Abstract: Objective To analyze the sensitivity of clinical isolates of Candida albicans to fluconazole,to detect mutations in their ERG11 genes,and to investigate the correlation between ERG11 gene mutation and resistance to fluconazole.Methods Candida albicans was identified from clinical isolates of Candida spp..The sensitivity to fluconazole was detected in vitro by microdilution-basesd method and Rosco tablets method.Three pairs of primers were designed to amplify three fragments of ERG11 gene(483 bps, from 295 bp to777 bp;482bps,from 723 bp to 1204 bp;489 bps,from 1179 bp to 1667 bp)after the extracting of genomic DNA.PCR products were sequenced.Results Eighty clinical isolates of Candida spp.were collected,which included 52 isolates of Candida albicans,all of which were sensitive to fluconazole.Nineteen mutations were detected in ERG11 gene of 5 fluconazole-sensitive clinical isolates.Of the 19 mutations,14 were samesense mutations,and the remaing 5 missense mutations(T495A,A530C, G640A,A945C and G1609A),resulting in amino acid substitution D116E,K128T,E165K,E266D and V488I,respectively in lanosterol 14 alpha-demethylase.E165K was a novel mutation.Conclusions The clinical isolates of Candida albicans were highly sensitive to fluconazole;E165K and V488I might not lead to the resistance of Candida albicans to fluconazole.

Key words: Candida albicans, Microbial sensitivity tests, Fluconazole, Mutation, ERG11, Lanosterol 14 alpha-demethylase