Alexidine as a Potent Antifungal Agent Against <i>Candida Hemeulonii</i><i>Sensu Stricto</i>

The increasing prevalence of infections by<i>Candida hemeulonii</i> <i>sensu stricto</i>, particularly due to its resistance to standard antifungal therapies, represents a significant healthcare challenge. Traditional treatments often fail, emphasizing the need to explore alternative therapeutic strategies. Drug repurposing, which reevaluates existing drugs for new applications, offers a promising path. This study examines the potential of repurposing alexidine dihydrochloride as an antifungal agent against<i>C. hemeulonii</i> <i>sensu stricto</i>. Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) values were established using broth microdilution methods. To further assess antifungal activity, different assays were conducted, including growth inhibition, biofilm inhibition, biofilm eradication, and cell damage. Checkerboard assays were employed to study the compound's fungicidal potential and interactions with other antifungals. Additional tests, sorbitol protection assay, efflux pump inhibition, cell membrane permeability assays, and nucleotide leakage were performed. <i>In vivo</i> efficacy and safety were evaluated in<i>Tenebrio molitor</i> larvae. Alexidine demonstrated fungicidal activity against<i>C. hemeulonii</i> <i>sensu stricto</i>, with an MIC of 0.5 μg/mL. Biofilm formation was significantly inhibited, with a reduction of 78.69%. Mechanistic studies revealed nucleotide leakage, indicating membrane impact, but no significant protein leakage was detected. <i>In vivo</i>, alexidine displayed a favorable safety profile, with no evidence of hemolysis or acute toxicity in the <i>T. molitor</i> model. These findings support alexidine as a strong candidate for antifungal drug repurposing, especially for treating<i>C. hemeulonii</i> <i>sensu stricto</i> infections. Its efficacy in inhibiting growth and biofilm formation, combined with a positive safety profile, underscores its potential for clinical development as an antifungal therapy.