966 resultados para methicillin-resistant staphylococcus aureus
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OBJETIVO: Relatar caso ilustrativo de doença granulomatosa crônica cujo diagnóstico ocorreu durante o aparecimento do primeiro episódio infeccioso, colaborando com a iniciativa do Brazilian Group for Immunodeficiency para a sensibilização do pediatra geral em relação ao diagnóstico precoce das imunodeficiências primárias, o que está associado a melhor qualidade de vida e maior sobrevida desses indivíduos. DESCRIÇÃO DE CASO: Paciente do sexo masculino, 39 dias de vida, admitido em pronto-socorro pediátrico por febre alta há cinco dias e irritabilidade. No dia seguinte, observou-se abscesso cervical, isolando-se Staphylococcus aureus comunitário. Durante a internação, ocorreram outros abscessos superficiais e em cadeias ganglionares profundas, além de resposta lenta aos antimicrobianos. Solicitou-se investigação para imunodeficiências, que confirmou a hipótese de doença granulomatosa crônica por quantificação dos ânions superóxido e teste de redução do nitrobluetetrazolio. Paciente foi encaminhado a serviço especializado, no qual identificou-se doador de medula óssea compatível, realizando-se o transplante seis meses após o diagnóstico. Quatro meses após o transplante, ocorreu normalização do burst oxidativo, indicando sucesso. COMENTÁRIOS: O paciente mostrou apresentação típica da doença, o que permitiu seu diagnóstico por pediatras gerais já na primeira infecção, tendo como consequência o acompanhamento por especialistas em imunodeficiências primárias, a introdução da profilaxia antimicrobiana e a procura bem sucedida de doador de medula HLA-compatível.
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Cyhalothrin, a pyrethroid insecticide, induces stress-like symptoms, increases c-fos immunoreactivity in the paraventricular nucleus of the hypothalamus, and decreases innate immune responses in laboratory animals. Macrophages are key elements in cellular immune responses and operate at the tumor-host interface. This study investigated the relationship among cyhalothrin effects on Ehrlich tumor growth, serum corticosterone levels and peritoneal macrophage activity in mice. Three experiments were done with 10 experimental (single gavage administration of 3.0 mg/kg cyhalothrin daily for 7 days) and 10 control (single gavage administration of 1.0 mL/kg vehicle of cyhalothrin preparation daily for 7 days) isogenic BALB/c mice in each experiment. Cyhalothrin i) increased Ehrlich ascitic tumor growth after ip administration of 5.0 x 106 tumor cells, i.e., ascitic fluid volume (control = 1.97 ± 0.39 mL and experimental = 2.71 ± 0.92 mL; P < 0.05), concentration of tumor cells/mL in the ascitic fluid (control = 111.95 ± 16.73 x 106 and experimental = 144.60 ± 33.18 x 106; P < 0.05), and total number of tumor cells in the ascitic fluid (control = 226.91 ± 43.22 x 106 and experimental = 349.40 ± 106.38 x 106; P < 0.05); ii) increased serum corticosterone levels (control = 200.0 ± 48.3 ng/mL and experimental = 420.0 ± 75.5 ng/mL; P < 0.05), and iii) decreased the intensity of macrophage phagocytosis (control = 132.3 ± 19.7 and experimental = 116.2 ± 4.6; P < 0.05) and oxidative burst (control = 173.7 ± 40.8 and experimental= 99.58 ± 41.7; P < 0.05) in vitro in the presence of Staphylococcus aureus. These data provide evidence that cyhalothrin simultaneously alters host resistance to Ehrlich tumor growth, hypothalamic-pituitary-adrenocortical (HPA) axis function, and peritoneal macrophage activity. The results are discussed in terms of data suggesting a link between stress, HPA axis activation and resistance to tumor growth.
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We examined the antibacterial activities of several types of propolis, including Africanized honey bee green propolis and propolis produced by meliponini bees. The antibacterial activity of green propolis against Micrococcus luteus and Staphylococcus aureus was superior to that of Melipona quadrifasciata and Scaptotrigona sp propolis. Only two samples of propolis (green propolis and Scaptotrigona sp propolis) were efficient against Escherichia coli. Melipona quadrifasciata propolis was better than green propolis and Scaptotrigona sp propolis against Pseudomonas aeruginosa. We concluded that these resins have potential for human and veterinary medicine.
