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https://www.readbyqxmd.com/read/29156265/occurrence-and-fate-of-most-prescribed-antibiotics-in-different-water-environments-of-tehran-iran
#1
Roya Mirzaei, Masud Yunesian, Simin Nasseri, Mitra Gholami, Esfandiyar Jalilzadeh, Shahram Shoeibi, Alireza Mesdaghinia
The presence of most prescribed antibiotic compounds from four therapeutic classes (β-lactam, cephalosporins, macrolides, fluoroquinolones) were studied at two full-scale WWTPs, two rivers, thirteen groundwater resources, and five water treatment plants in Tehran. Analytical methodology was based on high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction. Samples were collected at 33 sample locations on three sampling periods over four months from June to August 2016. None of the target antibiotics were detected in groundwater resources and water treatment plants, while seven out of nine target antibiotics were analyzed in two studied river waters as well as the influent and effluent of wastewater treatment plants at concentrations ranging from <LOQ to 926...
November 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29148816/assessment-of-anti-piperacillin-igg-binding-to-structurally-related-drug-protein-adducts
#2
Mohammed Amali, Rosalind Jenkins, Xioali Meng, Lee Faulkner, Paul Whitaker, Daniel Peckham, B Kevin Park, Dean John Naisbitt
The risk of developing hypersensitivity to alternative antibiotics is a concern for penicillin hypersensitive patients and healthcare pro-viders. Herein we use piperacillin hypersensitivity as a model to explore the reactivity of drug-specific IgG against alternative β-lactam protein adducts. Mass spectrometry was used to show the drugs (amoxicillin, flucloxacillin, benzyl penicillin, aztreonam and pipera-cillin) bind to similar lysine residues on the protein carrier bovine serum albumin. However, the hapten-specific IgG antibodies found in piperacillin hypersensitive patient plasma did not bind to other β-lactam protein conjugates...
November 17, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/29146833/draft-genome-sequences-of-eight-streptogramin-resistant-enterococcus-species-isolated-from-animal-and-environmental-sources-in-the-united-states
#3
Poonam Sharma, Sushim Kumar Gupta, John B Barrett, Lari M Hiott, Sandra L House, Tiffanie A Woodley, Jonathan G Frye, Charlene R Jackson
Here, we present the draft genome sequences of eight streptogramin-resistant Enterococcus species isolated from animals and an environmental source in the United States from 2001 to 2004. Antimicrobial resistance genes were identified conferring resistance to the macrolide-lincosamide-streptogramins, aminoglycosides, tetracyclines, beta-lactams, and glycopeptides.
November 16, 2017: Genome Announcements
https://www.readbyqxmd.com/read/29144958/isolation-of-blandm-producing-enterobacteriaceae-in-a-public-hospital-in-salvador-bahia-brazil
#4
Maria Goreth Barberino, Silvia de Araujo Cruvinel, Célio Faria, Marco Aurélio Salvino, Márcio Oliveira
Carbapenemases have great importance in the global epidemiological scenario since infections with carbapenemase-producing bacteria are associated with high mortality, especially in hospitalized patients in intensive care units. This study describes two microorganisms producers of the New Delhi Metallo-b-lactamase (NDM), Klebsiella pneumoniae and Citrobacter freundii, from two patients admitted to a public hospital in Salvador, Bahia. These are the first clinical cases of NDM described in microorganisms in the north and northeast Brazil...
November 13, 2017: Brazilian Journal of Infectious Diseases
https://www.readbyqxmd.com/read/29135242/computational-study-on-%C3%AE-c-h-functionalization-of-%C3%AE-%C3%AE-unsaturated-ester-catalyzed-by-n-heterocyclic-carbene-mechanisms-origin-of-stereoselectivity-and-role-of-catalyst
#5
Yang Wang, Donghui Wei, Mingsheng Tang
The N-heterocyclic carbene (NHC)-catalyzed γ-C-H deprotonation/functionalization of α,β-unsaturated esters with hydrazones leading to the δ-lactams has been theoretically investigated by using density functional theory. Three possible reaction mechanisms including Mechanism A, for which the NHC catalyst serves as a nucleophilic catalyst to attack on the carbonyl carbon atom to initiate the reaction, Mechanism B, in which NHC triggers the reaction through the hydrogen bond, and Mechanism C, which is the direct deprotonation/functionalization process without the presence of NHC, have been suggested and studied in detail...
