Production of Fibrinolysin In Vivo.

Abstract

It was recently reported 1 that the fibrinolysin of hemolytic streptococci may be found in vivo. The fibrinolytic agent could be demonstrated in the spinal fluid of patients with purulent meningitis due to streptococcus hemolyticus. Subsequently, purulent exudates from various sources have been examined for fibrinolytic potency. The exudates were centrifuged immediately and the supernatant fluids were tested according to the technic of Tillett and Garner. 2

Of 5 spinal fluids from patients with hemolytic streptococcal meningitis, 4 contained fibrinolysin; the fifth did not, in spite of the fact that the isolated strain produced fibrinolysin in vitro. Of 6 patients with pneumococcal meningitis, only one, due to pneumococcus type XIV, displayed fibrinolytic activity. The spinal fluids of 5 patients with meningococcal meningitis, and of a patient with tuberculous meningitis (proven bacteriologically), did not contain any fibrinolysin; nor did the spinal fluids of 4 patients with a clinical diagnosis of encephalitis.

Exudates from patients with purulent pericarditis, pleuritis and peritonitis also have been examined for fibrinolytic activity. The fibrinolysin was demonstrated in the peritoneal exudate of a patient with hemolytic streptococcal peritonitis and in the pleural fluid of another patient with β-streptococcal empyema. Fibrinolysin was also found in the exudates of 2 patients with pericarditis and peritonitis, respectively due to Staphylococcus aureus hemolyticus, the organism was present in the blood stream of both patients.

In order to determine whether fibrinolysin is produced in experimental animal diseases, various strains of pneumococci and hemolytic streptococci, suspended in saline, were intraäbdominally injected into white mice. The injected material was not fibrinolytic. Shortly after death of the mice, which usually occurred between 12 and 48 hours after the injection, the abdominal cavity was washed with about 10 cc. of normal saline; the specimens obtained were centrifuged and the supernatant fluid tested for fibrinolytic activity. Fibrinolysin was present in the washings from mice which had succumbed to hemolytic streptococcal infection. The fibrinolysin from washings dissolved clotted plasma; it was effective in high dilutions on human, but not rabbit or guinea pig plasmas; it was heat-labile, and could be neutralized by specific streptococcal antisera. The washings also contained hemolysin in high titer. Further experiments are necessary to determine whether the abdominal washings from mice infected with microörganisms other than hemolytic streptococci may contain fibrinolysin. Thus far, the washings from mice killed by various types of pneumococci did not display any fibrinolytic activity.