Fibrinolysis by Streptococci of Human and Animal Origin. ∗

Abstract

The discovery by Tillett and Garner 1 of an antihuman fibrinolytic function in S. hemolyticus isolated from human cases and the absence of this enzyme from apparently identical streptococci isolated from the environment or from lower animals, is of suggestive epidemiologic interest. We have, therefore, attempted to confirm their findings.

To do this, 193 cultures of typical hemolytic streptococci were kindly furnished by various clinics and veterinary institutions of Northern California. Antihuman fibrinolytic tests were made by the Tillett-Garner technic, each test being repeated 3 times with different samples of normal human blood. Control tests were made with stock cultures of known lytic powers.

For convenience in recording our data, the 193 cultures were divided into 3 groups: (a) 32 cultures originally isolated from internal human tissues, representing such diseases as pneumonia, septicemia, empyemia, endocarditis, osteomyelitis, and meningitis; (b) 123 typical hemolytic strains originally isolated from superficial human tissues, representing such diseases as erysipelas, furunculosis, and fistula, septic sore throat, sinusitis, and acute gastric disturbance; and (c) 38 cultures of veterinary origin, representing such animals as cow, horse, hog, dog, deer, and rabbit. The lytic tests thus grouped are recorded in Table I.

Groups I and III are in practical accord with the Tillett-Garner data. Group II, however, suggests a much less sharp differentiation between antihuman and antiveterinary streptococci than their data indicate. The low percentage of fibrinolytic hemolytic streptococci in this group suggests that a fibrinolytic typing of superficial human infections might be of clinical interest.

Thirty-three strains of S. viridans were tested in connection with this work. All were non-fibrinolytic.