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https://www.readbyqxmd.com/read/28915359/presence-of-%C3%AE-lactamase-encoding-genes-in-burkholderia-cepacia-complex-isolated-from-soil
#1
João Pedro Rueda Furlan, Danilo Garcia Sanchez, Ana Lúcia Fachin, Eliana Guedes Stehling
Burkholderia cepacia complex has emerged as an important opportunistic bacteria group for immunocompromised patients, and it has a high level of intrinsic resistance for different antibiotic classes. Hydrolysis of β-lactam antibiotics by β-lactamases is the most common resistance mechanism in Gram-negative bacteria, and the presence of such enzymes complicates the selection of appropriate therapy. This study aimed at investigating the antimicrobial resistance profile and the presence of β-lactamase encoding genes in B...
September 15, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28898936/aerobic-composting-reduces-antibiotic-resistance-genes-in-cattle-manure-and-the-resistome-dissemination-in-agricultural-soils
#2
Min Gou, Hang-Wei Hu, Yu-Jing Zhang, Jun-Tao Wang, Helen Hayden, Yue-Qin Tang, Ji-Zheng He
Composting has been suggested as a potential strategy to eliminate antibiotic residues and pathogens in livestock manure before its application as an organic fertilizer in agro-ecosystems. However, the impacts of composting on antibiotic resistance genes (ARGs) in livestock manure and their temporal succession following the application of compost to land are not well understood. We examined how aerobic composting affected the resistome profiles of cattle manure, and by constructing laboratory microcosms we compared the effects of manure and compost application to agricultural soils on the temporal succession of a wide spectrum of ARGs...
September 8, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28894966/targeting-cancer-specific-glycans-by-cyclic-peptide-lectinomimics
#3
Maria C Rodriguez, Austin B Yongye, Mihael Cudic, Karina Martinez Mayorga, Enbo Liu, Barbara M Mueller, Jon Ainsley, Tatyana Karabencheva-Christova, Christo Z Christov, Mare Cudic, Predrag Cudic
The transformation from normal to malignant phenotype in human cancers is associated with aberrant cell-surface glycosylation. Thus, targeting glycosylation changes in cancer is likely to provide not only better insight into the roles of carbohydrates in biological systems, but also facilitate the development of new molecular probes for bioanalytical and biomedical applications. In the reported study, we have synthesized lectinomimics based on odorranalectin 1; the smallest lectin-like cyclic peptide isolated from the frog Odorrana grahami skin, and assessed the ability of these peptides to bind specific carbohydrates on molecular and cellular levels...
September 11, 2017: Amino Acids
https://www.readbyqxmd.com/read/28888966/pursuing-sesterterpene-lactams-in-australian-irciniidae-sponges
#4
Pritesh Prasad, Ailian Zhang, Angela A Salim, Robert J Capon
Chemical investigation of two Irciniidae sponges collected by hand (SCUBA) from Australian near shore waters, afforded six new examples of a rare class of sesterterpene lactam; ircinialactams B (1), G (2), H (5), and I (6), and 8-hydroxyircinialactams C (3) and G (4); together with the new biosynthetically related lactone, ircinialactone A (7). Also isolated were seven biosynthetically related known Irciniidae metabolites; ircinialactams A (8) and C (9), (7E,12E,20Z,18S)-variabilin (10), (7Z,12Z,20Z,18S)-variabilin (11), (7E,12Z,20Z,18S)-variabilin (12), (7Z,12E,20Z,18S)-variabilin (13) and irciniafuran A (14)...
September 6, 2017: Fitoterapia
https://www.readbyqxmd.com/read/28887421/impact-of-raised-without-antibiotics-beef-cattle-production-practices-on-occurrences-of-antimicrobial-resistance
#5
Amit Vikram, Pablo Rovira, Getahun E Agga, Terrance M Arthur, Joseph M Bosilevac, Tommy L Wheeler, Paul S Morley, Keith E Belk, John W Schmidt
The specific antimicrobial resistance (AMR) decreases that can be expected from reducing antimicrobial (AM) use in United States (US) beef production have not been defined. To address this data gap, feces were recovered from 36 lots of "raised without antibiotics" (RWA) and 36 lots of "conventional" (CONV) beef cattle. Samples (N = 719) were collected during harvest and distributed over a year. AMR was assessed by: i) culture of six AM-resistant bacteria (ARB); ii) qPCR for 10 AMR genes (ARGs); iii) an qPCR array of 84 ARGs; and iv) metagenomic sequencing...
