白念珠菌对唑类药物耐药机制研究

A Study of the Resistant Mechanisms of Candida Albicans to Azhole Antifungal Agents.

目的探讨白念珠菌对唑类抗真菌药物耐药机制的分子生物学基础。方法３２株氟康唑耐药性白念珠菌被选为受试菌株；将分六段扩增出来的靶基因片段进行单链构象多态性（ＳＳＣＰ）分析；选择ＳＳＣＰ分析有阳性结果的３个代表片段进行克隆测序。结果所有受试菌株ＳＳＣＰ分析均呈阳性结果，其中第六对引物的扩增片段系突变热点所在部位（细胞色素Ｐ４５０Ｌ１Ａ１的高可变区），另外，耐药株之间也存在差异。且将诱变所得耐药菌落与其亲本的带型进行比较也得到了与上述类似的结果。通过测序共发现１１个突变点，其中５个为有意义突变位点，且有４个位于第六对引物所扩增出来的片段之内。结论一个或一个以上部位的基因突变造成了这些菌株耐药现象的发生。

Objective To detect the molecular biological mechanisms of the resistance of Candida albicans to azole antifungal agents.Method Thirty two FCZ resistant C.albicans were selected as testing strains.We analyzed the single strand conformation polymorphism (SSCP) of the fragments which were amplified by six sets of primers,and pre resistant sensitive strains were used as controls.Three representative fragments,A66,D66 and E78,were selected to be cloned and sequenced.Results All the tested 32 strains showed positive results of SSCP analysis,and the most variable sequence lied in the amplifier of the sixth pair of primer (the highly variable sequence of cytochrome P450L1A1),differences were seen between resistant strains,too.In 11 mutation points we found,five resulted in amino acid alternation.Conclusion One or more mutational alternations might lead to the azole resistant trait in these strains.