Demonstration of Streptococcal Fibrinolysin in Exudates. The Action of Sulfanilamide upon It

In a preliminary note 1 it was reported that exudates of streptococcal and staphylococcal origin may exhibit fibrinolytic activity. Subsequently, a more detailed study on the occurrence in vivo of staphylococcal fibrinolysin was presented. 2 Recently, Tillett 3 described the presence of fibrinolysin in empyema-fluids from which beta hemolytic streptococci were recovered. In the following communication, observations are presented dealing with the demonstration of fibrinolysin present in various exudates of beta hemolytic streptococcal origin and further with the action of sulfanilamide upon the fibrinolysin produced in vivo by this microörganism.

For the demonstration of the fibrinolysin present in exudates, the following technic was employed: The exudate was centrifuged and the supernatant fluid in serial dilutions (volume 0.5 cc) was mixed with 1 cc of 1:5 dilution of human plasma; then 0.25 cc of a 0.25% calcium-chloride solution in normal saline was added; the tubes were shaken thoroughly and incubated at 37°C. The plasma was obtained from healthy human beings by mixing 10 cc of blood with 1 cc of a 2% potassium-oxalate solution; the blood was shaken and centrifuged. Prior to the experiments the plasma was tested as to its susceptibility to the action of streptococcal fibrinolysin. The resulting coagulation of the plasma and dissolution of the clot was noted at various intervals. For the demonstration of the fibrinolysin produced in vitro, the supernatant fluid of an 18-hour infusion-broth culture of the respective strain was tested in like manner.

During the last 2 years, 48 specimens of purulent exudates obtained from patients with various infections due to beta hemolytic streptococci were tested for fibrinolytic activity. Thirty specimens were found to contain fibrinolysin, while 18 did not. These exudates included 31 empyema-fluids; 15 exhibited fibrinolytic activity, while 16 specimens failed to do so.