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This study describes the use of methylene blue (MB) plus light (photodynamic inactivation, PDI) in the presence of hydrogen peroxide (H(2)O(2)) to kill Staphylococcus aureus, Escherichia coli, and Candida albicans. When H(2)O(2) was added to MB plus light there was an increased antimicrobial effect, which could be due to a change in the type of ROS generated or increased microbial uptake of MB. To clarify the mechanism, the production of ROS was investigated in the presence and absence of H(2)O(2). It was observed that ROS production was almost inhibited by the presence of H(2)O(2) when cells were not present. In addition, experiments using different sequence combinations of MB and H(2)O(2) were performed and MB optical properties inside the cell were analyzed. Spectroscopy experiments suggested that the amount of MB was higher inside the cells when H(2)O(2) was used before or simultaneously with PDI, and ROS formation inside C. albicans cells confirmed that ROS production is higher in the presence of H(2)O(2). Moreover enzymatic reduction of MB by E. coli during photosensitizer uptake to the photochemically inactive leucoMB could be reversed by the oxidative effects of hydrogen peroxide, increasing ROS formation inside the microorganism. Therefore, the combination of a photosensitizer such as MB and H(2)O(2) is an interesting approach to improve PDI efficiency.
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A prenylated benzophenone, hyperibone A, was isolated from the hexane fraction of Brazilian propolis type 6. Its structure was determined by spectral analysis including 2D NMR. This compound exhibited cytotoxic activity against HeLa tumor cells (IC(50) = 0.1756 mu M), strong antimicrobial activity (MIC range-0.73-6.6 mu g/mL; MBC range-2.92-106 mu g/mL) against Streptococcus mutans, Streptococcus sobrinus, Streptococcus oralis, Staphylococcus aureus, and Actinomyces naeslundii, and the results of its cytotoxic and antimicrobial activities were considered good. (C) 2009 Elsevier Ltd. All rights reserved.
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The propolis has potential to be a natural food additive However its application is limited because It is alcohol-soluble and has strong flavour Microencapsulation may be an alternative for reducing these problems The aim of this study was to encapsulate propolis extract by complex coacervation using isolated soy protein and pectin as encapsulant agents The coacervation was studied as a function of pH (5 0 4 5 4 0 and 3 5) and the concentration of encapsulants and core (2 5 and 5 0 g/100 mL) Samples obtained at pH 4 0 in both concentrations were lyophilized and analyzed for hygroscopicity encapsulation efficiency particle size morphology thermal behavior stability of phenolic and flavonoids during storage as well as antioxidant and antimicrobial activities It was possible to encapsulate propolis extract by complex coacervation and to obtain it in the form of powder alcohol-free stable with antioxidant property antimicrobial activity against Staphylococcus aureus and with the possibility of controlled release in foods (C) 2010 Elsevier Ltd All rights reserved
Isolation and analysis of bioactive isoflavonoids and chalcone from a new type of Brazilian propolis
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Activity-directed fractionation and purification processes were employed to identify isoflavonoids with antioxidant and antimicrobial activities from Brazilian red propolis. Crude propolis was extracted with ethanol (80%. v/v) and fractioned by liquid-liquid extraction technique using hexane and chloroform. Since chloroform fraction showed strong antioxidant and antimicrobial activities it was purified and isolated using various chromatographic techniques. Comparing our spectral data (UV, NMR, and mass spectrometry) with values found in the literature, we identified two bioactive isoflavonoids (vestitol and neovestitol), together with one chalcone (isoliquiritigenin). Vestitol presented higher antioxidant activity against beta-carotene consumption than neovestitol. The antimicrobial activity of these three compounds against Staphylococcus aureus, Streptococcus mutans, and Actinomyces naeslundii was evaluated and we concluded that isoliquiritigenin was the most active one with lower MIC, ranging from 15.6 to 62.5 mu g/mL. Our results showed that Brazilian red propolis has biologically active isoflavonoids that may be used as a mild antioxidant and antimicrobial for food preservation. (C) 2010 Elsevier B.V. All rights reserved.
