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Polymyxin B

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https://www.readbyqxmd.com/read/28931287/enhanced-capture-of-bacteria-and-endotoxin-by-antimicrobial-wlbu2-peptide-tethered-on-polyethylene-oxide-spacers
#1
Ramya Raman, Miranda A Raper, Erik Hahn, Kate F Schilke
Severe sepsis is a life threatening immune response that may be caused by endotoxins (lipopolysaccharides) in circulating bacterial cell wall fragments. Hemoperfusion through a sorbent column coated with the antimicrobial peptide polymyxin B (PMB) is a promising treatment for sepsis. However, PMB is cytotoxic and neurotoxic, and is a membrane disruptor that may fragment endotoxin vesicles. In addition, the blood is not protected from nonspecific interactions with the synthetic surface of the solid support. These effects may be responsible for the variety of undesirable clinical outcomes, including nonspecific adsorption of proteins, blood cell damage, platelet activation, and a lack of clear evidence of efficacy of the current hemoperfusion products...
September 20, 2017: Biointerphases
https://www.readbyqxmd.com/read/28929089/two-novel-salmonella-bivalent-vaccines-confer-dual-protection-against-two-salmonella-serovars-in-mice
#2
Xinxin Zhao, Qinlong Dai, Renyong Jia, Dekang Zhu, Mafeng Liu, Mingshu Wang, Shun Chen, Kunfeng Sun, Qiao Yang, Ying Wu, Anchun Cheng
Non-typhoidal Salmonella includes thousands of serovars that are leading causes of foodborne diarrheal illness worldwide. In this study, we constructed three bivalent vaccines for preventing both Salmonella Typhimurium and Salmonella Newport infections by using the aspartate semialdehyde dehydrogenase (Asd)-based balanced-lethal vector-host system. The constructed Asd(+) plasmid pCZ11 carrying a subset of the Salmonella Newport O-antigen gene cluster including the wzx-wbaR-wbaL-wbaQ-wzy-wbaW-wbaZ genes was introduced into three Salmonella Typhimurium mutants: SLT19 (Δasd) with a smooth LPS phenotype, SLT20 (Δasd ΔrfbN) with a rough LPS phenotype, and SLT22 (Δasd ΔrfbN ΔpagL::T araC PBADrfbN) with a smooth LPS phenotype when grown with arabinose...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28923774/endotoxin-adsorption-direct-hemoperfusion-with-the-polymyxin-b-immobilized-fiber-column-pmx
#3
REVIEW
Tomoharu Shimizu, Toru Miyake, Naomi Kitamura, Masaji Tani, Yoshihiro Endo
Toraymyxin(®) is a medical device developed to adsorb circulating endotoxins in the blood using direct hemoperfusion therapy for patients with septic shock. In 1994, the Japanese National Health Insurance system approved the use of Toraymyxin for the treatment of endotoxemia and septic shock. Since then, Toraymyxin has been safely used in more than 100,000 cases in emergency and intensive care units in Japan. Toraymyxin is currently available for use in the clinical setting in 14 countries worldwide. In this study, we reviewed and introduced the development, clinical use, and efficacy of Toraymyxin and commented on its anticoagulant use and cartridge clotting issue in the treatment of severe sepsis and septic shock...
August 31, 2017: Transfusion and Apheresis Science
https://www.readbyqxmd.com/read/28920845/modified-use-of-real-time-pcr-detection-of-group-b-streptococcus-in-pregnancy
#4
Ali A Rabaan, Justin V Saunar, Ali M Bazzi, Joan L Soriano
The CDC recommends antenatal screening of vaginal/rectal samples for Streptococcus agalactiae at 35-37 weeks' gestation, with intra-partum antibiotic prophylaxis for positive cases. We tested a modified use of the Cepheid Xpert GBS real-time PCR kit on enrichment cultures from 554 vaginal/rectal swabs compared to the current subculturing gold standard method. Swabs were inoculated on polymyxin nalidixic acid agar plates, and Todd-Hewitt enrichment broth cultures were examined daily for growth. Todd-Hewitt broth culture was also used for Xpert GBS...
September 18, 2017: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/28915395/effects-of-polymyxin-b-hemoperfusion-on-hemodynamics-and-prognosis-in-septic-shock-patients
#5
Chen-Tse Lee, Yu-Kang Tu, Yi-Chun Yeh, Tzu Chang, Po-Yuan Shih, Anne Chao, Hsing-Hao Huang, Ya-Jung Cheng, Yu-Chang Yeh
PURPOSE: We designed this study to examine the clinical effects of polymyxin B hemoperfusion (PMX-HP) in septic shock patients. MATERIAL AND METHODS: We retrospectively examined the effects of PMX-HP in septic shock patients with intra-abdominal or gram-negative bacterial infection during October 2013-May 2016. A one-to-one matching between the PMX-HP and conventional groups was performed, and 28-day mortality, and change in inotropic score, Sequential Organ Failure Assessment (SOFA) score, and Acute Physiology and Chronic Health Evaluation II (APACHE II) score at 24h in the two groups were compared...
