Use of the antimicrobial potentiator (TricideTM) to improve efficacy of medications against fungal keratitis pathogens.

Abstract

Abstract: : Purpose: To determine if the antimicrobial potentiator (Tricide^TM) enhances in vitro activity of antifungal medications against fungal isolates from horses with mycotic keratitis. Horses develop keratomycosis more often than other domestic species, serving as a good model for human fungal keratitis. Methods: Fungal isolates were obtained from cases of equine mycotic keratitis. The NCCLS microdilution method was performed using reference grade antifungal powders (miconazole, ketoconazole, itraconazole and natamycin) against the fungal isolates and ATCC quality control strains (Candida albicans and Paecilomyces variotii). Serial dilutions were performed to achieve a range of antifungal drug and Tricide^TM concentrations. Minimum inhibitory concentrations (MIC’s) for Tricide^TM combined with the antifungal drugs were compared to the MIC’s of the antifungals alone. Results: MIC 50’s for the antifungal drugs were decreased (50 to 100%) when combined with Tricide^TM. % Decrease in MIC 50 achieved using a range of Tricide concentrations: 

Note: 100% reduction in MIC 50 indicates that Tricide^TM alone (no antifungal) caused 50 % inhibition of growth. NP=not performed. Conclusions:Tricide^TM has antifungal properties when used alone and increases the in vitro activity of antifungals against common fungal pathogens associated with equine keratomycosis. Tricide^TM is effective in reducing the MIC’s of antifungal medications against resistant fungi associated with mycotic keratitis.

Keywords: antibiotics/antifungals/antiparasitics • fungal disease • keratitis