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A simplex-lattice statistical project was employed to study an optimization method for a preservative system in an ophthalmic suspension of dexametasone and polymyxin B. The assay matrix generated 17 formulas which were differentiated by the preservatives and EDTA (disodium ethylene diamine-tetraacetate), being the independent variable: X-1 = chlorhexidine digluconate (0.010 % w/v); X-2 = phenylethanol (0.500 % w/v); X-3 = EDTA (0.100 % w/v). The dependent variable was the Dvalue obtained from the microbial challenge of the formulas and calculated when the microbial killing process was modeled by an exponential function. The analysis of the dependent variable, performed using the software Design Expert/W, originated cubic equations with terms derived from stepwise adjustment method for the challenging microorganisms: Pseudomonas aeruginosa, Burkholderia cepacia, Staphylococcus aureus, Candida albicans and Aspergillus niger. Besides the mathematical expressions, the response surfaces and the contour graphics were obtained for each assay. The contour graphs obtained were overlaid in order to permit the identification of a region containing the most adequate formulas (graphic strategy), having as representatives: X-1 = 0.10 ( 0.001 % w/v); X-2 = 0.80 (0.400 % w/v); X-3 = 0.10 (0.010 % w/v). Additionally, in order to minimize responses (Dvalue), a numerical strategy corresponding to the use of the desirability function was used, which resulted in the following independent variables combinations: X-1 = 0.25 (0.0025 % w/v); X-2 = 0.75 (0.375 % w/v); X-3 = 0. These formulas, derived from the two strategies (graphic and numerical), were submitted to microbial challenge, and the experimental Dvalue obtained was compared to the theoretical Dvalue calculated from the cubic equation. Both Dvalues were similar to all the assays except that related to Staphylococcus aureus. This microorganism, as well as Pseudomonas aeruginosa, presented intense susceptibility to the formulas independently from the preservative and EDTA concentrations. Both formulas derived from graphic and numerical strategies attained the recommended criteria adopted by the official method. It was concluded that the model proposed allowed the optimization of the formulas in their preservation aspect.
Brazilian Propolis: Seasonal Variation of the Prenylated p-Coumaric Acids and Antimicrobial Activity
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Brazilian green propolis, which is used in food and beverages to improve health and to prevent diseases, demostrates antioxidant, antimutagenic, and antimicrobial activities. Most biological activities are thought to be related to the high levels of drupanin, artepillin C, and baccharin, which are compounds also present in Baccharis dracunculifolia D.C. (Asteraceae). Since propolis chemical composition depends on the region and the period of collection, as well as its plant origin, the effect of seasonal variation on the both content of prenylated p-coumaric acids and in vitro antimicrobial activity of Brazilian propolis from four different sites, was performed. The results showed that MIC values ranged from 100 to 300 mu g/mL against both Staphylococcus aureus and Kocuria rhizophila, while none of the propolis samples was active against Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. HPLC analysis showed that the content of drupanin, artepillin C, and baccharin varied throughout the year, as well as among the different study sites. Also, it is suggested that Baccharis dracunculifolia is the main botanical source of Brazilian propolis in sites I and 2, while in sites 3 and 4, other plant species are also used by bees to produce propolis. All the evaluated propolis samples exhibited similar antibacterial activity, but different contents of prenylated p-coumaric acids throughout the year.
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Essential Oil of Thymus vulgaris: Preparation of Pharmaceutical Mouthwash Formulation and In Vitro Evaluation of the Bacterial Plaque-Inhibiting Properties. The aim of this study was to evaluate the in vitro effect of the essential oil of Thymus vulgaris (thyme) pure or incorporate in a alcohol-free pharmaceutical mouthwash formulation, against Streptococcus mutans (ATCC 25175), being determined the Minimal Inhibitory Concentration (MIC) and the effect in the bacterial plate formation. The MIC value obtained for the essential oil was 100 mu g/mL (1 %). The mouthwash pharmaceutical formulation containing commercial essential oil of T. vulgaris was preparated. Microbiological and macroscopic analysis as well as analyses for MEV confirmed the effectiveness of this new alcohol-free mouthwash formulation containing essential oil of T. vulgaris as agent with plaque-inhibiting properties and possible application in the preventive dentistry. The chemical characterization of the bioactive essential oil was accomplished by CG-MS, being verified the presence of carvacrol, p-cimene and alpha-pinene as major constituents.
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The dichloromethane crude extract from the roots of Viguiera arenaria (VaDRE) has been employed in an antimicrobial screening against several bacteria responsible for human pathologies. The main diterpenes isolated from this extract, as well as two semi-synthetic pimarane derivatives, were also investigated for the pathogens that were significantly inhibited by the extract (MIC values lower than 100 mu g mL(-1)). The VaDRE extract was significantly active only against Gram-positive microorganisms. The compounds ent-pimara-8(14),15-dien-19-oic acid (PA): PA sodium salt; ent-8(14),15-pimaradien-3 beta-ol; ent-15-pimarene-8 beta,19-diol; and ent-8(14),15-pimaradien-3 beta-acetoxy displayed the highest antibacterial activities (MIC values lower than 10 mu g mL(-1) for most pathogens). In conclusion, our results suggest that pimaranes are an important class of natural products for further investigations in the search of new antibacterial agents. (c) 2009 Elsevier B.V. All rights reserved.
