Objective: To study the relationship between fluconazole (FCZ)-resistance of Candida albicans and the mutation of ERG11 gene encoding FCZ-targeted enzyme.
Method: Three strains of FCZ-susceptible and 10 FCZ-resistent C. albicans were isolated from the urethra, vagina, oropharynx, respiratory tract, prostate secretion and blood samples. ERG11 gene was amplified by PCR using C.albicans genomic DNA extracts as the templates and the DNA sequences of the PCR products were determined and compared using BLAST and Clustal-W softwares.
Results: The comparison of ERG11 gene sequences identified mutations at 21 sites in 13 strains, including 17 same-sense and 4 missense mutations. Base substitutions at the sites of 348 bp and 383 bp resulting in D116E and K128T conversion may take place in both drug-resistant and drug-susceptible strains. The point mutation at the site of 1309 bp of FCZ-resistant strain may cause V437I change, and the base inversion at 1320 bp may give rise to A/C heterozygosity mutant of ERG11 gene, probably resulting in N440K conversion.
Conclusion: FCZ-resistance of C. albicans may be associated with point mutations of V437I and N440K in ERG11 gene, but not with the point mutations of D166E and K128T.