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Polymyxin resistance

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https://www.readbyqxmd.com/read/28636788/role-of-positively-charged-residues-on-the-polar-and-non-polar-faces-of-amphipathic-%C3%AE-helical-antimicrobial-peptides-amps-on-specificity-and-selectivity-for-gram-negative-pathogens
#1
Ziqing Jiang, Colin T Mant, Michael Vasil, Robert S Hodges
We have designed de novo and synthesized eight 26-residue all D-conformation amphipathic α-helical cationic antimicrobial peptides (AMPs), four with "specificity determinants" which provide specificity for prokaryotic cells over eukaryotic cells and four AMPs without specificity determinants. The eight AMPs contain six positively charged Lys residues on the polar face in four different arrangements to understand the role of these residues have on antimicrobial activity against 14 Acinetobacter baumannii strains, 7 of which were resistant to polymyxin B and colistin; 6 diverse Pseudomonas aeruginosa strains and 17 Staphylococcus aureus strains, 9 of which were Methicillin-sensitive (MSSA) and 8 of which were Methicillin-resistant (MRSA)...
June 21, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/28628170/recent-advances-and-perspectives-in-the-design-and-development-of-polymyxins
#2
REVIEW
Francesc Rabanal, Yolanda Cajal
Covering: 1947-early 2017, particularly from 2005-early 2017The rise of bacterial pathogens with acquired resistance to almost all available antibiotics is becoming a serious public health issue. Polymyxins, antibiotics that were mostly abandoned a few decades ago because of toxicity concerns, are ultimately considered as a last-line therapy to treat infections caused by multi-drug resistant Gram-negative bacteria. This review surveys the progress in understanding polymyxin structure, and their chemistry, mechanisms of antibacterial activity and nephrotoxicity, biomarkers, synergy and combination with other antimicrobial agents and antibiofilm properties...
June 19, 2017: Natural Product Reports
https://www.readbyqxmd.com/read/28616507/the-first-report-of-escherichia-fergusonii-isolated-from-non-human-primates-in-africa
#3
Barbara Glover, Jeanette Wentzel, Akinbowale Jenkins, Moritz Van Vuuren
The aim of this study was to determine the resistance phenotypes of selected enteric bacteria isolated from non-human primates at a wildlife-human interface. Bacterial isolates from faecal samples of non-human primates at two wildlife rehabilitation centres in South Africa were screened for the presence of Escherichia coli. The biochemical characterisation of E. coli and E. coli-like bacteria revealed both adonitol positive and sorbitol negative strains - a unique characteristic of Escherichia fergusonii and Escherichia coli K99...
June 2017: One Health
https://www.readbyqxmd.com/read/28615078/characterisation-of-roseomonas-mucosa-isolated-from-the-root-canal-of-an-infected-tooth
#4
Nina Diesendorf, Stefanie Köhler, Walter Geißdörfer, Tanja Grobecker-Karl, Matthias Karl, Andreas Burkovski
OBJECTIVE: The genus Roseomonas comprises a group of pink-pigmented, slow-growing, aerobic, non-fermentative Gram-negative bacteria, which have been isolated from environmental sources such as water and soil, but are also associated with human infections. In the study presented here, Roseomonas mucosa was identified for the first time as part of the endodontic microbiota of an infected root canal and characterised in respect to growth, antibiotic susceptibility and biofilm formation. RESULTS: The isolated R...
June 14, 2017: BMC Research Notes
https://www.readbyqxmd.com/read/28606644/comparison-of-methods-for-detection-of-plasmid-mediated-and-chromosomally-encoded-colistin-resistance-in-enterobacteriaceae
#5
Aurélie Jayol, Patrice Nordmann, Philippe Lehours, Laurent Poirel, Véronique Dubois
OBJECTIVES: Because of the emergence of plasmid-mediated (mcr-1 and mcr-2 genes) and chromosomally-encoded colistin resistance, reliable methods for detecting colistin resistance/susceptibility in routine laboratories are required. We evaluated the respective performances of the BD Phoenix automated system, the newly-developed Rapid Polymyxin NP test and the broth microdilution (BMD) reference method to detect colistin resistance in Enterobacteriaceae, and particularly those producing MCR-1 and MCR-2...
