An antimicrobial composition, including a synergistic combination of three or more agents as an active ingredient. Each of the three or more potentiating agents can be selected from the following types of compounds: sequestering agents, carbohydrates and carbohydrate derivatives, terpenes/terpenoids, amines and amine derivatives, plant-derived oils, sulfonates, phenols, fatty acids, dibenzofuran derivatives, organo isothiocyanates, quaternary ammonium compounds, peroxides and peroxide donors, and macrolide polyenes. At least two of the three or more potentiating agents are not of the same type of compound. The antimicrobial composition can have strong antimicrobial efficacy in control of microorganisms having resistance to currently used antimicrobials.