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https://www.readbyqxmd.com/read/29148878/molecular-characterization-of-fluoroquinolone-resistance-mechanisms-of-campylobacter-isolates-from-duck-meats
#1
Min Kang, Bai Wei, Sung-Woon Choi, Se-Yeoun Cha, Hyung-Kwan Jang
The purpose of this study was to identify the molecular basis of quinolone resistance of Campylobacter isolates recovered from duck meats. Sixty-one isolates from duck meat samples were studied using sequence analysis of the gyrA gene, and PCR assays were used to identify the presence of the CmeABC efflux pump and its restored sensitivity in the presence of efflux-pump inhibitors. High-level resistance to nalidixic acid and ciprofloxacin was attributed to amino acid substitutions Thr-86-Ile in some isolates...
November 17, 2017: Journal of Food Protection
https://www.readbyqxmd.com/read/29148846/preparation-and-evaluation-of-curcumin-loaded-self-assembled-micelles
#2
Lu-Lu Wang, Dan-Dan He, Shu-Xia Wang, Yun-Hao Dai, Jian-Ming Ju, Cheng-Lei Zhao
Objective Curcumin being used to treat various chronic diseases while its poor bioavailability issue limited its wide clinical application as a therapeutic agent. The aim of this work was to prepare curcumin-loaded self-assembled micelles using soluplus and solutol®HS15 (SSCMs) to enhance curcumin's solubility and thus oral bioavailability. Methods Optimum formulation was investigated and the optimized ratio of drugs and excipients was obtained and the SSCMs were prepared via ethanol solvent evaporation method...
November 17, 2017: Drug Development and Industrial Pharmacy
https://www.readbyqxmd.com/read/29146255/haemophilus-parasuis-cpxra-two-component-system-confers-bacterial-tolerance-to-environmental-stresses-and-macrolide-resistance
#3
Qi Cao, Fenfen Feng, Huan Wang, Xiaojuan Xu, Huanchun Chen, Xuwang Cai, Xiangru Wang
Haemophilus parasuis is an opportunistic pathogen localized in the upper respiratory tracts of pigs, its infection begins from bacterial survival under complex conditions, like hyperosmosis, oxidative stress, phagocytosis, and sometimes antibiotics as well. The two-component signal transduction (TCST) system serves as a common stimulus-response mechanism that allows microbes to sense and respond to diverse environmental conditions via a series of phosphorylation reactions. In this study, we investigated the role of TCST system CpxRA in H...
January 2018: Microbiological Research
https://www.readbyqxmd.com/read/29146106/the-hydrophobic-trap-the-achilles-heel-of-rnd-efflux-pumps
#4
Zachary Aron, Timothy J Opperman
Resistance-nodulation-division (RND) superfamily efflux pumps play a major role in multidrug resistance (MDR) of Gram-negative pathogens by extruding diverse classes of antibiotics from the cell. There has been considerable interest in developing efflux pump inhibitors (EPIs) of RND pumps as adjunctive therapies. The primary challenge in EPI discovery has been the highly hydrophobic, poly-specific substrate binding site of the target. Recent findings have identified the hydrophobic trap, a narrow phenylalanine-lined groove in the substrate-binding site, as the "Achilles heel" of the RND efflux pumps...
November 13, 2017: Research in Microbiology
https://www.readbyqxmd.com/read/29145976/not-only-p-glycoprotein-amplification-of-the-abcb1-containing-chromosome-region-7q21-confers-multidrug-resistance-upon-cancer-cells-by-coordinated-overexpression-of-an-assortment-of-resistance-related-proteins
#5
Ilaria Genovese, Andrea Ilari, Yehuda G Assaraf, Francesco Fazi, Gianni Colotti
The development of drug resistance continues to be a dominant hindrance toward curative cancer treatment. Overexpression of a wide-spectrum of ATP-dependent efflux pumps, and in particular of ABCB1 (P-glycoprotein or MDR1) is a well-known resistance mechanism for a plethora of cancer chemotherapeutics including for example taxenes, anthracyclines, Vinca alkaloids, and epipodopyllotoxins, demonstrated by a large array of published papers, both in tumor cell lines and in a variety of tumors, including various solid tumors and hematological malignancies...
