In vitro susceptibility of Geotrichum silvicola to five antifungal agents and electron microscopic observation of terbinafine-treated Geotrichum silvicola / 中华皮肤科杂志

ABSTRACT

Objective To evaluate in vitro antifungal activities of five clinically common antifungal agents against Geotrichum silvicola,and to observe morphological changes of Geotrichum silvicola after treatment with terbinafine.Methods Five antifungal agents commonly used in clinic,including terbinafine (TER),amphotericin B (AmB),flucytosine (FC),fluconazol (FCZ) and itraconazole (ICZ),were tested in this study.According to the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 document and relevant literatures,a susceptibility test was performed to determine the minimal inhibitory concentration (MIC) values of the five antifungal agents against G eotrichum silvicola.Scanning electron microscopy (SEM) was used to observe morphological changes of Geotrichum silvicola treated with different concentrations of TER.Results The MIC values against Geotrichum silvicola were as followsTER,0.01 μg/ml;AmB,0.4 μg/ml;FC,2 μg/ml;FCZ,2.69 μg/ml;ICZ,0.25 μg/ml.Geotrichum silvicola was sensitive to TER,AmB,FC and FCZ,and sensitive to ICZ in a dose-dependent manner.SEM revealed that after TER treatment,the surface of Geotrichum silvicola became rough and shrinking with irregular defects and holes,and even gave a fragment-like appearance.Conclusions Among the five tested antifungal agents,TER shows the strongest activity against Geotrichum silvicola.Within a certain range,the higher the concentration of TER,the more serious the damage to Geotrichum silvicola.