An aqueous antibacterial polymer emulsion and coating compositions are provided. The aqueous antibacterial polymer emulsion comprising a polymer A, an oxidant and a metal complexed with a copolymer B comprising heterocyclic containing monomers; wherein the metal is selected from copper, silver, gold, tin, zinc and combinations thereof; and wherein the emulsion is heat stable. The coating compositions made therefrom provide persistent, broad spectrum antibacterial activity without discoloration problem upon exposure to heat and/or sun light.