ERG11基因突变与白念珠菌对氟康唑耐药性的初步研究

Research on ERG11 gene mutations in Candida albicans resistance to fluconazole

目的探讨白念珠菌氟康唑作用的靶酶编码基因(ERG11)突变与氟康唑耐药性的关系。方法采用聚合酶链反应(PCR)扩增临床分离的23株白念珠菌ERG11基因,包括2株耐氟康唑株、9株氟康唑剂量依赖敏感株和12株氟康唑敏感株,并进行双向测序。应用B last软件,将测序结果与网上已发表序列(GenBankAY856352)进行比对,以确定是否发生基因突变。结果23株白念珠菌的ERG11基因序列共检出16个同义突变位点和18个错义突变位点。错义突变中Y205E、I437V、A255V、E260V、K487N、G472R、N435V、D502E、K143Q为新发现的突变位点。结论Y205E、I437V、A255V位点突变发现于敏感株,可能与白念珠菌耐药无关;K487N、G472R、N435V、D502E、E260V发现于剂量依赖敏感株,K143Q发现于耐药株,可能与耐药的形成有关。

Objective To study the relationship between fluconazole-resistance of Candida albicans and the mutation of ERG11 gene encoding fluconazole-targeted enzyme.Methods The genes of 23 strains Candida albicans isolated from patients,including 2 strains of fluconazole-resistance,9 strains of fluconazole-susceptible dose dependent and 12 strains of fluconazole-susceptible,were amplified by polymerase chain reaction（PCR） and bilaterally sequenced.The sequencing results were analyzed by Blast and compared with published sequence（GenBank AY856352） to find out the locations of mutation.Results 16 silent mutations and 18 missense mutations were identified in 23 Candida albicans isolates.Among the missense mutations,Y205E,I437V,A255V,E260V,K487N,G472R,N435V,D502E and K143Q had not been found yet in the previous studies.Conclusions Resistant mechanism of Candida albicans to fluconazole may be correlated with the mutations of K487N,G472R,N435V,D502E,E260V and K143Q in ERG11 gene which existed in fluconazole-susceptible dose dependent and fluconazole-resistance isolates,but not with mutations of Y205E,I437V and A255V which existed in fluconazole-susceptible isolates.