scholarly journals Synthetic Antimicrobial Peptides Exhibit Two Different Binding Mechanisms to the Lipopolysaccharides Isolated from Pseudomonas aeruginosa and Klebsiella pneumoniae

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Hanbo Chai ◽  
William E. Allen ◽  
Rickey P. Hicks
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Peptides ◽  
Inhibitory Activity ◽  
Binding Conformation ◽  
Cd Studies ◽  
Synthetic Antimicrobial Peptides ◽  
Activity Mechanism ◽  
Binding Mechanisms

Circular dichroism and 1H NMR were used to investigate the interactions of a series of synthetic antimicrobial peptides (AMPs) with lipopolysaccharides (LPS) isolated from Pseudomonas aeruginosa and Klebsiella pneumoniae. Previous CD studies with AMPs containing only three Tic-Oic dipeptide units do not exhibit helical characteristics upon interacting with small unilamellar vesicles (SUVs) consisting of LPS. Increasing the number of Tic-Oic dipeptide units to six resulted in five analogues with CD spectra that exhibited helical characteristics on binding to LPS SUVs. Spectroscopic and in vitro inhibitory data suggest that there are two possible helical conformations resulting from two different AMP-LPS binding mechanisms. Mechanism one involves a helical binding conformation where the AMP binds LPS very strongly and is not efficiently transported across the LPS bilayer resulting in the loss of inhibitory activity. Mechanism two involves a helical binding conformation where the AMP binds LPS very loosely and is efficiently transported across the LPS bilayer resulting in an increase in inhibitory activity. Mechanism three involves a nonhelical binding conformation where the AMP binds LPS very loosely and is efficiently transported across the LPS bilayer resulting in an increase in inhibitory activity.

Activité antibactérienne de l’huile essentielle de Pelargonium x asperum et son potentiel synergique avec la nisine

2019 ◽  
Vol 17 (3) ◽  
pp. 140-148 ◽  
Author(s):  
A. Ouelhadj ◽  
L. Ait Salem ◽  
D. Djenane
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Nous Avons ◽  
Activité Antibactérienne

Ce travail vise l’étude de l’activité antibactérienne de l’huile essentielle (HE) de Pelargoniumx asperum et de la bactériocine, la nisine seul et en combinaison vis-à-vis de six bactéries dont quatre sont multirésistantes d’origine clinique. L’activité antibactérienne in vitro a été évaluée par la méthode de diffusion sur gélose. La concentration minimale inhibitrice (CMI) est aussi déterminée pour HE. Les résultats ont révélé une activité antibactérienne significative exercée par HE visà-vis de Staphylococcus aureus (ATCC 43300), Staphylococcus aureus et Escherichia coli avec des diamètres d’inhibition de 36,00 ; 22,50 et 40,00 mm, respectivement. Cependant, l’HE de Pelargonium asperum a montré une activité antibactérienne supérieure par rapport à la nisine. Les valeurs des CMI rapportées dans cette étude sont comprises entre 1,98–3,96 μl/ml. Les combinaisons réalisées entre HE et la nisine ont montré un effet additif vis-à-vis de Escherichia coli (ATCC 25922) avec (50 % HE Pelargonium asperum + 50 % nisine). Par contre, nous avons enregistré une synergie vis-à-vis de Klebsiella pneumoniae avec (75 % HE Pelargonium asperum + 25 % nisine) et contre Pseudomonas aeruginosa avec les trois combinaisons testées. Les résultats obtenus permettent de dire que l’HE de Pelargonium asperum possède une activité antibactérienne ainsi que sa combinaison avec la nisine pourrait représenter une bonne alternative pour la lutte contre l’antibiorésistance.

scholarly journals Efeito antimicrobiano do extrato de Cranberry sobre micro-organismos causadores de infecção urinária

