Different sources of drug resistant Candida albicans clinical strains exist over-expression and novel mutation in ERG11 gene

Abstract

Objective To explore ERG11 gene mutations,over-expression and the relation between each other of Candida albicans in the role of fluconazole resistance.Methods ERG11 genes of 24 strains Candida albicans isolated from patients were amplified by PCR and bilaterally sequenced.The sequencing result was analyzed by Blast and compared with published sequence (GenBank AY856352) to analyze gene mutations.Then the total RNA was extracted from 24 strains Candida albicans and cDNA was synthesized.The expression of ERG11 gene was detected by fluorescence quantitative RT-PCR.Results 24 silent mutations and 5 missense mutations were identified in 24 strains Candida albicans isolates.Among missense mutations,E174A,T123I and V234F were not found yet in previous studies.Higher expression of ERG11 gene was observed in fluconazoleresistant isolates compared with fluconazole-susceptible isolates [(3.89 ± 2.4) vs.(0.78 ± 0.31)],with statistically significant difference (P ＜ 0.05).Conclusions Drug resistance of Candida albicans to fluconazole may be correlated with the mutations of A114V,E174A,T123I,Y132H,and V234F in ERG11 gene.Besides of this,it is likely that over-expression of ERG11 gene is relevant to fluconazole resistance in Candida albicans. Key words: Candida albicans; ERG11 gene; Resistance; Gene mutation; Over-expression