Bacterial Antifibrinolysins. ∗

Abstract

The specific antihuman fibrinolysin formed or secreted by certain strains of Streptococci is presumably one of the main factors causing the rapid spread of certain streptococcus infections on or within human tissues. The effect of associated bacterial species on this aggressive chemical factor, therefore, is of practical clinical interest.

To study such effects, an arbitrary dose of streptofibrinolysin was added to chloroformed broth cultures of the commoner associated microorganisms. At various times after this addition the fibrinolytic titers of the resulting mixtures were determined. Data thus obtained are recorded in Table I.

From the table it is seen that there is a suggestive parallelism between the destruction of the fibrinolysin and the power of the associated microorganisms to liquefy gelatin. Clinically important exceptions to this rule are: Staph. aureus (2 strains), Cl. welchii and Cl. oedematiens-maligni, which liquefy gelatin but are without demonstrable antifibrinolytic action.

The table further shows that the antifibrinolysin in certain bacterial cultures is partially or completely destroyed by heating to 60°C. for 30 minutes. All but one of the antifibrinolysins thus far tested are destroyed quantitatively by heating to 100°C. for 5 minutes.

Heating a non-lytic fibrinolysin-antifibrinolysin mixture to 100°C. for 5 minutes will not restore its fibrinolytic function. Such a restoration would be logical if the coctostable fibrinolysin were merely bound or inhibited by the coctolabile antifibrinolysin.

None of the associated bacteria thus far tested increase the lytic action of streptofibrinolysin.