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https://www.readbyqxmd.com/read/28738348/colistin-resistance-in-kpc-2-and-shv-5-producing-klebsiella-pneumoniae-clinical-isolates-in-bulgaria
#1
Encho Savov, Iva Todorova, Lida Politi, Angelina Trifonova, Maja Borisova, Elena Kioseva, Athanassios Tsakris
BACKGROUND/AIMS: Colistin resistance is increasingly recognized among carbapenemase-producing Klebsiella pneumoniae isolates in several European regions. The current study documents the appearance of colistin resistance among KPC-2 and SHV-5-produning K. pneumoniae strains in Bulgaria. METHODS: Four colistin-resistant K. pneumoniae isolates were recovered from 2 patients hospitalized in the anesthesiology and resuscitation clinic of a tertiary care university hospital in Sofia, Bulgaria...
July 22, 2017: Chemotherapy
https://www.readbyqxmd.com/read/28737794/heterogeneous-enantioselective-synthesis-of-chromans-via-the-oxa-michael-michael-cascade-reaction-synergically-catalyzed-by-grafted-chiral-bases-and-inherent-hydroxyls-on-mesoporous-silica-surface
#2
Shanshan Wang, Jing He, Zhe An
A heterogeneous enantioselective oxa-Michael-Michael reaction for the synthesis of chromans has been developed on a heterogeneous acid-base synergic catalyst with inherent silica as acidic sites and immobilized chiral amines as basic sites. Final products were afforded in selectivity of up to 98% and ee of 97% from 2-nitrovinyl phenol and 3-methyl-2-butenal. The heterogeneous synergistic catalytic mechanism has also been studied.
July 24, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28737463/prevalence-of-a-new-variant-oxa-204-and-oxa-48-carbapenemases-plasmids-encoded-in-klebsiella-pneumoniae-clinical-isolates-in-tunisia
#3
Rym Ouertani, Mariem Ben Jomàa-Jemili, Haythem Gharsa, Anne Limelette, Thomas Guillard, Lucien Brasme, Christophe de Champs, Chedly Chouchani
Carbapenemase-producing Klebsiella pneumoniae strains have emerged as a major problem for healthcare systems. The aim of this study was to determine the role and diversity of plasmids harboring carbapenemases encoding genes from a collection of K. pneumoniae isolates recovered between July 2011 and January 2012, with decreased susceptibility to carbapenems. Imipenem (IPM), ertapenem (ETP), meropenem (MEM), and doripenem (DOR) minimum inhibitory concentrations (MICs) were determined by E-test. Carbapenemase production was detected with the modified Hodge test...
July 24, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28735048/emergence-of-different-acinetobacter-baumannii-clones-in-a-croatian-hospital-and-correlation-with-antibiotic-susceptibility
#4
Ranko Ladavac, Branka Bedenić, Mirna Vranić-Ladavac, Nada Barišić, Natalie Karčić, Karoline Pompe, Antun Ferenčić, Aleksandar Stojanović, Harald Seifert, Stjepan Katić, Paul G Higgins
OBJECTIVES: During routine diagnostic laboratory work, the clinical microbiologist observed an increase of Acinetobacter baumannii isolates with three different carbapenem susceptibility patterns: susceptible, intermediate and resistant. Isolates belonging to the same carbapenem susceptibility phenotype exhibited identical susceptibility/resistance patterns to non-β-lactam antibiotics. This prompted us to analyze the mechanisms of carbapenem-resistance and the molecular epidemiology of the isolates...
July 19, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28732790/performance-of-the-%C3%AE-lacta-test-for-rapid-detection-of-expanded-spectrum-cephalosporin-nonsusceptible-enterobacteriaceae
#5
Georgia Vrioni, Vasiliki Mamali, Olympia Zarkotou, Evaggelia Voulgari, Evaggelia Dimitroulia, Katerina Themeli-Digalaki, Spyros Pournaras, Athanassios Tsakris
OBJECTIVES: To study the performance of the rapid chromogenic βLACTA test for the rapid detection of expanded-spectrum cephalosporin (ESC) nonsusceptibility among Enterobacteriaceae, in a region endemic for potent β-lactamases. METHODS: The βLACTA test was applied prospectively on 235 consecutive Enterobacteriaceae clinical isolates and163 previously characterized ESC-nonsusceptible Enterobacteriaceae producing a range of β-lactamases. RESULTS: βLACTA exhibited excellent sensitivity (96...