September 8, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28876489/structural-mechanistic-insights-into-the-efficacy-of-non-classical-%C3%AE-lactamase-inhibitors-against-extensively-drug-resistant-stenotrophomonas-maltophilia-clinical-isolates
#6
Karina Calvopiña, Philip Hinchliffe, Jürgen Brem, Kate J Heesom, Samar Johnson, Ricky Cain, Christopher T Lohans, Colin W G Fishwick, Christopher J Schofield, James Spencer, Matthew B Avison
Clavulanic acid and avibactam are clinically deployed serine β-lactamase inhibitors, important as a defence against antibacterial resistance. Bicyclic boronates are recently discovered inhibitors of serine and some metallo β-lactamases. Here we show that avibactam and a bicyclic boronate inhibit L2 (serine β-lactamase) but not L1 (metallo β-lactamase) from the extensively drug resistant human pathogen Stenotrophomonas maltophilia. X-ray crystallography revealed that both inhibitors bind L2 by covalent attachment to the nucleophilic serine...
September 6, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28868304/treatment-of-sepsis-what-is-the-antibiotic-choice-in-bacteremia-due-to-carbapenem-resistant-enterobacteriaceae
#7
REVIEW
Fatema Alhashem, Nicolette Leonie Tiren-Verbeet, Emine Alp, Mehmet Doganay
Sepsis is one of the major challenges of today. Although gram-positive bacteria related infections are more prevalent in hospital setting, the highest mortality rate is associated with gram-negative microorganisms especially Enterobacteriaceae. Enterobacteriaceae, including Escherichia coli, Klebsiella spp., Proteus spp., Enterobacter spp. and Serratia spp. Resistance to β-lactams in Enterobacteriaceae is primarily attributed to the production of B-lactamase enzymes with subsequent antibiotic hydrolysis and to a lesser extent by alteration of efflux pump or porins expression...
August 16, 2017: World Journal of Clinical Cases
https://www.readbyqxmd.com/read/28839493/diversity-of-multidrug-efflux-genes-and-phenotypic-evaluation-of-the-in-vitro-resistance-dynamics-of-clinical-staphylococcus-aureus-isolates-using-methicillin-a-model-%C3%AE-lactam
#8
John F Antiabong, Marleen M Kock, Nontombi M Bellea, Marthie M Ehlers
OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) across the world often leave clinicians with little or no choice of treatment options. The multi-drug efflux (MDE) genes are bacterial survival mechanisms responsible for the pumping out of antibiotics and other biocides from the cytoplasm. Whilst effort is being made in the development of antibiotic adjuvants such as efflux pumps inhibitors, information is needed on the diversity of these MDEs in the circulating S. aureus and on the growth dynamics of the clinical isolates in response to antibiotics is not regularly examined...
2017: Open Microbiology Journal
https://www.readbyqxmd.com/read/28835096/reversibility-of-covalent-broad-spectrum-serine-%C3%AE-lactamase-inhibition-by-the-diazabicyclooctenone-etx2514
#9
Adam B Shapiro, Ning Gao, Haris Jahić, Nicole M Carter, April Chen, Alita A Miller
ETX2514 is a non-β-lactam serine β-lactamase inhibitor in clinical development that has greater potency and broader spectrum of β-lactamase inhibition than the related diazabicyclooctanone avibactam. Despite opening of its cyclic urea ring upon acylation, avibactam can recyclize and dissociate intact from certain β-lactamases. We investigated reversibility of ETX2514 acylation of 10 serine β-lactamases representing Ambler classes A, C, and D. Dissociation rate constants varied widely between enzymes and were lowest for class D...
August 28, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/28812369/two-new-cassane-diterpene-lactams-from-the-fruits-of-caesalpinia-mimosoides-lam
#10
Dewen Bi, Guanghui Xia, Yuanping Li, Xuesong Liang, Lanjun Zhang, Liqin Wang
Two new cassane ditepenoid lactams, caesmimotam A (1) and B (2), along with eight known compounds (3-10) were isolated from the fruits of Caesalpinia mimosoides Lam. Their structures were identified by 1D and 2D NMR spectral data. Compounds 1 and 2 were evaluated for their cytotoxicity on HL-60, SMMC-7721, A-549, MCF-7 and SW-480 human cancer cell lines, but they were inactive.
