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oxazolidinone

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https://www.readbyqxmd.com/read/28793964/in-vitro-activities-of-tedizolid-and-comparator-antimicrobial-agents-against-clinical-isolates-of-staphylococcus-aureus-collected-in-12-countries-from-2014-to-2016
#1
James A Karlowsky, Meredith A Hackel, Samuel K Bouchillon, Jeff Alder, Daniel F Sahm
Clinical isolates of Staphylococcus aureus (n=3929) collected by 54 medical center laboratories in 12 countries in 2014-2016 were tested for in vitro susceptibility to tedizolid, linezolid, and 11 comparators using Clinical and Laboratory Standards Institute (CLSI) broth microdilution methodology with minimum inhibitory concentrations (MICs) interpreted by CLSI M100-S26 (2016) criteria. All isolates of S. aureus tested were susceptible to both tedizolid (MIC, ≤0.5μg/mL) and linezolid (MIC, ≤4μg/mL). The concentration of tedizolid that inhibited 90% of isolates (MIC90) was 0...
July 8, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/28783338/experimental-and-computational-evidence-of-the-biradical-structure-and-reactivity-of-titanium-iv-enolates
#2
Carlos Heras, Alejandro Gómez-Palomino, Pedro Romea, Fèlix Urpí, Josep Maria Bofill, Ibério de P R Moreira
Quantum chemical calculations have unveiled the unexpected biradical character of titanium(IV) enolates from N-acyl oxazolidinones and thiazolidinethiones. The electronic structure of these species therefore involves a valence tautomerism consisting of an equilibrium between a closed shell (formally Ti(IV) enolates) and an open shell, biradical, singlet (formally Ti(III) enolates) electronic states, whose origin is to be basically found in changes of the Ti-O distance. Spectroscopic studies of the intermediate species lend support to such a model, which also turns out to be crucial for a better understanding of the overall reactivity of titanium(IV) enolates...
August 7, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28760892/in-vitro-isolation-and-characterization-of-oxazolidinone-resistant-mycobacterium-tuberculosis
#3
Matthew B McNeil, Devon Dennison, Catherine Shelton, Tanya Parish
Oxazolidinones are promising candidates for the treatment of Mycobacterium tuberculosis infections. We isolated linezolid resistant strains from H37Rv (Euro-American) and HN878 (East-Asian) strains; resistance frequency was similar in both strains. Mutations were identified in ribosomal protein L3 (RplC) and the 23S rRNA (rrl). All mutant strains were cross resistant to sutezolid; a subset were cross-resistant to chloramphenicol. Mutations in rrl led to growth impairment and decreased fitness that could limit spread in clinical settings...
July 31, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28739794/population-pharmacokinetics-of-azd-5847-in-adults-with-pulmonary-tuberculosis
#4
Abdullah Alsultan, Jennifer J Furin, Jeannine Du Bois, Elana van Brakel, Phalkun Chheng, Amour Venter, Bonnie Thiel, Sara A Debanne, W Henry Boom, Andreas H Diacon, John L Johnson, Charles A Peloquin
AZD-5847 is a new oxazolidinone derivative under development for the treatment of tuberculosis. In this study we describe the population pharmacokinetics of AZD-5847 in patients with tuberculosis based on a recently completed phase II study. The study included 60 patients with drug susceptible TB. Patients were randomized to four doses (500 mg once daily, 1200 mg once daily, 500 mg twice daily and 800 mg twice daily). Patients were intensively sampled on day 1 and 14. AZD-5847 pharmacokinetics were best described with a two compartment system with tlag for absorption...
July 24, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28735054/linezolid-activity-against-clinical-gram-positive-cocci-with-advanced-antimicrobial-drug-resistance-in-iran
#5
Hamidreza Houri, Hossein Kazemian, Hadi Sedigh Ebrahim-Saraie, Asieh Taji, Zahra Tayebi, Hamid Heidari
OBJECTIVES: The aim of the study was to investigate the linezolid activity against clinical Gram-positive cocci with advanced antimicrobial drug resistance. METHODS: A collection of methicillin resistant Staphylococcus aureus (MRSA), vancomycin resistant enterococci (VRE), penicillin non-susceptible Streptococcus pneumoniae (PNSP), and group B streptococci (GBS) were isolated from various clinical samples. Antimicrobial susceptibility tests were done using standard methods Subsequently, we investigated linezolid antibacterial activities, the first approved oxazolidinone against isolates by the standard broth microdilution method...
