Improved therapeutic compositions having enhanced anti-microbial activity comprising a bactericidal/permeability-increasing (BPI) protein product and an bactericidal-activity enhancing polyoxyethylene block copolymer surfactant (poloxamer) surfactant or a bacterial and fungal growth-inhibiting enhancing poloaxamer surfactant, optionally with EDTA, and methods for treating bacterial infection by administering such compositions, alone or concurrently with antibiotics.