念珠地丝菌对五种抗真菌药的体外敏感性及电镜观察

目的 探讨5种临床常见抗真菌药对念珠地丝菌的体外抑制作用，并观察用药后念珠地丝菌的形态学变化。方法 5种临床常见抗真菌药为特比萘芬、两性霉素B、氟胞嘧啶、氟康唑和伊曲康唑。参照美国国家临床试验标准委员会修订的M27?A2方案及相关文献，测定各药物对念珠地丝菌的MIC值。应用扫描电镜观察特比萘芬作用后念珠地丝菌的形态学变化。结果 5种药物对念珠地丝菌的MIC值依次为：特比萘芬0.01 μg/ml、两性霉素B 0.4 μg/ml、氟胞嘧啶2 μg/ml、氟康唑2.69 μg/ml、伊曲康唑 0.25 μg/ml。念珠地丝菌对特比萘芬、两性霉素B、氟胞嘧啶、氟康唑均敏感，对伊曲康唑为剂量依赖性敏感。扫描电镜可见，经特比萘芬作用后念珠地丝菌菌体表面出现粗糙、皱缩、不规则缺损及孔洞，甚至呈碎片状。结论 特比萘芬对念珠地丝菌的抗菌活性最显著，在一定范围内，特比萘芬浓度越高，念珠地丝菌被破坏的程度越严重。

In vitro susceptibility of Geotrichum silvicola to five antifungal agents and electron microscopic observation of terbinafine-treated Geotrichum silvicola

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 follows:TER,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.