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Antimicrobial activity of crude extratcs of Petiveria alliacea L.. Petiveria alliacea L. (Phytolaccacea) is an herbaceous plant of great importance in traditional medicine. This species have been widely used in several applications such as antirheumatic, anticarcinogenic, anti-flu, antitussive, analgesic, insecticidal, acaricidal, as well as bactericide and fungicide. Currently, the pathogenic microorganisms are acquiring resistence against the traditional antibiotics, and the search for new herbal antimicrobial agents has been intensified. The objective of this study was to evaluate the antifungal and antibacterial activity of several leaf crude extracts of P. alliacea against several strains of bacterias and yeasts namely Bacilus subtilis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus mutans, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Candida parapsilosis, Candida kefyr and Candida albicans, using microdilution method. Promising results were observed for the 70% v/v ethanolic extract which presented minimum inhibitory concentration (MIC) from 250 to 760 mu g/mL for yeast. For the bacteria strains tested the MIC ranged between 240 to 3960 mu g/mL, depending of the extractive solution tested.
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The objective of the present study was to characterize the innate immune responses induced by in vitro stimulation of bovine primary mammary epithelial cells (bMEC) using gram-negative lipopolysaccharide (LPS) and gram-positive lipoteichoic acid (LTA) bacterial cell wall components. Quantitative real-time PCR (qRT-PCR) was employed to examine the mRNA expression of a panel of 22 cytokines, chemokines, beta-defensins and components of the Toll-Like Receptor signaling pathway. Stimulation of bMEC with LPS for 24 h elicited a marked increase in mRNA expression for IL-1 beta, IL-8, TNF alpha, CXCL6 and beta-defensin while members of the Toll-Like Receptor pathway.. although present, were largely unaffected. Surprisingly, stimulation of these cells with LTA for 24 h did not significantly alter the expression of these genes. A time course of the expression of IL-1 beta, IL-8, TNF alpha, CXCL6 and beta-defensin was subsequently performed. The mRNA levels of all genes increased rapidly after stimulation for 2-4 h with both LPS and LTA but only the former treatment resulted in sustained responses. In contrast, the increased gene expression for LTA stimulated cells returned to resting levels after 8-16 h with the exception of beta-defensin, which remained up-regulated. The limited and unsustained cytokine response to LTA may explain why mastitis caused by gram-positive bacteria has greater potential for chronic intra-mammary infection than gram-negative infection. It was concluded that bovine mammary epithelial cells have a strong but differential capacity to mount innate immune responses to bacterial cell wall components. Crown Copyright (c) 2005 Published by Elsevier Ltd. All rights reserved.
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Innate immunity plays a vital role in the protection of the bovine mammary gland against mastitis. Until recently, the migration of effector cells such as neutrophils and monocytes into the mammary gland was thought to provide the only defence against invading pathogens. However, mammary epithelial cells may also play an important role in the immune response, contributing to the innate defence of the mammary tissue through secretion of antimicrobial peptides and attraction of circulating immune effector cells. This paper reviews the innate immune pathways in mammary epithelial cells and examines their role in the initiation of an innate immune response to Gram-positive and Gram-negative bacteria.
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It has been suggested that phosphate binders may reduce the inflammatory state of hemodialysis (HD) patients. However, it is not clear whether it has any effect on oxidative stress. The objective of this study was to evaluate the effect of sevelamer hydrochloride (SH) and calcium acetate (CA) on oxidative stress and inflammation markers in HD patients. Hemodialysis patients were randomly assigned to therapy with SH (n=17) or CA (n=14) for 1 year. Before the initiation of therapy (baseline) and at 12 months, we measured in vitro reactive oxygen species (ROS) production by stimulated and unstimulated polymorphonuclear neutrophils and serum levels of tumor necrosis factor alpha, interleukin-10, C-reactive protein, and albumin. There was a significant reduction of spontaneous ROS production in both groups after 12 months of therapy. There was a significant decrease of Staphylococcus aureus stimulated ROS production in the SH group. There was a significant increase in albumin serum levels only in the SH group. In the SH group, there was also a decrease in the serum levels of tumor necrosis factor alpha and C-reactive protein. Our results suggest that compared with CA treatment, SH may lead to a reduction in oxidative stress and inflammation. Therefore, it is possible that phosphate binders exert pleiotropic effects on oxidative stress and inflammation, which could contribute toward decreasing endothelial injury in patients in HD.