July 18, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28732061/melatonin-pre-treatment-mitigates-shsy-5y-cells-against-oxaliplatin-induced-mitochondrial-stress-and-apoptotic-cell-death
#6
Mohammad Waseem, Upasana Sahu, Mohd Salman, Arnab Choudhury, Sudeshna Kar, Heena Tabassum, Suhel Parvez
Oxaliplatin (Oxa) treatment to SH-SY5Y human neuroblastoma cells has been shown by previous studies to induce oxidative stress, which in turn modulates intracellular signaling cascades resulting in cell death. While this phenomenon of Oxa-induced neurotoxicity is known, the underlying mechanisms involved in this cell death cascade must be clarified. Moreover, there is still little known regarding the roles of neuronal mitochondria and cytosolic compartments in mediating Oxa-induced neurotoxicity. With a better grasp of the mechanisms driving neurotoxicity in Oxa-treated SH-SY5Y cells, we can then identify certain pathways to target in protecting against neurotoxic cell damage...
2017: PloS One
https://www.readbyqxmd.com/read/28731274/synthesis-and-characterization-of-2-2-dinitramino-5-5-bi-1-oxa-3-4-diazole-and-derivatives-as-economic-and-highly-dense-energetic-materials
#7
Tobias S Hermann, Konstantin Karaghiosoff, Thomas M Klapötke, Jörg Stierstorfer
2,2'-Dinitramino-5,5'-bi(1-oxa-3,4-diazole) (2) is a new highly energetic material with superior calculated detonation performance in comparison to cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) and penta-erythritoltetranitrate (PETN) and can be prepared by an economical and practical two-step synthesis. The starting material 2,2'-diamino-5,5'-bi(1-oxa-3,4-diazole) (1) is synthesized by the reaction of oxalyl dihydrazide with cyanogen bromide. Nitration of 1 yields the title compound in perfect yield and purity...
July 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28728159/oxamate-enhances-the-anti-inflammatory-and-insulin-sensitizing-effects-of-metformin-in-diabetic-mice
#8
Mu-Chao Wu, Wei-Ran Ye, Yi-Jia Zheng, Shan-Shan Zhang
Metformin (MET) is the first-line drug for treating type 2 diabetes mellitus (T2DM). However, MET increases blood lactate levels in patients with T2DM. Lactate possesses proinflammatory properties and causes insulin resistance (IR). Oxamate (OXA), a lactate dehydrogenase inhibitor, can decrease tissue lactate production and blood lactate levels. This study was conducted to examine the effects of the combination of OXA and MET on inflammation, and IR in diabetic db/db mice. Supplementation of OXA to MET led to lowered tissue lactate production and serum lactate levels compared to MET alone, accompanied with further decreased tissue and blood levels of pro-inflammatory cytokines, along with better insulin sensitivity, beta-cell mass, and glycemic control in diabetic db/db mice...
July 21, 2017: Pharmacology
https://www.readbyqxmd.com/read/28726963/comment-on-an-unexpected-formation-of-the-novel-7-oxa-2-azabicyclo-2-2-1-hept-5-ene-skeleton-during-the-reaction-of-furfurylamine-with-maleimides-and-their-bioprospection-using-a-zebrafish-embryo-model-by-c-e-puerto-galvis-and-v-v-kouznetsov-org-biomol-chem
#9
F I Zubkov, E A Kvyatkovskaya, E V Nikitina, P N-A Amoyaw, V V Kouznetsov, V A Lazarenko, V N Khrustalev
It has been proved that the reaction between furfuryl amines and N-R-maleimides leads to the formation of aza-Michael addition products - 3-(furylmethylamino)-N-R-pyrrolidine-2,5-diones, instead of 7-oxa-2-azabicyclo[2.2.1]hept-5-enes, as this journal reported previously.
July 20, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28726918/two-hybrid-lanthanide-complexes-exhibiting-a-large-magnetocaloric-effect-and-slow-magnetic-relaxation
#10
Song-De Han, Jin-Hua Li, Hao-Hao Liu, Guo-Ming Wang
Two isostructural lanthanide (Ln) hybrid complexes co-bridged by organic oxalate and inorganic hypophosphite, [Ln(oxa)(H2PO2)(H2O)2] (oxa = oxalate; Ln = Gd (1), Dy (2)), were solvothermally prepared with the goal of elucidating the role of a hybrid framework in the generation of novel molecular magnetic materials. The title compounds feature a two dimensional (2D) hybrid layer. The Ln(III) ions are octa-coordinated with distorted square antiprism geometry. The adjacent Ln(III) ions are co-bridged by hypophosphite and one type of oxalate ligand to form 1D hybrid chains, which are further linked by a second type of oxalate ligand to generate the resulting 2D framework...
