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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Avaliação de moléculas bioativas produzidas por isolados actinomicetos contra cocos Gram positivos de origem clínica / Characterization of bioactive molecules produced by actinomycetes isolated against clinical cocos gram positive

Antunes, Themis Collares January 2013 (has links)
Os actinomicetos são bactérias Gram positivas caracterizadas por sua habilidade em formar hifas, são amplamente distribuídos no ambiente e conhecidos pela diversidade na produção de moléculas biologicamente ativas. O presente trabalho teve por objetivo avaliar a atividade de compostos produzidos por quarenta isolados de actinomicetos contra isolados clínicos de Enterococcus sp, Staphylococcus aureus e Staphylococcus epidermidis. O perfil de suscetibilidade das amostras clínicas foi avaliado empregando a técnica de disco difusão em ágar. A atividade antimicrobiana dos actinomicetos foi avaliada pela técnica da dupla camada. Os isolados que apresentaram atividade foram cultivados em caldo amido caseína à temperatura de 30ºC por sete dias, com agitação constante. Após o crescimento, a cultura foi filtrada para obtenção do extrato bruto. A atividade antibiótica do extrato foi avaliada através da técnica de difusão em poço. O isolado que apresentou maior espectro de ação foi selecionado para otimização dos compostos. A otimização da produção dos compostos com atividade antibiótica foi realizada através da avaliação de curva de produção, variação da fonte de carbono, tempo de incubação, pH tamponado e pH não tamponado. No ensaio de sobrecamada os isolados 50 e 8S apresentaram atividade contra a 90% das amostras de microrganismos clínicos de Staphylococcus sp. e Enterococcus sp. No ensaio de difusão em poço o isolado 50 apresentou maior atividade antibiótica que o isolado 8S. Na otimização do extrato as melhores condições de produção foram: 72 h de crescimento, fonte de carbono amido e sem tamponamento de pH. Não foi observada influência de biomassa na produção dos compostos. A cromatografia em camada delgada revelou a presença de duas bandas com fator de retenção de 0,28 (Rf1) e 0,57 (Rf2). / Actinomycetes are Gram positive bacteria, characterized by their ability to form hyphae. They are widely distributed in the environment and known for their diversity in producing biological active molecules. This study aimed to evaluate the activity of compounds produced by forty isolates of Actinomycetes against clinical isolates of Enterococcus sp, Staphylococcus aureus and Staphylococcus epidermidis. The susceptibility profile of the samples was evaluated using the disk diffusion technique in agar. The antimicrobial activity of actinomycetes was assessed by means of the double layer. Isolates that showed activity were grown in starch casein broth at a temperature of 30 ºC for seven days, with constant agitation. After growth the culture was filtered to obtain a crude extract. The antimicrobial activity of the extract was evaluated by the well diffusion technique. The actinomycete that showed activity against most of the test samples was selected for optimization(s) of the compound(s) production. The optimization of the production was performed by evaluating: growth curve, the use of different carbon source, changes in the incubation time, and culture media with buffered and unbuffered pH. In the overlay assay isolates 50 and 8S presented activity against most of Staphylococcus sp. and Enterococcus sp samples. In diffusion assay isolate 50 showed higher antibiotic activity than the isolated 8S. Compiling the results the best production conditions were: 72 h of growth, carbon source starch without pH buffering at 30°C. There was no effect of biomass (s) compound (s) activity. The thin layer chromatography revealed the presence of two bands with a retention factor of 0.28 (Rf1) and 0.57 (Rf2).
52

Avaliação in vitro da eficácia de técnicas endodônticas de preparo mecânico na redução de Enterococcus faecalis