2016 ◽  
Vol 11 (31) ◽  
pp. 113-122
Author(s):  
Carla Franco Porto Belmont Souza ◽  
Luiz Eduardo Souza da Silva Irineu ◽  
Renan Silva De Souza ◽  
Renato da Silva Teixeira ◽  
Ivina Sanches Pereira ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Proteus Mirabilis ◽  
Enterococcus Faecium ◽  
Vaccinium Macrocarpon ◽  
Mueller Hinton

A resistência microbiana tem se mostrado um problema de proporções mundiais, causando estado de morbidade e mortalidade em diversos pacientes. Em vista disso, tem crescido a busca por métodos alternativos naturais de profilaxia. A investigação clínica sugere que o Extrato de Cranberry está entre as melhores propostas de prevenção natural. O Cranberry (Vaccinium macrocarpon) é um fruto que tem crescido comercialmente pelo sabor e propriedades benéficas à saúde. Dentre as formas comercializadas estão: o suco, o chá e as cápsulas contendo o extrato seco. A ação desta planta está relacionada ao tratamento de doenças do trato urinário, por possuir substâncias que inibem a adesão bacteriana ao epitélio do trato urinário, dificultando sua proliferação e reprodução. Dentre todas as infecções relacionadas à assistência a saúde, a Infecção do Trato Urinário é a mais frequentemente associada a procedimentos invasivos. Se não for tratada, pode resultar em complicações como pielonefrite aguda, bacteremia e pionefrose. Portanto, cranberry pode ser uma nova alternativa para o combate das infecções uroepiteliais, por ser um produto natural de preço acessível, e com formas de comercialização diversificada, ao contrário dos antimicrobianos convencionais, que por sua vez são caros e podem acabar causando resistência nos micro-organismos. Este trabalho teve como objetivo avaliar in vitro a atividade antimicrobiana do extrato de Cranberry, adquirido em farmácia de manipulação, sobre 8 micro-organismos isolados de infecções urinárias. As cepas utilizadas, adquiridas da coleção da FIOCRUZ, foram: Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, Serratia marscecens, Staphylococcus aureus, Enterococcus faecalis e Enterococcus faecium. No estudo, foram utilizados o caldo Mueller Hinton (MH), Extrato de Cranberry e as bactérias patogênicas. O ensaio foi realizado em triplicata, com o uso de um controle de crescimento dos micro-organismos e o experimento para avaliação do crescimento bacteriano na presença do extrato. A turbidez foi medida com o auxílio de um espectrofotômetro, no comprimento de onda de 600 nm, antes e após 24 horas de incubação à 37 ºC. O procedimento forneceu a Densidade Ótica, do qual possibilitou a identificação da inibição microbiana. Para análise estatística foi utilizado o Teste t de Student. O Extrato de Cranberry apresentou atividade antimicrobiana sobre as bactérias Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Serratia marscecens e Enterococcus faecalis (p < 0,05), confirmando seu efeito benéfico em infecções urinárias. No entanto, não teve efeito inibitório significativo sobre Pseudomonas aeruginosa, Proteus mirabilis e Enterococcus faecium (p > 0,05).

scholarly journals Actividad antibacteriana in vitro de aceites esenciales de diferentes especies del género Citrus

2017 ◽  
Vol 46 (2) ◽  
Author(s):  
Miladys Esther Torrenegra Alarcón ◽  
Nerlis Paola Pájaro ◽  
Glicerio León Méndez
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
E Coli

Se evaluó la actividad antibacteriana in vitro de aceites esenciales de diferentes especiesdel género Citrus frente a cepas ATCC de Staphylococcus aureus, Staphylococcus epidermidis,Klebsiella pneumoniae, Pseudomonas aeruginosa y Escherichia coli, determinandola concentración mínima inhibitoria (CMI) y la concentración mínima bactericida(CMB). Las bacterias se replicaron en medios de agar y caldos específicos. Se determinóel momento de máxima densidad óptica (DO620) para emplearlo como tiempode incubación; luego se hicieron pruebas de evaluación de sensibilidad con la exposiciónde las cepas a concentraciones a 1000 g/mL del extracto en caldo. Para solubilizarse empleó dimetilsulfóxido (DMSO) al 1%. Posteriormente, se le determinó laconcentración mínima inhibitoria mediante metodologías de microdilución en caldoy la concentración mínima bactericida. Encontrándose una actividad de los aceitesesenciales del género Citrus, con valores de CMI ≥ 600 mg/mL frente a S. aureus,S. epidermidis, K. pneumoniae, P. aeruginosa y E. coli. En función a los resultados obtenidos,se concluye que las diferentes especies del género Citrus son consideradas comopromisorias para el control del componente bacteriano.

