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Jordan R Smith, Juwon Yim, Seth Rice, Kyle Stamper, Razie Kebriaei, Michael J Rybak
Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen responsible for healthcare-associated infections, and treatment options are limited. Tedizolid (TZD), is a novel, oxazolidinone antibiotic with activity against MRSA. Previously, daptomycin (DAP), has demonstrated synergy with other antibiotics against MRSA. We sought to determine the efficacy of the combination of TZD + DAP against MRSA in an in vitro model of simulated endocardial vegetations (SEVs). Methods: TZD simulations of 200 mg once daily and DAP simulations of 6-mg/kg and 10-mg/kg once daily were tested alone and in the combinations of TZD + DAP 6-mg/kg or DAP 10-mg/kg against two clinical strains of MRSA, 494 and 67...
March 12, 2018: Antimicrobial Agents and Chemotherapy
Asher M Siddiqui, Jitendra A Sattigeri, Kalim Javed, Syed Shafi, M Shamim, Smita Singhal, Zubbair M Malik
Gram-positive bacteria are among the most common human pathogens associated with clinical infections which range from mild skin infections to sepsis. Resistance towards existing class of drugs by Gram-positive bacteria including methicillin resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis (MRSE) and vancomycin resistant enterococci (VRE) is a growing concern. There is an urgent need to discover new antibiotics which are active against resistant strains of Gram positive bacteria. We report herein a novel class of spiropyrimidinetrione oxazolidinone derivatives as novel antibacterial agents...
March 6, 2018: Bioorganic & Medicinal Chemistry Letters
Tarani Kanta Barman, Manoj Kumar, Tridib Chaira, Manu Dalela, Dikshi Gupta, Paras Kumar Jha, Ajay Singh Yadav, Dilip J Upadhyay, V Samuel Raj, Harpal Singh
RBx 11,760 is a bi-aryl oxazolidinone antibacterial agent active against Staphylococcus aureus but has poor solubility. Here we have encapsulated RBx 11,760 in PLA-PEG NPs with an aim to improve physicochemical, pharmacokinetics and in vivo efficacy. The average size and zeta potential of RBx 11,760 loaded NPs were found to be 106.4 nm and -22.2 mV, respectively. The absolute size of nanoparticles by HRTEM was found to be approximately 80 nm. In vitro antibacterial agar well diffusion assay showed clear zone of inhibition of bacterial growth...
March 7, 2018: Nanomedicine: Nanotechnology, Biology, and Medicine
Chih-Ning Cheng, Shu-Wen Lin, Chien-Chih Wu
Linezolid, an oxazolidinone antibiotic, does not required dose adjustment in patients with Child's class A and B liver cirrhosis. The dose adjustment data for Child's class C liver cirrhosis is inadequate. We reported a case of Child's class C liver cirrhosis, in which lactic acidosis, an adverse effect related to prolonged use, occurred only after two weeks of linezolid treatment. A 63-year old male had underlying diseases, such as end-stage renal disease (ESRD) and Child's class C liver cirrhosis, and was admitted for hepatic encephalopathy management and liver transplantation evaluation...
March 1, 2018: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
Janis Jermaks, Evan H Tallmadge, Ivan Keresztes, David B Collum
Building on structural and mechanistic studies of lithiated enolates derived from acylated oxazolidinones (Evans enolates) and chiral lithiated amino alkoxides, we found that amino alkoxides amplify the enantioselectivity of aldol additions. The pairing of enantiomeric series affords matched and mismatched stereoselectivities. The structures of mixed tetramers showing 2:2 and 3:1 (alkoxide-rich) stoichiometries are determined spectroscopically. Rate and computational studies provide a viable mechanistic and stereochemical model based on the direct reaction of the 3:1 mixed tetramers, but they raise unanswered questions for the 2:2 mixed aggregates...
February 19, 2018: Journal of the American Chemical Society
Pierre Delpech, Muna ALeryan, Brian Jones, Curtis Gemmell, Sue Lang
Skin and soft tissue infections (SSTI) are among the most commonly occurring infections and evidence suggests that these are increasing world-wide. The aetiology is diverse, but Staphylococcus aureus predominate and these are often resistant to antimicrobials that were previously effective. Tedizolid is a new oxazolidinone-class antibacterial indicated for the treatment of adults with SSTI caused by Gram-positive pathogens, including S. aureus. The aim of this study was to evaluate the in vitro efficacy of tedizolid in comparison to other clinically used antibacterials against antibiotic sensitive- and resistant-staphylococci, grown in planktonic cultures and as biofilms reflecting the growth of the microorganism during episodes of SSTI...
January 10, 2018: Diagnostic Microbiology and Infectious Disease
Chengtao Sun, Peng Zhang, Xing Ji, Run Fan, Baoli Chen, Yang Wang, Stefan Schwarz, Congming Wu
Objectives: To investigate the presence and molecular characteristics of oxazolidinone resistance genes cfr and optrA in staphylococci from household animals in rural China. Methods: Various samples were collected from household animals in 12 rural villages. Staphylococcal isolates showing florfenicol MICs ≥10 mg/L were identified and screened for the presence of cfr and/or optrA. PCR-positive isolates were characterized by antimicrobial susceptibility testing, S1 nuclease PFGE and Southern blotting...
