Microbiology Spectrum (Sep 2025)
Leveraging synthetic genetic array screening to identify therapeutic targets and inhibitors for combatting azole resistance in Candida glabrata
Abstract
ABSTRACT Fungal infections affect over 6.55 million individuals annually, with Candida glabrata (recently reclassified as Nakaseomyces glabratus) being the second most common cause of invasive candidiasis and candidemia, conditions that carry a high mortality rate of approximately 63.6%. C. glabrata exhibits significant genomic plasticity, enabling rapid adaptation to antifungal treatments. This ability is largely driven by gain-of-function (GOF) mutations in the CgPDR1 gene, which enhance the activity of efflux pumps and confer azole resistance. Over 80 unique CgPDR1 mutations have been identified, leading to diverse resistance profiles, from single-azole resistance to pan-azole resistance. These mutations not only increase resistance but also enhance the virulence of C. glabrata. To combat multi-drug-resistant (MDR) strains, which show resistance to azoles, echinocandins, and polyenes, novel multi-target therapeutic approaches are essential. This study employs synthetic genetic array (SGA) screening to explore the genetic interactions underlying CgPDR1+-mediated azole resistance, using the clinical allele R592S. By generating genome-wide double mutant strains, we identified gene deletions that cause synthetic sick (SS) and synthetic lethal (SL) interactions, providing potential therapeutic targets. In silico screening identified inhibitors of these targets, and one was validated in vitro. Our findings support the potential of SGA screening to identify antifungal adjuvants that can slow the emergence of azole resistance in C. glabrata.IMPORTANCECandida glabrata is a significant cause of life-threatening fungal infections, especially concerning due to its rapid development of resistance to commonly used antifungal drugs like azoles. The growing prevalence of multi-drug-resistant C. glabrata strains, coupled with their high mortality rate, underscores the urgency of identifying new treatment strategies. This study investigates the genetic mechanisms underlying drug resistance, specifically focusing on mutations in the CgPDR1 gene, which increase azole resistance. By leveraging a novel genetic screening method, this work identifies genes that interact with drug-resistant mutations, offering potential new therapeutic targets. Additionally, an inhibitor identified through in silico screening shows promise in delaying azole resistance when tested in vitro. The findings highlight the potential of multi-target therapies to combat drug resistance, paving the way for more effective treatment options for C. glabrata infections and addressing an urgent clinical need.
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