August 16, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28800411/antimicrobial-resistance-and-resistance-genes-in-salmonella-strains-isolated-from-broiler-chickens-along-the-slaughtering-process-in-china
#11
Yuanting Zhu, Haimei Lai, Likou Zou, Sheng Yin, Chengtao Wang, Xinfeng Han, Xiaolong Xia, Kaidi Hu, Li He, Kang Zhou, Shujuan Chen, Xiaolin Ao, Shuliang Liu
A total of 189 Salmonella isolates were recovered from 627 samples which were collected from cecal contents of broilers, chicken carcasses, chicken meat after cutting step and frozen broiler chicken products along the slaughtering process at a slaughterhouse in Sichuan province of China. The Salmonella isolates were subjected to antimicrobial susceptibility testing to 10 categories of antimicrobial agents using the Kirby-Bauer disk diffusion method. Those antibiotics-resistant isolates were further investigated for the occurrence of resistance genes, the presence of class 1 integron as well as the associated gene cassettes, and the mutations within the gyrA and parC genes...
August 1, 2017: International Journal of Food Microbiology
https://www.readbyqxmd.com/read/28797068/virulence-profiles-and-innate-immune-responses-against-highly-lethal-multidrug-resistant-nosocomial-isolates-of-acinetobacter-baumannii-from-a-tertiary-care-hospital-in-mexico
#12
Roberto Rosales-Reyes, Catalina Gayosso-Vázquez, José Luis Fernández-Vázquez, Ma Dolores Jarillo-Quijada, César Rivera-Benítez, José Ignacio Santos-Preciado, María Dolores Alcántar-Curiel
Virulence profiles and innate immune responses were studied in Acinetobacter baumannii from nosocomial infections collected over one year in a tertiary care hospital in Mexico. A. baumannii were identified by VITEK 2 System followed by susceptibility tests. Carbapenemase genes, active efflux mechanism to imipenem and meropenem and outer membrane proteins profile were analyzed to evaluate their role on the activity of carbapenem resistance. All isolates were genotyped by pulsed field gel electrophoresis. The ability to form biofilm was determined on a polystyrene surface...
2017: PloS One
https://www.readbyqxmd.com/read/28774360/-pathogen-distribution-risk-factors-and-outcomes-of-nosocomial-infection-in-very-premature-infants
#13
De-Shuang Zhang, Dong-Ke Xie, Na He, Wen-Bin Dong, Xiao-Ping Lei
OBJECTIVE: To study the pathogen distribution and risk factors of nosocomial infection in very preterm infants, as well as the risk of adverse outcomes. METHODS: A retrospective analysis was performed for the clinical data of 111 very preterm infants who were born between January and December, 2016 and had a gestational age of <32 weeks and a birth weight of <1 500 g. According to the presence or absence of nosocomial infection after 72 hours of hospitalization, the infants were divided into infection group and non-infection group...
August 2017: Zhongguo Dang Dai Er Ke za Zhi, Chinese Journal of Contemporary Pediatrics
https://www.readbyqxmd.com/read/28760708/experimental-design-and-modeling-approach-to-evaluate-efficacy-of-%C3%AE-lactam-%C3%AE-lactamase-inhibitor-combinations
#14
REVIEW
Sherwin K B Sy, Hartmut Derendorf
BACKGROUND: A β-lactamase inhibitor (BLI) confers susceptibility of β-lactamase-expressing multidrug resistant (MDR) organisms to the partnering β-lactam (BL). AIMS: To discuss the experimental design and modeling strategies for 2-drug combination, using ceftazidime- and aztreonam-avibactam combinations, as examples. SOURCES: The information came from several publications on avibactam in vitro time-kill studies and corresponding pharmacodynamic models...
July 28, 2017: Clinical Microbiology and Infection
https://www.readbyqxmd.com/read/28759625/combination-therapy-with-ampicillin-and-azithromycin-improved-outcomes-in-a-mouse-model-of-group-b-streptococcal-sepsis
#15
Kirtikumar Upadhyay, Basu Hiregoudar, Elizabeth Meals, Boyce Keith English, Ajay J Talati
BACKGROUND: Evidence suggests that β-lactam monotherapy of streptococcal infections may incite stronger inflammation and is inferior to combination therapy with macrolides. We hypothesized that use of macrolides alone or in combination with a β-lactam for group B streptococcal (GBS) sepsis would improve outcomes by reducing inflammation. METHODS: TNF-α was measured from supernatants of RAW 264.7 cells stimulated with GBS isolates, in presence of four treatment regimens: ampicillin alone, azithromycin alone, or combination of azithromycin plus ampicillin...
