Otomycosis represents a small percentage of clinical external otitis. This well documented entity is often a stubborn clinical problem and, in contrast to bacterial external otitis, there is no otic preparation with specific antifungal activity. In response to this Iack of otic preparations, we have surveyed in vitro a variety of available preparations to determine the general spectrum of activity against appropriate bacterial and fungal species. An agar-disc diffusion system was used testing the drugs against (1.) bacteria common in external otitis, and (2.) a variety of yeast and filamentous fungi.
Aqueous Merthiolate and Cresylate demonstrated good non-specific antimicrobial activity, while nystatin and clotrimazole demonstrated specific antifungal activity. Otic preparations can now be used which have demonstrated in vitro effectiveness and give an alternate means of therapy to the now empirically selected otic preparation used for otomycosis.