May 2017: Drug Resistance Updates: Reviews and Commentaries in Antimicrobial and Anticancer Chemotherapy
https://www.readbyqxmd.com/read/29145855/generation-of-a-platform-strain-for-ionic-liquid-tolerance-using-adaptive-laboratory-evolution
#6
Elsayed T Mohamed, Shizeng Wang, Rebecca M Lennen, Markus J Herrgård, Blake A Simmons, Steven W Singer, Adam M Feist
BACKGROUND: There is a need to replace petroleum-derived with sustainable feedstocks for chemical production. Certain biomass feedstocks can meet this need as abundant, diverse, and renewable resources. Specific ionic liquids (ILs) can play a role in this process as promising candidates for chemical pretreatment and deconstruction of plant-based biomass feedstocks as they efficiently release carbohydrates which can be fermented. However, the most efficient pretreatment ILs are highly toxic to biological systems, such as microbial fermentations, and hinder subsequent bioprocessing of fermentative sugars obtained from IL-treated biomass...
November 16, 2017: Microbial Cell Factories
https://www.readbyqxmd.com/read/29144454/dynamics-of-p-type-atpase-transport-revealed-by-single-molecule-fret
#7
Mateusz Dyla, Daniel S Terry, Magnus Kjaergaard, Thomas L-M Sørensen, Jacob Lauwring Andersen, Jens Peter Andersen, Charlotte Rohde Knudsen, Roger B Altman, Poul Nissen, Scott C Blanchard
Phosphorylation-type (P-type) ATPases are ubiquitous primary transporters that pump cations across cell membranes through the formation and breakdown of a phosphoenzyme intermediate. Structural investigations suggest that the transport mechanism is defined by conformational changes in the cytoplasmic domains of the protein that are allosterically coupled to transmembrane helices so as to expose ion binding sites to alternate sides of the membrane. Here, we have used single-molecule fluorescence resonance energy transfer to directly observe conformational changes associated with the functional transitions in the Listeria monocytogenes Ca(2+)-ATPase (LMCA1), an orthologue of eukaryotic Ca(2+)-ATPases...
November 16, 2017: Nature
https://www.readbyqxmd.com/read/29142069/cat-02-106-a-site-specifically-conjugated-anti-cd22-antibody-bearing-an-mdr1-resistant-maytansine-payload-yields-excellent-efficacy-and-safety-in-preclinical-models
#8
Penelope M Drake, Adam Carlson, Jesse M McFarland, Stefanie Banas, Robyn M Barfield, Wesley Zmolek, Yun Cheol Kim, Betty C B Huang, Romas Kudirka, David Rabuka
Hematologically-derived tumors make up ~10% of all newly-diagnosed cancer cases in the U.S. Of these, the non-Hodgkin lymphoma (NHL) designation describes a diverse group of cancers that collectively rank among the top 10 most commonly diagnosed cancers worldwide. Although long-term survival trends are improving, there remains a significant unmet clinical need for treatments to help patients with relapsed or refractory disease, one cause of which is drug efflux through upregulation of xenobiotic pumps, such as MDR1...
November 15, 2017: Molecular Cancer Therapeutics
https://www.readbyqxmd.com/read/29140706/a-galactosylated-pro-drug-of-ursodeoxycholic-acid-design-synthesis-characterization-and-pharmacological-effects-in-a-rat-model-of-estrogen-induced-cholestasis
#9
Francesca Di Guida, Claudio Pirozzi, Salvatore Magliocca, Anna Santoro, Adriano Lama, Roberto Russo, Maria Nieddu, Lucia Burrai, Gianpiero Boatto, Maria Pina Mollica, Federica Sodano, Loretta Lazzarato, Konstantin Chegaev, Rosaria Meli, Giuseppina Mattace Raso, Maria Grazia Rimoli
Ursodeoxycholic acid (UDCA) is considered the first-choice therapy for cholestatic disorders. To enhance solubility and exploit specific transporters in liver, we synthesized a new galactosyl pro-drug of UDCA (UDCAgal). Ethinylestradiol (EE)-induced cholestasis was used to study and compare the effects of UDCAgal with UDCA on bile flow, hepatic canalicular efflux transporter expression, and inflammation. UDCAgal resulted quite stable both at pH 7.4 and 1.2 and regenerated the parent drug after incubation in human plasma...
November 15, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/29139345/herbicide-ingredients-change-salmonella-enterica-sv-typhimurium-and-escherichia-coli-antibiotic-responses
#10
Brigitta Kurenbach, Paddy S Gibson, Amy M Hill, Adam S Bitzer, Mark W Silby, William Godsoe, Jack A Heinemann
Herbicides are frequently released into both rural and urban environments. Commercial herbicide formulations induce adaptive changes in the way bacteria respond to antibiotics. Salmonella enterica sv. Typhimurium and Escherichia coli were exposed to common co-formulants of formulations, and S. enterica sv. Typhimurium was exposed to active ingredients dicamba, 2,4-D and glyphosate to determine what ingredients of the commercial formulations caused this effect. Co-formulants Tween80 and carboxymethyl cellulose induced changes in response, but the pattern of the responses differed from the active ingredients, and effect sizes were smaller...