June 9, 2017: Clinical Microbiology and Infection
https://www.readbyqxmd.com/read/28605374/laboratory-techniques-used-to-maintain-and-differentiate-biotypes-of-vibrio-cholerae-clinical-and-environmental-isolates
#6
Kyle D Brumfield, Bailey M Carignan, Jordan N Ray, Panagiota E Jumpre, Mike S Son
The aquatic Gram-negative bacterium Vibrio cholerae is the etiological agent of the infectious gastrointestinal disease cholera. Due to the global prevalence and severity of this disease, V. cholerae has been extensively studied in both environmental and laboratory settings, requiring proper maintenance and culturing techniques. Classical and El Tor are two main biotypes that compose the V. cholerae O1 serogroup, each displaying unique genotypic and phenotypic characteristics that provide reliable mechanisms for biotype characterization, and require distinct virulence inducing culturing conditions...
May 30, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28592552/colistin-and-polymyxin-b-susceptibility-testing-for-carbapenem-resistant-and-mcr-positive-enterobacteriaceae-comparison-of-sensititre-microscan-vitek-2-and-etest-with-broth-microdilution
#7
Ka Lip Chew, My-Van La, Raymond T P Lin, Jeanette W P Teo
Colistin and polymyxin B remain part of the last line of antibiotics for multi-drug-resistant Gram negative bacteria such as carbapenem-resistant-Enterobacteriaceae Current EUCAST-CLSI joint recommendations are for broth microdilution to be performed for MIC testing of colistin. Commercial susceptibility testing methods were evaluated and compared against reference broth microdilution (BMD), using a susceptible breakpoint of ≤2mg/L for both colistin and polymyxin B. Seventy-six Enterobacteriaceae were included, of which twenty-one were mcr-1 positive...
June 7, 2017: Journal of Clinical Microbiology
https://www.readbyqxmd.com/read/28590820/activity-of-ceftazidime-avibactam-against-clinical-isolates-of-klebsiella-pneumoniae-including-kpc-carrying-isolates-endemic-to-new-york-city
#8
Nyla Manning, Gregory Balabanian, Michael Rose, David Landman, John Quale
In this report, we examined the (1) activity of ceftazidime-avibactam against clinical isolates Klebsiella pneumoniae, including those harboring blaKPC, (2) potential mechanisms leading to reduced susceptibility, and (3) activity of ceftazidime-avibactam when combined with other agents. Of 802 carbapenem-resistant isolates of K. pneumoniae gathered from New York City from 1999 to 2014, all were susceptible to ceftazidime-avibactam. Minimum inhibitory concentrations (MICs) were higher in isolates with K. pneumoniae, with the carbapenemase (KPC)-3 (compared to KPC-2), and those with a frameshift mutation in ompK35...
June 7, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28586429/hafnia-an-enterobacterial-genus-naturally-resistant-to-colistin-revealed-by-three-susceptibility-testing-methods
#9
Aurélie Jayol, Marion Saly, Patrice Nordmann, Armelle Ménard, Laurent Poirel, Véronique Dubois
Objectives: To determine the susceptibility to colistin of Hafnia alvei and Hafnia paralvei , and to compare methods for colistin resistance detection in the Hafnia genus. Methods: A collection of 25 Hafnia isolates was studied. Species were identified by using 16S rRNA gene sequencing with subsequent phylogeny analysis. Susceptibility to colistin was determined using the broth microdilution (BMD) reference method, the Phoenix automated system, the Rapid Polymyxin NP test, the Etest system and the disc diffusion method...
June 6, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28584102/crystal-structures-of-the-burkholderia-multivorans-hopanoid-transporter-hpnn
#10
Nitin Kumar, Chih-Chia Su, Tsung-Han Chou, Abhijith Radhakrishnan, Jared A Delmar, Kanagalaghatta R Rajashankar, Edward W Yu
Strains of the Burkholderia cepacia complex (Bcc) are Gram-negative opportunisitic bacteria that are capable of causing serious diseases, mainly in immunocompromised individuals. Bcc pathogens are intrinsically resistant to multiple antibiotics, including β-lactams, aminoglycosides, fluoroquinolones, and polymyxins. They are major pathogens in patients with cystic fibrosis (CF) and can cause severe necrotizing pneumonia, which is often fatal. Hopanoid biosynthesis is one of the major mechanisms involved in multiple antimicrobial resistance of Bcc pathogens...
June 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28578555/infections-due-to-acinetobacter-baumannii-in-the-icu-treatment-options
#11
Joseph P Lynch, George G Zhanel, Nina M Clark
Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that may cause nosocomial infections in critically ill or debilitated patients (particularly ventilator-associated pneumonia and infections of the bloodstream, urinary tract, and wounds). Treatment of Acinetobacter infections is difficult, as Acinetobacter spp. are intrinsically resistant to multiple antimicrobial agents, and have a remarkable ability to acquire new resistance determinants via mechanisms that include plasmids, transposons, integrons, and resistance islands...
