Curcumin-Mediated Antimicrobial Photodynamic Therapy Combined with Fluconazole against Candida albicans and Fluconazole-Resistant Candida auris

Öz

Rising rates of azole resistance among Candida species, and the emergence of the multidrug-resistant pathogen Candida auris, have renewed interest in non-antibiotic antifungal strategies such as antimicrobial photodynamic therapy (aPDT). We evaluated curcumin, a natural polyphenolic photosensitizer, as an aPDT agent against Candida albicans (ATCC 14053) and C. auris (DSM 21092), and tested whether sub-lethal aPDT could enhance the activity of fluconazole against a confirmed fluconazole-resistant strain. Curcumin (1, 5, or 10 µM) combined with blue-light doses of 5, 10, or 15 J/cm² was tested in triplicate against planktonic cells of both species. One-way ANOVA and pairwise comparisons against untreated controls showed statistically significant, dose-dependent reductions in viable count for nearly every curcumin/light-dose combination (P<0.05, Bonferroni-corrected), with 1 µM curcumin + 10 J/cm² producing an approximately 2-log reduction in both species and 15 J/cm² producing complete inactivation at all curcumin concentrations tested. Fluconazole MIC, determined by a six-point two-fold dilution series and TTC assay, was 3.2 µg/mL for C. albicans and 50 µg/mL for C. auris, confirming a genuinely fluconazole-resistant phenotype. Sequential application of sub-lethal aPDT (1 µM curcumin + 10 J/cm²) followed immediately by a strain-specific, approximately half-MIC dose of fluconazole abolished detectable metabolic activity (TTC assay) in both species, whereas either treatment alone left viable cells. These results indicate that curcumin-mediated aPDT can substantially potentiate fluconazole activity against a confirmed multidrug-resistant Candida strain, and support further, quantitatively replicated investigation of this combination as a low-toxicity adjunct to conventional antifungal therapy.

Anahtar Kelimeler

• Photodynamic therapy
• Curcumin
• Candida auris
• Candida albicans
• Fluconazole
• Antifungal resistance

Destekleyen Kurum

İzmir Konak Vocational School

Proje Numarası

202525

Etik Beyan

Ethics committee approval was not required for this study because of there was no study on animals or humans.

Teşekkür

This study was carried out with the support of the İzmir Konak Vocational School Scientific Research Projects Coordination Unit (Project No. 202525) as a Research Project. The author gratefully thanks Dr. Ecem Saygılı for her support.

Kaynakça

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