Fibrinolysins from Gas Gangrene Anaerobes.

In an earlier paper, Reed, Orr and Smith (1941), demonstrated that the more actively pathogenic species of gas-gangrene anaerobes produce fibrinolysis when tested by the familiar procedure of Tillet and Garner (1933). Carlsen (1939) has previously shown that Clostridium histolyticum produces an active fibrinolysin. The eleven species of the genus Clostridium (some seventy-seven strains) tested fall into two distinct groups: a majority of cultures of C. welchii, C. novyi, C. septicum, C. sordellii, C. chauvoei, C. histolyticum, C. s'porogenes and C. tyrosinogenes produce fibrinolysis of coagulated plasma from man, guinea pig, rabbit (except C. sordellii) and sheep (except C. wekhii). In contrast no cultures of C. fallax, C. tertium, C. aerofoetidum produce measurable fibrinolysis of human, guinea pig, rabbit or sheep plasma. In the case of human plasma, C. welchii produced the most active fibrinolysis; 83% of twenty-six strains produced complete solution in 24 hours or less, 17% produced complete solution in 7 hours or less and a few in 1 to 2 hours. C. histolyticum cultures were about equally active. All the other active species required from 7 to 24 hours to complete solution of coagulated human plasma. For the most part, guinea pigs' and rabbits' plasma was more rapidly, and sheep plasma less rapidly, broken down than plasma from man by all the fibrinolytically active species of Clostridium. In this respect the fibrinolysins of clostridia resemble those of staphylococci (Madison and Dart, 1936; and Meter, 1937), and stand in sharp contrast to the fibrinolysin of Streptococcus haemolyticus (Le Mar and Gunderson, 1940). In the following experiments, as well as those summarized above, all organisms were grown in chopped meat medium and tests for fibrinolysis, anticlotting or clotting factors made after 18 to 20 hours' iincubation. Cultures in Brewer's medium or peptone-thioglycollate medium (Reed and Orr, 1942) generally gave reactions the same as parallel cultures in chopped meat, but after several generations in the thioglycollate-containing media results were more irregular. 1. C. tetani. In sharp contrast with the fibrinolytic activity of the toxigenic gas-gangrene species of Clostridium, five strains of C. tetani, all active toxinproducing strains, failed to produce any fibrinolytic activity when tested by the same methods used with the gas-gangrene species. It seems probable that this difference is an important factor in the manner of spread of the two groups of species in the animal body. 2. Nature of fibrinolytic enzyme of Clostridia. The species distribution of fibrinolytic activity does not suggest any relationship between this action and proteolysis. Garner and Tillet (1934) have shown that the fibrinolysin of haemolytic Streptococcus will resist heating to 100'C. for 60 minutes and that the