Estudo da ação antifúngica da Quitosana sobre leveduras do gênero Candida.

Abstract

Chitosan is a polymer derived from chitin, of low cost, renewable and biodegradable, being of great importance economic and environmental. Although in recent years, this compound has been described as a potent antimicrobial, its action antifungal remains little explored. This work aimed evaluate the antifungal action of low, medium and high chitosans molecular weight on different Candida species. To the main strains of the genus Candida (ATCC) were investigated: Candida sp ATCC 34147, C. albicans serotype A ATCC 36801 and C. albicans serotype B ATCC 36802, C. glabrata ATCC 2001, C. Krusei ATCC 34135 and Candida tropicalis ATCC 28707. They were obtained by request to Fundação Oswaldo Cruz, through the Minimum inhibitory concentration (MIC) in solid medium and in medium liquid. The compound was tested at different weights against the pure concentrations, 20mg/mL, and in the dilutions referring to the concentrations of 10 mg/mL, 5 mg/mL, 1.75 mg/mL and 0.875 mg/mL. It was observed that all strains tested were sensitive to at least least one type of chitosan, thus demonstrating the character fungistatic of the studied compound. In view of the results, it was selected chitosan with greater antifungal action, as well as the most sensitive strain, for detailed evaluation in different growth times of the species, the result of which MIC up to 24 hours was 0.875 mg/mL, the lowest value tested in the study, and the Minimum Fungicide Concentration (MFC) was 1.75 mg/mL, while in the 144-hour growth the MIC was 5mg/mL and CFM of 20mg/mL. Such results demonstrated a high power of fungicidal action of chitosan against a fungus pathogen, being even more effective when compared to to fluconazole.