November 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29120635/total-synthesis-of-himalensine-a
#6
Heyao Shi, Iacovos N Michaelides, Benjamin Darses, Pavol Jakubec, Quynh Nhu N Nguyen, Robert S Paton, Darren J Dixon
The first enantioselective synthesis of (-)-himalensine A has been achieved in 22 steps. The synthesis was enabled by a novel catalytic, enantioselective prototropic shift / furan Diels-Alder (IMDAF) cascade to construct the ACD tricyclic core. A reductive radical cyclization cascade was utilized to build the B ring, and end game manipulations featuring a molecular oxygen mediated γ-CH oxidation, a Stetter cyclization to access the pendant cyclopentenone and a highly chemoselective lactam reduction delivered the natural product target...
November 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29107079/clonal-spread-of-carbapenem-resistant-acinetobacter-baumannii-in-neonatal-intensive-care-unit
#7
Wirlaine Glauce Maciel, Kesia Esther da Silva, Julio Croda, Rodrigo Cayô, Ana Carolina Ramos, Romário Oliveira de Sales, Gleyce Hellen de Almeida de Souza, José Victor Bortolotto Bampi, Leticia Cristina Limiere, Junior César Casagrande, Ana Cristina Gales, Simone Simionatto
Acinetobacter baumannii has been frequently associated with colonization and/or infection in neonatal intensive care units (NICU). In this study, we describe a clonal spread of carbapenem-resistant A. baumannii (CRAB) isolates in a NICU. A total of 21 CRAB isolates were collected from premature newborns. Only polymyxin B was active against such isolates. Nineteen CRAB isolates were clonally related (cluster C that belonged to worldwide-disseminated ST1). All newborns had peripheral access and previously received β-lactams therapy...
October 26, 2017: Journal of Hospital Infection
https://www.readbyqxmd.com/read/29098663/antibiotics-reduce-retinal-cell-survival-in-vitro
#8
Amy E Lindsey, Ellen Townes-Anderson
Antibiotics such as gentamicin (an aminoglycoside) and penicillin (a beta-lactam antibiotic) are routinely used in retinal cell and explant cultures. In many cases, these in vitro systems are testing parameters regarding photoreceptor transplantation or preparing cells for transplantation. In vivo, milligram doses of gentamicin are neurotoxic to the retina. However, little is known about the effects of antibiotics to retina in vitro and whether smaller doses of gentamicin are toxic to retinal cells. To test toxicity, retinal cells were dissociated from tiger salamander, placed in culture, and treated with either 20 μg/ml gentamicin, 100 μg/ml streptomycin, 100 U/ml antibiotic/antimycotic, 0...
November 2, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/29091730/probing-the-interaction-of-aspergillomarasmine-a-with-metallo-%C3%AE-lactamases-ndm-1-vim-2-and-imp-7
#9
Alexander Bergstrom, Andrew Katko, Zach Adkins, Jessica Hill, Zishuo Cheng, Mia Burnett, Hao Yang, Mahesh Aitha, M Rachel Mehaffey, Jennifer S Brodbelt, Kamaleddin H M E Tehrani, Nathaniel I Martin, Robert A Bonomo, Richard C Page, David L Tierney, Walter Fast, Gerard D Wright, Michael W Crowder
Metallo-β-lactamases (MBLs) are a growing threat to the continued efficacy of β-lactam antibiotics. Recently, aspergillomarasmine A (AMA) was identified as an MBL inhibitor, but the mode of inhibition was not fully characterized. Equilibrium dialysis and metal analysis studies revealed that 2 equiv of AMA effectively removes 1 equiv of Zn(II) from MBLs NDM-1, VIM-2, and IMP-7 when the MBL is at micromolar concentrations. Conversely, (1)H NMR studies revealed that 2 equiv of AMA remove 2 equiv of Co(II) from Co(II)-substituted NDM-1, VIM-2, and IMP-7 when the MBL/AMA are at millimolar concentrations...
