85株皮肤癣菌感染的病原菌分析及标准化体外药物敏感性研究

Analysis on pathogenic characteristics of dermatophyte infection and in vitro drug susceptibility of 85 strains of dermatophyte

目的分析深圳地区教学医院门诊皮肤癣菌感染的病原菌特点,测定7种抗真菌药物对85株皮肤癣菌的体外抗真菌活性。方法收集疑诊为皮肤癣菌感染的患者的皮屑(或甲板刮屑、毛发)进行KOH直接镜检和培养。并通过测定皮肤癣菌临床分离菌株的核糖体DNA内转录间隔区(ITS)区序列鉴定菌种。参考CLSI M38-A2方案,测定7种抗真菌药物对85株鉴定为皮肤癣菌的临床分离菌株的体外抗真菌活性。结果 161例疑诊为皮肤癣菌感染的患者中KOH直接镜检皮肤癣菌的阳性率为67.7%,真菌培养皮肤癣菌的阳性率为52.8%。菌种鉴定结果为红色毛癣菌68例、犬小孢子菌7例、石膏样小孢子菌3例、趾间毛癣菌5例、紫色毛癣菌1例、断发毛癣菌1例。体外药敏试验显示特比萘芬(GM MIC,0.032μg·mL^-1, MIC范围, 0.001~0.125μg·mL^-1)对6种皮肤癣菌表现出良好的体外抗真菌活性,而伏立康唑(GM MIC, 0.041μg·mL^-1, MIC范围, 0.032~0.125μg·mL^-1)在唑类药物中的体外MIC值相对较低。结论本研究中皮肤癣菌感染的致病菌以红色毛癣菌为主。标准化药敏试验证实特比萘芬和伏立康唑对分离的皮肤癣菌具有较强体外抗菌活力,适用于本地区皮肤癣菌感染的治疗。

Objective To analyze the pathogenic characteristics of dermatophyte infection in the out-patient department of a teaching hospital in Shenzhen area and to investigate in vitro activity of 7 antifungal agents against 85 strains of dermatophyte. Methods Skin scales(or nail scraps, hairs) were collected from suspected patients with dermatophyte infection for KOH direct microscopic examination and culture. The species of dermatophyte were identified by sequencing the ribosomal DNA internal transcribed spacer(ITS). The antifungal susceptibility testing was performed following Clinical and Laboratory Standards Institute(CLSI) M38-A2 reference broth microdilution methods. Seven antifungal agents were evaluated against 85 strains of dermatophytes. Results Among 161 suspected patients with dermatophyte infection, the positive rate of KOH direct microscopic examination of dermatophyte was 67.7%, and the positive rate of fungal culture of dermatophyte was 52.8%. A total of 85 isolates of positive fungal culture were identified as 68 strains of Trichophyton rubrum, 7 strains of Microsporum canis, 3 strains of Microsporum gypseum, 5 strains of Trichophyton interdigitale, 1 strain of Trichophyton violaceum and 1 strain of Trichophyton tonsurans. In vitro drug susceptibility test results revealed that terbinafine(GM MIC,0.032μg·mL^-1, MIC range, 0.001~0.125μg·mL^-1) had the strongest in vitro antifungal activity against 6 dermatophytes. And voriconazole(GM MIC,0.041μg·mL^-1, MIC range, 0.032~0.125μg·mL^-1)had the lowest MIC among the azole drugs. Conclusions Trichophyton rubrum was the most common pathogen of dermatophyte infection in our hospital.The standardized antifungal susceptibility testing confirmed that terbinafine and voriconazole had strong in vitro antifungal activity against isolated dermatophyte and were suitable for the treatment of dermatophyte infection in this area.