scholarly journals Comparison of the Activity of a Human Simulated, High-Dose, Prolonged Infusion of Meropenem against Klebsiella pneumoniae Producing the KPC Carbapenemase versus That against Pseudomonas aeruginosa in an In Vitro Pharmacodynamic Model

2009 ◽  
Vol 54 (2) ◽  
pp. 804-810 ◽  
Author(s):  
Catharine C. Bulik ◽  
Henry Christensen ◽  
Peng Li ◽  
Christina A. Sutherland ◽  
David P. Nicolau ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
High Performance ◽  
Resistance Mechanisms ◽  
Free Drug ◽  
Pharmacodynamic Model ◽  
High Dose ◽  
Prolonged Infusion ◽  
Drug Concentrations

ABSTRACT We have previously demonstrated that a high-dose, prolonged-infusion meropenem regimen (2 g every 8 h [q8h]; 3-hour infusion) can achieve 40% free drug concentration above the MIC against Pseudomonas aeruginosa with MICs of ≤16 μg/ml. The objective of this experiment was to compare the efficacy of this high-dose, prolonged-infusion regimen against carbapenemase-producing Klebsiella pneumoniae isolates with the efficacy against P. aeruginosa isolates having similar meropenem MICs. An in vitro pharmacodynamic model was used to simulate human serum concentrations. Eleven genotypically confirmed K. pneumoniae carbapenemase (KPC)-producing isolates and six clinical P. aeruginosa isolates were tested for 24 h, and time-kill curves were constructed. High-performance liquid chromatography (HPLC) was used to verify meropenem concentrations in each experiment. Meropenem achieved a rapid ≥3 log CFU reduction against all KPC isolates within 6 h, followed by regrowth in all but two isolates. The targeted %fT>MIC (percent time that free drug concentrations remain above the MIC) exposure was achieved against both of these KPC isolates (100% fT>MIC versus MIC = 2 μg/ml, 75% fT>MIC versus MIC = 8 μg/ml). Against KPC isolates with MICs of 8 and 16 μg/ml that did regrow, actual meropenem exposures were significantly lower than targeted due to rapid in vitro hydrolysis, whereby targeted %fT>MIC was reduced with each subsequent dosing. In contrast, a ≥3 log CFU reduction was maintained over 24 h for all Pseudomonas isolates with meropenem MICs of 8 and 16 μg/ml. Although KPC and P. aeruginosa isolates may share similar meropenem MICs, the differing resistance mechanisms produce discordant responses to a high-dose, prolonged infusion of meropenem. Thus, predicting the efficacy of an antimicrobial regimen based on MIC may not be a valid assumption for KPC-producing organisms.

scholarly journals Production and Purification of Two Bioactive Antimicrobial Peptides Using a Two-Step Approach Involving an Elastin-Like Fusion Tag

2021 ◽  
Vol 14 (10) ◽  
pp. 956
Author(s):  
Ana Margarida Pereira ◽  
André da Costa ◽  
Simoni Campos Dias ◽  
Margarida Casal ◽  
Raul Machado
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Peptides ◽  
Formic Acid ◽  
Cleavage Site ◽  
Burkholderia Cenocepacia ◽  
High Recovery ◽  
Temperature Cycles ◽  
Acid Cleavage

