophomonas maltophilia is an opportunistic human pathogen causing nosocomial infections worldwide. S. maltophilia infection is of particular concern due to its inherent resistance to currently used antibiotics. Proton motive force-driven transporters of the major facilitator superfamily frequently contribute to the efflux of substances, including antibiotics, across cell membranes. Methods: An mfsA expression plasmid (pMfsA) was constructed and transferred into bacterial strains by electroporation...
February 14, 2018: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29458656/stress-responses-outer-membrane-permeability-control-and-antimicrobial-resistance-in-enterobacteriaceae
#5
Sushovan Dam, Jean-Marie Pagès, Muriel Masi
Bacteria have evolved several strategies to survive a myriad of harmful conditions in the environment and in hosts. In Gram-negative bacteria, responses to nutrient limitation, oxidative or nitrosative stress, envelope stress, exposure to antimicrobials and other growth-limiting stresses have been linked to the development of antimicrobial resistance. This results from the activation of protective changes to cell physiology (decreased outer membrane permeability), resistance transporters (drug efflux pumps), resistant lifestyles (biofilms, persistence) and/or resistance mutations (target mutations, production of antibiotic modification/degradation enzymes)...
January 25, 2018: Microbiology
https://www.readbyqxmd.com/read/29455385/transcriptome-analysis-of-wild-type-and-afss-deletion-mutant-strains-identifies-synergistic-transcriptional-regulator-of-afss-for-a-high-antibiotic-producing-strain-of-streptomyces-coelicolor-a3-2
#6
Min Woo Kim, Bo-Rahm Lee, SungYong You, Eun-Jung Kim, Ji-Nu Kim, Eunjung Song, Yung-Hun Yang, Daehee Hwang, Byung-Gee Kim
Most secondary metabolism in Actinobacteria is controlled by multi-layered, gene-regulatory networks. These regulatory mechanisms are not easily identified due to their complexity. As a result, when a strong transcriptional regulator (TR) governs activation of biosynthetic pathways of target antibiotics such as actinorhodin (ACT), additional enhancement of the biosynthesis is difficult in combination with other TRs. To find out any "synergistic transcriptional regulators (sTRs)" that show an additive effect on the major, often strong, transcriptional regulator (mTR), here, we performed a clustering analysis using the transcriptome datasets of an mTR deletion mutant and wild-type strain...
February 17, 2018: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/29454787/trans-envelope-multidrug-efflux-pumps-of-gram-negative-bacteria-and-their-synergism-with-the-outer-membrane-barrier
#7
Helen I Zgurskaya, Valentin V Rybenkov, Ganesh Krishnamoorthy, Inga V Leus
Antibiotic resistance is a serious threat to public health. Significant efforts are currently directed toward containment of the spread of resistance, finding new therapeutic options concerning resistant human and animal pathogens, and addressing the gaps in the fundamental understanding of mechanisms of resistance. Experimental data and kinetic modeling revealed a major factor in resistance, the synergy between active efflux and the low permeability barrier of the outer membrane, which dramatically reduces the intracellular accumulation of many antibiotics...
February 15, 2018: Research in Microbiology
https://www.readbyqxmd.com/read/29451043/murepavadin-a-new-antibiotic-class-in-the-pipeline
#8
Ignacio Martin-Loeches, Glenn E Dale, Antoni Torres
With the increase in multi-drug resistant P. aeruginosa, antimicrobials with a novel mechanism of action are needed that can target these infections. Areas covered: Intravenous murepavadin is in Phase 3 development for the treatment of HABP/VABP due to P. aeruginosa. This paper summarizes the available information on the discovery, the in vitro activity, pharmacokinetic and pharmacodynamic properties and the clinical pharmacology of murepavadin to date. Expert commentary: P. aeruginosa has an intrinsic resistance to many antibiotics due to high cellular impermeability and efficient drug efflux mechanisms, and the recent increase in prevalence of multidrug-resistant P...
February 16, 2018: Expert Review of Anti-infective Therapy
https://www.readbyqxmd.com/read/29448209/metagenomic-analysis-revealed-the-prevalence-of-antibiotic-resistance-genes-in-the-gut-and-living-environment-of-freshwater-shrimp
#9
Yanting Zhao, Xu-Xiang Zhang, Zhonghua Zhao, Cuilan Duan, Huangen Chen, Miaomiao Wang, Hongqiang Ren, Ying Yin, Lin Ye
Antibiotic resistance disseminating from animals and their environments is a public issue that poses significant threats to human health. In the present study, the diversity and abundance of antibiotic resistance genes (ARGs) in 15 samples from the guts and related aquaculture environments (water and sediment) of shrimp were investigated. In total, 60 ARGs, 102 ARGs and 67 ARGs primarily belonging to 13, 15 and 15 different types were detected in the shrimp gut, pond water and sediment samples, respectively...