July 20, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28715633/diastereoselective-construction-of-the-6-oxa-2-azabicyclo-3-2-1-octane-scaffold-from-chiral-%C3%AE-hydroxyaldehyde-derivatives-by-aza-prins-reaction
#11
Alejandro Mahia, Ramon Badorrey, Jose Antonio Galvez, Maria Dolores Diaz-De-Villegas
(R)-2,3-Di-O-benzylglyceraldehyde and N-tosyl homoallylamine undergo aza-Prins cyclization to afford (1R,5S,7S)-7-[(benzyloxy)methyl]-2-tosyl-6-oxa-2-azabicyclo[3.2.1]octane in a highly diastereoselective manner through an unexpected intramolecular nucleophilic attack. Our work has opened a new route toward the asymmetric synthesis of 7-(alkyl or aryl)-6-oxa-2-azabicyclo[3.2.1]octane derivatives from chiral α-hydroxyaldehyde derivatives in one step.
July 17, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28712369/a-hospital-based-matched-case-control-study-to-identify-risk-factors-for-clinical-infection-with-oxa-48-producing-klebsiella-pneumoniae-in-rectal-carriers
#12
A Madueño, J Gonzalez Garcia, A Aguirre-Jaime, M Lecuona
Asymptomatic colonisation of the gastrointestinal tract by carbapenemase-producing Enterobacteriaceae is an important reservoir for transmission, which may precede infection. This retrospective observational case-control study was designed to identify risk factors for developing clinical infection with OXA-48-producing Klebsiella pneumoniae in rectal carriers during hospitalisation. Case patients (n = 76) had carbapenemase-producing K. pneumoniae (CPKP) infection and positive rectal culture for CPKP. Control patients (n = 174) were those with rectal colonisation with CPKP but without CPKP infection...
July 17, 2017: Epidemiology and Infection
https://www.readbyqxmd.com/read/28708476/a-long-term-study-of-the-diversity-of-oxa-48-like-carbapenemase-producing-bacterial-strains-in-infected-patients-and-carriers
#13
Paul-Louis Woerther, Taha Jardak, Inès Ben Hassine, Sébastien Forget, Elisabeth Chachaty, Guillaume Arlet, Dominique Decré
PURPOSE: Since their emergence at the beginning of the century, OXA-48 carbapenemases have spread in the community and in hospitals. To assess the diversity of OXA-48-producing bacterial strains and plasmids in the hospital setting, we studied the strains isolated from patients in three hospitals in the Paris area. MATERIALS AND METHODS: All possible OXA-48-like strains were included in the study. OXA-48-like and extended-spectrum beta-lactamase-encoding genes were identified, and fingerprinting analysis was performed for all Escherichia coli and Klebsiella pneumoniae strains...
July 14, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28708291/total-syntheses-of-the-reported-structures-of-curcusone-i-and-j-via-tandem-gold-catalysis
#14
Yong Li, Mingji Dai
Total syntheses of the reported structures of the rhamnofolane diterpene natural products curcusone I and J in racemic forms have been achieved. The synthetic strategy features a novel tandem gold-catalyzed furan formation and furan-allene [4+3] cycloaddition to build the 5,7-fused ring system with an oxa-bridge in one step and a stereoselective exo-Diels-Alder reaction to form the 6-membered ring. The newly developed tandem gold catalysis is quite general and can be scaled up. Our syntheses suggested that structural revisions of curcusone I and J are needed...
July 14, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28707886/diarylheptanoids-from-rhizomes-of-alpinia-officinarum-inhibit-aggregation-of-alpha-synuclein
#15
Guangmiao Fu, Wei Zhang, Dongsheng Du, Yu Pong Ng, Fanny C F Ip, Rongbiao Tong, Nancy Y Ip
Two new diarylheptanoids, alpinins A (1) and B (2), together with eighteen known diarylheptanoids (3-20), were isolated from the rhizomes of Alpinia officinarum. Their structures were elucidated by comprehensive spectroscopic analysis including HRMS, IR, and 1D- and 2D-NMR. Structurally, alpinin A is a new member of the small family of oxa-bridged diarylheptanoids and contains the characteristic 2,6-cis-configured tetrahydropyran motif (C1-C5 oxa-bridge). The absolute configuration of alpinin A was confirmed by asymmetric total synthesis of the enantiomer (ent-1), corroborating the assignment of the molecular structure...
