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https://www.readbyqxmd.com/read/28102305/structure-and-membrane-interactions-of-the-homodimeric-antibiotic-peptide-homotarsinin
#1
Rodrigo M Verly, Jarbas M Resende, Eduardo F C Junior, Mariana T Q de Magalhães, Carlos F C R Guimarães, Victor H O Munhoz, Marcelo Porto Bemquerer, Fábio C L Almeida, Marcelo M Santoro, Dorila Piló-Veloso, Burkhard Bechinger
Antimicrobial peptides (AMPs) from amphibian skin are valuable template structures to find new treatments against bacterial infections. This work describes for the first time the structure and membrane interactions of a homodimeric AMP. Homotarsinin, which was found in Phyllomedusa tarsius anurans, consists of two identical cystine-linked polypeptide chains each of 24 amino acid residues. The high-resolution structures of the monomeric and dimeric peptides were determined in aqueous buffers. The dimer exhibits a tightly packed coiled coil three-dimensional structure, keeping the hydrophobic residues screened from the aqueous environment...
January 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102062/the-role-of-il-17-in-a-lipopolysaccharide-induced-rhinitis-model
#2
Jun Sang Bae, Ji Hye Kim, Eun Hee Kim, Ji Hun Mo
PURPOSE: Lipopolysaccharide (LPS) is a cell wall component of Gram-negative bacteria and important for pro-inflammatory mediators. This study aimed to establish a rhinitis model using ovalbumin (OVA) and LPS in order to evaluate the role of interleukin (IL)-17 in the pathogenesis of an LPS-induced non-eosionophilic rhinitis model. METHODS: Mice were divided into 4 groups and each group consisted of 10 mice (negative control group, allergic rhinitis model group, 1-μg LPS treatment group, and 10-μg LPS treatment group)...
March 2017: Allergy, Asthma & Immunology Research
https://www.readbyqxmd.com/read/28101334/implementation-of-short-incubation-maldi-tof-ms-identification-from-positive-blood-cultures-in-routine-diagnostics-and-effects-on-empiric-antimicrobial-therapy
#3
Robin Köck, Jörg Wüllenweber, Dagmar Horn, Christian Lanckohr, Karsten Becker, Evgeny A Idelevich
BACKGROUND: Results of blood culture (BC) diagnostics should be swiftly available to guide treatment of critically ill patients. Conventional BC diagnostics usually performs species identification of microorganisms from mature solid medium colonies. Species identification might be speed up by using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) of biomass from shortly incubated solid media. METHODS: This single-center analysis compared the applicability of MALDI-TOF-based species identification from shortly incubated cultures in laboratory routine vs...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/28100574/clostridium-hastiforme-bacteraemia-secondary-to-pyometra-in-a-64-year-old-woman
#4
Matilde Ørum, David Fuglsang-Damgaard, Hans Linde Nielsen
The Gram-negative, rod-shaped, anaerobe bacteria Tissierella praeacuta was first described in 1908 by Tissier. However, during the past decade, Clostridium hastiforme has been recognised as a later synonym of T. praeacuta. C. hastiforme/T. praeacuta has only rarely been described in previous literature as a cause of human infection. We present here a case report of C. hastiforme/T. praeacuta bacteraemia secondary to pyometra in a 64-year-old woman with a history of multiple sclerosis and an intrauterine device inserted three decades earlier...
January 18, 2017: BMJ Case Reports
https://www.readbyqxmd.com/read/28100315/flavobacterium-arcticum-sp-nov-isolated-from-arctic-seawater
#5
Dan-Dan Li, Chang Liu, Yan-Qi Zhang, Xiu-Juan Wang, Ning Wang, Ming Peng, Xiao-Yan Song, Hai-Nan Su, Xi-Ying Zhang, Yu-Zhong Zhang, Mei Shi
A Gram-reaction-negative, aerobic, non-flagellated, rod-shaped and yellow-pigmented bacterium, designated strain SM1502T, was isolated from Arctic seawater. The isolate grew at 10-40 oC and with 0-8.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was affiliated with the genus Flavobacterium, with the highest sequence similarity (96.0 %) found with Flavobacterium suzhouense. The major fatty acids of strain SM1502T were iso-C15:0, iso-C17:1ω9c, iso-C15:1 G, C15:0, iso-C17:0 3-OH and unknown ECL 13...