February 6, 2018: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/29438542/discovery-and-development-of-new-antibacterial-drugs-learning-from-experience
#10
Nicole Jackson, Lloyd Czaplewski, Laura J V Piddock
Antibiotic (antibacterial) resistance is a serious global problem and the need for new treatments is urgent. The current antibiotic discovery model is not delivering new agents at a rate that is sufficient to combat present levels of antibiotic resistance. This has led to fears of the arrival of a 'post-antibiotic era'. Scientific difficulties, an unfavourable regulatory climate, multiple company mergers and the low financial returns associated with antibiotic drug development have led to the withdrawal of many pharmaceutical companies from the field...
February 9, 2018: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29435265/prevalence-and-molecular-characterization-of-oqxab-in-clinical-escherichia-coli-isolates-from-companion-animals-and-humans-in-henan-province-china
#11
Baoguang Liu, Hua Wu, Yajun Zhai, Zhipei He, Huarun Sun, Tian Cai, Dandan He, Jianhua Liu, Shanmei Wang, Yushan Pan, Li Yuan, Gongzheng Hu
Background: The plasmid-encoded multidrug efflux pump oqxAB confers bacterial resistance primarily to olaquindox, quinolones, and chloramphenicol. The aims of this study were to investigate the prevalence of oqxAB among Escherichia coli isolates from dogs, cats, and humans in Henan, China and the susceptibilities of E. coli isolates to common antibiotics. Methods: From 2012 to 2014, a total of 600 samples which included 400 rectal samples and 200 clinical human specimens were tested for the presence of E...
2018: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/29434938/genetic-characterization-and-in-vitro-activity-of-antimicrobial-combinations-of-multidrug-resistant-acinetobacter-baumannii-from-a-general-hospital-in-china
#12
Fang Chen, Ling Wang, Min Wang, Yixin Xie, Xiaomeng Xia, Xianping Li, Yanhua Liu, Wei Cao, Tingting Zhang, Pengling Li, Min Yang
The present study aimed to develop a rational therapy based on the genetic epidemiology, molecular mechanism evaluation and in vitro antibiotic combinations activity in multidrug-resistant Acinetobacter baumannii (MDRAB). MDRAB was screened by the Kirby-Bauer method. The random amplified polymorphic DNA technique was used to establish genetic fingerprinting, and a series of resistance genes were detected by polymerase chain reaction. Antimicrobial agents including amikacin (AK), cefoperazone/sulbactam (SCF I/II), meropenem (MEM), minocycline (MINO) and ciprofloxacin (CIP) were used to determine the minimum inhibitory concentrations (MICs) and interactions between antibiotics by the broth microdilution method and chequerboard assays...
February 2018: Oncology Letters
https://www.readbyqxmd.com/read/29434398/a-highly-promiscuous-integron-plasmids-extended-spectrum-beta-lactamases-and-efflux-pumps-as-factors-governing-multidrug-resistance-in-a-highly-drug-resistant-vibrio-fluvialis-isolate-bd146-from-kolkata-india
#13
Neha Rajpara, Mrinalini Nair, Ashima Kushwaha Bhardwaj
In an earlier study from this laboratory, Vibrio fluvialis BD146, a clinical isolate from Kolkata, India, 2002, was found to be resistant to all the fourteen antibiotics tested. It harboured a high copy number plasmid pBD146 and a low copy number plasmid. In the present study, a more detailed analysis was carried out to unravel different resistance mechanisms in this isolate. Sequencing showed that variable region of class 1 integron located on low copy number plasmid harbored arr3-cmlA-blaOXA10-aadA1 gene cassettes...
March 2018: Indian Journal of Microbiology
https://www.readbyqxmd.com/read/29428235/sequence-and-structure-based-computational-analyses-of-gram-negative-tripartite-efflux-pumps-in-the-context-of-bacterial-membranes
#14
Timothy Travers, Katherine J Wang, Cesar A López, S Gnanakaran
Gram-negative multidrug resistance currently presents a serious threat to public health with infections effectively rendered untreatable. Multiple molecular mechanisms exist that cause antibiotic resistance and in addition, the last three decades have seen slowing rates of new drug development. In this review, we summarize the use of various computational techniques for investigating the mechanisms of multidrug resistance mediated by Gram-negative tripartite efflux pumps and membranes. Recent work in our lab combines data-driven sequence and structure analyses to study the interactions and dynamics of these bacterial components...
February 8, 2018: Research in Microbiology
https://www.readbyqxmd.com/read/29424299/medicinal-chemistry-updates-on-bacterial-efflux-pump-modulators
#15
Fernando Andre Pereira Marques Duraes, Madalena Maria Magalhaes Pinto, Maria Emilia Silva Pereira de Sousa
Antibiotic resistance is one of the most pressing health issues of our days. It can arise due to a multiplicity of factors, such as target modification, decrease in the drug uptake, changes in the metabolic pathways and activation of efflux pumps. The overexpression of efflux pumps is responsible for the extrusion of drugs, making antibiotic therapy fail, as the quantity of intracellular antibiotic is not enough to provide the desired therapeutic effect. Efflux pumps can be included in five families according to their composition, nature of substrates, energy source, and number of transmembrane spanning regions...