July 14, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28707695/lewis-acid-catalyzed-diastereoselective-3-4-annulation-of-donor-acceptor-cyclopropanes-with-anthranils-synthesis-of-tetrahydro-1-benzazepine-derivatives
#16
Zhe-Hao Wang, Huan-Huan Zhang, Dao-Ming Wang, Peng-Fei Xu, Yong-Chun Luo
A Lewis acid catalyzed [3+4]-annulation reaction between cyclopropane 1,1-diesters and anthranils has been developed. This annulation consists of a reaction sequence involving ring-opening/aromatization/nucleophilic addition. Thereinto, aromatization is the driving force for this annulation. Using this reaction, a series of 8-oxa-1-azabicyclo[3.2.1]octanes can be prepared conveniently with excellent diastereoselectivity.
July 14, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28705668/in-vitro-activity-of-the-novel-fluorocycline-eravacycline-against-carbapenem-non-susceptible-acinetobacter-baumannii
#17
Harald Seifert, Danuta Stefanik, Joyce A Sutcliffe, Paul G Higgins
The activity of eravacycline was compared with anti-Acinetobacter reference antimicrobials against carbapenem non-susceptible Acinetobacter baumannii isolates associated with an acquired OXA or up-regulation of the intrinsic OXA-51-like enzyme. Antimicrobial susceptibility testing was performed by broth microdilution of 286 non-duplicate, carbapenem non-susceptible A. baumannii isolates to eravacycline, amikacin colistin, doxycycline, imipenem, levofloxacin, meropenem, minocycline, sulbactam, tigecycline, and tobramycin...
July 10, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28704760/synthesis-and-anti-oxidant-activity-evaluation-of-%C3%A2-anastatins-a-b-and-their-analogs
#18
Guojun Pan, Xuehui Li, Long Zhao, Meng Wu, Chao Su, Xuzhe Li, Yongmin Zhang, Peng Yu, Yuou Teng, Kui Lu
Two novel flavonoids (±)-Anastatins A and B as well as 14 analogs, which containing a benzofuran moiety, were synthesized by using halogenation, Suzuki coupling reaction and an oxidation/Oxa-Michael reaction cascade as the key steps. The structures of the new flavonoids were confirmed by (1)H NMR, (13)C NMR and HRMS. The antioxidant activities of them as well as the key intermediates were evaluated by ferric reducing antioxidant power (FRAP) assay and the active compounds were evaluated in the PC12 cell model of hydrogen peroxide (H2O2)-induced oxidative damage...
June 27, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28701421/carbapenemase-detection-amongst-carbapenem-resistant-glucose-nonfermenting-gram-negative-bacilli
#19
Patricia J Simner, Belita N A Opene, Krizia K Chambers, Matthew E Naumann, Karen C Carroll, Pranita D Tamma
Background: Accurate detection of carbapenemase-producing glucose nonfermenting gram-negative bacilli (CPNF), including Pseudomonas aeruginosa and Acinetobacter baumannii, is necessary to prevent their dissemination within health care settings. We performed a methods comparison study of 11 phenotypic carbapenemase-detection assays to evaluate their accuracy for the detection of CPNFs.Methods: 96 carbapenem-resistant glucose nonfermenting isolates were included, of which 29% produced carbapenemases. All CPNFs were molecularly characterized to identify β-lactamase genes...
July 12, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28700049/molecular-detection-of-%C3%AE-lactamase-and-integron-genes-in-clinical-strains-of-klebsiella-pneumoniae-by-multiplex-polymerase-chain-reaction
#20
Mansour Sedighi, Masoumeh Halajzadeh, Rashid Ramazanzadeh, Noor Amirmozafari, Mohsen Heidary, Serve Pirouzi
INTRODUCTION: Infections caused by β-lactamase-producing gram-negative bacteria, such as Klebsiella pneumoniae, are increasing globally with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the prevalence of antibiotic resistance genes (β-lactamase and integron genes) using multiplex PCR. METHODS: One-hundred K. pneumoniae isolates were collected from different clinical samples. Antibiotic susceptibility testing was performed with thirteen different antibiotics...
May 2017: Revista da Sociedade Brasileira de Medicina Tropical
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