982 resultados para BIOFILM


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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To evaluate the porosity, surface roughness and anti-biofilm activity of a glass-ionomer cement (GIC) after incorporation of different concentrations of chlorhexidine (CHX) gluconate or diacetate. Methods: For the porosity and surface roughness tests, 10 test specimens were fabricated of the GIC Ketac Molar Easy Mix (KM) and divided into the following groups: Control, GIC and 0.5% CHX diacetate; GIC and 1.0% CHX diacetate; GIC and 2.0% CHX diacetate; GIC and 0.5% CHX gluconate; GIC and 1.0% CHX gluconate; GIC and 2.0% CHX gluconate. To evaluate porosity, the test specimens were fractured. The fragments were photographed by scanning electron microscopy (SEM), and the images analyzed with the aid of the software program Image J. The surface roughness (Ra) was obtained by the mean value of three readouts performed on the surface of each specimen, always through the center. To analyze the anti-biofilm activity, strains of S. mutans ATCC 35688 were used, and the groups control and GIC +CHX diacetate 1% were divided as follows: GIC (1 day); GIC (7 days), GIC (14 days), GIC (21 days); GIC+CHX (1 day), GIC+CHX (7 days), GIC+CHX (14 days), GIC+CHX (21 days); GIC+ CHX (1 day), GIC+ CHX (7 days), GIC+ CHX (14 days) and GIC+ CHX (21 days) using 10 test specimens per group. For biofilm growth, the specimens were placed in a vertical position in 24-well plates and incubated overnight 10 times. The culture medium was renewed every 24 hours. The suspension was diluted and seeded on BHI agar for quantification of the bacteria present. For evaluation of all the tests the two-way ANOVA was used, and if necessary, the Tukey test was applied, with a level of significance of 5%. Results: Regarding GIC porosity, the ANOVA showed that the presence of CHX increased the porosity (P< 0.001) proportionally to the increase in concentrations (P= 0.001), without however, presenting interaction between material and concentration (P= 0.705). Regarding the number of pores, a significant increase in pores was observed with the increase in CHX concentration (P= 0.003). The surface roughness test demonstrated no statistically significant effect as to increase or reduction in roughness at any of the CHX concentrations used (P> 0.05). Anti-biofilm activity analysis pointed out a significant effect of the factors material (P= 0.006) and time (P< 0.001), with CHX diacetate CHX presenting greater effectiveness in reducing microorganisms.

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Coordenação de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Bacterial quorum sensing (QS) is a density dependent communication system that regulates the expression of certain genes including production of virulence factors in many pathogens. Bioactive plant extract/compounds inhibiting QS regulated gene expression may be a potential candidate as antipathogenic drug. In this study anti-QS activity of peppermint (Menthe piperita) oil was first tested using the Chromobacterium violaceum CVO26 biosensor. Further, the findings of the present investigation revealed that peppermint oil (PMO) at sub-Minimum Inhibitory Concentrations (sub-MICs) strongly interfered with acyl homoserine lactone (AHL) regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Aeromonas hydrophila. The result of molecular docking analysis attributed the QS inhibitory activity exhibited by PMO to menthol. Assessment of ability of menthol to interfere with QS systems of various Gram-negative pathogens comprising diverse AHL molecules revealed that it reduced the AHL dependent production of violacein, virulence factors, and biofilm formation indicating broad-spectrum anti-QS activity. Using two Escherichia colt biosensors, MG4/pKDT17 and pEAL08-2, we also confirmed that menthol inhibited both the las and pqs QS systems. Further, findings of the in vivo studies with menthol on nematode model Caenorhabditis elegans showed significantly enhanced survival of the nematode. Our data identified menthol as a novel broad spectrum QS inhibitor.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Bovine mastitis is an inflammation of the mammary glands of cows and causes significant economic losses in dairy cattle. Staphylococcus aureus is one of the microorganisms most commonly isolated. Novel agents are required in agricultural industries to prevent the development of mastitis. The production of biofilm by Staph. aureus facilitates the adhesion of bacteria to solid surfaces and contributes to the transmission and maintenance of these bacteria. The effect of the essential oils of Syzygium aromaticum (clove; EOSA) and Cinnamomum zeylanicum (cinnamon; EOCZ) and their major components, eugenol and cinnamaldehyde, on Staph. aureus biofilm formation on different surfaces was investigated. The results showed a significant inhibition of biofilm production by EOSA on polystyrene and stainless steel surfaces (69.4 and 63.6%, respectively). However, its major component, eugenol, was less effective on polystyrene and stainless steel (52.8 and 19.6%, respectively). Both EOCZ and its major component, cinnamaldehyde, significantly reduced biofilm formation on polystyrene (74.7 and 69.6%, respectively) and on stainless steel surfaces (45.3 and 44.9%, respectively). These findings suggest that EOSA, EOCZ, and cinnamaldehyde may be considered for applications such as sanitization in the food industry.