Role and mechanism of hexyl-aminolevulinate ethosome-mediated antimicrobial photodynamic therapy in reversing fluconazole resistance in Nakaseomyces glabrata (Candida glabrata)

<b>Introduction.</b> Azoles are extensively employed as clinical antifungal agents; however, their long-term and widespread application contributed to the progressive emergence of azole resistance. A significant increase in infections caused by azole-resistant <i>Nakaseomyces glabrata</i> highlights the need for novel therapeutic strategies.<b>Hypothesis/Gap Statement.</b> The efficacy of hexyl-aminolevulinate ethosome-mediated antimicrobial photodynamic therapy (HAL-ES-aPDT) against drug-resistant fungal pathogens, as well as its underlying mechanisms, remains to be elucidated. Our previous studies have demonstrated that HAL-ES-aPDT, which utilizes the photosensitizer HAL-ES, eliminates pathogens via photochemical reactions.<b>Aim.</b> This study aimed to evaluate the effects and mechanisms of HAL-ES-aPDT on clinical isolates of <i>N. glabrata</i> exhibiting varying levels of azole susceptibility, with a focus on changes in resistance and virulence.<b>Methodology.</b> Several clinical isolates of <i>N. glabrata</i> were collected, and the effects and mechanisms of HAL-ES-aPDT treatment on azole-resistant strains were investigated.<b>Results.</b> HAL-ES-aPDT reduced <i>N. glabrata</i> tolerance to environmental stress and reversed azole resistance by inhibiting drug efflux and downregulating genes encoding the target enzymes. It also attenuated <i>in vivo</i> virulence by downregulating the expression of the epithelial adhesin gene <i>EPA1</i>.<b>Conclusion.</b> These results confirm the efficacy of HAL-ES-aPDT against azole-resistant <i>N. glabrata</i> and provide novel mechanistic insights that may facilitate the development of effective therapeutic interventions for resistant fungal infections.