Coating compositions having a peptidic antimicrobial additive and an antimicrobial additive of another configuration are provided. The concentrations of the antimicrobial agents within the coating composition are sufficient to synergistically inhibit microbial growth on an inanimate surface coated with the surface coating composition or within a container storing the coating composition. Methods for making and using such compositions to inhibit microbial growth in stored coatings and on susceptible surfaces are also provided.