Study on the mechanism of fluconazole resistance in Candida albicans

FENG Xiaochuan; YUAN Hang; ZHENG Yingying; BAI Jiangmiao; ZHANG Qianqian

doi:10.3969/j.issn.1673-3827.2023.06.001

Abstract：Objective To study the expression levels of fluconazole resistant genes ERG11,CDR1,CDR2,and MDR1 in Candida albicans and their relationship with drug resistance,and to provide a basis for the prevention and treatment of inva-sive candidiasis mainly caused by Candida albicans infection in this region.Methods Ten fluconazole resistant strains and 10 fluconazole sensitive strains were selected from each hospital in two tertiary and first-class hospitals in Yan'an area.Am-plifying the target enzyme coding gene ERG11,analyzing the mutation sites,fluorescent dye using rhodamine 6 G were used to analyze the efflux of strains from drug resistant and sensitive groups.Then,fluorescence quantitative PCR was used to de-tect the expression level of the gene encoding the efflux pump of Candida albicans.Results ERG11 amplification and se-quencing results showed that although the resistant strain C3 had a base site mutation,it did not cause changes in the coding amino acid.The resistant strain C7 and the sensitive strain C12 had a base site mutation,causing changes in the coding ami-no acid;fluorescent dye rhodamine 6 G was used to detect the efflux of Candida albicans.The results showed that the efflux of resistant isolate and sensitive isolate were significantly different whether glucose was added or not,and the efflux of drug resistant isolate with glucose was significantly higher than that without glucose,and the difference was statistically signifi-cant(P＜0.05);the RT-PCR detection of efflux pump genes showed a statistically significant difference in the expression levels of CDR1 and CDR2 efflux pump genes between drug-resistant and sensitive isolate(P＜0.05).Conclusion The re-sults of gene expression and efflux pump function testing in this study indicate that the resistance mechanism of Candida al-bicans to fluconazole in this region was mainly related to overexpression of efflux pump genes,and no significant mutations were found in the target enzyme coding genes.