从花斑糠疹皮损分离的马拉色菌随机扩增多态性DNA研究

目的 用随机扩增多态性DNA方法研究分离自花斑糠疹的马拉色菌种间和株间差异，了解随机扩增多态性DNA分析（RAPD）与生理生化方法在菌种分型上的差异及菌株DNA型别和菌种间的关系。方法 用氯化苄法提取马拉色菌标准株（10株7个种）和临床分离株（47株）的基因组DNA，其中临床株分离自34例花斑糠疹患者，经形态学和生理生化方法鉴定为5个种（合轴马拉色菌、糠秕马拉色菌、钝形马拉色菌、球形马拉色菌、限制马拉色菌），用4种随机引物（S22、S24、S25、S33）对菌株DNA做PCR随机扩增，NTSYS软件自动生成树状分支图。结果 绝大多数标本均可被4种引物扩增而获得清晰条带，其中2种引物（S22、S24）的条带更为稳定、清晰。共82条DNA片段被扩增，所有菌株均可见种间和株间多态性。有4例患者皮损同时分离出不同种的菌株显示遗传相似性高，在树状图中归入一类。结论 来自同一宿主的不同菌株遗传趋同现象提示马拉色菌的种特异性、菌种演化与宿主间存在密切关系。

Random amplified polymorphic DNA analysis of Malassezia isolates from cutaneous lesions of pityriasis versicolor

Objective To investigate intraspecific and interspecific variation within Malassezia iso-lates from patients with pityriasis versicolor by random amplified polymorphic DNA (RAPD) analysis, to learn the difference between RAPD analysis and physiological and biochemical methods in the typing of Malassezia species, and to explore the relationship between RAPD patterns and Malassezia species. Methods A total of 47 Malassezia isolates were obtained from 34 patients with pityriasis versicolor, and they were classified into 5 species by morphological, physiological and biochemical features, I.e., M. Fin'fur, M. Obtusa, M. Globosa, M. Restricta and M. Sympodialis. Genomic DNA was extracted from the 47 clinical isolates and 10 reference strains (including 7 species) of Malassezia. PCR was performed using 4 random primers including S22, S24, S25 and S33. RAPD patterns were analyzed by NTSYS software and dendrogram was autogenerated. Results Genomic DNA of most strains was successfully amplified with four primers, espe-cially with primers S22 and S24 that resulted in rather stable and clear DNA bands. A total of 82 fragments were amplified from all tested strains. These strains showed both interspecifie and intraspecific variation. Multiple swains were isolated from different body sites of 4 patients and identified into different species by biochemical and morphological typing; those swains from same hosts occupied contiguous positions in the dendrogram and exhibited a high genetic convergence. Conclusion The phenomenon that different strains from a co-host show a high genetic convergence indicates that species specificity and evolution of Malassezia are closely related to its hosts.