Atividade antifúngica da prometazina e clorpromazina contra células planctônicas e biofilmes de espécies do complexo Cryptococcus neoformans / Cryptococcus gattii

Abstract

Cryptococcus neoformans / Cryptococcus gattii are opportunistic fungal pathogens that affect the central nervous system, mainly of immunocompromised individuals. Resistance in Cryptococcus spp. has been reported in some studies, pointing out the need to search for new products with antimicrobial potential. Thus, the work aimed to evaluate the inhibitory effect of phenothiazines (promethazine and chlorpromazine) on planktonic cells and biofilms of C. neoformans / C. gattii (n = 20). Planktonic sensitivity in vitro was performed according to CLSI document M27-A3. The readings for promethazine and chlorpromazine were evaluated for 100% inhibition. Biofilms were analyzed during the formation stage and the maturation stage. Metabolic activity and biomass, as well as biofilm morphology and ultrastructure, were also evaluated by scanning electron microscopy. Promethazine and chlorpromazine showed antifungal activity against planktonic cells with MICs of 8-32 μg/mL and 4-16 μg/mL, respectively. Cell adhesion was reduced by up to 70% for promethazine and 75% for chlorpromazine at concentrations of 64 μg/mL. In the stages of biofilm formation, phenothiazines reduced biomass by 60% and biofilm metabolic activity by 64 μg/mL, while in biofilms formed this reduction increased to 80% and 90% of biomass and metabolic activity, at a concentration of 1024 μg/mL. In addition to biofilms pre-exposed to phenothiazines, the ability to form biofilm has been impaired. Phenothiazines reduced the metabolic activity of Cryptococcus spp. Melanized biofilm by 80%, with concentrations of 512 and 1024 μg/mL. It was also observed that promethazine and chlorpromazine were able to break down and fragment biofilms. In conclusion, promethazine and chlorpromazine have antifungal properties against planktonic cells and in the different stages of development of the Cryptococcus spp. These data show the potential of phenothiazines promethazine and chlorpromazine as antibiofilm drugs.