Variation in Streptococcus Fibrinolytic Action on Human Plasma

Abstract

Tillett and Garner 1 have shown that filtrates of young broth cultures of hemolytic streptococci of human origin can liquefy fibrin clots of normal human plasma. Tillett, Edwards and Garner 2 further found that resistance to this fibrinolytic action in plasma of patients during convalescence from streptococcus infections might indicate antibacterial immunity to that organism. Myers, Keefer and Holmes 3 recorded that this resistance in plasma of patients with rheumatic fever is comparable to that observed in plasma of patients with hemolytic streptococcus infections. Both groups of investigators used the same strain of organism having high fibrinolytic action (i. e., strain CO) as the test organism. Hadfield, Magee and Perry, 4 however, called special attention to the variation in the fibrinolytic activity of different strains of hemolytic streptococci and they proposed to use at least 3 strains of lytic organisms in all tests. In view of the importance of this test in immunological studies, it occurred to us to determine the extent of the variation in the fibrinolytic action of different streptococci of human origin on plasma from normal individuals as well as from patients suffering from acute hemolytic streptococcus infections. An attempt to find a possible relation between this difference of action and the organisms isolated from different groups of diseases due to streptococci was also made at the same time.

The original technique of Tillett and Garner 1 was followed. All except one strain of streptococci were recovered from patients suffering from acute infections, the other being Dochez N. Y. 5, which was obtained from stock. They were grown in 0.05% dextrose meat infusion broth, pH 7.6, for from 18 to 24 hours before use. Blood specimens were collected by venapuncture into tubes containing 0.01 gm. potassium oxalate per cc. of blood. The plasma, after being separated by centrifugation, was tested within 24 hours. The actual test was assembled by mixing 0.2 cc. plasma diluted with saline to one cc., 0.5 cc. broth culture, and 0.25 cc. of 0.25% calcium chloride in normal saline.