January 18, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28100309/nioella-sediminis-sp-nov-isolated-from-the-surface-sediment-and-emended-description-of-the-genus-nioella
#6
Yang Liu, Juan Du, Qiliang Lai, Chunming Dong, Zongze Shao
A bacterial strain, designated JS7-11T, was isolated from the surface sediment of the Jiulong River and characterized using a polyphasic taxonomic approach. Cells of strain JS7-11T was Gram-staining-negative, non-motile and short-rod-shaped. Growth was observed at 10-40°C (optimum 25-30°C), at pH 6-8 (optimum 7) and in 1-12% NaCl (optimum 3-4%, w/v). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JS7-11T and type strain Nioella nitratireducens SSW136T formed an independent cluster, sharing 97...
January 18, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/28099062/rectal-carriage-of-extended-spectrum-beta-lactamase-and-carbapenemase-producing-gram-negative-bacilli-in-intensive-care-units-in-tunisia
#7
Samia Hammami, Chaima Dahdeh, Kelthoum Mamlouk, Sana Ferjeni, Elaa Maamar, Zeineb Hamzaoui, Mabrouka Saidani, Salma Ghedira, Mohamed Houissa, Amin Slim, Ilhem Boutiba-Ben Boubaker
This study was conducted to evaluate the rate of fecal carriage of Gram-negative bacilli (GNB) resistant to third-generation cephalosporins (third GC) in patients hospitalized in the intensive care unit (ICU) of Charles Nicolle Hospital of Tunis and to identify the enzymatic mechanisms involved. From February to April 2014, rectal swabs were collected from all patients (n = 38) at admission and once weekly thereafter to identify acquisition. They were cultured on desoxycholate-lactose-agar plates supplemented with cefotaxime (2 mg/L)...
January 18, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28098784/fused-ring-oxazolopyrrolopyridopyrimidine-systems-with-gram-negative-activity
#8
Yiyuan Chen, Jonathan G Moloney, Kirsten E Christensen, Mark G Moloney
Fused polyheterocyclic derivatives are available by annulation of a tetramate scaffold, and been shown to have antibacterial activity against a Gram-negative, but not a Gram-positive, bacterial strain. While the activity is not potent, these systems are structurally novel showing, in particular, a high level of polarity, and offer potential for the optimization of antibacterial activity.
January 13, 2017: Antibiotics
https://www.readbyqxmd.com/read/28098735/optical-coherence-tomography-angiography-of-the-fovea-in-children-born-preterm
#9
Khalil Ghasemi Falavarjani, Nicholas A Iafe, Federico G Velez, Steven D Schwartz, Srinivas R Sadda, David Sarraf, Irena Tsui
PURPOSE: To compare the foveal avascular zone (FAZ) area measured by optical coherence tomography angiography in children who had been born preterm with age-matched controls. METHODS: In this cross-sectional observational comparative case series, 43 eyes of 26 children (28 eyes of 15 former preterm infants and 15 eyes of 11 former term infants) between the ages of 4 and 12 years old were included. Optical coherence tomography angiography with a scan size of 3 × 3 was performed for all eyes...
January 16, 2017: Retina
https://www.readbyqxmd.com/read/28098548/nosocomial-infections-with-imp-19-producing-pseudomonas-aeruginosa-linked-to-contaminated-sinks-france
#10
Lucie Amoureux, Karena Riedweg, Angélique Chapuis, Julien Bador, Eliane Siebor, André Péchinot, Marie-Lorraine Chrétien, Claire de Curraize, Catherine Neuwirth
We isolated IMP-19-producing Pseudomonas aeruginosa from 7 patients with nosocomial infections linked to contaminated sinks in France. We showed that blaIMP-19 was located on various class 1 integrons among 8 species of gram-negative bacilli detected in sinks: P. aeruginosa, Achromobacter xylosoxidans, A. aegrifaciens, P. putida, Stenotrophomonas maltophilia, P. mendocina, Comamonas testosteroni, and Sphingomonas sp.
February 2017: Emerging Infectious Diseases
https://www.readbyqxmd.com/read/28098447/the-stories-tryptophans-tell-exploring-protein-dynamics-of-heptosyltransferase-i-from-escherichia-coli
#11
Joy M Cote, Carlos Andres Ramirez-Mondragon, Zarek S Siegel, Daniel Joseph Czyzyk, Jiali Gao, Yuk Yin Sham, Ishita Mukerji, Erika A Taylor
Heptosyltransferase I (HepI) catalyzes the addition of a single L-glycero-β-D-manno-heptose sugar (heptose) onto the membrane incorporated Kdo2-Lipid A as part of the biosynthesis of the core region of lipopolysaccharide (LPS). Gram-negative bacteria with gene knockouts of HepI have reduced virulence with enhanced susceptibility to hydrophobic antibiotics, making design of inhibitors against HepI of interest. Previous studies have shown that HepI protein dynamics are partially rate limiting, and therefore disruption of protein dynamics might provide a new strategy for inhibiting HepI...