April 25, 2017: Journal of Critical Care
https://www.readbyqxmd.com/read/28906444/short-term-intake-of-a-fructose-fat-and-cholesterol-rich-diet-causes-hepatic-steatosis-in-mice-effect-of-antibiotic-treatment
#6
Annette Brandt, Cheng Jun Jin, Katja Nolte, Cathrin Sellmann, Anna Janina Engstler, Ina Bergheim
Intestinal microbiota and barrier functions seem to play an important role in the development of non-alcoholic fatty liver disease (NAFLD). However, whether these changes are an early event in the development of NAFLD or are primarily associated with later stages of the disease, has not yet been clarified. Using a pair-feeding model, we determined the effects of a short-term intake of a fat-, fructose- and cholesterol-rich diet (FFC) on the development of early hepatic steatosis and markers of intestinal barrier function in mice treated with and without non-resorbable antibiotics (AB)...
September 14, 2017: Nutrients
https://www.readbyqxmd.com/read/28904326/intravenous-polymyxins-revival-with-puzzle
#7
Yun Yu, Aihua Fei, Zengbin Wu, Chengjin Gao, Shuming Pan
With the increasing incidence of multi-drug resistant strains, especially carbapenem resistant strains, polymyxsins (mainly colistin and polymyxin B) based regimens seem to be a revival as an effective treatment of last resort in these infections. Evidence from 47 clinical trials or case series we reviewed showed that polymyxins based regimens are effective and have less toxicity compared with previous trials. When used alone, the mortality of intravenous polymyxsins ranged from 0% to 74.3%, clinical response (cure and improvement) rate was 7-82...
2017: Bioscience Trends
https://www.readbyqxmd.com/read/28893646/whole-genome-sequence-of-a-carbapenem-resistant-hypermucoviscous-klebsiella-pneumoniae-isolate-swu01-with-capsular-serotype-k47-that-belongs-to-st11-from-a-patient-in-china
#8
Luhua Zhang, Ying Li, Wei Shen, Guangxi Wang, Yingshun Zhou
OBJECTIVES: In recent years, Klebsiella pneumoniae is emerging as a leading cause of nosocomial infection due to the rapid prevalence of multidrug resistant strains, particularly the carbapenem resistant isolates. In this study, we completed the genome sequence of a carbapenem-resistant K. pneumoniae SWU01. METHODS: Antimicrobial susceptibilities and hypermucoviscous phenotype were determined by the disk diffusion method and a positive string test, respectively...
September 8, 2017: Journal of Global Antimicrobial Resistance
https://www.readbyqxmd.com/read/28887199/temporal-evolution-of-polymyxin-b-resistant-klebsiella-pneumoniae-clones-recovered-from-blood-cultures-in-a-teaching-hospital-during-a-7-year-period
#9
Graziela Braun, Rodrigo Cayô, Adriana Pereira Matos, Juliane de Mello Fonseca, Ana Cristina Gales
The polymyxins have become one of the last resorts to treat serious infections caused by KPC-2-producing Klebsiella pneumoniae worldwide. However, the increase of polymyxin consumption has favored the emergence of resistance to these compounds. In this study we observed an increase in the polymyxin B resistance rates from 0 to 30.6% among 224 K. pneumoniae isolates recovered from blood cultures between 2009 and 2015. Only gentamicin, tigecycline and fosfomycin remained active against the polymyxin B-resistant K...
