Role of hyaluronidase and the hyaluronic acid capsule in the survival and dissemination of group A streptococci in the hamster cheek pouch.

The effect of hyaluronidase on host connective tissue and the protective action of the hyaluronic acid capsule against phagocytosis have been the basis for a number of studies on the relation of these products to the virulence of streptococci. Duran-Reynals (1933) demonstrated that the areas of dermal lesions produced by several strains of streptococci were largely a function of the amount of hyaluronidase produced by these strains. Sallman and Birkeland (1950) found that streptococcal strains isolated from patients produced higher hyaluronidase titers than strains isolated from normal people, and furthermore, the higher titers were associated with the more clinically severe infections. These workers also demonstrated a correlation between hyaluronidase production in vitro and virulence for the chick embryo. Other investigators, however, (Crowley, 1944; Russell and Sherwood, 1949; Sherwood et al., 1952) have indicated a lack of correlation between hyaluronidase production in vitro and virulence for mouse, chick, or man. Warren (1950) studied the influence of high concentrations of hyaluronidase on the course of experimental infections in the flanks of rabbits and reported no enhancement of the infections nor increase in the size of the lesions. The resistance of streptococci of groups A and C to phagocytosis has been shown to be related in part to the presence of the hyaluronic acid capsule (Seastone, 1934; Ward and Lyons, 1935; Kass and Seastone, 1944; Rothbard, 1948; Morris and Seastone, 1955). Hirst (1941) successfully protected mice infected with group C encapsu-