January 18, 2017: Biochemistry
https://www.readbyqxmd.com/read/28098416/motuporamine-derivatives-as-antimicrobial-agents-and-antibiotic-enhancers-against-resistant-gram-negative-bacteria
#12
Diane Borselli, Marine Blanchet, Jean-Michel Bolla, Aaron Muth, Kristen Skruber, Otto Phanstiel, Jean Michel Brunel
Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump...
January 18, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28097898/two-approaches-to-the-use-of-benzo-c-1-2-oxaboroles-as-active-fragments-for-synthetic-transformation-of-clarithromycin
#13
Gennady B Lapa, Elena P Mirchink, Elena B Isakova, Maria N Preobrazhenskaya
Clarithromycin (active against Gram positive infections) and 1-hydroxy-1,3-dihydrobenzo[c][1,2]oxaborole derivatives (effective for Gram negative microbes) are the ligands of bacterial RNA. The antimicrobial activities of these benzoxaboroles linked with clarithromycin at 9 or 4″ position were compared. Two synthetic pathways for these conjugates were elaborated. First pathway explored the substitution of the C-9 carbonyl group of macrolactone's cycle via oxime linker, the second direction used the modification of the 4″-O-group of cladinose via the formation of carbamates of benzoxaboroles...
December 2017: Journal of Enzyme Inhibition and Medicinal Chemistry
https://www.readbyqxmd.com/read/28097724/unphosphorylated-eiia-ntr-induces-clpap-mediated-degradation-of-rpos-in-azotobacter-vinelandii
#14
Luis Felipe Muriel-Millán, Soledad Moreno, Ramsés Gallegos-Monterrosa, Guadalupe Espín
The nitrogen-related phosphotransferase system (PTS(Ntr) ) is composed of the EI(Ntr) , NPr and EIIA(Ntr) proteins that form a phosphorylation cascade from phosphoenolpyruvate. PTS(Ntr) is a global regulatory system present in most Gram-negative bacteria that controls some pivotal processes such as potassium and phosphate homeostasis, virulence, nitrogen fixation and ABC transport activation. In the soil bacterium Azotobacter vinelandii, unphosphorylated EIIA(Ntr) negatively regulates the expression of genes related to the synthesis of the bioplastic polyester poly-β-hydroxybutyrate (PHB) and cyst-specific lipids alkylresorcinols (ARs)...
January 18, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28097714/photoantimicrobial-biohybrids-by-supramolecular-immobilization-of-cationic-phthalocyanines-onto-cellulose-nanocrystals
#15
Eduardo Anaya-Plaza, Eveline van de Winckel, Joona Mikkilä, Jani-Markus Malho, Olli Ikkala, Oscar Gulías, Roger Bresolí-Obach, Montserrat Agut, Santi Nonell, Tomás Torres, Mauri A Kostiainen, Andrés de la Escosura
The development of photoactive and biocompatible nanostructures is a highly desirable goal to address the current threat of antibiotic resistance. Here, we describe a novel supramolecular biohybrid nanostructure based on the non-covalent immobilization of cationic zinc phthalocyanine (ZnPc) derivatives onto unmodified cellulose nanocrystals (CNC), following an easy and straightforward protocol, in which binding is driven by electrostatic interactions. These non-covalent biohybrids show strong photodynamic activity against S...
January 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28097633/meropenem-dosing-based-on-a-population-pharmacokinetic-pharmacodynamic-model-in-elderly-patients-with-infection-of-the-lower-respiratory-tract
#16
Qing-Tao Zhou, Bei He, Ning Shen, Ying Liang, Li-Na Sun
BACKGROUND: Meropenem is used for the treatment of severe lower respiratory tract infections (LRTIs) caused by multidrug-resistant Gram-negative bacilli. OBJECTIVE: We evaluated the clinical benefits of a strategy of meropenem dosing based on a population pharmacokinetics/pharmacodynamics (PK/PD) model in elderly patients with an LRTI. METHODS: In this prospective single-center open-label randomized controlled trial, 79 elderly patients with an LRTI caused by Gram-negative bacilli were randomized to a study group (SG) or a control group (CG)...
