分离自艾滋病患者白念珠菌唑类药物耐药株中Erg11基因突变研究

Mutation of Erg11 gene of Candida anbicans azole-resistance isolated from AIDS

目的:探讨分离自艾滋病患者的白念珠菌唑类药物耐药株中Erg11基因的突变及其与唑类耐药的关系。方法:分离自艾滋病患者的100株真菌标本,经科玛嘉显色培养鉴定为白念珠菌85株,根据美国临床实验室标准化协会制订的M27-A方案的液体微量稀释法行体外药物敏感试验,共鉴定出27株唑类耐药株(耐氟康唑和/或伊曲康唑和/或伏立康唑)。27株耐药株提取基因组DNA后,对其Erg11基因行PCR扩增、测序并与Genebank中敏感株进行比对分析。结果:在27株唑类耐药株中共发现25处不同点突变,其中5处引起氨基酸替换,分别为D116E、E266D、H485T、V447I和V488I,27株均发生H485T突变,7株耐药株发生E266D突变,4株耐药株发生V488I突变,其中1株同时发生E266D和V488I突变,1株发生V447I突变。结论:分离自艾滋病患者的白念珠菌唑类耐药株中Erg11基因的突变热变区和有意义突变与分离自其他宿主的唑类耐药株的突变情况基本一致;分离自艾滋病患者的白念珠菌唑类耐药株Erg11基因突变并非唯一致耐药因素。

Objective To investigate the point mutation of cytochrome P450 lanosterol 14a-demethylase Erg11 and its relationship with azole-resistance Candida albicans isolated from AIDS. Methods In 100 hundred fungi strains isolated from AIDS patients identified by Chromagar, 85 strains were identified as Candida albicans. Antifungal susceptibility test was performed with CLSI M27-A microdilution method. A total of 27 strains were found as azole-resistance （resistance to fluconazol or and hraconazole or and voriconazole）. Genomic DNA was extracted from 27 resistant strains. The Erg11 gene was amplified with PCR, sequenced and compared with susceptible strains in gene bank. Results In the 27 azole-resistance strains, 25 pionts mutation were found, in which 5 significant sites had made amino acids replacement：D116E, E266D, H485T, V4471 and V4881. In azole-resistance strains, H485T mutation occurred in all strains, EE66D mutation occurred in 7, V488I mutation occurred in 4, E266D and V488I mutation simultaneously occurred in 1, and V447I mutation occurred in 1. Conclusion The Ergl I of azole-resistance Candida albicans isolated from AIDS has the same host mutation area with that from other host. Thepiont mutation is not the only factor for azole resistance Candida albicans isolated from AIDS.