Antifungal activity of deferiprone and EDTA against Sporothrix spp.: Effect on planktonic growth and biofilm formation.

The present study evaluated the antifungal activity of the chelators deferiprone (DFP) and ethylenediaminetetraacetic acid (EDTA) and their effect on biofilm formation of the S. schenckii complex. Eighteen strains of Sporothrix spp. (seven S. brasiliensis, three S. globosa, three S. mexicana and five Sporothrix schenckii sensu stricto) were used. Minimum inhibitory concentration (MIC) values for EDTA and DFP against filamentous forms of Sporothrix spp. ranged from 32 to 128 µg/ml. For antifungal drugs, MIC values ranged from 0.25 to 4 µg/ml for amphotericin B, from 0.25 to 4 µg/ml for itraconazole, and from 0.03 to 0.25 µg/ml for terbinafine. The chelators caused inhibition of Sporothrix spp. in yeast form at concentrations ranging from 16 to 64 µg/ml (for EDTA) and 8 to 32 µg/ml (for DFP). For antifungal drugs, MIC values observed against the yeast varied from 0.03 to 0.5 µg/ml for AMB, 0.03 to 1 µg/ml for ITC, and 0.03 to 0.13 µg/ml for TRB. Both DFP and EDTA presented synergistic interaction with antifungals against Sporothrix spp. in both filamentous and yeast form. Biofilms formed in the presence of the chelators (512 µg/ml) showed a reduction of 47% in biomass and 45% in metabolic activity. Our data reveal that DFP and EDTA reduced the growth of planktonic cells of Sporothrix spp., had synergistic interaction with antifungal drugs against this pathogen, and reduced biofilm formation of Sporothrix spp. LAY SUMMARY: Our data reveal that iron chelators deferiprone and ethylenediaminetetraacetic acid reduced the growth of planktonic cells of Sporothrix spp. as well as had synergistic interaction with antifungal drugs against this pathogen and reduced biofilm formation of Sporothrix spp.