Streptococcus Anticoagulant. ∗

Abstract

It was shown by Neter and Witebsky 1 that many bacterial species which produce no demonstrable fibrinolysin in veal-infusion broth do produce fibrinolytic factors if grown in the same medium plus 0.4–2% glucose. They found that in this glucose broth many fibrinolytic bacteria often produce 2 fibrinolysins; S. hemolyticus, for example, producing: (a) the highly specific Tillett-Garner fibrinolytic enzyme and (b) a hitherto undescribed, relatively non-specific lytic factor. The new lytic factor prevents the coagulation of human plasma, a property rarely demonstrable with the Tillett-Garner enzyme.

We have repeated their work, using the isolated-fibrin technic 2 in place of their relatively crude plasma-clot technic. Confirming their results, we have found that many apparently non-fibrinolytic strains of S. hemolyticus will produce anticoagulants if grown in veal-infusion broth plus 0.4% glucose. Demonstrably fibrinolytic strains produce this anticoagulant in addition to a normal amount of the routine Tillett-Garner fibrinolysin. Unlike the fibrinolysin, the anticoagulant is not specific for human fibrin; but will also prevent the clotting of isolated fibrinogen-thrombin-complex from rabbit, sheep, cow and domestic swine. The anticoagulant is not neutralized with concentrations of commercial streptococcal antiserum sufficient to neutralize the specific fibrinolysin. The anticoagulant and fibrinolysin are apparently independent variables in different streptococcal strains.

Chemical differences between the anticoagulant and the routine fibrinolysin are demonstrable by the enzyme-concentration technic of Tillett and Garner. From 24-hour glucose-broth cultures of relatively high anticoagulative titers, purified fibrinolysin is obtained by alcohol (75%, ice-cold) precipitation. Even in a 10-fold concentration this purified fibrinolysin is without demonstrable anticoagulating effects. The anticoagulant remains in solution in the supernatant alcohol, from which it can be recovered by evaporation. The anticoagulant thus recovered is thermostable. It resists heating to 100°C. for 30 minutes.