June 2017: Seminars in Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28576561/antimicrobial-activity-of-polymyxin-loaded-solid-lipid-nanoparticles-plx-sln-characterization-of-physicochemical-properties-and-in-vitro-efficacy
#12
Patrícia Severino, Elisânia F Silveira, Kahynna Loureiro, Marco V Chaud, Danilo Antonini, Marcelo Lancellotti, Victor Hugo Sarmento, Classius F da Silva, Maria Helena A Santana, Eliana B Souto
Antimicrobial resistance is a current public health concern, limiting the available therapeutic options used for the treatment of common bacterial infections. The development of new drug entities via biotechnological processes is however expensive and time-consuming. Therefore, old antimicrobial agents have been recovered for clinical use. An example of these drugs is polymyxin, which is known for its serious adverse side effects, such as nephrotoxicity, neurotoxicity and promotion of skin pigmentation. To overcome these limitations, the use of biodegradable nanoparticles has been proposed to allow site-specific targeting, increasing the drug's bioavailability and decreasing its side effects...
May 30, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28559256/aerosolized-polymyxin-b-for-treatment-of-respiratory-tract-infections-determination-of-pharmacokinetic-pharmacodynamic-indices-for-aerosolized-polymyxin-b-against-pseudomonas-aeruginosa-in-a-mouse-lung-infection-model
#13
Yu-Wei Lin, Qi Tony Zhou, Nikolas J Onufrak, Veronika Wirth, Ke Chen, Jiping Wang, Alan Forrest, Hak-Kim Chan, Jian Li
Pulmonary administration of polymyxins is increasingly used for the treatment of respiratory tract infections caused by multidrug-resistant Gram-negative bacteria, such as those in patients with cystic fibrosis. However, there is a lack of pharmacokinetics (PK), pharmacodynamics (PD) and toxicity data of aerosolized polymyxin B to inform rational dosage selection. The PK and PD of polymyxin B following pulmonary and intravenous dosing were conducted in neutropenic infected mice and the data were analyzed by a population PK model...
May 30, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28559252/occurrence-of-plasmid-and-chromosome-encoded-mcr-1-in-water-borne-enterobacteriaceae-in-china
#14
Hong-Wei Zhou, Ting Zhang, Ji-Hua Ma, Ying Fang, Han-Yu Wang, Zi-Xian Huang, Yang Wang, Congming Wu, Gong-Xiang Chen
The aim of this study was to investigate the prevalence of the polymyxin resistance gene mcr-1 in Enterobacteriaceae from environmental water sources in Hangzhou, China. Colistin-resistant bacteria were isolated from environmental water samples using an enrichment broth culture method and screened for mcr-1, and then analyzed for the location and transferability of mcr-1 Isolates positive for mcr-1 were further examined to determine their susceptibility profiles, and screened for the presence of additional resistance genes...
May 30, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28552659/antimicrobial-activity-evaluation-and-comparison-of-methods-of-susceptibility-for-klebsiella-pneumoniae-carbapenemase-kpc-producing-enterobacter-spp-isolates
#15
Daniele Zendrini Rechenchoski, Angélica Marim Lopes Dambrozio, Ana Carolina Polano Vivan, Paulo Alfonso Schuroff, Tatiane das Neves Burgos, Marsileni Pelisson, Marcia Regina Eches Perugini, Eliana Carolina Vespero
The production of KPC (Klebsiella pneumoniae carbapenemase) is the major mechanism of resistance to carbapenem agents in enterobacterias. In this context, forty KPC-producing Enterobacter spp. clinical isolates were studied. It was evaluated the activity of antimicrobial agents: polymyxin B, tigecycline, ertapenem, imipenem and meropenem, and was performed a comparison of the methodologies used to determine the susceptibility: broth microdilution, Etest(®) (bioMérieux), Vitek 2(®) automated system (bioMérieux) and disc diffusion...
