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Updated: Feb 23, 2026
Whole Genome Sequencing of Candida glabrata for Detection of Markers of Antifungal Drug Resistance
Published on: December 28, 2017
Quantification of CDR1 Gene Expression in Fluconazole Resistant Candida Glabrata Strains Using Real-time PCR
Shadi Shahrokhi1, Fatemeh Noorbakhsh1, Sassan Rezaie2
1Dept. of Microbiology, Islamic Azad University, Varamin-Pishva Branch, Varamin, Iran.
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.
Insights
Fluconazole resistance in Candida glabrata is linked to increased CDR1 gene expression. This study highlights the role of CDR1 in antifungal resistance, suggesting it as a target for further investigation.
Area of Science:
- Medical Mycology
- Molecular Biology
- Antimicrobial Resistance
Background:
- Candida glabrata is a significant cause of life-threatening fungal infections.
- Increasing fluconazole resistance in C. glabrata is a growing clinical concern.
- Overexpression or mutations in ATP-binding cassette (ABC) transporter genes, like CgCDR1 and CgCDR2, contribute to fluconazole resistance.
Purpose of the Study:
- To evaluate the CDR1 gene expression level as a key mechanism in fluconazole resistance of C. glabrata.
Main Methods:
- Clinical isolates of C. glabrata were collected and validated.
- Antifungal susceptibility testing to fluconazole was performed using CLSI protocols.
- Real-time PCR was used to measure CDR1 mRNA expression levels in selected isolates.
Main Results:
- 32% of strains were susceptible, 64% showed dose-dependent (DD) resistance, and 4% were resistant to fluconazole.
- Resistant C. glabrata strains (MIC≥64 μg/ml) exhibited significant overexpression of the CDR1 gene compared to susceptible strains.
- Real-time PCR analysis confirmed the correlation between CDR1 overexpression and fluconazole resistance.
Conclusions:
- The CgCDR1 gene plays a crucial role in fluconazole resistance in Candida glabrata.
- Investigating the transporter functions of CgCDR1 is necessary for understanding and combating antifungal resistance.
- Findings emphasize the importance of monitoring gene expression in clinical isolates to guide treatment strategies.
