Overexpression of MDR-1 and CDR-2 genes in fluconazole resistance of Candida albicans isolated from patients with vulvovaginal candidiasis.

BACKGROUND AND PURPOSE: Candida albicans (C. albicans) is an opportunistic fungus that can colonize women's mucosal epithelial cell surfaces, causing vulvovaginitis in specific circumstances. The major genes contributing to drug resistance in C. albicans are the candida drug resistance (CDR) and multi drug resistance (MDR) genes. The purpose of this study was to evaluate the CDR-2 and MDR-1 gene expression patterns in C. albicans strains isolated from patients with recurrent vulvovaginal candidiasis.

MATERIALS AND METHODS: In this study, 40 isolates of fluconazole-resistant C. albicans were cultured on Sabouraud dextrose agar. These isolates were collected from women with vulvovaginitis who were referred to a clinic in Tehran, Iran, and transferred to a mycology laboratory. Then, RNA was extracted from the isolates using phenol-chloroform and glass beads, and the complementary DNA (cDNA) was synthetized. To detect the semi-quantitative expression of CDR-2 and MDR-1 genes, the reverse transcriptase-PCR (RT-PCR) technique was performed using specific primers.

RESULTS: Our findings indicated that of the 40 C. albicans isolates, 35 (87.5%) strains were positive for mRNA of the CDR-2 gene, 32 (80%) strains expressed mRNA of the MDR-1 gene, and 30 (75%) strains were confirmed to express mRNA of both the CDR-2 and MDR-1 genes simultaneously using the RT-PCR assay.

CONCLUSION: According to the obtained results, the expression rates of CDR-2 and MDR-1 genes were high in fluconazole-resistant C. albicans isolates, which can cause treatments to fail and result in chronic infections. Inhibiting these important genes using novel or natural agents can help with the treatment of chronic and recurrent vaginitis.