Streptokinase gene variable region classification in streptococci: lack of correlation with post-streptococcal glomerulonephritis.

ABSTRACT

To investigate a possible causal role of streptokinase (SKase) in acute post-streptococcal glomerulonephritis (APSGN), the major variable region of SKase genes of Streptococcus pyogenes strains isolated from patients with and without APSGN were analyzed using the polymerase chain reaction, restriction enzyme analysis and the direct sequencing of SKase genes. In the APSGN-associated strains, six of nine revealed mutant classes corresponding to the nephritogenic classes I and II proposed by Johnston et al. [1992], the remaining three belonged to non-nephritogenic classes. In twenty strains not associated with APSGN, seventeen belonged to classes I and II, while three were from other classes. The major variable region of the SKase gene shows no apparent relation with induction of APSGN in humans, suggesting that unique classes of streptococcal SKase do not play a role in the pathogenesis of APSGN.