Streptokinases Produced by Pathogenic Group C Streptococci Demonstrate Species-Specific Plasminogen Activation

Abstract

The species specificities of plasminogen activation and binding of plasmin by pathogenic group C streptococci isolated from humans, horses, and pigs were examined. Of 56 streptococcal isolates, 52 elaborated plasminogen activator activity and 49 of these had specificity for plasminogen of the homologous host. Analysis of supernatants from 13 isolates indicated that the plasminogen activator activity resulted from secreted streptokinases. These 13 streptokinases were antigenically related and bound all three plasminogens, indicating that the binding recognition sites were conserved despite the observed species-specific activation. In addition, all group C isolates tested demonstrated surface receptors that bound human, equine, and porcine plasmin. Species-specific plasminogen activation may be an early step in events resulting in infection and may account for the species preference of certain streptococci.

The pathogenic equine streptococci

“…Streptokinase released by S. equi interacts with the C-terminal serine protease domain of equine plasminogen to form active plasmin, which hydrolyses fibrin [34]. A role for plasmin in pathogenesis has not been proven but its lytic action on fibrin may aid in spread and dispersion of the bacteria in tissue.…”

Mouse skin passage of Streptococcus pyogenes results in increased streptokinase expression and activity

“…This organism can acquire surface plasminogen enzymic activity in a complex multi-step pathway (D'Costa & Boyle, 1998Wang et al, 1994Wang et al, , 1995a. Although streptokinase (SK) from S. pyogenes isolates demonstrated a species-specific plasminogen activator with preference for human plasminogen (Boyle & Lottenberg, 1997;Marcum & Kline, 1983;McCoy et al, 1991;Nowicki et al, 1994;Schroeder et al, 1999;Wohl et al, 1983), previous studies have shown that streptococcal isolates that can activate mouse plasminogen are more invasive when injected into the skin of plg +/+ but not plg 2/2 mice (Li et al, 1999a).…”

Bovine Mastitis Caused By Streptococcus uberis: Virulence Factors and Biofilm

“…Streptococci agents are able to activate plasminogen thanks to the action of secreted enzymes [52]. Bacterial plasminogen activators comprise streptokinase produced by different Streptococcus pathogen species and differ greatly in structure [44,53].…”