July 19, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28732783/future-trends-in-the-treatment-of-meticillin-resistant-staphylococcus-aureus-mrsa-infection-an-in-depth-review-of-newer-antibiotics-active-against-an-enduring-pathogen
#6
REVIEW
A M Bal, M Z David, J Garau, T Gottlieb, T Mazzei, F Scaglione, P Tattevin, I M Gould
Meticillin-resistant Staphylococcus aureus (MRSA) continues to be a major public health problem. Vancomycin and teicoplanin have been in clinical use for several decades but their drawbacks are well described. In the last 10 years several antibiotics have been made available for clinical use. Daptomycin and linezolid have been extensively used during this period. Other agents such as ceftaroline, ceftobiprole, dalbavancin, oritavancin, tedizolid, and telavancin have been approved by regulatory agencies since 2009...
July 18, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28731121/unified-total-synthesis-of-chinensiolide-b-and-8-epigrosheimin
#7
Saumen Hajra, Susit Acharyya, Abhisek Mandal, Ramkrishna Maity
An expedient synthetic approach has been developed for the unified total synthesis of (+)-chinensiolide B and (+)-8-epigrosheimin. The point of divergence was provided by the lactone aldehyde 6, in which four contiguous stereocenters were achieved by a stereocontrolled Evans syn-aldol reaction of a R-carvone derived enantiopure aldehyde and chiral N-succinyl-oxazolidinone. The lactone aldehyde 6 was synthesized in multigram quantity in three steps. Highly optimized chemo- and stereoselective reactions and functional group interconversion enabled us to assemble (+)-chinensiolide B and (+)-8-epigrosheimin from 6...
August 2, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28729052/tedizolid-inhibits-muc5ac-production-induced-by-methicillin-resistant-staphylococcus-aureus-in-human-airway-epithelial-cells
#8
Kazuaki Takeda, Norihito Kaku, Yoshitomo Morinaga, Kosuke Kosai, Naoki Uno, Yoshifumi Imamura, Hiroo Hasegawa, Taiga Miyazaki, Koichi Izumikawa, Hiroshi Mukae, Katsunori Yanagihara
The innate immune system plays an important role in early immunity against respiratory tract infection. Although airway epithelial cells produce mucus to eliminate pathogens and irritants, hypersecretion of mucus is harmful for the host as it may cause airway obstruction and inhibit influx of antimicrobial agents. It has been reported that several antimicrobial agents have an immunomodulatory effect in vitro and in vivo, but little is known about whether tedizolid, a novel oxazolidinone, can modulate immune responses...
September 2017: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
https://www.readbyqxmd.com/read/28726865/recent-advances-in-the-ruthenium-ii-catalyzed-chelation-assisted-c-h-olefination-of-substituted-aromatics-alkenes-and-heteroaromatics-with-alkenes-via-the-deprotonation-pathway
#9
Rajendran Manikandan, Masilamani Jeganmohan
The transition-metal-catalyzed chelation-assisted alkenylation at the inert C-H bond of aromatics with alkenes is one of the efficient methods to synthesize substituted vinylarenes in a highly regio- and stereoselective manner. Palladium, rhodium and ruthenium complexes are frequently used as catalysts for this type of transformation. The present review describes the recent advances in the ruthenium-catalyzed chelation-assisted alkenylation at the C-H bond of aromatics, alkenes and heteroaromatics with alkenes via the deprotonation pathway...
August 8, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28697197/increased-and-normalized-uptake-of-18-f-fdg-in-a-case-of-bone-periprosthetic-infection-treated-by-antibiotics
#10
Valentina Lavelli, Cristina Ferrari, Artor Niccoli Asabella, Corinna Altini, Francesco Saverio Vella, Giuseppe Rubini
We report the case of a 69 years old man with left hip prosthesis, who presented clinical, biochemical and imaging signs of periprosthetic infection treated with linezolid, an antibacterial agent of the oxazolidinone class. Two weeks after this treatment, a fluorine-18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) scan showed increased uptake in the skeleton and also increased uptake in several focal areas in the spine and near the prosthesis and the surgical wound on the left gluteus medius...