Manoel Matos Neto 30 January 2007 (has links)
O preparo mecânico tem por objetivo a modelagem dos canais radiculares e redução de microrganismos nele presentes. Para sua execução foram utilizados instrumentos endodônticos confeccionados em aço inoxidável ou ligas de níquel-titânio. Esse estudo tem como objetivo avaliar a eficácia de três sistemas de preparo mecânico na redução da contagem de Enterococcus faecalis no interior de canais radiculares. Para isso foram utilizados 24 dentes humanos unirradiculares, divididos em três grupos: G1 - instrumentação com o sistema ProTaper rotatório, G2 - com sistema ProTaper manual e G3 - com limas tipo Kerr manuais. Os canais radiculares foram contaminados com Enterococcus faecalis, e após formação de biofilme, submetidas ao preparo mecânico. As unidades formadoras de colônia foram contadas antes e depois da instrumentação e a porcentagem de redução calculada. Os resultados demonstraram que todos os sistemas reduziram significantemente a quantidade de microrganismos dentro do canal radicular. Contudo, quando se comparou a redução promovida pelos sistemas entre si não houve diferença significativa. O estudo confirmou a eficácia do preparo mecânico, entretanto nenhum dos sistemas avaliados foi superior ao outro na redução do número de Enterococcus faecalis no interior dos canais radiculares. / The objects of mechanical preparation are to model root canals and reduce the number of microorganisms present in them. For this purpose, endodontic instruments made of stainless steel or nickel-titanium alloys are used. The aim of this study was to assess the efficacy of three systems of mechanical preparation for reducing the counting of Enterococcus faecalis inside root canals. To do this, 24 single rooted human teeth were used, divided into three groups: G1 instrumentation with the ProTaper rotary system, G2 with the manual ProTaper system and G3 manual Kerr type files. The root canals were contaminated with Enterococcus faecalis, and after biofilm had formed, they were submitted to mechanical preparation. The colony forming units were counted before and after instrumentation and the percentage of reduction was calculated. The results demonstrated that all the systems significantly reduced the number of microorganisms inside the root canal. However, when the reduction promoted by the systems was compared among them, there was no significant difference. The study confirmed the efficacy of mechanical preparation, however, none of the assessed systems was superior to the other for reducing the number of microorganisms inside root canals.
53

Testování antimikrobiální aktivity obalových materiálů s rostlinnými extrakty proti bakteriím rodu Enterococcus

Maňáková, Simona January 2017 (has links)
This thesis deals with testing of antimicrobial activity of plant essential oils as part of packaging systems for foodpackaging against bacteria genus Enterococcus. The first literature part is focused on characteristic of genus Enterococcus and his possible apperace in food and his negative effect on human health. Next topic of literature section is targeted on using plants as producers of essential oils and their use in food industry as active compounds with antimicrobial and atifugal activity. This includes also characteristic of selected aromatic plants growing in our geographical conditions. Last part of literature section is introduction of characteristic of packaging materials and theirs big importance in food industry. Practical part of this thesis is dealing with testing of packaging materials containg essential oils on theirs surface against E. faecalis. Another part of this experiment is testing these antimicrobial packaging materials on selected foods in this case meat product following with microbiological analysis of selected bacteria.
54

Transferencia de plásmidos con resistencia a antibióticos en especies de Enterococcus provenientes del mar de Lima

Sumi Jáuregui, Ada Lizbeth January 2008 (has links)
El género Enterococcus es conocido por ser de origen fecal o intestinal, pero tiene una amplia distribución en la naturaleza y se le puede encontrar en suelos, aguas, plantas y en productos alimenticios, siendo capaz de sobrevivir en medios poco enriquecidos. Los estudios reportados sobre estos microorganismos generalmente inciden en su aspecto clínico y su resistencia a antibióticos, y algunos se ubican en un contexto ambiental evaluando métodos para su detección o enumeración para uso en aguas recreacionales. Está aumentando la importancia de este microorganismo como agente causal de infecciones adquiridas en hospitales, pero el interés de estudio en este género radica en su alta resistencia natural a múltiples antimicrobianos y a su capacidad de adquirir y transferir dicha resistencia. Se sabe que Enterococcus es un microorganismo introducido al ecosistema marino debido a la contaminación de éste ambiente con desechos orgánicos, pero son pocos los reportes sobre estudios de resistencia antimicrobiana de éste género provenientes de muestras de agua de mar, siendo necesario este tipo de investigación que nos permita conocer la importancia de estos microorganismos en estos ambientes. / The genus Enterococcus is recognized as being of fecal origin but have a wide distribution in nature, they can be found in soil, water, plants and food products, being able to survive in low-enriched media. Studies on these microorganisms usually affect their appearance and clinical resistance to antibiotics, and there are some who are placed in an environmental context, evaluating methods of detection or enumeration in waters for recreational use. It is increasing the importance of this microorganism as a causative agent of infections acquired in hospitals, but the interest in this kind of study lies in its high natural resistance to multiple antimicrobials and their ability to acquire and transfer the resistance. Despite that Enterococcus is a microorganism introduced to the marine ecosystem by contamination with organic wastes, there are few reports on studies of antimicrobial resistance of the Enterococcus genus water samples from the sea, being necessary to this type of research that allows us to know the importance of these microorganisms in these environments.
55

