Effect of the antibacterial serum factor on staphylococcal infections.

Yotis, W. W. (Loyola University Medical School, Chicago, Ill.). Effect of the antibacterial serum factor on staphylococcal infections. J. Bacteriol. 83:137-143. 1962-Intracerebral injections of mice with 1 to 5 x 10(6) washed viable cells previously exposed for 1 hr at 4 C to 2 mg/ml of the serum factor resulted in 0 to 30% mortality when three recent isolates of yellow, hemolytic, coagulase-positive strains of Staphylococcus aureus were used. Mice inoculated in the same manner with the above strains, but exposed to an inactive preparation of the serum factor, showed a 60 to 90% mortality. Addition of partially purified coagulase to the serum factor neutralized the protective action of the serum factor. The serum factor was found primarily in the supernatant obtained following 62% (NH(4))(2)SO(4) saturation of the water-soluble globulin portion and precipitated by one-half volume of undiluted 95% ethanol. Plate counts, manometric techniques, and animal protection studies were employed to follow purification of the serum factor. If dry weight is taken as the criterion of purification, the active substance showed a 40-fold purification over a previous preparation of this substance.