ATP-binding-cassette transporters and fluconazole-resistance of clinical Candida albicans strains / 第二军医大学学报

ABSTRACT

Objective: To explore the relationship between CDR1 and CDR2 expression and fluconazole-resistance in clinical Candida albicans strains, so as to explore the mechanism of drug-resistance in Candida albicans. Methods: The minimal inhibitory concentrations (MICs) of clinical Candida albicans strains to fluconazole were determined by broth microdilution method. The total RNA of fluconazole-susceptible and fluconazole-resistant Candida albicans strains were extracted, and the expression of the CDR1 and CDR2 genes was examined by real-time RT-PCR. The efflux of Rhodamine 6G was determined in the strains highly expressing CDR1 and CDR2 genes. Results: The incidences of CDR1 and (or) CDR2 overexpression in fluconazole-resistant strains were significantly higher than those in the fluconazole-sensitive stains. The efflux of Rhodamine 6G was significantly increased in the fluconazole-resistant strains when glucose was added, and overexpression of CDR1 and CDR2 were observed in theses strains. Some resistant strains showed no overexpression of CDR1 and CDR2. Conclusion: Fluconazole-resistance in clinical Candida albicans strains is related to the overexpression of ABC transporter proteins. Overexpression of ABC transporters can increase the efflux of drugs and therefore lead to drug-resistance. Other mechanisms may also participate in the development of drug resistance in the clinical Candida albicans strains.