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Ctx m hybrid

Tianyang Ren, Jingxin Gou, Wanxiao Sun, Xiaoguang Tao, Xinyi Tan, Puxiu Wang, Yu Zhang, Haibing He, Tian Yin, Xing Tang
In this work, a nano-in-micro carrier was constructed by loading polymer-lipid hybrid nanoparticles (NPs) into porous and hollow yeast cell wall microparticles (YPs) for macrophage-targeted oral delivery of cabazitaxel (CTX). The YPs, primarily composed of natural β-1,3-D-glucan, can be recognized by the apical membrane receptor, dectin-1, which has a high expression on macrophages and intestinal M cells. By combining electrostatic force-driven self-deposition with solvent hydration/lyophilization methods, the positively charged NPs loaded with CTX or fluorescence probes were efficiently packaged into YPs, as verified by scanning electron microscope (SEM), atomic force mircoscope (AFM) and confocal laser scanning microscopy (CLSM) images...
June 4, 2018: Molecular Pharmaceutics
Agnese Lupo, Estelle Saras, Jean-Yves Madec, Marisa Haenni
Objectives: In Asian countries, blaCTX-M-55 is the second most common ESBL-encoding gene. blaCTX-M-55 frequently co-localizes with fosA and rmtB genes on epidemic plasmids, which remain sporadic outside Asia. During 2010-13, we investigated CTX-M-55-producing Escherichia coli isolates and their co-resistance to fosfomycin, aminoglycosides, fluoroquinolones and colistin as part of a global survey of ESBLs in animals in France. Methods: blaCTX-M-55, fosA, rmtB and plasmidic quinolone and colistin resistance genes were characterized by PCR, sequencing and hybridization experiments...
April 1, 2018: Journal of Antimicrobial Chemotherapy
Kathy Hiu Laam Po, Edward Wai Chi Chan, Sheng Chen
This work investigated the molecular events driving the evolution of the CTX-M-type β-lactamases by the use of DNA shuffling of fragments of the bla CTX-M-14 and bla CTX-M-15 genes. Analysis of a total of 51 hybrid enzymes showed that enzymatic activity could be maintained in most cases, yet hybrids that were active possessed fewer amino acid substitutions than those that were inactive, suggesting that point mutations in the constructs rather than reshuffling of the fragments of the two target genes would more likely cause disruption of CTX-M activity...
December 2017: Antimicrobial Agents and Chemotherapy
Ignacio Lizana, Eduardo J Delgado
The reaction between the antibiotic cefotaxime and the CTX-M-14 class A serine hydrolase is addressed from a theoretical point of view, by means of hybrid quantum mechanics/molecular mechanical (QM/MM) calculations, adopting a new approach that postulates that the residue Ser70 itself should play the role of the acid-base species required for the cefotaxime acylation. The proposed mechanism differs from earlier proposals existing in literature for other class A β-lactamases. The results confirm the hypothesis, and show that the reaction should occur via a concerted mechanism in which the acylation of the lactam carbonyl carbon, protonation of the N7 lactam atom, and opening of the β-lactam ring occurs simultaneously...
July 2017: Journal of Molecular Modeling
L Vezzulli, C Grande, G Tassistro, I Brettar, M G Höfle, R P A Pereira, D Mushi, A Pallavicini, P Vassallo, C Pruzzo
The detection and typing of Vibrio cholerae in natural aquatic environments encounter major methodological challenges related to the fact that the bacterium is often present in environmental matrices at very low abundance in nonculturable state. This study applied, for the first time to our knowledge, a whole-genome enrichment (WGE) and next-generation sequencing (NGS) approach for direct genotyping and metagenomic analysis of low abundant V. cholerae DNA (<50 genome unit/L) from natural water collected in the Morogoro river (Tanzania)...
April 2017: Microbial Ecology
Song-Tao Han, Ying Fei, Jin-You Huang, Mei Xu, Li-Chan Chen, D Joshua Liao, Yu-Jie Tan
Extended-spectrum β-lactamase (ESBL) genes that render bacteria resistant to antibiotics are commonly detected using phenotype testing, which is time consuming and not sufficiently accurate. To establish a better method, we used phenotype testing to identify ESBL-positive bacterial strains and conducted PCR to screen for TEM (named after the patient Temoneira who provided the first sample), sulfhydryl reagent variable (SHV), cefotaxime (CTX)-M-1, and CTX-M-9, the 4 most common ESBL types and subtypes. We then performed multiplex PCR with 1 primer containing a biotin and hybridized the PCR products with gene-specific probes that were coupled with microbeads and coated with a specific fluorescence...
December 2016: Journal of Biomolecular Techniques: JBT
M M J van Riet, S Millet, A Liesegang, E Nalon, B Ampe, F A M Tuyttens, D Maes, G P J Janssens
Bone metabolism fluctuates throughout the reproductive cycle of sows to enable foetal growth and milk production. Although increased bone mineralisation is conceivable in sows during reproduction, a study of mineralisation in function of parity has not been performed. This study evaluated the fluctuations of markers for bone metabolism in primiparous and multiparous sows throughout a reproductive cycle. The experiment included ten multiparous and five primiparous commercial hybrid sows from one herd. The sows were monitored for one reproductive cycle and fed according to commercial dietary standards...
