Quantitative PCR Analysis of FKS1 Gene Expression in Candida glabrata Isolated from Clinical Specimens in Al-Baghdad Governorate

Abstract

The Candida glabrata has become a major opportunistic pathogen, and there is growing resistance to echinocandins, mainly through the changes in FKS1 gene. This paper took on the objective of quantifying the expression of FKS1 gene in C. glabrata isolates of Al-Diwaniyah Province, Iraq, and testing its relationship with antifungal susceptibility. 43 isolates were obtained in the urine and bloodstream and wound samples. They were identified by conventional and automated techniques. The expression of FKS1 was measured using quantitative real-time PCR (qPCR), by normalizing to the expression of the housekeeping gene of ACT1 in the 2−ΔΔCt method. Per CLSI guidelines, caspofungin, micafungin and anidulafungin antifungal susceptibility was also determined. High levels of FKS1 expression (>2-fold) were seen in urinary isolates and were strongly correlated with a decreased sensitivity to echinocandins (p < 0.05). Blood isolates recorded the highest resistance rates, in particular, to micafungin and anidulafungin. Prior antifungal exposure was noted to be the most important risk factor related to increments in gene expressions. The results of these studies indicate the involvement of FKS1 upregulation in echinocandin resistance and the importance of molecular surveillance and optimized antifungal stewardship measures to enhance clinical outcomes.