Miconazole Activity Against Candida Biofilms on Acrylic Discs

Objective:

Miconazole is commonly used in the treatment of Candida-associated denture stomatitis (CaDS). New research into CaDS is focused on the reduction of Candida biofilms developed on the denture surface. We investigated the activity of miconazole towards in vitro grown mature Candida biofilms formed on denture acrylic discs.

Method:

The effect of miconazole on Candida biofilms developed on acrylic discs was determined for: C. albicans MYA-2732 (ATCC), C. glabrata MYA-275 (ATCC) and four clinical isolates, C. albicans 6122/06, C. glabrata 7531/06, C. tropicalis 8122/06, and C. parapsilosis 11375/07. The MICs of miconazole were determined using the broth dilution susceptibility method. Biofilms were developed on poly(methyl methacrylate) discs incubated for 90 min at 37°C (adherence). After removal of non-adherent cells, discs were submerged in YNB/100 mM glucose and incubated for 48 h at 37°C (biofilm formation). Miconazole 0.5 – 96 µg/ml was added in YNB medium and the biofilms were incubated for 24 h at 37°C. The metabolic activity of the biofilms was measured by the XTT assay.

Result:

MICs for miconazole for the investigated strains ranged from 0.016 – 32 µg/ml. Miconazole demonstrated significant activity against all Candida biofilms studied. Treatment with miconazole in the range 5 – 96 µg/ml resulted in a significant reduction of biofilm metabolic activity for all strains, the highest reduction (84%-48%) was observed at 96µg/ml. For C. albicans MYA-2732, C. glabrata 7531/06 and C. parapsilosis 11375/07, 0.5 µg/ml miconazole had no effect. Biofilms of C. albicans 6122/06, C. glabrata MYA-275, and C. tropicalis 8122/06 were susceptible to 0.5 µg/ml miconazole; reducing the metabolic activity of the biofilms by 14%, 47% and 45%, respectively.

Conclusion:

Miconazole exhibits high antifungal activity against Candida biofilms developed on acrylic discs. Our findings suggest that miconazole may be useful for the treatment of biofilm-related CaDS.