February 9, 2018: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/29420585/distribution-of-triclosan-resistant-genes-in-major-pathogenic-microorganisms-revealed-by-metagenome-and-genome-wide-analysis
#16
Raees Khan, Nazish Roy, Kihyuck Choi, Seon-Woo Lee
The substantial use of triclosan (TCS) has been aimed to kill pathogenic bacteria, but TCS resistance seems to be prevalent in microbial species and limited knowledge exists about TCS resistance determinants in a majority of pathogenic bacteria. We aimed to evaluate the distribution of TCS resistance determinants in major pathogenic bacteria (N = 231) and to assess the enrichment of potentially pathogenic genera in TCS contaminated environments. A TCS-resistant gene (TRG) database was constructed and experimentally validated to predict TCS resistance in major pathogenic bacteria...
2018: PloS One
https://www.readbyqxmd.com/read/29413231/application-of-six-multiplex-pcr-s-among-200-clinical-isolates-of-pseudomonas-aeruginosa-for-the-detection-of-20-drug-resistance-encoding-genes
#17
Nandagopal Murugan, Jambulingam Malathi, K Lily Therese, Hajib NarahariRao Madhavan
Pseudomonas aeruginosa (P. aeruginosa) is a menacing opportunistic, nosocomial pathogen; become a growing concern as conventional antimicrobial therapy is now futile against it. Multi-drug resistant P. aeruginosa (MDRPA) has distinctive resistance mechanisms such as production of β-lactamases, repression of porin genes and over-expression of efflux pumps. The focus of this study is to standardize and application of multiplex PCR (mPCR) to detect the presence of betalactamase genes encoding blaTem, blaOXA, blaCTX-M-15, blaVim, blaGes, blaVeb, blaDIM, AmpC and Efflux pump genes encoding Mex A,B-oprM, Mex C,D-oprJ, Mex X,Y-oprN, oprD, nfxB, MexR...
February 2018: Kaohsiung Journal of Medical Sciences
https://www.readbyqxmd.com/read/29412107/genetic-mechanisms-of-antibiotic-resistance-and-the-role-of-antibiotic-adjuvants
#18
Daniela Santos Pontes, Rodrigo Santos Aquino de Araujo, Natalina Dantas, Luciana Scotti, Marcus Tullius Scotti, Ricardo Olimpio de Moura, Francisco Jaime Bezerra Mendonca-Junior
The ever increasing number of multidrug-resistant microorganism pathogens has become a great and global public health threat. Antibiotic mechanisms of action and the opposing mechanisms of resistance are intimately associated, but comprehension of the biochemical and molecular functions of such drugs is not a simple exercise. Both the environment, and genetic settings contribute to alterations in phenotypic resistance (natural bacterial evolution), and make it difficult to control the emergence and impacts of antibiotic resistance...
February 5, 2018: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/29404421/the-odyssey-of-the-ancestral-escherich-strain-through-culture-collections-an-example-of-allopatric-diversification
#19
M Desroches, G Royer, D Roche, M Mercier-Darty, D Vallenet, C Médigue, K Bastard, C Rodriguez, O Clermont, E Denamur, J-W Decousser
More than a century ago, Theodor Escherich isolated the bacterium that was to become Escherichia coli, one of the most studied organisms. Not long after, the strain began an odyssey and landed in many laboratories across the world. As laboratory culture conditions could be responsible for major changes in bacterial strains, we conducted a genome analysis of isolates of this emblematic strain from different culture collections (England, France, the United States, Germany). Strikingly, many discrepancies between the isolates were observed, as revealed by multilocus sequence typing (MLST), the presence of virulence-associated genes, core genome MLST, and single nucleotide polymorphism/indel analyses...
January 2018: MSphere
https://www.readbyqxmd.com/read/29399654/size-dependent-inhibitory-effects-of-antibiotic-drug-nanocarriers-against-pseudomonas-aeruginosa
#20
Feng Ding, Preeyaporn Songkiatisak, Pavan Kumar Cherukuri, Tao Huang, Xiao-Hong Nancy Xu
Multidrug membrane transporters (efflux pumps) are responsible for multidrug resistance (MDR) and the low efficacy of therapeutic drugs. Noble metal nanoparticles (NPs) possess a high surface-area-to-volume ratio and size-dependent plasmonic optical properties, enabling them to serve both as imaging probes to study sized-dependent MDR and as potential drug carriers to circumvent MDR and enhance therapeutic efficacy. To this end, in this study, we synthesized three different sizes of silver nanoparticles (Ag NPs), 2...
January 31, 2018: ACS Omega
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