Erg11基因突变与白念珠菌对唑类药物耐药性的初步研究

Contribution of mutations in the cytochrome P450 lanosterol demethylase (Erg11) gene to azole resistance in Candida albicans

目的探讨Erg11基因突变与白念珠菌对唑类药物耐药的关系,以初步了解白念珠菌对唑类药物耐药的机制。方法从临床分离耐唑类药物的白念珠菌,通过PCR扩增Erg11基因并测序,与敏感白念珠菌进行对照,以确定是否发生基因突变。结果2株唑类药物敏感的白念珠菌中,通过Erg11基因测序,未发现有义突变;6株耐唑类药物的白念珠菌中,Erg11基因存在E266D、Y257H、K259E、A114S、F487L突变,其中A114S、Y257H、K259E、F487L为新发现的突变位点。结论白念珠菌对唑类药物耐药与Erg11基因的突变有关,通过Erg11基因突变,可引起Erg11P的蛋白结构发生改变,最终可导致唑类药物与Erg11P亲和力下降而产生耐药。

Objective To determine the mechanisms of resistance to azoles by sequencing analysis of Erg11 gene in 8 isolates of Candida albicans. Methods The Erg11 genes of 8 resistant C. albicans isolates from patients were amplified by PCR and were directly sequenced. The sequencing results were analyzed by BLAST and compared with Erg11 gene of C. albicans strain B59630 to find out the locations of mutation. Results All mutations of Erg11 gene were silent in 2 susceptible isolates. However five mutations E266D, Y257H, K259E, All4S, and F487L were identified from the 6 resistant isolates. Y257H, K259E, A114S, and F487L were characterized as novel mutations. Conclusions Resistant mechanism to azole agents is correlated with gene mutation of Erg11, which results in the alteration of Erg11P structure, and reduces the affinity of the enzyme to azoles. This finally leads to the resistance to azole agents.