Introduction: Scopulariopsis is a common soil saprophyte. In the last years the infections caused by Scopulariopsis species have increased, included superficial and invasive mycoses. This fungi has been reported resistant in vitro to some antifungal agents, although there is little information about this. The aim of the study was to establish in vitro antifungal susceptibility of clinical isolates of Scopulariopsis species against to broad-spectrum antifungal agents.
Methods: A total of 28 Scopulariopsis strains (10 S. brevicaulis, 7 S. koningii, 3 S. acremonium, 3 S. candida, 3 S. flava, 1 S. brumptii and 1 S. fusca) were tested using Sensititre Yeast One and broth microdilution methods to determine the minimum inhibitory concentrations (MICs) to amphotericin B, fluconazole, itraconazole, posaconazole, voriconazole and 5-fluorocytosine, and minimun effective concentration (MECs) to anidulafungin, caspofungin and micafungin.
Results: Our data confirm the high in vitro resistance of Scopulariopsis to antifungal agents. Anidulafungin, caspofungin, micafungin (MICs ≥ 8 mg/L), 5-fluorocytosine (MICs ≥ 64 mg/L), and fluconazole (MICs ≥ 128 mg/L) were inactive in vitro in all species. MICs of amphotericin B (range 2 to ≥ 8 mg/L) and itraconazole (0.5 to ≥ 16 mg/L) were high. The best antifungal activity was observed for posaconazole and voriconazole (0.5 to ≥ 8 mg/L). With Sensititre Yeast One method MICs obtained slightly lower. Scopulariopsis candida, S. flava and S. fusca were the most resistant species, while S. acremonium and S. brevicaulis showed the lowest MICs.
Conclusions: MICs of all tested antifungal agents for Scopulariopsis were very high. Infections caused by Scopulariopsis species may not respond to antifungal treatment. Voriconazole is the drug of choice for treatment. We consider it appropriate to add amphotericin B in serious infections.