November 9, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29063318/method-of-selection-of-bacteria-antibiotic-resistance-genes-based-on-clustering-of-similar-nucleotide-sequences
#10
I S Balashov, V A Naumov, P I Borovikov, A B Gordeev, D V Dubodelov, L A Lyubasovskaya, Yu V Rodchenko, A A Bystritskii, N V Aleksandrova, D Yu Trofimov, T V Priputnevich
A new method for selection of bacterium antibiotic resistance genes is proposed and tested for solving the problems related to selection of primers for PCR assay. The method implies clustering of similar nucleotide sequences and selection of group primers for all genes of each cluster. Clustering of resistance genes for six groups of antibiotics (aminoglycosides, β-lactams, fluoroquinolones, glycopeptides, macrolides and lincosamides, and fusidic acid) was performed. The method was tested for 81 strains of bacteria of different genera isolated from patients (K...
October 2017: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/29062329/dissemination-and-genetic-support-of-broad-spectrum-beta-lactam-resistant-escherichia-coli-strain-isolated-from-two-tunisian-hospitals-during-2004-2012
#11
Khaoula Ayari, Amel Bourouis, Hela Chihi, Sihem Mahrouki, Thierry Naas, Omrane Belhadj
BACKGROUND: The dissemination of extended-spectrum β-lactamase (ESBL)-producing bacteria presented a great concern worldwide. Gram-negative organisms such as Escherichia coli and Klebsiella pneumoniae are the most frequently isolated pathogens responsible for nosocomial infections. OBJECTIVES: The aim of this study was to investigate and to follow the emergence of resistance and the characterization of Extended-Spectrum Beta-Lactamases (ESBL) among broad-spectrum beta-lactam-Escherichia coli clinical isolates recovered from the military hospital and Habib Thameur hospital in Tunisia...
June 2017: African Health Sciences
https://www.readbyqxmd.com/read/29054871/engineering-the-enantioselectivity-and-thermostability-of-a-%C3%AE-lactamase-from-microbacterium-hydrocarbonoxydans-for-the-kinetic-resolution-of-vince-lactam
#12
Shuaihua Gao, Shaozhou Zhu, Rong Huang, Hongxia Li, Hao Wang, Guojun Zheng
To produce promising biocatalysts, natural enzymes often need to be engineered to increase their catalytic performance. In this study, the enantioselectivity and thermostability of a (+)-γ-lactamase from Microbacterium hydrocarbonoxydans as the catalyst in the kinetic resolution of Vince lactam were improved. Enantiomerically pure (-)-Vince lactam is the key synthon in the synthesis of antiviral drugs such as carbovir and abacavir, which are used to fight against human HIV and hepatitis B viruses. The work was initialized by using the combinatorial active-site saturation test strategy to engineer the enantioselectivity of the enzyme...
October 20, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/29034069/scaffold-hopping-via-anchor-query-%C3%AE-lactams-as-potent-p53-mdm2-antagonists-%C3%A2
#13
S Shaabani, C G Neochoritis, A Twarda-Clapa, B Musielak, T A Holak, A Dömling
Using the pharmacophore-based virtual screening platform ANCHOR.QUERY, we morphed our recently described Ugi-4CR scaffold towards a β-lactam scaffold with potent p53-MDM2 antagonizing activities. 2D-HSQC and FP measurements confirm potent MDM2 binding. Molecular modeling studies are used to understand the observed SAR in the β-lactam series.
May 1, 2017: MedChemComm
https://www.readbyqxmd.com/read/29029194/envelope-proteome-changes-driven-by-rama-overproduction-in-klebsiella-pneumoniae-that-enhance-acquired-%C3%AE-lactam-resistance
#14
Juan-Carlos Jiménez-Castellanos, Wan Ahmad Kamil Wan Nur Ismah, Yuiko Takebayashi, Jacqueline Findlay, Thamarai Schneiders, Kate J Heesom, Matthew B Avison
Objectives: In Klebsiella pneumoniae, overproduction of RamA results in reduced envelope permeability and reduced antimicrobial susceptibility but clinically relevant resistance is rarely observed. Here we have tested whether RamA overproduction can enhance acquired β-lactam resistance mechanisms in K. pneumoniae and have defined the envelope protein abundance changes upon RamA overproduction during growth in low and high osmolarity media. Methods: Envelope permeability was estimated using a fluorescent dye accumulation assay...