November 17, 2017: Microbiology
https://www.readbyqxmd.com/read/29138446/antimicrobial-resistance-and-genetic-diversity-in-ceftazidime-non-susceptible-bacterial-pathogens-from-ready-to-eat-street-foods-in-three-taiwanese-cities
#11
Lin Lin, Sheng-Fan Wang, Tsung-Ying Yang, Wei-Chun Hung, Min-Yu Chan, Sung-Pin Tseng
Bacterial contamination of ready-to-eat (RTE) street foods is a major concern worldwide. Dissemination of antibiotic resistant pathogens from food is an emerging public-health threat. To investigate the prevalence of antibiotic resistance genes and ceftazidime resistance-associated efflux pumps in foodborne pathogens, 270 RTE street foods samples were collected in three densely populated Taiwanese cities. Among 70 ceftazidime non-susceptible isolates, 21 Stenotrophomonas maltophilia, 12 Pseudomonas spp., 22 Acinetobacter spp...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29138424/structure-function-relationships-in-abcg2-insights-from-molecular-dynamics-simulations-and-molecular-docking-studies
#12
Ricardo J Ferreira, Cátia A Bonito, M Natália D S Cordeiro, Maria-José U Ferreira, Daniel J V A Dos Santos
Efflux pumps of the ATP-binding cassette transporters superfamily (ABC transporters) are frequently involved in the multidrug-resistance (MDR) phenomenon in cancer cells. Herein, we describe a new atomistic model for the MDR-related ABCG2 efflux pump, also named breast cancer resistance protein (BCRP), based on the recently published crystallographic structure of the ABCG5/G8 heterodimer sterol transporter, a member of the ABCG family involved in cholesterol homeostasis. By means of molecular dynamics simulations and molecular docking, a far-reaching characterization of the ABCG2 homodimer was obtained...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29136186/clonal-spread-and-azole-resistant-mechanisms-of-non-susceptible-candida-albicans-isolates-from-vulvovaginal-candidiasis-patients-in-three-shanghai-maternity-hospitals
#13
YongQin Wu, Cui Li, ZhiHeng Wang, Jing Gao, ZhenHua Tang, HuiFen Chen, ChunMei Ying
In our multicenter study, 43 fluconazole non-susceptible and 45 fluconazole-susceptible isolates were collected from vulvovaginal candidiasis (VVC) patients from three Shanghai maternity hospitals to analyze their molecular epidemiological features and fluconazole resistant mechanisms. Cross-resistance to fluconazole, itraconazole and voriconazole was observed in 53.5% of the nonsusceptible isolates. Though we acquired 12 clonal complexes (CCs) of diploid sequence types (DSTs) in clinical isolates by a multilocus sequence typing method, fluconazole nonsusceptible isolates all belonged to CC69 with a predominant genotype of DST 79...
November 9, 2017: Medical Mycology: Official Publication of the International Society for Human and Animal Mycology
https://www.readbyqxmd.com/read/29133912/the-multiple-antibiotic-resistance-operon-of-enteric-bacteria-controls-dna-repair-and-outer-membrane-integrity
#14
Prateek Sharma, James R J Haycocks, Alistair D Middlemiss, Rachel A Kettles, Laura E Sellars, Vito Ricci, Laura J V Piddock, David C Grainger
The multiple antibiotic resistance (mar) operon of Escherichia coli is a paradigm for chromosomally encoded antibiotic resistance in enteric bacteria. The locus is recognised for its ability to modulate efflux pump and porin expression via two encoded transcription factors, MarR and MarA. Here we map binding of these regulators across the E. coli genome and identify an extensive mar regulon. Most notably, MarA activates expression of genes required for DNA repair and lipid trafficking. Consequently, the mar locus reduces quinolone-induced DNA damage and the ability of tetracyclines to traverse the outer membrane...
