Influence of blood and serum on the antistaphylococcal activity of lysostaphin.

Zygmunt, Walter A. (Mead Johnson & Co., Evansville, Ind.), Henry P. Browder, and Peter A. Tavormina. Influence of blood and serum on the antistaphylococcal activity of lysostaphin. J. Bacteriol. 91:725-728. 1966.-Human and animal sera, and in certain instances whole blood, exhibited a minimal antagonizing effect on the antistaphylococcal activity of lysostaphin. The presence of 50% human serum only temporarily inhibited cell lysis of viable suspensions of Staphylococcus aureus by lysostaphin. The results obtained on the recovery of viable cells after exposure of S. aureus to lysostaphin actually suggest an enhancement of the antistaphylococcal activity of the antibiotic in the presence of 50% human serum. The growth-inhibitory activity of the antibiotic against 30 clinical isolates of S. aureus was only slightly depressed by the presence of 25% bovine plasma. The data suggest that some binding may occur between the antibiotic and serum proteins, but it is not of an irreversible type. Lysostaphin does not bind readily to red blood cells nor does it enter these cells to any significant degree.