Activity of the amidoamine myristamidopropyl dimethylamine against keratitis pathogens

Objectives: Microbial keratitis accounts for up to 30% of blindness in some less developed societies. The development of a single broad-spectrum topical antimicrobial effective against bacteria, fungi and Acanthamoeba would have a major impact on reducing the morbidity and simplifying the treatment of microbial keratitis. To this end, the activity of the amidoamine myristamidopropyl dimethylamine (MAPD) was investigated against common causes of microbial keratitis. Methods: Challenge test assays were used to study the efficacy of 50 mg/L MAPD against Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Fusarium solani and Acanthamoeba polyphaga. Results: MAPD gave a 3.7 log kill of P. aeruginosa after 60 min, 5.4 log for S. aureus by 45 min and 5 log for C. albicans and F. solani within 15 min. A. polyphaga cysts were reduced by 4 log within 120 min. Conclusions: The findings of this study confirm that MAPD is an effective Acanthamoeba cysticidal agent and extend the observation to demonstrate that it also possesses excellent antifungal and antibacterial activity. MAPD may represent a broad-spectrum therapeutic antimicrobial for keratitis and surgical prophylaxis and deserves further evaluation in these roles.