Quantification of CDR1 Gene Expression in Fluconazole Resistant Candida Glabrata Strains Using Real-time PCR

BACKGROUND The opportunistic fungi, particularly Candida glabrata has been known as main etiologic agents of life-threating infections in some patients. Although fluconazole is the most effective antifungal agent against candidiasis, C. glabrata, fluconazole-resistant strains have been increased recently overexpression or mutations of ATP-binding cassette (ABC) transporter family membrane proteins such as; Cg CDR1, Cg CDR2 are responsible for fluconazole resistance in a large proportion of candidiasis cases. The aim of this study was to evaluate CDR1 gene expression level as one of main mechanism involved in this resistance using. METHODS Candida glabrata strains were collected from various clinical samples in hospitals of Tehran in 2015 . After validation of all isolates by conventional and molecular methods, the susceptibility analysis to fluconazole of all isolates was performed using CLSI broth microdilution M27-A3 and M27-S4 protocols. Two isolates have been selected based on difference in susceptibility and CDR1-mRNA expression level of isolates was measured by Real-time PCR method. RESULTS Susceptibility results revealed that 32%, 64% and 4% of strains were susceptible, dose-dependent (DD) and resistant to fluconazole respectively. Furthermore, resistance strain of C. glabrata (MIC≥64 μg/ml) showed overexpression of CDR1 compared with sensitive strain in Real-time PCR analysis. CONCLUSION Thus, it is necessary to investigate the functions of CgCDR1 genes as a transporter-related gene.