Fluconazole resistance in Candida species most commonly occurs via upregulation of which efflux transporter?

• A P-glycoprotein (ABCB1) encoded by the MDR1 gene on chromosome 5
• B CDR1/CDR2 (Candida Drug Resistance) ABC transporters and Mdr1p (major facilitator superfamily) ✓
• C OmpC/OmpF porin downregulation reducing cell wall permeability to azoles
• D Erg3 mutation eliminating ergosterol precursor accumulation

Explanation

Azole (fluconazole) resistance in Candida albicans and C. glabrata predominantly involves upregulation of CDR1/CDR2 (Candida Drug Resistance 1 and 2) ATP-binding cassette (ABC) transporters and Mdr1p (a major facilitator superfamily pump), which efflux azoles from the fungal cell. Point mutations in ERG11 (encoding lanosterol 14-alpha demethylase, the azole target) also contribute. Option C describes a bacterial mechanism; option D (Erg3 mutations) causes azole resistance in C. glabrata by blocking accumulation of toxic sterol intermediates rather than efflux.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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