Overcoming Drug Resistance in a Clinical <i>C. albicans</i> Strain Using Photoactivated Curcumin as an Adjuvant

• Main Authors: Carmen-Ecaterina Leferman (Author), Laura Stoica (Author), Mirela Tiglis (Author), Bogdan Alexandru Stoica (Author), Monica Hancianu (Author), Alin Dumitru Ciubotaru (Author), Delia Lidia Salaru (Author), Aida Corina Badescu (Author), Camelia-Margareta Bogdanici (Author), Ioan-Adrian Ciureanu (Author), Cristina-Mihaela Ghiciuc (Author)
• Format: Book
• Published: MDPI AG, 2023-07-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/antibiotics12081230; 2079-6382
• Keywords: PDT; fungi; <i>Candida albicans</i>; curcumin; antimicrobial photodynamic chemotherapy; efflux pumps; Therapeutics. Pharmacology; RM1-950
• Source: Antibiotics, Vol 12, Iss 8, p 1230 (2023)

The limited antifungal drugs available and the rise of multidrug-resistant <i>Candida</i> species have made the efforts to improve antifungal therapies paramount. To this end, our research focused on the effect of a combined treatment between chemical and photodynamic therapy (PDT) towards a fluconazole-resistant clinical <i>Candida albicans</i> strain. The co-treatment of PDT and curcumin in various doses with fluconazole (FLC) had an inhibitory effect on the growth of the FLC-resistant hospital strain of <i>C. albicans</i> in both difusimetric and broth microdilution methods. The proliferation of the cells was inhibited in the presence of curcumin at 3.125 µM and FLC at 41 µM concentrations. The possible involvement of oxidative stress was analyzed by adding menadione and glutathione as a prooxidant and antioxidant, respectively. In addition, we examined the photoactivated curcumin effect on efflux pumps, a mechanism often linked to drug resistance. Nile Red accumulation assays were used to evaluate efflux pumps activity through fluorescence microscopy and spectrofluorometry. The results showed that photoactivated curcumin at 3.125 µM inhibited the transport of the fluorescent substrate that cells usually expel, indicating its potential in combating drug resistance. Overall, the findings suggest that curcumin, particularly when combined with PDT, can effectively inhibit the growth of FLC-resistant <i>C. albicans</i>, addressing the challenge of yeast resistance to azole antifungals through upregulating multidrug transporters.