In vitro antifungal susceptibility of coelomycete agents of black grain eumycetoma to eight antifungals

Abstract

Fungal mycetoma (eumycetoma) represents one of the most difficult infections to appropriately manage. The current recommended treatment is based on extensive surgical debridement combined with prolonged antifungal therapy with ketoconazole or itraconazole. Despite the different phylogenetic positions of black-grain eumycetoma species, they are all treated with the same antifungal agents. The in vitro antifungal susceptibility of coelomycetous eumycetoma agents in the order of Pleosporales presently is largely unknown. Here we determined the in vitro activity of eight antifungal agents against seven species causing human eumycetoma using the Sensititre YeastOne method. High minimum inhibitory concentrations (MICs) were found with fluconazole, caspofungin, flucytosine, and amphotericin B. Voriconazole and posaconazole were found to be active against all species tested. Of the species included in the investigation, MICs of Medicopsis romeroi differed from the rest of the mycetoma causative agents belonging to the order of the Pleosporales. We found significantly lower MICs for amphotericin B and significantly higher MICs for fluconazole, ketoconazole, and itraconazole against this species. Our results emphasised that identification of black grain mycetoma agent is important as well as performing susceptibility testing before starting of antifungal treatment.