Successful combination therapy with voriconazole and micafungin for voriconazole-resistant Scedosporium dehoogii pulmonary infection: A case report with in vitro analysis.

Scedosporium infections are challenging to treat due to broad antifungal resistance. Voriconazole (VRCZ) is the recommended first-line therapy for scedosporiosis; however, resistance has been reported in several species. We report the case of a 57-year-old female with Philadelphia chromosome-positive acute lymphoblastic leukemia who developed a pulmonary infection caused by Scedosporium dehoogii following cord blood transplantation. Despite VRCZ monotherapy, the lung mass enlarged. Antifungal susceptibility testing revealed a VRCZ minimum inhibitory concentration of 8 mg/L, indicating that the strain is resistant to VRCZ. Combination therapy with VRCZ and micafungin (MCFG) was initiated, leading to progressive radiological improvement over 8 weeks. In vitro checkerboard testing of the isolate revealed no synergistic effects. To explore reproducibility, we also tested four stored S. dehoogii strains; one demonstrated synergy, whereas the others showed no interaction. This case suggests that VRCZ-MCFG combination therapy may be clinically effective against VRCZ-resistant S. dehoogii, even when in vitro synergy is not observed.