September 5, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28878761/effect-of-different-antibiotic-chemotherapies-on-pseudomonas-aeruginosa-infection-in-vitro-of-primary-human-corneal-fibroblast-cells
#10
Maria Del Mar Cendra, Myron Christodoulides, Parwez Hossain
Pseudomonas aeruginosa is a major cause of bacterial keratitis (BK) worldwide. Inappropriate or non-optimal antibiotic chemotherapy can lead to corneal perforation and rapid sight loss. In this study, we tested the hypothesis that P. aeruginosa strain PAO1 invades primary human corneal fibroblasts (hCFs) in vitro and persists intracellularly, despite chemotherapy with antibiotics used commonly to treat BK. In rank order, ciprofloxacin, levofloxacin and polymyxin B showed the highest activity against planktonic PAO1 growth (100% inhibitory concentration ≤10 μg/mL; 50% inhibitory concentration ≤1 μg/mL), followed by gentamicin and ofloxacin (100% inhibitory concentration ≤50 μg/mL; 50% inhibitory concentration ≤10 μg/mL)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28874470/inhibition-of-the-atp-synthase-eliminates-the-intrinsic-resistance-of-staphylococcus-aureus-towards-polymyxins
#11
Martin Vestergaard, Katrine Nøhr-Meldgaard, Martin Saxtorph Bojer, Christina Krogsgård Nielsen, Rikke Louise Meyer, Christoph Slavetinsky, Andreas Peschel, Hanne Ingmer
Staphylococcus aureus is intrinsically resistant to polymyxins (polymyxin B and colistin), an important class of cationic antimicrobial peptides used in treatment of Gram-negative bacterial infections. To understand the mechanisms underlying intrinsic polymyxin resistance in S. aureus, we screened the Nebraska Transposon Mutant Library established in S. aureus strain JE2 for increased susceptibility to polymyxin B. Nineteen mutants displayed at least 2-fold reductions in MIC, while the greatest reductions (8-fold) were observed for mutants with inactivation of either graS, graR, vraF, or vraG or the subunits of the ATP synthase (atpA, atpB, atpG, or atpH), which during respiration is the main source of energy...
September 5, 2017: MBio
https://www.readbyqxmd.com/read/28873428/evaluation-of-robenidine-analog-ncl195-as-a-novel-broad-spectrum-antibacterial-agent
#12
Abiodun D Ogunniyi, Manouchehr Khazandi, Andrew J Stevens, Sarah K Sims, Stephen W Page, Sanjay Garg, Henrietta Venter, Andrew Powell, Karen White, Kiro R Petrovski, Geraldine Laven-Law, Eliane G Tótoli, Hérida R Salgado, Hongfei Pi, Geoffrey W Coombs, Dean L Shinabarger, John D Turnidge, James C Paton, Adam McCluskey, Darren J Trott
The spread of multidrug resistance among bacterial pathogens poses a serious threat to public health worldwide. Recent approaches towards combating antimicrobial resistance include repurposing old compounds with known safety and development pathways as new antibacterial classes with novel mechanisms of action. Here we show that an analog of the anticoccidial drug robenidine (4,6-bis(2-((E)-4-methylbenzylidene)hydrazinyl)pyrimidin-2-amine; NCL195) displays potent bactericidal activity against Streptococcus pneumoniae and Staphylococcus aureus by disrupting the cell membrane potential...
2017: PloS One
https://www.readbyqxmd.com/read/28870091/high-prevalence-of-oxa-type-carbapenemases-among-acinetobacter-baumannii-strains-in-a-teaching-hospital-of-tehran
#13
Mandana Zafari, Mohamad Mehdi Feizabadi, Sirous Jafari, Alireza Abdollahi, Azar Sabokbar
Nosocomial infection caused by carbapenem-resistant Acinetobacter baumannii (CRAB) has created a public health concern all around the world. In this study, 100 isolates of CRAB from hospitalized patients during 2015-2016 at Imam Khomeini Hospital were investigated to determine the rates of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains using Kirby-Bauer disk diffusion method. The minimum inhibitory concentrations (MICs) of six antibiotics were determined by broth microdilution method...
September 5, 2017: Acta Microbiologica et Immunologica Hungarica
https://www.readbyqxmd.com/read/28864654/exogenous-polyunsaturated-fatty-acids-pufas-impact-membrane-remodeling-and-affect-virulence-phenotypes-among-pathogenic-vibrio-species
#14
Anna R Moravec, Andrew W Siv, Chelsea R Hobby, Emily N Lindsay, Layla V Norbash, Daniel J Shults, Steven J K Symes, David K Giles
The pathogenic Vibrio species (cholerae, parahaemolyticus and vulnificus) represent a constant threat to human health, causing food-borne and skin wound infections as a result of ingestion or exposure to contaminated water and seafood. Recent studies have highlighted Vibrio's ability to acquire fatty acids from environmental sources and assimilate them into cell membranes. The possession and conservation of such machinery provokes consideration of fatty acids as important factors in the pathogenic lifestyle of Vibrio species...
September 1, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28853858/enhanced-photobactericidal-and-targeting-properties-of-a-cationic-porphyrin-following-the-attachment-of-polymyxin-b
#15
Florent Le Guern, Vincent Sol, Catherine Ouk, Philippe Arnoux, Céline Frochot, Tan-Sothea Ouk
A novel compound consisting of a cationic porphyrin covalently attached to a derivative of polymyxin B has been synthesized and presents enhanced activity and targeting properties compared to the usual cationic porphyrins recognized as efficient photosensitizers in photodynamic antimicrobial chemotherapy (PACT). A synthesis pathway was established to preserve the bactericidal activity of the peptide. Accordingly, the N-terminal amino acid (l-2,4-diaminobutyric acid) of polymyxin B (PMB) was switched for a cysteine residue...
