微量液基稀释法与琼脂稀释法测定马拉色菌体外抗真菌药物敏感性

Comparison of broth microdilution and agar dilution methods for antifungal susceptibility testing of Malassezia species in vitro

目的比较微量液基稀释法与琼脂稀释法检测马拉色菌体外对氟康唑、酮康唑及伊曲康唑敏感性的差异。方法对临床分离的5种27株马拉色菌，分别用微量液基稀释法与琼脂稀释法测定氟康唑、酮康唑及伊曲康唑对这些马拉色菌的最低抑菌浓度（MIC）。结果微量液基稀释法显示氟康唑MIC值范围0．25～≥64mg／L，酮康唑≤0．03～0．5mg／L，伊曲康唑≤0．03～0．125mg／L；琼脂稀释法显示氟康唑MIC值范围2～≥64mg／L，酮康唑≤O．03～0．5mg／L，伊曲康唑≤O．03—0．25mg／L。两种方法测定3种唑类抗真菌药对马拉色菌的活性由高到低为：伊曲康唑、酮康唑、氟康唑。两种方法测得氟康唑、酮康唑及伊曲康唑MIC值符合率分别为78．8％、85．2％、88．9％，组内相关系数分别为O．88、0．80、0．76。结论氟康唑、酮康唑及伊曲康唑对马拉色菌均有较好的抗菌活性，以伊曲康唑对各菌种的抗菌活性最强。微量液基稀释法与琼脂稀释法相比具有良好的一致性，均适用于马拉色菌体外药敏试验。

Objective To compare broth microdilution and agar dilution methods for in vitro testing of activities of fluconazole, ketoconazole and itraeonazole against clinical Malassezia isolates. Methods Broth microdilution and agar dilution methods were used to determine the minimal inhibitory concentration （MIC） of flnconazole, ketoeonazole and itraconazole for 27 clinical strains （5 species） of Malassezia Results The minimal inhibitory concentration （MIC） ranges of fluconazole, ketoconazole and itraconazole were 0.25 - ≥64 mg/L, ≤0.03 - 0.5 mg/L and ≤0.03 - 0.125 mg/L respectively as shown by broth microdilution method, 2 - ≥ 64 mg/L, ≤0.03 - 0.5 mg/L and ≤0.03 - 0.25 mg/L respectively as revealed by agar dilution method. Both methods demonstrated that itraconazole possessed the strongest activity against Malassezia species, followed by ketoconazole and fluconazole. The agreement rate in MICs between the two methods was 78.8%, 85.2% and 88.9%, respectively for fluconazole, ketoeonazole and itraconazole, with the intraclass correlation coefficients （ICCs） being 0.88, 0.80 and 0.76 respectively. Conclusions Fluconazole, ketoconazole and itraeonazole are highly active against Malassezia species in vitro, and itraeonazole is the most active. Broth microdilution and agar dilution method coincide well in, and are applicable for, the antifungal susceptibility testing of Malassezia species in vitro.