[DUPLICATE OF ark:/67531/metadc501171] Immunoflorescence as a method for the rapid identification of streptococcus faecalis in water

Abshire, Robert Louis 08 1900 (has links)
The serum of an immunized animal will contain antibodies referred to as agglutinins, precipitins, opsonins, bacteriolysins, or complement-fixing antibodies (Zinsser 1952). The presence of such antibodies may be demonstrated in the laboratory, the type of reaction depending on the circumstance and the laboratory manipulation employed. Regardless of the specific serolological method utilized, the manifestation of the antigen-antibody reaction is the visible observation that such a combination has occurred.
56

Prevalência, Virulência e sensibilidade às terapias antimicrobianas das cepas de enterecoccus faecalis e enterococcus faecium isoladas de infecções endodônticas /

Santos, Ana Carolina Chipoletti dos. January 2014 (has links)
Orientador: Juliana Campos Junqueira / Banca: Antonio Olavo Cardoso Jorge / Banca: José Chibebe Junior / Resumo: Enterococcus faecium se tornou um dos mais temidos micro-organismos em infecções hospitalares, por apresentar maior facilidade em adquirir resistência aos antibióticos do que E. faecalis. Entretanto, faltam estudos voltados para o isolamento e identificação de E. faecium na cavidade bucal. Os objetivos deste trabalho foram isolar e identificar E. faecalis e E. faecium em canais radiculares com infecções endodônticas e comparar as cepas de E. faecalis e E. faecium em relação à sensibilidade aos antibióticos convencionais e à terapia fotodinâmica antimicrobiana (PDT). Além disso, essas espécies foram comparadas quanto à virulência in vivo, utilizando o modelo de infecção experimental de Galleria mellonella. As cepas de E. faecalis e E. faecium isoladas de canais radiculares foram identificadas pelo sistema Rapid ID 32 Strep e PCR multiplex. Todos os isolados identificados como E. faecalis e E. faecium, foram testadas quanto à sensibilidade aos antibióticos pelo método E-test para determinação da concentração inibitória mínima (MIC). A seguir, foram selecionadas algumas cepas de E. faecalis e E. faecium sensíveis e resistentes aos antibióticos de uso clínico na odontologia para testes de sensibilidade in vitro à terapia fotodinâmica antimicrobiana. A virulência das cepas de E. faecalis e E. faecium foram testadas in vivo no modelo de infecção experimental de G. mellonella por meio da análise da curva de sobrevivência das larvas e quantificação de UFC/mL de células bacterianas presentes na hemolinfa desses animais. Os dados de UFC/mL obtidos na terapia fotodinâmica e na infecção em G. mellonella foram submetidos à análise de variância e teste de Tukey. Os dados obtidos na curva de sobrevivência de G. mellonella foram analisados pelo método de Log-rank. Foram realizadas coletas de 38 canais radiculares de diferentes pacientes, sendo que 22 apresentaram culturas positivas para enterococcus spp.(58%).... / Abstract: Enterococcus faecium has become one of the most dreaded micro-organisms in nosocomial infections, due to its greater ease in acquiring resistance to antibiotics than E. faecalis. However, lack of studies focused on the isolation and identification of E. faecium in the oral cavity. The objectives of this study was to isolate and identify E. faecalis and E. faecium in root canals with endodontic infections and to compare strains of E. faecalis and E. faecium in sensitivity to conventional antibiotics and antimicrobial photodynamic therapy (PDT). Furthermore, these species were compared for virulence in vivo, using the model of experimental infection of Galleria mellonella. The strains of E. faecalis and E. faecium isolated from root canals were identified by the Rapid ID 32 Strep system and multiplex PCR. All isolates identified as E. faecalis and E. faecium were tested for antibiotic susceptibility E-test method for determination of minimal inhibitory concentration (MIC). Next, we selected some strains of E. faecalis and E. faecium sensitive and antibiotic-resistant clinical use in dentistry for in vitro susceptibility testing to antimicrobial photodynamic therapy. The virulence of strains of E. faecalis and E. faecium were tested in in vivo experimental model of infection of G. mellonella by analysis of larval survival curve and quantitation of CFU/mL bacterial cells present in the hemolymph of these animals. Data from CFU/mL obtained in photodynamic therapy and infection in G. mellonella were subjected to analysis of variance and Tukey test. The data on the survival of G. mellonella curves were analyzed by log-rank method. Samples of 38 root canals from different patients were performed and 22 had cultures positive for Enterococcus spp. (58%). Of these patients, all showed E. faecalis and only 2 had mixed infections with E. faecalis and E. faecium 6 isolates (27%) E. faecalis resistant to .... / Mestre
57

