Efeito in vitro do diclofenaco em combinação com fluconazol, voriconazol e anfotericina B frente a células planctônicas e biofilme de Candida tropicalis

Abstract

Antifungal resistance in Candida spp. constitutes a serious public health problem. Thus, an approach to enhance the therapeutic effectiveness of antifungals is to test them in compounds with other compounds in order to obtain synergistic interactions. Diclofenac sodium (DIC) is an anti-inflammatory with potential antifungal against Candida albicans. In this context, this study aimed to evaluate the effects of the combination of DIC with the antifungals fluconazole (FLC), voriconazole (VRC) and amphotericin B (AMB) against planktonic cells and biofilms forming the clinical strains of C.tropicalis. The Minimum Inhibitory Concentrations of the drugs against planktonic forms (CIM) and biofilm (CIMB) were determined from the microdilution testicles in broth. The synergistic potential between DIC and antifungals was assessed using the checkerboard method. The interaction between drugs was defined by calculating the Fractional Inhibitory Concentration Index (ICIF). Furthermore, the ultrastructure and viability of biofilms were analyzed by scanning electron microscopy (SEM) and confocal microscopy. The DIC presented MIC of 1024 µg / mL in all tested grants. The antifungals FLC, VRC and AMB exhibited MIC from 0.25 to 128 μg / mL; 0.0625 to 64 μg / mL and 0.125 to 1 μg / mL, respectively. The combination of DIC with FLC or VRC against azole-resistant planktonic cells reduced the MIC of the FLC by 8 to 32 times, and of the VRC by 16 to 32 times (p <0.05), therefore amusing synergism. In strains sensitive to VRC, this drug combination presents a MIC reduction of 0.5 to 2 times for azole, showing indifference. The association between DIC and AMB in planktonic cells altered as necessary synergism in 2/10 strains with reduction of MIC in 4 times and indifferent interactions in 8/10 strains. Regarding biofilms in formation, synergism was observed with a 8-fold reduction in CIMB to associate DIC with FLC or VRC, and indifference between DIC and AMB. The microscopic images of the biofilms in formation exposed to the combination of DIC and FLC demonstrated a reduction in the number of cells and changes in the morphology of yeast cells. In conclusion, sodium diclofenac reduced the MIC of azoles against planktonic cells and resistant C. tropicalis biofilm, with consolidated synergism and indifference in the combination with AMB. In addition, DIC combined with FLC reduces the viability and formation of biofilm in a resistant strain.