An antimicrobial composition containing a synergistic combination of an imidazole antifungal agent and activated creatinine is provided, wherein the imidazole antifungal agent represents in the range of about 0.5 mol % to about 30 mol % of the combination of the antifungal agent and the activated creatinine in the composition. Methods for treating bacterial infections, fungal infections, viral infections, and wounds are also provided, as are other methods of use, including methods for disinfecting inert surfaces, methods for preserving food products, and methods for treating plants. In addition, the invention provides a method for enhancing the antifungal effect of an imidazole antifungal agent as well as a method for enhancing the antibacterial effect of activated creatinine. Compositions and methods involving use of activated 2-amino-imidazol-4-one analogs other than activated creatinine are also provided.