May 2017: Hellenic Journal of Nuclear Medicine
https://www.readbyqxmd.com/read/28695990/isocyanurate-formation-during-oxazolidinone-synthesis-from-epoxides-and-isocyanates-catalysed-by-a-chromium-salphen-complex
#11
Michael North, Jess Mason, Xiao Wu
Chromium(salphen) complex 10 is found to be a catalyst for the preparation of oxazolidinones from epoxides and isocyanates. Using the optimal reaction conditions (1.5 mol% of chromium(salphen) complex 10 at 80 oC in toluene for 4 hours), six epoxides were reacted with five isocyanates, providing 15 oxazolidinones in up to 90% yield. With electron-deficient isocyanates, cyclotrimerisation of the isocyanate to the corresponding isocyanurates is a competing reaction, showing the importance of matching catalyst activity to that of the substrates...
July 11, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28689875/contribution-of-acrab-tolc-to-multidrug-resistance-in-an-escherichia-coli-sequence-type-131-isolate
#12
Sabine Schuster, Martina Vavra, Tobias Schweigger, John W A Rossen, Yasufumi Matsumura, Winfried V Kern
Drug efflux by resistance-nodulation-cell division (RND)-type transporters, such as AcrAB-TolC of Escherichia coli, is an important resistance mechanism in Gram-negative bacteria; however, its contribution to multidrug resistance (MDR) in clinical isolates is poorly defined. We inactivated acrB of a sequence type 131 E. coli human isolate that showed high-level MDR, but had no mutations within the known efflux-associated local or global regulators. The resistance profile of the acrB deletion mutant revealed significantly increased susceptibility to drugs from seven antibiotic classes, including agents usually inactive against Gram-negative bacteria, notably the new oxazolidinone, tedizolid (512-fold enhanced susceptibility)...
July 6, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28686020/evans-enolates-structures-and-mechanisms-underlying-the-aldol-addition-of-oxazolidinone-derived-boron-enolates
#13
Zirong Zhang, David B Collum
The soft enolization of an acylated oxazolidinone using di-n-butylboron triflate (n-Bu2BOTf) and trialkylamines and subsequent aldol addition was probed structurally and mechanistically using a combination of IR and NMR spectroscopies. None of the species along the reaction coordinate show a penchant for aggregating. Complexation of the acylated oxazolidinone by n-Bu2BOTf was too rapid to monitor, as was the subsequent enolization with Et3N (triethylamine). The preformed n-Bu2BOTf·Et3N complex, displaying muted Lewis acidity and affiliated tractable rates, reveals a rate-limiting complexation via a transition structure with a complicated counterion...
July 7, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28674049/activities-of-lcb01-0371-a-novel-oxazolidinone-against-mycobacterium-abscessus
#14
Tae Sung Kim, Jin Ho Choe, Young Jae Kim, Chul-Su Yang, Hyun-Jin Kwon, Jinsun Jeong, Guehye Kim, Da Eun Park, Eun-Kyeong Jo, Young-Lag Cho, Jichan Jang
Mycobacterium abscessus is a highly pathogenic, drug-resistant, rapidly growing mycobacterium. In this study, we evaluated the in vitro, intracellular, and in vivo activities of LCB01-0371, a novel and safe oxazolidinone derivative, for the treatment of M. abscessus infection and compared its resistance to that of other oxazolidinone drugs. LCB01-0371 was effective against several M. abscessus strains in vitro and in a macrophage model of infection. In the murine model, a similar efficacy to linezolid was achieved, especially in the lungs...
July 3, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28664966/water-chromophore-electron-transfer-determines-the-photochemistry-of-cytosine-and-cytidine
#15
Rafał Szabla, Holger Kruse, Jiří Šponer, Robert W Góra
Many of the UV-induced phenomena observed experimentally for aqueous cytidine were lacking the mechanistic interpretation for decades. These processes include the substantial population of the puzzling long-lived dark state, photohydration, cytidine to uridine conversion and oxazolidinone formation. Here, we present quantum-chemical simulations of excited-state spectra and potential energy surfaces of N1-methylcytosine clustered with two water molecules using the second-order approximate coupled cluster (CC2), complete active space with second-order perturbation theory (CASPT2), and multireference configuration interaction with single and double excitation (MR-CISD) methods...
