Laboratory study reveals rapid dissolution of human fibrin clots by hemolytic streptococci, indicating an excreted bacterial principle targeting host coagulation proteins.
Key Points
To examine the capacity of hemolytic streptococci and their cell-free filtrates to dissolve fibrin clots and to evaluate susceptibility across species and immune states.
Tested whole broth cultures and sterile cell-free filtrates (via Berkefeld V, Seitz, and Chamberland filters) of 28 human-derived and 18 animal-derived Streptococcus hemolyticus strains, alongside 38 other bacterial species.
Assayed clot liquefaction using human oxalated plasma mixed with calcium chloride and purified human fibrinogen clotted with thrombin under standardized conditions.
Evaluated species specificity using rabbit plasma/fibrinogen and investigated inhibitory antifibrinolytic activity using plasma and serum from convalescent human patients.
All 28 human-derived Streptococcus hemolyticus strains induced rapid fibrinolysis, achieving complete dissolution of human plasma clots in approximately 10 minutes and purified fibrinogen clots in about 2 minutes.
Fibrinolytic activity was absent in 38 non-streptococcal bacterial species and observed in only 3 of 18 animal-derived Streptococcus hemolyticus strains.
Normal rabbit fibrin clots resisted dissolution when formed with rabbit components, but became susceptible when clotted using human thrombin, while convalescent human serum conferred antifibrinolytic resistance to normal human clots.