Using PCR to Compare the Expression of CDR1, CDR2, and MDR1 in Candida Albicans Isolates Resistant and Susceptible to Fluconazole

Abstract       Background and objectives: More Candida albicans strains are reported resistant to fluconazole in patients with AIDS, cancer and organ recipients. Fluconazole resistance can be attributed to changes in pathways of sterol biosynthesis, mutation in or overexpression of ERG11 and the expression of CDR1, CDR2, and MDR1. This study aimed to compare the expression of CDR1, CDR2, and MDR1 in C. albicans resistant and susceptible to fluconazole.        Methods: MIC testing for fluconazole was performed on C. albicans isolates isolated from patients with oral and vaginal candidiasis to determine resistant and susceptible strains. Then real time PCR was performed on the resistant and susceptible isolates and the expression of CDR1, CDR2, and MDR1 was compared in C. albicans.      Results: Of 46 Candida albicans isolates, 20 susceptible isolates, 12 semi-susceptible isolates and 14 resistant isolates were identified by MIC. After real time PCR was performed, Candida albicans isolates susceptible to fluconazole showed moderate expression of CDR1, CDR2, and MDR1 genes, while resistant isolates showed slight or no expression.       Conclusion: Increased expression of CDR1, CDR2, and MDR1 had less and insignificant role in resistance to fluconazole.       Keywords: Candida Albicans, Gene Expression, Real time PCR method