100 resultados para amphotericin B deoxycholate
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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The genus Astronium (Anacardiaceae) includes species, such as Astronium fraxinifolium, Astronium graveolens, and Astronium urundeuva, which possess anti-inflammatory, anti-ulcerogenic, healing, and antimicrobial properties. Nanostructured lipid systems are able to potentiate the action of plant extracts, reducing the required dose and side effects and improving antimicrobial activity. This work aims to evaluate a nanostructured lipid system that was developed as a strategy to improve the anti-Candida albicans activity of hydroethanolic extracts of stems and leaves from Astronium sp. The antifungal activity against C. albicans (ATCC 18804) was evaluated in vitro by a microdilution technique. In addition to the in vitro assays, the Astronium sp. that showed the best antifungal activity and selectivity index was submitted to an in vivo assay using a model of vulvovaginal candidiasis infection. In these assays, the extracts were either used alone or were incorporated into the nanostructured lipid system (comprising 10% oil phase, 10% surfactant, and 80% aqueous phase). The results indicated a minimal inhibitory concentration of 125.00 µg/mL before incorporation into the nanostructured system; this activity was even more enhanced when this extract presented a minimal inhibitory concentration of 15.62 µg/mL after its incorporation. In vivo assay dates showed that the nanostructure-incorporated extract of A. urundeuva leaves was more effective than both the unincorporated extract and the antifungal positive control (amphotericin B). These results suggest that this nanostructured lipid system can be used in a strategy to improve the in vitro and in vivo anti-C. albicans activity of hydroethanolic extracts of Astronium sp.
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Background: Human fungal infections have increased at an alarming rate in recent years, particularly in immunocompromised individuals. Cryptococcosis is the second most prevalent systemic fungal infection worldwide, and the most prevalent systemic infection in immunocompromised individuals, representing more than 70% of cases. The incidence of cryptococcosis is high in people with HIV/acquired immunodefi- ciency syndrome (AIDS), with recent estimates indicating that there are one million cases of cryptococcal meningitis globally per year in AIDS patients. Aims: The aim of this research was to develop a rapid flow cytometric antifungal susceptibility test and to compare the results with the standard methods. Methods: A reference strain and clinical isolates of Cryptococcus neoformans and Cryptococcus gattii were tested for susceptibility to amphotericin B by flow cytometry using propidium iodide as indicator of viability. Flow cytometry (FC) results were compared with the minimum inhibitory concentration (MIC) values determined by microdilution. Results: The antifungal activity of amphotericin B ranged from MICs of 0.06 to 2 g/ml for the 11 isolates studied. The same results were found by FC. Conclusions: The FC method allows same-day results, assisting in the selection of appropriate antifungal therapies. These results demonstrate an excellent correlation between FC and the classic methods of testing for susceptibility to antifungal agents. This rapid diagnosis method makes it possible to quickly administer effective therapeutic interventions, often saving lives.
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Candida yeasts are common in the oral cavity and can cause candidosis in the presence of predisposing factors, especially diabetes. The manifestation of the disease is related to this set of local factors such as the presence of dental prostheses, salivary pH, salivary flow and tobacco and the ability to form biofilms. Biofilms are specific and organized communities of cells under the control of signaling molecules rather than random accumulations of cells resulting from cell division and frequently are drugs resistance. Aim: The objectives of this study were to determine the genetic patterns of these C. albicans isolates and to evaluate the in vitro activity amphotericin B and caspofungin against C. albicans biofilms. Methods: Microbial samples were collected from subgingival sites and seeded in CHROMagar for subsequent identification of C. albicans by PCR. Genotypes were defined based on the identification of the transposable introns in the 25S rDNA by PCR. Results: In this study, 6 strains were identified as C. albicans and of these, 3 strains were genotype A and 3 were genotype B. The results showed that both amphotericin B and caspofungin exhibited strong antifungal activities against C. albicans biofilm formation and inhibiting the biofilm formation ranging from 70.8 – 95.3% and 77.7 - 88.7%, respectively. The antifungals studied had low inhibitory effect on preformed biofims, ranging from 39.5 - 50.8% for amphotericin B and from 23.1 - 36.9% for caspofungin at the same concentration. The activity of the two drugs was most effective in inhibit biofilm formation.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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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)