January 17, 2017: Drugs & Aging
https://www.readbyqxmd.com/read/28096976/effect-of-handrubbing-using-locally-manufactured-alcohol-based-handrubs-in-paediatric-wards-in-harare-zimbabwe
#17
Muchaneta Gudza-Mugabe, Marcelyn T Magwenzi, Hilda A Mujuru, Mutsa Bwakura-Dangarembizi, Valerie Robertson, Alexander M Aiken
We assessed bacterial contamination of hands of adults present in paediatric wards in two tertiary-care hospitals in Harare, Zimbabwe and the microbiologic efficacy of locally-manufactured alcohol-based hand rub (ABHR). During unannounced visits, samples were collected using hand-print and hand-rinse methods. Samples were collected from 152 individuals (16 nurses, 10 doctors, 28 students, 86 parents/guardians, 12 others). Contamination of hands with Gram-negative bacteria was found in 91% of adults tested with a mean of 14...
2017: Antimicrobial Resistance and Infection Control
https://www.readbyqxmd.com/read/28096686/peptide-consensus-sequence-determination-for-the-enhancement-of-the-antimicrobial-activity-and-selectivity-of-antimicrobial-peptides
#18
Ammar Almaaytah, Ya'u Ajingi, Ahmad Abualhaijaa, Shadi Tarazi, Nizar Alshar'i, Qosay Al-Balas
The rise of multidrug-resistant bacteria is causing a serious threat to the world's human population. Recent reports have identified bacterial strains displaying pan drug resistance against antibiotics and generating fears among medical health specialists that humanity is on the dawn of entering a post-antibiotics era. Global research is currently focused on expanding the lifetime of current antibiotics and the development of new antimicrobial agents to tackle the problem of antimicrobial resistance. In the present study, we designed a novel consensus peptide named "Pepcon" through peptide consensus sequence determination among members of a highly homologous group of scorpion antimicrobial peptides...
2017: Infection and Drug Resistance
https://www.readbyqxmd.com/read/28096310/characterization-of-the-dtdp-fuc3n-and-dtdp-qui3n-biosynthetic-pathways-in-campylobacter-jejuni-81116%C3%A2
#19
Zack Z Li, Alexander S Riegert, Marie-France Goneau, Anna M Cunningham, Evgeny Vinogradov, Jianjun Li, Ian C Schoenhofen, James B Thoden, Hazel M Holden, Michel Gilbert
The Gram-negative bacterium Campylobacter jejuni 81116 (Penner serotype HS:6) has a class E lipooligosaccharide (LOS) biosynthesis locus containing 19 genes, which encode for 11 putative glycosyltransferases, 1 lipid A acyltransferase and 7 enzymes thought to be involved in the biosynthesis of dideoxyhexosamine (ddHexN) moieties. Although the LOS outer core structure of C. jejuni 81116 is still unknown, recent mass spectrometry analyses suggest that it contains acetylated forms of two ddHexN residues. For this investigation, five of the genes encoding enzymes reportedly involved in the biosyntheses of these sugar residues were examined, rmlA, rmlB, wlaRA, wlaRB and wlaRG Specifically, these genes were cloned and expressed in Escherichia coli, and the corresponding enzymes were purified and tested for biochemical activity...
January 16, 2017: Glycobiology
https://www.readbyqxmd.com/read/28096166/the-role-of-renal-drug-exposure-in-polymyxin-b-induced-nephrotoxicity
#20
Pooja Manchandani, Jian Zhou, Jessica T Babic, Kimberly R Ledesma, Luan D Truong, Vincent H Tam
Despite dose-limiting nephrotoxic potentials, polymyxin B has re-emerged as the last line of therapy against multidrug-resistant Gram-negative bacterial infections. However, the handling of polymyxin B by the kidneys is still not thoroughly understood. The objectives of this study were to evaluate the impact of renal polymyxin B exposure on nephrotoxicity and to explore the role of megalin in renal drug accumulation. Sprague-Dawley rats (225-250 g) were divided into 3 dosing groups, and polymyxin B was administered (5 mg/kg, 10 mg/kg and 20 mg/kg) subcutaneously once daily...
January 17, 2017: Antimicrobial Agents and Chemotherapy
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