Análise da comunidade bacteriana de animais marinhos recolhidos do litoral norte do Rio Grande do Sul / Analysis of the bacterial community from marine animals found in the coastal north Rio Grande do Sul

Medeiros, Aline Weber January 2016 (has links)
O conhecimento sobre a microbiota de animais marinhos fornece uma base que pode ser usada para comparação em virtude de mudanças futuras, apesar disso pouco se sabe sobre a natureza das bactérias associadas com o intestino desses animais. Esse estudo visou a obtenção de um panorama sobre a microbiota de animais marinhos selvagens recolhidos no litoral do Rio Grande do Sul através de ferramentas independentes de cultivo, como o sequenciamento de última geração e PCR quantitativa em tempo real (qPCR), que permitem a inferência sobre as bactérias pertencentes a microbiota intestinal a partir do DNA genômico total obtido diretamente da amostra. A partir do sequenciamento parcial do gene de 16S rRNA utilizando a plataforma de alta desempenho Ion Torrent PGM, seis amostras fecais de lobo-marinho-sul-americano (Arctocephalus australis) e quatro lobo-marinho- subantártico (Arctocephalus tropicalis) foram avaliadas. Verificou-se que o filo Firmicutes (86,28%) foi mais frequente nas fezes de ambas as espécies, seguido por Actinobacteria(6,74%) e Proteobacteria (3,34%), sendo Bacteroidetes e Fusobacteria os filos menos frequente. A qPCR foi empregada para quantificar as espécies de enterococos, mais frequentemente isoladas de fezes de animais (Enterocococcus faecalis, E. hirae, E. mundtti, E. faecium, E. gallinarum e E. casseliflavus), em amostras fecais de animais marinhos selvagens. A partir de DNAs totais isolados de 24 amostras fecais de lobos marinhos, tartarugas-verdes e aves marinhas, verificou-se que E. faecalis (1,82x1012 cópias/ng) foi a espécie mais frequente em todas as amostras analisadas e E. hirae (5,89x1010), E. mundtti (7,57x1010 cópias/ng), E. faecium (4,94x1009 cópias/ng), E. casseliflavus (1,22x1009 cópias/ng) e E. gallinarum (3,84x1010 cópias/ng) também demonstraram estar presentes na microbiota desses animais. / Knowledge about the marine animals microbiota provides a base that can be used for comparison due to future changes, nevertheless little is known about the nature of the bacteria associated with the animal gut. This study aimed to obtain an overview of the microbiota of wild marine animals collected in the Rio Grande do Sul coast using cultive independent methods, as the next-generation sequencing and quantitative real-time PCR ( qPCR ), which allow the inference about the bacteria belonging to the intestinal microbiota from total genomic DNA obtained directly from the sample. Using the high performance Ion Torrent PGM platform six fecal samples of South American fur seal (Arctocephalus australis) and four Subantartic fur seals (Arctocephalus tropicalis) were evaluated. It was found that the phylum Firmicutes (86.28%) was more common in faeces of both species, followed by Actinobacteria (6.74%) and Proteobacteria (3.34%), Fusobacteria and Bacteroidetes were the least frequent. The qPCR was used to quantify the Enterococci species commonly isolated from faecal samples of animal (Enterocococcus faecalis, E. hirae, E. mundtti, E. faecium, E. gallinarum e E. casseliflavus) in faecal samples or cloacal swabs / rectal wild marine animals. From total DNA isolated of 24 fecal samples from sea lions, green turtles , sea birds, it was observed that E. faecalis (1.82x1012 copy/ng) was the most common species in all samples analyzed and E. hirae (5.89x1010), E. mundtti (7.57x1010), E. faecium (4.94x1009), E. casseliflavus (1.22x1009) and E. gallinarum (3.84x1010) also shown to be present in the microflora of these animals.
58