September 11, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28839223/polymyxin-b-containing-polyion-complex-pic-nanoparticles-improving-the-antimicrobial-activity-by-tailoring-the-degree-of-polymerisation-of-the-inert-component
#16
Ignacio Insua, Laimdota Zizmare, Anna F A Peacock, Anne Marie Krachler, Francisco Fernandez-Trillo
Here, we describe the preparation and characterisation of polyion complex (PIC) nanoparticles containing last resort antimicrobial polymyxin B (Pol-B). PIC nanoparticles were prepared with poly(styrene sulphonate) (PSS) as an inert component, across a range of degrees of polymerisation to evaluate the effect that multivalency of this electrolyte has on the stability and antimicrobial activity of these nanoparticles. Our results demonstrate that while nanoparticles prepared with longer polyelectrolytes are more stable under simulated physiological conditions, those prepared with shorter polyelectrolytes have a higher antimicrobial activity...
August 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28834821/therapeutic-femtosecond-laser-assisted-lamellar-keratectomy-for-multidrug-resistant-nocardia-keratitis
#17
Parth Shah, Dagny Zhu, William W Culbertson
PURPOSE: To describe the novel use of femtosecond laser technology for therapeutic resection of infectious foci in a case of multidrug-resistant Nocardia asteroides keratitis. METHODS: A 30-year-old man presented with a corneal infiltrate. Cultures were taken, and fortified vancomycin and tobramycin were initiated. After 3 negative cultures and minimal improvement on various broad-spectrum antibiotics, all topical medications were stopped and a final fourth corneal culture grew N...
August 22, 2017: Cornea
https://www.readbyqxmd.com/read/28807222/polymyxin-b-as-an-inhibitor-of-lipopolysaccharides-contamination-of-herb-crude-polysaccharides-in-mononuclear-cells
#18
Xiao-Xiao Lu, Yi-Fan Jiang, Hong Li, Ying-Ye Ou, Zhi-De Zhang, Hong-Ye DI, Dao-Feng Chen, Yun-Yi Zhang
Lipopolysaccharides (LPS) contamination in herbal crude polysaccharides is inevitable. The present study was performed to explore the effect of polymyxin B on abolishing the influence of LPS contamination in mononuclear cells. LPS was pretreated with polymyxin B sulfate (PB) at different concentrations for 1, 5 or 24 h, and then used to stimulate RAW264.7 and mouse peritoneal macrophages (MPMs). The nitric oxide (NO) and tumor necrosis factor-α (TNF-α) in cell culture supernatant, as the indications of cell response, were assayed...
July 2017: Chinese Journal of Natural Medicines
https://www.readbyqxmd.com/read/28805387/polymyxin-binding-to-the-bacterial-outer-membrane-reveals-cation-displacement-and-increasing-membrane-curvature-in-susceptible-but-not-in-resistant-lipopolysaccharide-chemotypes
#19
Denys E S Santos, Laércio Pol-Fachin, Roberto D Lins, Thereza A Soares
Lipid-A is the causative agent of Gram-negative sepsis and is responsible for an increasingly high mortality rate among hospitalized patients. Compounds that bind Lipid-A can limit this inflammatory process. The cationic antimicrobial peptide polymyxin B (Pmx-B) is one of the simplest molecules capable of selectively binding to Lipid-A and may serve as a model for further development of Lipid-A binding agents. Gram-negative bacteria resistance to Pmx-B relies on the upregulation of a number of regulatory systems, which promote chemical modifications of the lipopolysaccharide (LPS) structure and leads to major changes in the physical-chemical properties of the outer membrane...
August 25, 2017: Journal of Chemical Information and Modeling
https://www.readbyqxmd.com/read/28804940/effects-of-polymyxin-b-on-tnf-%C3%AE-production-in-equine-whole-blood-stimulated-with-three-different-bacterial-toxins
#20
J R Bauquier, B S Tennent-Brown, E Tudor, S R Bailey
Polymyxin-B is used to treat equine systemic inflammation. Bacterial toxins other than lipopolysaccharide (LPS) contribute to systemic inflammation but the effects of polymyxin-B on these are poorly defined. Whole blood aliquots from six healthy horses diluted 1:1 with RPMI were incubated for 21 hr with 1 μg/ml of LPS, lipoteichoic acid (LTA) or peptidoglycan (PGN) in the presence of increasing concentrations of polymyxin-B (10-3000 μg/ml). A murine L929 fibroblast bioassay was used to measure TNF-α activity...
August 14, 2017: Journal of Veterinary Pharmacology and Therapeutics
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