Basal expression of ERG11, MDR1 and CDR1 genes in clinical isolates of Candida albicans from Ecuador: insights into azole resistance surveillance

Introduction: Candida albicans is an opportunistic pathogen linked to severe, often fatal, infections. Azoles are the first line of treatment, but its resistance has increasingly been reported worldwide. Azole resistance mechanisms involve the overexpression and mutations of genes such as ERG11, MDR1, and CDR1. Our research is focused on comprehending the baseline expression of azole resistance-related genes to monitoring the prevalence of drug resistance within Ecuador. Methodology: A total of 53 C. albicans clinical isolates were analysed. The isolates were cultured, stored, and processed for gene expression analysis of MDR1, CDR1, and ERG11 genes by RT-qPCR. Results: Most samples (75,47%) expressed the three genes, with ERG11 the most frequently expressed (94,34%). However, the CDR1 gene had the highest expression level (9,37E + 04) among the three evaluated genes. Remarkably, only one sample showed no gene expression. Correlation analyses did not reveal a relationship between the origin of the sample and gene expression levels. Most isolates with high expression of these azoles resistant genes come from urine samples. Conclusion: This is the first study that analyses the basal expression of genes related to azole resistance in C. albicans and highlights the importance of epidemiological surveillance of this pathogen in the country's health system.