May 10, 2017: Brazilian Journal of Microbiology: [publication of the Brazilian Society for Microbiology]
https://www.readbyqxmd.com/read/28533232/potentiation-of-antibiotic-activity-by-a-novel-cationic-peptide-potency-and-spectrum-of-activity-of-spr741
#16
David Corbett, Andrew Wise, Tara Langley, Kirsty Skinner, Emily Trimby, Stephen Birchall, Alain Dorali, Stephanie Sandiford, Jennifer Williams, Peter Warn, Martti Vaara, Troy Lister
Novel approaches to the treatment of multi-drug resistant Gram-negative bacterial infections are urgently required. One approach is to potentiate the efficacy of existing antibiotics whose spectrum of activity is limited by the permeability barrier presented by the Gram-negative outer membrane. Cationic peptides derived from polymyxin B have been used to permeabilize the outer membrane, granting antibiotics that would otherwise be excluded access to their targets. We assessed the in vitro efficacy of combinations of SPR741 with conventional antibiotics against Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii Of 35 antibiotics tested, the MICs of eight were reduced 32- to 8,000-fold against E...
May 22, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28505268/pharmacodynamics-of-dose-escalated-front-loading-polymyxin-b-regimens-against-polymyxin-resistant-mcr-1-harbouring-escherichia-coli
#17
Nicholas M Smith, Zackery P Bulman, Arthur O Sieron, Jürgen B Bulitta, Patricia N Holden, Roger L Nation, Jian Li, Gerard D Wright, Brian T Tsuji
Objectives: Gram-negative bacteria harbouring the mcr-1 plasmid are resistant to the 'last-line' polymyxins and have been reported worldwide. Our objective was to define the impact of increasing the initial polymyxin B dose intensity against an mcr-1 -harbouring strain to delineate the impact of plasmid-mediated polymyxin resistance on the dynamics of bacterial killing and resistance. Methods: A hollow fibre infection model (HFIM) was used to simulate polymyxin B regimens against an mcr-1 -harbouring Escherichia coli (MIC 8 mg/L) over 10 days...
May 15, 2017: Journal of Antimicrobial Chemotherapy
https://www.readbyqxmd.com/read/28497462/skin-hyperpigmentation-following-intravenous-polymyxin-b-treatment-associated-with-melanocyte-activation-and-inflammatory-process
#18
K P H Mattos, M L Cintra, I R Gouvêa, L Á Ferreira, P E N F Velho, P Moriel
What is known and objective Polymyxins were widely used until the 1960s; however, they fell into disfavour owing to their toxicity. The subsequent growth of infections caused by multidrug-resistant Gram-negative bacteria has led to renewed use of this class of antimicrobials in clinical practice. Acquired skin hyperpigmentation (SH) following intravenous polymyxin B treatment has been previously reported, but little is known about its pathogenesis, clinical course and treatment. To improve understanding of these issues, we conducted a prospective study of adult patients receiving intravenous polymyxin B treatment...
May 11, 2017: Journal of Clinical Pharmacy and Therapeutics
https://www.readbyqxmd.com/read/28487432/deciphering-mcr-2-colistin-resistance
#19
Jian Sun, Yongchang Xu, Rongsui Gao, Jingxia Lin, Wenhui Wei, Swaminath Srinivas, Defeng Li, Run-Shi Yang, Xing-Ping Li, Xiao-Ping Liao, Ya-Hong Liu, Youjun Feng
Antibiotic resistance is a prevalent problem in public health worldwide. In general, the carbapenem β-lactam antibiotics are considered a final resort against lethal infections by multidrug-resistant bacteria. Colistin is a cationic polypeptide antibiotic and acts as the last line of defense for treatment of carbapenem-resistant bacteria. Very recently, a new plasmid-borne colistin resistance gene, mcr-2, was revealed soon after the discovery of the paradigm gene mcr-1, which has disseminated globally. However, the molecular mechanisms for MCR-2 colistin resistance are poorly understood...
May 9, 2017: MBio
https://www.readbyqxmd.com/read/28475585/acinetobacter-baumannii-strains-isolated-from-patients-in-intensive-care-units-in-goi%C3%A3-nia-brazil-molecular-and-drug-susceptibility-profiles
#20
Suellen Rocha Araújo Castilho, Cássia Silva de Miranda Godoy, Adriana Oliveira Guilarde, Juliana Lamaro Cardoso, Maria Cláudia Porfirio André, Ana Paula Junqueira-Kipnis, André Kipnis
Resistance to antimicrobial agents is increasing worldwide and imposes significant life-threatening risks to several different populations, especially those in intensive care units (ICUs). Bacteria can quickly develop or acquire resistance to antimicrobial drugs, and combined with their intrinsic potential to cause disease in humans, these bacteria can become deadly. Among Gram-negative bacteria, Acinetobacter baumannii is notorious as a frequent opportunistic pathogen associated with critically ill patients, and understanding the genetic basis of A...
2017: PloS One
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