Prospecção de novos agentes no combate de leveduras do complexo Candida haemulonii e Candida auris

Abstract

Candida auris and the Candida haemulonii complex are emerging threats due to their multidrug-resistant (MDR) profiles and high associated mortality rates. The limited efficacy of current antifungal therapies highlights the urgent need for the development of new treatments. In this context, drug repurposing, leveraging compounds with established safety and pharmacological profiles, presents a promising avenue. Zinc pyrithione (ZnPT) and nystatin (NYS) are recognized for their antifungal properties. Tafenoquine (TAF) and alexidine (ALX) further showcase the potential of repurposed drugs in tackling resistant pathogens. This study aimed to evaluate the antifungal potential of ZnPT, NYS, TAF, and ALX against multidrug-resistant yeasts of the Candida haemulonii complex and Candida auris, contributing to the development of effective therapeutic alternatives.Antifungal susceptibility was assessed using the broth microdilution method to determine the minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of the compounds against clinical isolates of C. auris and C. haemulonii. The inhibition and eradication of biofilms were tested. Ex vivo models using porcine skin were employed to evaluate biofilm inhibition by ZnPT + NYS. Mechanism-of-action studies included protein and nucleotide leakage assays to assess cell membrane permeability, efflux pump inhibition tests, and osmoprotection assays with sorbitol to investigate the potential effects of the compounds on fungal cell walls. Biological safety was evaluated through hemolysis assays to determine hemocompatibility, acute toxicity tests in Tenebrio molitor larvae, and the Ames test to assess mutagenicity.ZnPT + NYS demonstrated a synergistic effect, significantly inhibiting biofilm formation on porcine skin, with nearly complete eradication achieved in short exposure times. Mechanism-of-action studies revealed selective membrane disruption without significant nucleotide leakage. Efflux pump assays confirmed that the efficacy of ZnPT + NYS was not compromised by resistance mechanisms. Safety evaluations showed that while ZnPT alone exhibited toxicity in T. molitor, the combination with NYS mitigated these effects. The Ames test confirmed the low mutagenic risk of ZnPT + NYS treatment. ZnPT and NYS, especially in combination, showed significant antifungal activity against C. auris, highlighting their potential as a powerful treatment option. TAF and ALX demonstrated promising antifungal activity against C. haemulonii. The compatibility with repurposed agents such as TAF and ALX further reinforces their therapeutic versatility, offering a promising strategy to combat fungal infections caused by C. haemulonii.This study innovates by repurposing drugs such as zinc pyrithione, nystatin, alexidine, and tafenoquine, providing a solution for fungal infections caused by Candida auris and the Candida haemulonii complex. The combination of these compounds demonstrated not only antifungal efficacy, including biofilm eradication, but also resistance to fungal defense mechanisms and low toxicity. These findings provide a proposal for the development of new therapies utilizing combinations of repurposed drugs. This approach represents a promising advancement in addressing the studied pathogens, with potential to positively impact the clinical management of these infections. These results underscore the need for clinical trials to confirm the efficacy of these compounds, paving the way for innovative and effective solutions in managing challenging fungal pathogens.