Susceptibilidade frente a drogas antifúngicas de amostras de Croptococcus neoformans de origem ambiental e clínica isoladas no estado de Minas Gerais.

Abstract

For the accomplishment of this work, forty eight isolated of Cryptococcus neoformans were obtained starting from clinical and environmental samples collected in Minas Gerais. The clinical isolateds were obtained starting from patients of the Hospital das Clínicas of Federal University of Minas Gerais samples and of the Hospital Universitário of the Federal University of Juiz de Fora by the cultivation in Sabouraud agar. The environmental samples, starting, were obtained from several samples of you excrete of birds, hollow of trees and wood in decomposition. For the isolation, through the environmental samples, cultivation was accomplished in Staib media and in Sabouraud agar, for the clinical samples. The identification of the microorganisms was confirmed by the microscopic analysis of presence of the polysaccharide capsule, urea use in Christensen media, nitrate assimilation and thermotolerance test to 35° C. The variety determination was accomplished using the Canavanina-Glicina-Bromotimol blue (CGB) media. Susceptibility tests of in vitro using antifungical drugs amphotericin B, 5-flucitosine, fluconazole, itraconazole, voriconazole and terbinafine according to the methodology of the microdilution in liquid media of the Clinical and Laboratory Standards Institute (CLSI, 2005), document M27-A2 and the method of the E-test (ABBiodisk, Solna, Sweden). The susceptibility with to antifungal drugs voriconazole and terbinafine was not tested using this last methodology. The great majority of the isolated samples showed sensitive or sensitive dose dependent and just a small number was resistant or with intermediary resistance with all the antifungal drugs studied. The readings were accomplished after 48 and 72 hours of incubation and was not found significant differences among these intervals, considering the two methodologies. This study allowed to evidence that there were not significant differences among the two used methodologies, being able to, both, be used in laboratorial practice with the objective to determine the minimum inhibitory concentration of Cryptococcus neoformans. However, should be considered the relationship cost-benefit, since in the method of agar diffusion, the band impregnated with gradient concentrations of antifungal drugs possess onerous cost and in the method of the microdilution in liquid media, according to CLSI, there are limits of each individual visual interpretation.