In vitro susceptibility testing of 16 strains of Exophiala dermatitidis to 6 commonly used antifungal agents.

Abstract

：Objective To investigatethe in vitro susceptibility of 16 strains of Exophiala dermatitidis to 6 commonly usedantifungal agents. Methods The Glinical and Laboratory Standards Institute (CLSI)M27-A2protocol was carried out to determine the MIGs of terbinafine (TRB), itraconazole (ITC),amphotericin B (AMB), fluconazole (FLC), voriconazole (VRC), and caspofungin (GAS) to 16strains of E. dermatitidis, and E-test was performed to determine those of VRG, ITC andAMB. Besides, the minimal fungicidal concentrations (MFGs) of the above antifungal agentsto the 16 strains of E. dermatitidis were further assessed.The activity of TRB incombination with ITC and VRG against E. dermatitidis was also estimated. Results The MICranges of TRB, VRC, ITC, AMB, FLC, and CAS were 0.125 - 0.25 mg/L, 0.25 - 0.5 mg/L, 2.0mg/L,2.0 mg/L, 16 - 32 mg/L and 16 - 64 mg/L respectively as shown by M27-A2 microdilutionassay, while the MIC ranges of VRG, ITG and AMB, as determined by E-test, were 0.032 -0.094 mg/L, 0.047 - 0.5 mg/L and 0.125 - 3.0 mg/L, respectively. The MFC ranges of TRB,VRC, ITG, AMB and FLG were 0.125 - 0.5 mg/L,0.25 - 0.5 mg/L, 2.0 - 4.0 mg/L, 2.0 - 4.0mg/L and 16 - 64 mg/L, respectively. No synergism in the acitivity against E. dermatitidiswas observed for the combination of TBR with ITC or VRC. Conclusion E. dermatitidis issusceptible to TRB, ITC, AMB, and VRC, but less sensitive to both FLC and GAS.