April 5, 2016: Animal: An International Journal of Animal Bioscience
Seon Young Choi, Shah M Rashed, Nur A Hasan, Munirul Alam, Tarequl Islam, Abdus Sadique, Fatema-Tuz Johura, Mark Eppinger, Jacques Ravel, Anwar Huq, Alejandro Cravioto, Rita R Colwell
UNLABELLED: An outbreak of cholera occurred in 1991 in Mexico, where it had not been reported for more than a century and is now endemic. Vibrio cholerae O1 prototype El Tor and classical strains coexist with altered El Tor strains (1991 to 1997). Nontoxigenic (CTX(-)) V. cholerae El Tor dominated toxigenic (CTX(+)) strains (2001 to 2003), but V. cholerae CTX(+) variant El Tor was isolated during 2004 to 2008, outcompeting CTX(-) V. cholerae. Genomes of six Mexican V. cholerae O1 strains isolated during 1991 to 2008 were sequenced and compared with both contemporary and archived strains of V...
March 15, 2016: MBio
T G Ribeiro, Â Novais, L Peixe, E Machado
OBJECTIVES: The objective of this study was to investigate the distribution and molecular epidemiology of ESBLs, acquired AmpCs and carbapenemases in Enterobacteriaceae from non-clinical niches in Angola, an under-researched sub-Saharan country. METHODS: Eighty-one samples were recovered from healthy persons (n = 18), healthy animals (n = 33) and their environments (n = 10) or aquatic settings (n = 20) in south Angola (2013). Samples were plated onto CHROMagar™ Orientation with/without antibiotics...
May 2016: Journal of Antimicrobial Chemotherapy
Ana Maravić, Mirjana Skočibušić, Željana Fredotović, Ivica Šamanić, Svjetlana Cvjetan, Mia Knezović, Jasna Puizina
Some Acinetobacter species have emerged as very important opportunistic pathogens in humans. We investigated Acinetobacter spp. from the polluted urban riverine environment in Croatia in regard to species affiliation, antibiotic resistance pattern, and resistance mechanisms. Considerable number of isolates produced acquired extended-spectrum β-lactamase(s) (ESBLs), CTX-M-15 solely or with TEM-116. By Southern blot hybridization, bla TEM-116 was identified on plasmids ca. 10, 3, and 1.2 kb in Acinetobacter junii, A...
February 2016: Environmental Science and Pollution Research International
A Baraniak, R Izdebski, J Fiett, I Gawryszewska, K Bojarska, M Herda, E Literacka, D Żabicka, H Tomczak, N Pewińska, M Szarata, T Ozorowski, A Milner, W Hryniewicz, M Gniadkowski
OBJECTIVES: The objective of this study was to characterize New Delhi metallo-β-lactamase (NDM)-producing Enterobacteriaceae isolates reported in Poland in 2012-14. METHODS: Representative isolates were typed by PFGE and MLST. NDM and other β-lactamase genes were amplified and sequenced. Plasmids with blaNDM genes were analysed by nuclease S1 plus hybridization profiling, by transfer assays and by PCR-based replicon typing. The blaNDM genetic context was studied by PCR mapping assays...
January 2016: Journal of Antimicrobial Chemotherapy
Ann M Hemmerle, Rebecca Ahlbrand, Stefanie L Bronson, Kerstin H Lundgren, Neil M Richtand, Kim B Seroogy
Maternal immune activation (MIA) is an environmental risk factor for schizophrenia, and may contribute to other developmental disorders including autism and epilepsy. Activation of pro-inflammatory cytokine systems by injection of the synthetic double-stranded RNA polyriboinosinic-polyribocytidilic acid (Poly I:C) mediates important neurochemical and behavioral corollaries of MIA, which have relevance to deficits observed in schizophrenia. We examined the consequences of MIA on forebrain expression of neuregulin-1 (NRG-1), brain-derived neurotrophic factor (BDNF) and their receptors, ErbB4 and trkB, respectively, genes associated with schizophrenia...
October 2015: Schizophrenia Research
Dandan He, Jiachi Chiou, Zhenling Zeng, Lanping Liu, Xiaojie Chen, Li Zeng, Edward Wai Chi Chan, Jian-Hua Liu, Sheng Chen
A variety of CTX-M-type extended-spectrum β-lactamases (ESBLs), including hybrid ones, have been reported in China that are uncommon elsewhere. To better characterize the substrate profiles and enzymatic mechanisms of these enzymes, we performed comparative kinetic analyses of both parental and hybrid CTX-M enzymes, including CTX-M-15, -132, -123, -64, -14 and -55, that are known to confer variable levels of β-lactam resistance in the host strains. All tested enzymes were susceptible to serine β-lactamase inhibitors, with sulbactam exhibiting the weakest inhibitory effects...