November 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/29133568/activity-of-ceftolozane-tazobactam-against-carbapenem-resistant-carbapenemase-non-producing-pseudomonas-aeruginosa-and-associated-resistance-mechanisms
#15
Yu Mi Wi, Kerryl E Greenwood-Quaintance, Audrey N Schuetz, Kwan Soo Ko, Kyong Ran Peck, Jae-Hoon Song, Robin Patel
Although carbapenems are effective for treating serious multidrug-resistant Pseudomonas aeruginosa infections, carbapenem-resistant P. aeruginosa (CRPA) is now being reported worldwide. Ceftolozane/tazobactam (C/T) demonstrates activity against many multidrug-resistant isolates. We evaluated the activity of C/T and compared its activity to that of ceftazidime/avibactam (C/A) using a well-characterized collection of carbapenemase non-producing CRPA isolates. Forty-two carbapenemase non-producing CRPA isolates from a previous study (Int J Antimicrob Agents 2012;40:168-72) were included...
November 13, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29133559/mutations-in-gene-fusa1-as-a-novel-mechanism-of-aminoglycoside-resistance-in-clinical-strains-of-pseudomonas-aeruginosa
#16
Arnaud Bolard, Patrick Plesiat, Katy Jeannot
Resistance of clinical strains of Pseudomonas aeruginosa to aminoglycosides can result from production of transferable aminoglycoside-modifying enzymes, of 16S rRNA methylases, and/or mutational derepression of intrinsic multidrug efflux pump MexXY(OprM). The present study reports on characterization of a new type of mutants 4- to 8-fold more resistant to 2-deoxystreptamine derivatives (e.g., gentamicin, amikacin, tobramycin), as compared with wild-type strain PAO1. The genetic alterations of three in vitro mutants were mapped on fusA1, and found to result in single amino acid substitutions in domains II, III and V of elongation factor G (EF-G1A), a key component of translational machinery...
November 13, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/29128373/regulation-of-the-acrab-tolc-efflux-pump-in-enterobacteriaceae
#17
Natasha Weston, Prateek Sharma, Vito Ricci, Laura J V Piddock
Bacterial multidrug efflux systems are a major mechanism of antimicrobial resistance and are fundamental to the physiology of Gram-negative bacteria. The resistance-nodulation-division (RND) family of efflux pumps is the most clinically significant, as it is associated with multidrug resistance. Expression of efflux systems is subject to multiple levels of regulation, involving local and global transcriptional regulation as well as post-transcriptional and post-translational regulation. The best-characterised RND system is AcrAB-TolC, which is present in Enterobacteriaceae...
November 8, 2017: Research in Microbiology
https://www.readbyqxmd.com/read/29126275/active-antimicrobial-efflux-in-staphylococcus-epidermidis-building-up-of-resistance-to-fluoroquinolones-and-biocides-in-a-major-opportunistic-pathogen
#18
Sofia Santos Costa, Miguel Viveiros, Constança Pomba, Isabel Couto
Objectives: To analyse the efflux-mediated response of Staphylococcus epidermidis to ethidium bromide (EtBr), a substrate of multidrug efflux pumps (EPs). Methods: The susceptible reference strain S. epidermidis ATCC 12228 was exposed to a step-wise adaptation to EtBr. The resulting EtBr-adapted strains were characterized regarding their antibiotic and biocide susceptibility by MIC determination and evaluation of efflux activity by re-determination of MICs in the presence of known efflux inhibitors and real-time fluorometry...
November 8, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29123510/upregulation-of-the-patab-transporter-confers-fluoroquinolone-resistance-to-streptococcus-pseudopneumoniae
#19
María Alvarado, Antonio J Martín-Galiano, María J Ferrándiz, Ángel Zaballos, Adela G de la Campa
We characterized the mechanism of fluoroquinolone-resistance in two isolates of Streptococcus pseudopneumoniae having fluoroquinolone-efflux as unique mechanism of resistance. Whole genome sequencing and genetic transformation experiments were performed together with phenotypic determinations of the efflux mechanism. The PatAB pump was identified as responsible for efflux of ciprofloxacin (MIC of 4 μg/ml), ethidium bromide (MICs of 8-16 μg/ml) and acriflavine (MICs of 4-8 μg/ml) in both isolates. These MICs were at least 8-fold lower in the presence of the efflux inhibitor reserpine...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/29122871/draft-genome-sequences-of-nonclinical-and-clinical-enterobacter-cloacae-isolates-exhibiting-multiple-antibiotic-resistance-and-virulence-factors
#20
Mitali Mishra, Shashank Patole, Harapriya Mohapatra
Enterobacter spp. have been implicated as opportunistic pathogens which over the years have gained resistance toward most of the available therapeutic drugs. We sequenced two multidrug-resistant Enterobacter cloacae isolates harboring multiple efflux pump genes. These isolates exhibited strain-specific modulation of efflux pump protein expression.
November 9, 2017: Genome Announcements
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