February 7, 2018: Journal of Antimicrobial Chemotherapy
Xiaojie Wu, Yunfei Li, Jing Zhang, Yingyuan Zhang, Jicheng Yu, Guoying Cao, Yuancheng Chen, Beining Guo, Yaoguo Shi, Jun Huang, Yuran Cao, Xiaofang Liu, Jufang Wu, Mikhail Fedorovich Gordeev, Hong Yuan, Wen Wang
PURPOSE: This study was designed to evaluate the safety and pharmacokinetic profiles of MRX-I tablet, an oxazolidinone antibacterial agent, in healthy Chinese subjects. METHODS: The study was composed of 3 sequential periods. Period 1 was a randomized, double-blind, placebo-controlled, sequential ascending dose (50 to 1800 mg) study. Period 2 included one arm as a randomized, open-label, 3-period, 3 × 3 Latin square single-dose study of 300, 600, and 900 mg MRX-I administration and another arm as a crossover study to evaluate high-fat diet effect...
February 2, 2018: Clinical Therapeutics
Bing Bai, Kaitao Hu, Hui Li, Weiming Yao, Duoyun Li, Zhong Chen, Hang Cheng, Jinxin Zheng, Weiguang Pan, Minggui Deng, Xiaojun Liu, Zhiwei Lin, Qiwen Deng, Zhijian Yu
Enterococcal infections have become one of the most challenging nosocomial problems. Tedizolid, the second oxazolidinone is four- to eight-fold more potent in vivo and in vitro than linezolid against enterococci. However, the characteristics of tedizolid related to enterococci isolates in China remain elusive. The aim of this study was to evaluate in vitro activity of tedizolid against enterococcal isolates from patients with infections at a teaching hospital in China and to investigate the correlations between in vitro tedizolid activity against enterococci and the distribution of multilocus sequence types (MLST), resistance genes, and virulence factors...
December 27, 2017: FEMS Microbiology Letters
Emilio Bouza, Patricia Muñoz, Almudena Burillo
PURPOSE OF REVIEW: Tedizolid is a second-generation oxazolidinone with activity against Gram-positive bacteria, including MRSA isolates resistant to linezolid. Pivotal clinical trials showed that tedizolid at 200 mg once-daily for 6 days is not inferior to linezolid 600 mg twice daily for 10 days in patients with SSTI. The comparison of adverse events is favorable to tedizolid under the circumstances of the clinical trials. This is a review of recent literature on tedizolid, its use in special populations and potential adverse effects...
April 2018: Current Opinion in Infectious Diseases
Joan Guasch, Irene Giménez, Ignacio Funes-Ardoiz, Isabel Matheu, Feliu Maseras, Sergio Castillón, Yolanda Díaz, Miguel Bernús
Regio- and stereoselective oxyamination of dienes through a tandem rhodium catalysed aziridination-nucleophilic opening affords racemic oxazolidinone derivatives, which undergo a kinetic resolution acylation process using ABCs (amidine-based catalysts) achieving s values up to 117. This protocol was applied to the enantioselective synthesis of sphingosine.
January 17, 2018: Chemistry: a European Journal
N Lokesh, Andreas Seegerer, Johnny Hioe, Ruth M Gschwind
The low sensitivity of NMR and transient key intermediates below detection limit are the central problems studying reaction mechanisms by NMR. Sensitivity can be enhanced by hyperpolarization techniques such as dynamic nuclear polarization or the incorporation/interaction of special hyperpolarized molecules. However, all of these techniques require special equipment, are restricted to selective reactions or undesirably influence the reaction pathways. Here, we apply the Chemical Exchange Saturation Transfer (CEST) technique for the first time to NMR detect and characterize previously unobserved transient reaction intermediates in organocatalysis...
January 16, 2018: Journal of the American Chemical Society
Engeline van Duijkeren, Anne-Kathrin Schink, Marilyn C Roberts, Yang Wang, Stefan Schwarz
During the past decades resistance to virtually all antimicrobial agents has been observed in bacteria of animal origin. This chapter describes in detail the mechanisms so far encountered for the various classes of antimicrobial agents. The main mechanisms include enzymatic inactivation by either disintegration or chemical modification of antimicrobial agents, reduced intracellular accumulation by either decreased influx or increased efflux of antimicrobial agents, and modifications at the cellular target sites (i...
