Antifungal effect of chitosan against Malassezia pachydermatis isolated from the dog with otitis externa

The effect of pH of chitosan solution (w/v) on antifungal activity against Malassezia pachydermatis isolated from a dog with otitis externa was evaluated. This study was investigated to find out the optimal pH of chitosan solution that could be able to eliminate yeast cells. For comparison of antifungal activity of chitosan solution 2% chlorhexidine that have been already proved the antifungal effect against M. pachydermatis was used as positive control. The chitosan solution at different pH (2.5, 3.0, 3.5, 4.0, 4.5, 5.0) were involved this experiment. The chitosan solutions at each pH could eliminate a number of yeast cells when they were compared to other antifungal agents. In chitosan solution's antifungal effect of varying degrees according to the pH M. pachydermatis was inhibited at pH of < 5.0. Especially it has been proved an effective antifungal effect at pH 3.5. Therefore, the pH of chitosan solution had a effect on antifungal activity and the optimal pH was 3.5 in vitro. The possibility of topical therapy with acidific solution of chitosan has a potential in skin infection against M. pachydermatis.