Efecto in vitro de la medicación intraconducto hidróxido de calcio con omeprazol frente al crecimiento bacteriano de Enterococcus faecalis

Padilla Contreras, María del Carmen, Roncal Espinoza, Rosa Josefina, Padilla Contreras, María del Carmen, Roncal Espinoza, Rosa Josefina January 2014 (has links)
El objetivo del estudio fue determinar el efecto in vitro de la medicación intraconducto hidróxido de calcio con omeprazol frente al crecimiento bacteriano del Enterococcus faecalis. El diseño de estudio fue experimental. Los medicamentos hidróxido de calcio y omeprazol fueron diluidos, obteniéndose las concentraciones requeridas. Posteriormente, se colocó 9 ml de cada uno en placas petri, agregando 1 ml del inóculo; procediéndose a la siembra. No se observó Unidades Formadoras de Colonias (UFC), por lo que se evidencia que el efecto in vitro del hidróxido de calcio, así como la asociación de hidróxido de calcio con omeprazol inhiben el crecimiento de Enterococcus faecalis. Se realizó una prueba binomial donde los eventos esperados fueron que haya o no crecimiento bacteriano. La significación estadística fue del 5%. El estudio concluyó que la asociación in vitro de hidróxido de calcio con omeprazol, inhibió el crecimiento bacteriano del Enterococcus faecalis, sin evidenciarse potencialización con el uso del inhibidor de la bomba de protones. / Tesis
59

Presencia de Enterococcus faecalis en un grupo de pacientes chilenos con periodontitis crónica

Vázquez de Ponson Du Terrail, Joaquín Amadeo January 2017 (has links)
Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista / Introducción: Dentro de la microbiota normal de la cavidad oral se presenta E. faecalis, una bacteria anaerobia facultativa, Gram positivo, frecuentemente asociada a tratamientos endodónticos fallidos, en saliva de pacientes con periodontitis recurrente y población infantil con alto número de lesiones de caries. Dentro de sus características está el poseer diversos factores de virulencia, gran porcentaje de ADN móvil, y el asociarse a otras bacterias del biofilm teniendo de esa manera alta resistencia a antimicrobianos. En estudios recientes ha sido identificado en periodontitis crónica. Objetivos: El objetivo de este estudio fue determinar la presencia de E. faecalis en un grupo de pacientes chilenos diagnosticados con periodontitis crónica. Materiales y métodos: La muestra en estudio se conformó por 28 pacientes, con diagnóstico de periodontitis crónica, sin tratamiento periodontal previo ni compromiso sistémico por enfermedades o antibióticos asociados. Una muestra por cada cuadrante de cada paciente fue procesada en laboratorio, realizando la detección de E. faecalis por medio de la Reacción en Cadena de la Polimerasa (PCR). Resultados: Nuestros resultados determinaron que E. faecalis fue identificado en el 64,23% de las muestras provenientes de pacientes con diagnóstico de Periodontitis Crónica. También se aprecia la diferencia en la detección de E. faecalis entre distintos tipos de sitios de acuerdo a las características clínicas de cada uno, encontrándose con mayor frecuencia en sitios con PS ≥ 5 mm y IS (+) versus PS ≥ 5 mm y IS (-) y PS < 5 mm. Conclusión: El porcentaje de detección de E. faecalis sugiere que este patógeno forma parte de la microbiota en la periodontitis crónica en la población estudiada. / Adscrito a proyecto de investigación FONDECYT No1130570
60