January 2018: Microbiology Spectrum
Ruoyi Hua, Yun Xia, Wenyao Wu, Jia Yan, Mi Yang
Linezolid is an oxazolidinone antibiotic commonly used to treat serious infections caused by vancomycin-resistant enterococcus. Recently, low-level linezolid resistant Enterococcus faecalis strains have emerged worldwide, but the resistant mechanisms remain undefined. Whole-transcriptome profiling was performed on an E. faecalis strain P10748 with low-level linezolid resistance in comparison with a linezolid-susceptible strain 3138 and the standard control strain ATCC29212. The functions of differentially expressed genes (DEGs) were predicted, with some DEGs potentially involved in drug resistance were validated by PCR and quantitative PCR (qPCR)...
January 8, 2018: Gene
Erico S Loreto, Juliana S M Tondolo, Daniele C Oliveira, Janio M Santurio, Sydney H Alves
We tested 29 isolates of Pythium insidiosum and one isolate of Pythium aphanidermatum to investigate their susceptibility to miltefosine and antibacterial drugs from macrolide, oxazolidinone, and pleuromutilin classes. We found that miltefosine, azithromycin, clarithromycin, josamycin, linezolid, sutezolid, retapamulin, tiamulin, and valnemulin had inhibitory and cidal activity against the pathogens at concentrations ranging from 0.25 to 64 μg/ml. Our results suggest that these antimicrobials are promising candidates for future studies on pythiosis in animals and humans...
January 8, 2018: Antimicrobial Agents and Chemotherapy
Fadi Aldeek, Kevin Hsieh, Obiadada Ugochukwu, Ghislain Gerard, Walter Hammack
We developed and validated a method for the extraction, identification, and quantitation of four nitrofuran metabolites: (3-amino-2-oxazolidinone (AOZ); 3-amino-5-morpholinomethyl-2-oxazolidinone (AMOZ); semicarbazide (SC); and 1-aminohydantoin (AHD)), as well as chloramphenicol and florfenicol, in a variety of seafood commodities. Samples were extracted by liquid-liquid extraction techniques, analyzed by UHPLC-MS/MS, and quantitated using commercially sourced, derivatized nitrofuran metabolites, with their isotopically-labelled internal standards in-solvent...
December 28, 2017: Journal of Agricultural and Food Chemistry
Zhu-Bao Yin, Jian-Heng Ye, Wen-Jun Zhou, Yi-Han Zhang, Li Ding, Yong-Yuan Gui, Si-Shun Yan, Jing Li, Da-Gang Yu
A selective oxy-difluoroalkylation of allylamines with carbon dioxide (CO2) via visible-light photoredox catalysis is reported. These multicomponent reactions are efficient and environmentally friendly to generate a series of important 2-oxazolidinones with functionalized difluoroalkyl groups. The good functional group tolerance, broad substrate scope, easy scalability, mild reaction conditions, and facile functionalization of products provide great potential for application in organic synthesis and pharmaceutical chemistry...
December 27, 2017: Organic Letters
Tatsuya Ishikawa, Tomoko Kawasaki-Takasuka, Toshio Kubota, Takashi Yamazaki
As an extension of the boron enolate-based aldol reactions, the oxazolidinone-installed bisimide 1a from 3-(trifluoromethyl)glutaric acid was employed for Mannich reactions with tosylated imines 2 as electrophiles to successfully obtain the corresponding adducts in a stereoselective manner.
2017: Beilstein Journal of Organic Chemistry
Vishnu C Damalanka, Yunjeong Kim, Anushka C Galasiti Kankanamalage, Athri D Rathnayake, Nurjahan Mehzabeen, Kevin P Battaile, Scott Lovell, Harry Nhat Nguyen, Gerald H Lushington, Kyeong-Ok Chang, William C Groutas
Acute nonbacterial gastroenteritis caused by noroviruses constitutes a global public health concern and a significant economic burden. There are currently no small molecule therapeutics or vaccines for the treatment of norovirus infections. A structure-guided approach was utilized in the design of a series of inhibitors of norovirus 3CL protease that embody an oxazolidinone ring as a novel design element for attaining optimal binding interactions. Low micromolar cell-permeable inhibitors that display anti-norovirus activity have been identified...
January 1, 2018: European Journal of Medicinal Chemistry
J Zhu, J Hu, Y F Mao, F Y Chen, J Y Zhu, J M Shi, D D Yu, S G Hao, R Tao, P Liu, S Y Gu, J Hou, H Y He, A B Liang, Y Ding, L G Liu, Y H Xie, Q Zhu, Y H Yu, Y H Yao, W Chen, H L Xu, X H Han, C Wang
Objective: To investigate the pathogen spectrum distribution and drug resistance of febrile neutropenic patients with hematological diseases in Shanghai. Methods: A retrospective study was conducted on the clinical isolates from the febrile neutropenic patients hospitalized in the departments of hematology in 12 general hospitals in Shanghai from January 2012 to December 2014. The drug susceptibility test was carried out by Kirby-Bauer method. WHONET 5.6 software was used to analyze pathogenic bacteria and drug susceptibility data...
November 14, 2017: Zhonghua Xue Ye Xue za Zhi, Zhonghua Xueyexue Zazhi
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