须癣毛癣菌的形态学及分子生物学鉴定

Morphology and molecular biological identification of Trichophyton mentagrophytes

目的对临床上分离自人(36株)及狐狸(5株)的须癣毛癣菌菌株进行新的分类系统鉴定,并检测传统的分类方法是否能满足临床鉴定需要。方法①观察原鉴定为须癣毛癣菌菌株在沙氏培养基、1%蛋白胨培养基、溴甲酚紫乳固体葡萄糖琼脂培养基(BCP-MSG)和显微镜下形态学及尿素酶、毛发穿孔等生理学试验表现。②通过ITS区段和LSU区段分子生物学序列分析进行新的分类系统的菌种分型,并对传统形态学和生理学鉴定方法进行检测。结果①41株须癣毛癣菌形态学及生理学试验符合须癣毛癣菌(38株)和红色毛癣菌(3株)菌落的特点。②ITS区段序列分析发现ITS区段能将须癣毛癣菌和红色毛癣菌准确的鉴定到种,但无法明确其种内分型;而LSU区段序列分析可对36株(36/38)须癣毛癣菌有性型做出明确的鉴定。结论传统实验室鉴定方法仍具有其有效性及可靠性。通过分子生物学鉴定,临床分离的须癣毛癣菌皆为指(趾)间毛癣菌(38/38),而LSU区段的序列分析鉴定狐狸源性菌株皆属于本海姆节皮菌,有别于大多数人源性菌株有性型为万博节皮菌,对于须癣毛癣菌的菌种鉴定更优于ITS区段,但分子生物学试验还需结合形态学的观察,才能够对菌种做出正确的鉴定。

Objective To reclassify 36 strains of Trichophyton mentagrophytes from patients and 5 strains from foxes by the new classification system,and to evaluate if the traditional methods satisfy the clinical identification.Methods Trichophyton mentagrophytes were cultured on SDA,1% peptone agar and BCP-MSG.The morphology was observed and urease test and hair perforation test were performed.Then the new identification was reclassified by ITS and LSU sequence analysis.Results ①Morphology and physiology of 41 tested strains met the characteristics of Trichophyton mentagrophytes（38 strains） and Trichophyton rubrum（3 strains）.②ITS sequence analysis identified the species of Trichophyton mentagrophytes and Trichophyton rubrum but LSU sequence analysis only identified the telemorph of Trichophyton mentagrophytes（36/38）.Conclusions Traditional identification methods are still effective and reliable.Trichophyton mentagrophytes from patients are identified as Trichophyton interdigitale（38/38）,but strains from foxes belong to Arthroderma benhamiae,not to Arthroderma vanbreuseghemii by LSU sequence analysis,which is more useful than ITS sequence analysis.