Antimicrobial systems of the surgical wound. II. Detection of antimicrobial protein in cell-free wound fluid.

Human wound fluid contains heat-stable proteins with moderate antibacterial activity against Staphylococcus aureus and Escherichia coli, and different heat-labile proteins with antibacterial activity against E coli. Blood serum also contains heat-labile antibacterial substances, but little heat-stable activity against Staphylococcus aureus. Both blood serum and wound fluid have bacteriostatic activity against S epidermidis, and early growth of Streptococcus fecalis occurs in serum and wound fluids. The concentration or activity of antimicrobial proteins increases during the first week in the fresh wound and then decreases as the wound matures.