July 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28663118/a-cfr-like-gene-cfr-c-conferring-linezolid-resistance-is-common-in-clostridium-difficile
#16
Thomas Candela, Jean-Christophe Marvaud, Tiep Khac Nguyen, Thierry Lambert
Clostridium difficile T10 and Clostridium bolteae 90B3 were co-resistant to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A (PhLOPSA) and harbored an unreported cfr-like determinant that may alter the 23S rRNA by m(8)A2503 methylation. The cfr-like cfr(C) gene was cloned in C. difficile 630Δerm in which it conferred PhLOPSA resistance. In C. bolteae 90B3: (i) qRT-PCR analysis indicated that cfr(C) was similarly expressed in the absence or presence of either chloramphenicol or clindamycin or linezolid; and (ii) cfr(C) was part of a putative 24 kb-transposon, which generated a detectable circular intermediate...
June 27, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28650659/asymmetric-radical-bicyclization-of-allyl-azidoformates-via-cobalt-ii-based-metalloradical-catalysis
#17
Huiling Jiang, Kai Lang, Hongjian Lu, Lukasz Wojtas, X Peter Zhang
Cobalt(II)-based metalloradical catalysis has been successfully applied to radical bicyclization of allyl azidoformates to construct aziridine/oxazolidinone-fused bicyclic structures. The Co(II) complex of D2-symmetric chiral amidoporphyrin 3,5-Di(t)Bu-QingPhyrin has been identified as an effective metalloradical catalyst for the intramolecular radical aziridination of this type of carbonyl azides, allowing for high-yielding formation of synthetically useful chiral [3.1.0]-bicyclic aziridines with high diastereo- and enantioselectivity...
July 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28567125/synthesis-and-functional-evaluation-of-novel-aldose-reductase-inhibitors-bearing-a-spirobenzopyran-scaffold
#18
Maria Digiacomo, Stefania Sartini, Giulia Nesi, Simona Sestito, Vito Coviello, Concettina La Motta, Simona Rapposelli
BACKGROUND: Aldose reductase, the first enzyme of the polyol pathway, is the key determinant for the pathogenesis of long term diabetic complications. Accordingly, its inhibition represents the major therapeutic strategy to treat this kind of pathologies. OBJECTIVES: In this work we describe the synthesis and the functional evaluation of a number of spiro-oxazolidinone and spiro-morpholinone acetic acid derivatives, and their benzyloxy analogs, developed as aldose reductase inhibitors...
2017: Open Medicinal Chemistry Journal
https://www.readbyqxmd.com/read/28557457/oxazolidinones-and-2-5-dihydrofurans-via-zinc-catalyzed-regioselective-allenylation-reactions-of-l-%C3%AE-amino-aldehydes
#19
Farzad Zamani, Stephen G Pyne, Christopher J T Hyland
The simultaneous control of diastereoselectivity and regioselectivity in Zn-catalyzed allenylation reactions of N-protected l-α-amino aldehydes is reported. A reversal in diastereoselectivity could be realized by variation of the α-amino aldehyde protecting groups. A range of 1-allenyl-2-amino alcohols were obtained with excellent regioselectivity and converted to oxazolidinones and dihydrofurans. Many of which could be isolated as single diastereoisomers and without significant erosion of ee, making this a practical catalytic synthesis of highly functionalized heterocycles...
June 14, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28537316/5-benzylidene-4-oxazolidinones-potently-inhibit-biofilm-formation-in-methicillin-resistant-staphylococcus-aureus
#20
Grant A Edwards, Nataliia V Shymanska, Joshua G Pierce
Investigation into the biological function of 5-benzylidene-4-oxazolidinones revealed dose-dependent inhibition of biofilm formation in Methicillin-resistant S. aureus (MRSA). This structurally unusual class of small molecules inhibit up to 89% of biofilm formation with IC50 values as low as 0.78 μM, and disperse pre-formed biofilms with IC50 values as low as 4.7 μM. Together, these results suggest that 4-oxazolidinones represent new chemotypes to enable the study of bacterial biofilms with small molecule chemical probes...
June 29, 2017: Chemical Communications: Chem Comm
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