Interaction of Candida albicans With Combination of Fluconazole/Clotrimazole: Effect on Hyphae Formation and Expression Levels of Hyphal Wall Protein 1 (HWP1)

Candida albicans is the most prevalent opportunistic human pathogen. Therapeutic options for Candida infections are limited to available antifungal drugs. The aim of this study was to investigate the effect of combination of fluconazole/clotrimazole on C. albicans hyphae formation.

We have established the effectiveness combination of fluconazole/clotrimazole on C. albicans hyphae formation. Interaction of C. albicans with combination of fluconazole/clotrimazole were performed using the CLSI standard method and time-killing curves. In order to investigate the effectiveness combination of fluconazole/clotrimazole on C. albicans hyphae formation, XTT and crystal violet (CV) assays as well as scanning electron microscopy (SEM) and expression of HWP1 gene were carried out.

The interaction of C. albicans with fluconazole and clotrimazole resulted in synergistic, partial synergistic and indifferent effects. The interaction of fluconazole/clotrimazole were confirmed by time-killing curves. In XTT and CV assays, C. albicans treated with combination of fluconazole/clotrimazole reduced metabolic activity and hyphae formation. Images taken by SEM microscopy indicated the effectiveness on hyphae disruption. According to relative real time RT-PCR analysis, the mean Ct values revealed the significant decrease in expression level of the HWP1 gene (P<0.05). A 2.86- and 2.33-fold decrease in HWP1 gene expression was observed in combination of fluconazole/clotrimazole treatment at 2× MIC and 1× MIC concentrations, respectively (P<0.05).

We confirmed that the hyphae is a target for the combination of fluconazole/clotrimazole in C. albicans. HWP1 gene is likely to be considered as a probable targets synergistic interaction of fluconazole/clotrimazole against C. albicans.