Influence de la structure 3D du site catalytique de la protéine PBP5 dEnterococcus faecium sur son affinité vis-à-vis des β-lactamines

Henry, Xavier 21 June 2010 (has links)
Summary : Enterococcus faecium possesses a low affinity PBP5 that, like in other enterococci, is an important factor contributing to the intrinsic resistance to penicillin. The structure of PBP5 soluble form in complex with benzylpenicillin has been solved at 2.1 Å resolution. On the basis of this 3D structure, it was proposed that the I623KEKQDEKG631 turn connecting β3 and β4 strands and constituting one wall of the active site, as well as, R464 involved in a salin-bridge near the active site could be responsible for the low β-lactam affinity of PBP5fm The k2/K of sPBP5fm acylation by various b-lactams have been determined and, as expected for a low affinity PBP, they are very low. Mutants were constructed to determinate the role of the residues pointed in the 3D structure as related to the observed low affinity. For the sPBP5fm∆I7G mutant, the acylation rate constants are similar to those measured for sPBP5fm. However, when compared to the wild type, the mutants without salin-bridge show a higher affinity that could be explained as the consequence of an easier accessibility to the active site for the inactivator. This study allows mapping active site cavity and determines the importance of structural elements to understand the low affinity of PBP5. Furthermore, three news β-lactams (ceftaroline, ceftobiprole and ME1036) were tested against PBP5fm and they all exhibit inhibitory activity against the protein. Ceftaroline appears as the best inhibitor of sPBP5fm as well as the best inhibitor while tested on Enterococcus faecium cultures. Résumé : Enterococcus faecium possède une protéine PBP5 de faible affinité, qui est un facteur important de la résistance intrinsèque à la pénicilline. La structure de la forme soluble dans PBP5 complexés avec la benzylpénicilline a été résolue à 2,1 Å. Sur la base de cette structure 3D, il a été proposé que la boucle I623KEKQDEKG631 reliant brins β3 et β4 et pouvant constituer une barrière pour atteindre le site actif, ainsi que, R464 impliqué dans un pont-salin près du site actif qui pourrait être responsable de la faible affinité β-lactamines de PBP5fm. Dans un 1er temps, les k2/K de sPBP5fm sauvage par diverses β-lactamines ont été déterminées, et comme prévu, elles sont très faibles. Dans un 2nd temps, les mutants ont été produits, purifiés et caractérisés de manière à déterminer le rôle des résidus choisis dans la faible affinité. Pour le mutant sPBP5fmΔI7G, les constantes de vitesse acylation sont similaires à ceux mesurée pour sPBP5fm sauvage. Tandis que les mutants sans le pont salin R464-D481 montrent une relative plus grande affinité par rapport au type sauvage, qui pourrait être expliqué par un accès plus facile de linhibiteur au site actif. Cette étude permet une première cartographie de la cavité du site actif de PBP5fm et qui détermine limportance ou non déléments de structure pour comprendre la faible affinité. Trois nouvelles β-lactamines (ceftaroline, ceftobiprole et ME1036) ont été testés contre PBP5fm et elles présentent une activité inhibitrice de PBP5fm. La ceftaroline apparaît comme le meilleur inhibiteur de PBP5fm ainsi que le meilleur inhibiteur lors des essais sur les cultures Enterococcus faecium.

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