October 2015: Antimicrobial Agents and Chemotherapy
Stephen E Mshana, Moritz Fritzenwanker, Linda Falgenhauer, Eugen Domann, Torsten Hain, Trinad Chakraborty, Can Imirzalioglu
BACKGROUND: Multi-drug resistant Klebsiella pneumoniae strains are a common cause of health care associated infections worldwide. Clonal spread of Klebsiella pneumoniae isolates carrying plasmid mediated CTX-M-15 have been commonly reported. Limited data is available regarding dissemination of chromosomally encoded CTX-M-15 in Klebsiella pneumoniae worldwide. RESULTS: We examined 23 non-repetitive ESBL-producing Klebsiella pneumoniae strains isolated from clinical specimens over a period of 4 months in a German University Hospital...
2015: BMC Microbiology
Lanping Liu, Dandan He, Luchao Lv, Wuling Liu, Xiaojie Chen, Zhenling Zeng, Sally R Partridge, Jian-Hua Liu
Three hybrid CTX-M β-lactamases, CTX-M-64, CTX-M-123, and CTX-M-132, with N and C termini matching CTX-M-1 group enzymes and centers matching CTX-M-9 group enzymes, have been identified. The hybrid gene sequences suggested recombination between blaCTX-M-15 and blaCTX-M-14, the two most common blaCTX-M variants worldwide. However, blaCTX-M-64 and blaCTX-M-123 are found in an ISEcp1-blaCTX-M transposition unit with a 45-bp "spacer," rather than the 48 bp usually associated with blaCTX-M-15, and 112 bp of IncA/C plasmid backbone...
August 2015: Antimicrobial Agents and Chemotherapy
Zhiyong Zong, Andrew N Ginn, Hana Dobiasova, Jonathan R Iredell, Sally R Partridge
The bla(CTX-M-15) gene, encoding the globally dominant CTX-M-15 extended-spectrum β-lactamase, has generally been found in a 2.971-kb ISEcp1-bla(CTX-M-15)-orf477Δ transposition unit, with ISEcp1 providing a promoter. In available IncF plasmid sequences from Escherichia coli, this transposition unit interrupts a truncated copy of transposon Tn2 that lies within larger multiresistance regions. In E. coli, bla(CTX-M-15) is also commonly associated with IncI1 plasmids and here three such plasmids from E. coli clinical isolates from western Sydney 2006-2007 have been sequenced...
July 2015: Plasmid
Amy J Mathers, Gisele Peirano, Johann D D Pitout
Escherichia coli sequence type 131 (ST131) and Klebsiella pneumoniae ST258 emerged in the 2000s as important human pathogens, have spread extensively throughout the world, and are responsible for the rapid increase in antimicrobial resistance among E. coli and K. pneumoniae strains, respectively. E. coli ST131 causes extraintestinal infections and is often fluoroquinolone resistant and associated with extended-spectrum β-lactamase production, especially CTX-M-15. K. pneumoniae ST258 causes urinary and respiratory tract infections and is associated with carbapenemases, most often KPC-2 and KPC-3...
July 2015: Clinical Microbiology Reviews
David C Klinzing, Seon Young Choi, Nur A Hasan, Ronald R Matias, Enrique Tayag, Josefina Geronimo, Evan Skowronski, Shah M Rashed, Kent Kawashima, C Nicole Rosenzweig, Henry S Gibbons, Brian C Torres, Veni Liles, Alicia C Alfon, Maria Luisa Juan, Filipinas F Natividad, Thomas A Cebula, Rita R Colwell
UNLABELLED: Cholera continues to be a global threat, with high rates of morbidity and mortality. In 2011, a cholera outbreak occurred in Palawan, Philippines, affecting more than 500 people, and 20 individuals died. Vibrio cholerae O1 was confirmed as the etiological agent. Source attribution is critical in cholera outbreaks for proper management of the disease, as well as to control spread. In this study, three V. cholerae O1 isolates from a Philippines cholera outbreak were sequenced and their genomes analyzed to determine phylogenetic relatedness to V...
2015: MBio
Kenneth E Pierce, Lawrence J Wangh
The amplification and detection of diverse strains of an infectious virus or bacteria, or variants within a gene family is important for both clinical and basic research but can be difficult using conventional PCR. This report describes and illustrates a novel closed-tube method for amplifying and characterizing heterogeneous target sequences using members of the CTX-M beta-lactamase gene family. Different subgroups of CTX-M genes exhibit low sequence identity, but accurate and efficient detection of these variants is critical because they all confer resistance to penicillin, cefotaxime, and other antibiotics of the beta-lactam class...
2015: Methods in Molecular Biology
Carla Rodrigues, Elisabete Machado, Helena Ramos, Luísa Peixe, Ângela Novais
The aim of this study was to characterize by a multi-level approach extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolates other than E. coli from Portuguese hospitals. Eighty-eight ESBL-producing clinical isolates (69 Klebsiella pneumoniae, 13 Enterobacter cloacae complex, 3 Klebsiella oxytoca, 1 Enterobacter asburiae, 1 Proteus mirabilis and 1 Serratia marcescens) recovered from hospitals located in the North (A) or Centre (B, C) regions during two time periods (2006-7 and 2010) were analyzed...
November 2014: International Journal of Medical Microbiology: IJMM
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