Antimicrobial resistance is an increasing global threat, demanding new therapeutic biomolecules against multidrug-resistant bacteria. Antimicrobial peptides (AMPs) are promising candidates for a new generation of antibiotics, but their potential application is still in its infancy, mostly due to limitations associated with large-scale production. The use of recombinant DNA technology for the production of AMPs fused with polymer tags presents the advantage of high-yield production and cost-efficient purification processes at high recovery rates. Owing to their unique properties, we explored the use of an elastin-like recombinamer (ELR) as a fusion partner for the production and isolation of two different AMPs (ABP-CM4 and Synoeca-MP), with an interspacing formic acid cleavage site. Recombinant AMP-ELR proteins were overproduced in Escherichia coli and efficiently purified by temperature cycles. The introduction of a formic acid cleavage site allowed the isolation of AMPs, resorting to a two-step methodology involving temperature cycles and a simple size-exclusion purification step. This simple and easy-to-implement purification method was demonstrated to result in high recovery rates of bioactive AMPs. The minimum inhibitory concentration (MIC) of the free AMPs was determined against seven different bacteria of clinical relevance (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two Burkholderia cenocepacia strains), in accordance with the EUCAST/CLSI antimicrobial susceptibility testing standards. All the bacterial strains (except for Pseudomonas aeruginosa) were demonstrated to be susceptible to ABP-CM4, including a resistant Burkholderia cenocepacia clinical strain. As for Synoeca-MP, although it did not inhibit the growth of Pseudomonas aeruginosa or Klebsiella pneumoniae, it was demonstrated to be highly active against the remaining bacteria. The present work provides the basis for the development of an efficient and up-scalable biotechnological platform for the production and purification of active AMPs against clinically relevant bacteria.

Phänotypische Antibiotikaresistenzen von Bakterienisolaten aus Zier-, Zoo- und falknerisch gehaltenen Greifvögeln

2020 ◽  
Vol 48 (04) ◽  
pp. 260-269
Author(s):  
Leonie Steger ◽  
Monika Rinder ◽  
Rüdiger Korbel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Enterococcus Faecalis ◽  
Enterobacter Cloacae ◽  
Coli Isolate ◽  
Aureus Isolate ◽  
E Coli ◽  
Klinische Relevanz

Zusammenfassung Gegenstand und Ziel Die Prävalenz von antibiotikaresistenten Bakterien bei Zier-, Zoo- und falknerisch gehaltenen Greifvögeln ist noch weitgehend unbekannt. Daher sollten retrospektiv Antibiogramme schnellwachsender aerober Bakterienarten ausgewertet werden. Material und Methoden Im Auswertungszeitraum von 2007 bis 2016 standen 1036 Antibiogramme zur Verfügung. Die Bakterienisolate stammten vorzugsweise aus Süddeutschland und von 811 Vögeln aus 20 zoologischen Ordnungen (am häufigsten Papageienvögel [61,8 %] und Sperlingsvögel [14,5 %]) sowie aus Proben von klinischen Patienten und Sektionsmaterial. Die phänotypische In-vitro-Empfindlichkeit wurde mittels Plattendiffusionstest ermittelt. Ergebnisse Die meisten Antibiogramme lagen für E. coli (n = 386 Isolate) vor, gefolgt von Staphylococcus (S.). aureus (n = 150), Enterobacter cloacae (n = 122), Klebsiella pneumoniae (n = 86) und Pseudomonas aeruginosa (n = 64). Resistenzen gegen mindestens einen antibiotischen Wirkstoff zeigten 53,1 % der E. coli-Isolate, dabei am häufigsten gegen Doxycyclin (50,3 %) und Ampicillin (46,1 %). Bei 78,0 % der S. aureus-Isolate und bei 95,9 % der Enterococcus faecalis-Isolate wurden Resistenzen gegenüber mindestens einem Wirkstoff nachgewiesen. Multiresistenzen (Resistenz gegenüber ≥ 3 Antibiotikagruppen) traten bei 37,3 % der Isolate von S. aureus auf. Bei Isolaten von Zier- und Greifvögeln wurden höhere Resistenzraten festgestellt als bei Isolaten von Zoovögeln und bei Papageienvögeln höhere Resistenzraten als bei Sperlingsvögeln. Im Untersuchungszeitraum zeigte sich bei E. coli ein tendenzieller Anstieg der Resistenzrate für Fluorchinolone (Minimum von 0 % im Jahr 2013 und Maximum von 27,3 % im Jahr 2015) und bei S. aureus eine tendenzielle Abnahme der Resistenzraten für Tetrazykline (Maximum von 39,4 % im Jahr 2007 und Minimum von 0 % in den Jahren 2014 und 2015). Schlussfolgerung und klinische Relevanz Die Resistenzsituation von Bakterien aus Zier-, Zoo- und falknerisch gehaltenen Greifvögeln ist als problematisch zu bewerten und verdeutlicht die Wichtigkeit der Empfindlichkeitsprüfung für eine gewissenhafte Therapie. Im Fall einer Infektion mit S. aureus bei Zier-, Zoo- oder falknerisch gehaltenen Greifvögeln kann es zu einem Therapienotstand kommen.

