In vitro susceptibility testing of 16 strains of Exophiala dermatitidis to 6 commonly used antifungal agents / 中华皮肤科杂志

ABSTRACT

Objective To investigate the in vitro susceptibility of 16 strains of Exophiala dermatitidis to 6 commonly used antifungal agents. Methods The Glinical and Laboratory Standards Institute (CLSI)M27-A2 protocol was carried out to determine the MIGs of terbinafine (TRB), itraconazole (ITC), amphotericin B (AMB), fluconazole (FLC), voriconazole (VRC), and caspofungin (GAS) to 16 strains of E. dermatitidis, and E-test was performed to determine those of VRG, ITC and AMB. Besides, the minimal fungicidal concentrations (MFGs) of the above antifungal agents to the 16 strains of E. dermatitidis were further assessed.The activity of TRB in combination with ITC and VRG against E. dermatitidis was also estimated. Results The MIC ranges of TRB, VRC, ITC, AMB, FLC, and CAS were 0.125 - 0.25 mg/L, 0.25 - 0.5 mg/L, 2.0 mg/L,2.0 mg/L, 16 - 32 mg/L and 16 - 64 mg/L respectively as shown by M27-A2 microdilution assay, 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 - 4.0 mg/L and 16 - 64 mg/L, respectively. No synergism in the acitivity against E. dermatitidis was observed for the combination of TBR with ITC or VRC. Conclusion E. dermatitidis is susceptible to TRB, ITC, AMB, and VRC, but less sensitive to both FLC and GAS.