2017: PloS One
https://www.readbyqxmd.com/read/28758006/enantioselective-%C3%AE-borylation-of-unsaturated-amides-and-stereoretentive-suzuki-miyaura-cross-coupling
#16
Gia L Hoang, James M Takacs
The rhodium-catalyzed, directed catalytic asymmetric hydroboration of γ,δ-unsaturated amides affords a direct route to chiral acyclic secondary γ-borylated carbonyl derivatives in high enantiomeric purity. In contrast to a similar β-borylated amide derivative, the γ-borylated amide undergoes Suzuki-Miyaura cross-coupling with stereoretention. The utility of the boronic ester products is further illustrated by other stereospecific C-B bond transformations leading to γ-amino acid derivatives, 1,4-amino alcohols, and 5-substituted-γ-lactone and γ-lactam ring systems...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28749949/2-aminoimidazoles-potentiate-%C3%A3-lactam-antimicrobial-activity-against-mycobacterium-tuberculosis-by-reducing-%C3%A3-lactamase-secretion-and-increasing-cell-envelope-permeability
#17
Albert B Jeon, Andrés Obregón-Henao, David F Ackart, Brendan K Podell, Juan M Belardinelli, Mary Jackson, Tuan V Nguyen, Meghan S Blackledge, Roberta J Melander, Christian Melander, Benjamin K Johnson, Robert B Abramovitch, Randall J Basaraba
There is an urgent need to develop new drug treatment strategies to control the global spread of drug-sensitive and multidrug-resistant Mycobacterium tuberculosis (M. tuberculosis). The ß-lactam class of antibiotics is among the safest and most widely prescribed antibiotics, but they are not effective against M. tuberculosis due to intrinsic resistance. This study shows that 2-aminoimidazole (2-AI)-based small molecules potentiate ß-lactam antibiotics against M. tuberculosis. Active 2-AI compounds significantly reduced the minimal inhibitory and bactericidal concentrations of ß-lactams by increasing M...
2017: PloS One
https://www.readbyqxmd.com/read/28745223/structure-function-of-serine-and-metallo-%C3%AE-lactamases-and-their-inhibitors
#18
Parveen Salahuddin, Amit Kumar, Asad U Khan
Antibiotic resistance in gram-negative bacteria has emerged as a major health threat that occurs because these bacteria actively produce β-lactamases responsible for the inactivation of β-lactam antibiotics. The first β lactamase was reported in E. coli back in 1940, before the release of the first antibiotic penicillin in clinical settings. Later on, large numbers of β-lactamases have been discovered in Gram-positive, Gram-negative bacteria as well as mycobacteria. Currently, numerous three-dimensional structures of serine and metallo-β-lactamases have been solved...
July 24, 2017: Current Protein & Peptide Science
https://www.readbyqxmd.com/read/28743651/resistance-to-quinolones-cephalosporins-and-macrolides-in-escherichia-coli-causing-bacteremia-in-peruvian-children
#19
Noemí Palma, Maria J Pons, Cláudia Gomes, Judit Mateu, Maribel Riveros, Wilfredo García, Jan Jacobs, Coralith García, Theresa J Ochoa, Joaquim Ruiz
OBJECTIVE: To characterize the β-lactam, quinolone and macrolide resistance levels and mechanisms in 62 Escherichia coli isolates causing children bacteremia. METHODS: Minimal inhibitory concentration of ciprofloxacin, nalidixic acid (NAL) and azithromycin was determined in presence and absence of Phe-Arg-β-Naphtylamyde. Additionally, the susceptibility levels to other 14 antimicrobial agents was established. Extended Spectrum β-lactamases (ESBLs) were identified, while mutations in gyrA and parC genes, presence of transferable mechanisms of quinolone-resistance (TMQR) and macrolide-resistance (TMMR) was also determined...
July 22, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28687975/prevalence-and-drug-resistance-characteristics-of-carbapenem-resistant-enterobacteriaceae-in-hangzhou-china
#20
Yan Yang, Jian Chen, Di Lin, Xujian Xu, Jun Cheng, Changgui Sun
With the abuse of antimicrobial agents in developing countries, increasing number of carbapenem-resistant Enterobacteriaceae (CRE) attracted considerable public concern. A retrospective study was conducted based on 242 CRE strains from a tertiary hospital in Hangzhou, China to investigate prevalence and drug resistance characteristics of CRE in southeast China. Bacterial species were identified. Antimicrobial susceptibility was examined by broth microdilution method or epsilometer test. Resistant β-lactamase genes were identified by polymerase chain reaction and sequencing...
July 8, 2017: Frontiers of Medicine
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