October 6, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/29028569/occurrence-of-transferable-antibiotic-resistances-in-commercialized-ready-to-eat-mealworms-tenebrio-molitor-l
#15
Andrea Osimani, Federica Cardinali, Lucia Aquilanti, Cristiana Garofalo, Andrea Roncolini, Vesna Milanović, Marina Pasquini, Stefano Tavoletti, Francesca Clementi
The present study aimed to assess the occurrence of transferable determinants conferring resistance to tetracyclines, macrolide-lincosamide-streptogramin B, vancomycin, beta-lactams, and aminoglycosides in 40 samples of commercialized edible mealworms (Tenebrio molitor L.) purchased from European Union (EU) and non-EU producers. A high prevalence of tet(K) was observed in all of the samples assayed, with percentages of PCR-based positivity that ranged from 80% (samples from Thailand) to 100% (samples from the Netherlands, Belgium and France)...
October 5, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/29020311/noncarbapenem-%C3%AE-lactams-for-the-treatment-of-extended-spectrum-%C3%AE-lactamase-infections-what-are-the-remaining-drugs-outside-the-united-states
#16
B Davido, A Dinh
No abstract text is available yet for this article.
September 9, 2017: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
https://www.readbyqxmd.com/read/28992919/genotypic-and-epidemiologic-characterization-of-extended-spectrum-cephalosporin-resistant-salmonella-enterica-from-us-beef-feedlots
#17
D F Mollenkopf, D A Mathys, D A Dargatz, M M Erdman, G G Habing, J B Daniels, T E Wittum
In the US, nontyphoidal Salmonellae are a common foodborne zoonotic pathogen causing gastroenteritis. Invasive Salmonella infections caused by extended-spectrum cephalosporin resistant (ESCR) phenotypes are more likely to result in treatment failure and adverse health outcomes, especially in severe pediatric Salmonella infections where the extended-spectrum β-lactams are the therapy of choice. To examine the genetic and epidemiologic characteristics of ESCR Salmonellae which may enter the food chain, we characterized 44 ceftiofur-resistant Salmonella isolates from the National Animal Health Monitoring System (NAHMS) 2011 beef cattle feedlot health and management study...
October 1, 2017: Preventive Veterinary Medicine
https://www.readbyqxmd.com/read/28980026/-bacterial-sepsis-diagnostics-and-calculated-antibiotic-therapy
#18
REVIEW
D C Richter, A Heininger, T Brenner, M Hochreiter, M Bernhard, J Briegel, S Dubler, B Grabein, A Hecker, W A Krüger, K Mayer, M W Pletz, D Störzinger, N Pinder, T Hoppe-Tichy, S Weiterer, S Zimmermann, A Brinkmann, M A Weigand, Christoph Lichtenstern
The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment...
October 2017: Der Anaesthesist
https://www.readbyqxmd.com/read/28971872/kinetics-of-sulbactam-hydrolysis-by-%C3%AE-lactamases-and-their-inhibition
#19
Adam B Shapiro
Sulbactam is one of 4 β-lactamase inhibitors in current clinical use to counteract drug resistance caused by degradation of β-lactam antibiotics by these bacterial enzymes. As a β-lactam itself, sulbactam is susceptible to degradation by β-lactamases. We investigated the Michaelis-Menten kinetics of sulbactam hydrolysis by 14 β-lactamases representing clinically widespread groups within all 4 Ambler classes: CTX-M-15, KPC-2, SHV-5, and TEM-1 for class A; IMP-1, NDM-1, and VIM-1 for class B; Acinetobacter baumannii ADC-7, Pseudomonas aeruginosa AmpC and Enterobacter cloacae P99 for class C; and OXA-10, OXA-23, OXA-24, and OXA-48 for class D...
October 2, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28969552/back-to-non-basics-an-update-on-neutral-and-charge-balanced-glycosidase-inhibitors
#20
Michela I Simone, Laura Mares, Clothilde Eveleens, Adam McCluskey, Brighid B Pappin, Milton J Kiefel, Todd A Houston
Glycosidases have important anti-cancer, anti-viral and anti-diabetic properties. This review covers the literature in the past 15 years since our initial review in this journal on "neutral" glycosidase inhibitors lacking a basic nitrogen found in iminosugars and azasugars or inhibitors that are neutral by virtue of being "charge-balanced" (zwitterionic). These structurally diverse inhibitors include lactones, lactams, epoxides such as cyclophellitol, and sulfonium ion derivatives of the natural product salacinol...
October 2, 2017: Mini Reviews in Medicinal Chemistry
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