scholarly journals Global trends of antimicrobial susceptibility of ceftaroline and ceftazidime-avibactam: a surveillance study from the ATLAS program (2012-2016)

2020 ◽  
Author(s):  
Hui Zhang ◽  
Yingchun Xu ◽  
Peiyao Jia ◽  
Ying Zhu ◽  
Ge Zhang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
North America ◽  
Middle East ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Asia Pacific ◽  
Global Trends ◽  
Specific Species

Abstract Background:This study reports the global trends of antimicrobial susceptibility toceftaroline and ceftazidime-avibactam using data from the Antimicrobial Testing Leadership And Surveillance (ATLAS)programbetween2012and2016.Methods:For the 2012-2016 ATLAS program, 205 medical centers located in Africa-Middle East (n=12), Asia-Pacific (n=32), Europe (n=94), Latin America (n=26), North America (n=31), and Oceania (n=10) consecutively collected the clinical isolates. Theminimum inhibitory concentrations (MICs) andin vitro susceptibilities toceftarolineandceftazidime-avibactam were assessed using the Clinical andLaboratory Standards Institute (CLSI) 2019and European Committee on Antimicrobial Susceptibility Testing (EUCAST) 2019 guidelines.Results:Between 2012 and 2016, 176,345 isolates were collectedfrom around the globeand included in theanalysis.Regarding Gram-negative bacteria, ceftazidime-avibactam demonstrated high susceptibility (>90%) against EnterobacteriaceaeandPseudomonas aeruginosa, with increasedantimicrobial activity observed from the addition of avibactam (4 mg/L) to ceftazidime.Regarding Gram-positive bacteria, ceftaroline showed >90% susceptibility againstStaphylococcus aureus, Streptococcus pneumoniae, α-and β-hemolytic Streptococcus.The antimicrobial susceptibilitiestoceftaroline and ceftazidime-avibactam were mostly stable from 2012 to 2016, but the susceptibilitiestoceftazidime-avibactam to carbapenem-resistant (CR)Klebsiella pneumoniae(88.4% to 81.6%) and to CR-Pseudomonas aeruginosa(89.6% to 72.7%) decreased over time. In terms of regional difference, the susceptibilities of methicillin-resistant Staphylococcus aureusto ceftaroline in Asia and of CR-Klebsiella pneumoniaeto ceftazidime-avibactam in Asia/Africa-Middle East were lowercompared with other regions,while the susceptibility of CR-Pseudomonas aeruginosa to ceftazidime-avibactam in North America was higher.Conclusion: The addition of avibactam improves the activity of ceftazidime against EnterobacteriaceaeandPseudomonas aeruginosa. The global antimicrobial susceptibilitiestoceftaroline and ceftazidime-avibactam were, in general, stable from 2012 to 2016, but a marked reduction in the susceptibilities of specific species andCR-Pseudomonas aeruginosa toceftazidime-avibactam was observed.

Sign in / Sign up

Export Citation Format

Share Document