Abstract
A fluorescent antibody technique was developed for the determination of the type of capsule of strains of S. epidermidis. Of 300 fresh isolates, 27 were mouse virulent strains and of these 74.1 and 25.9% were mono- and polyvalent, respectively. The frequency of capsular type antigens I, II and III produced by the 27 virulent strains was 18.5, 88.9 and 18.5%, respectively, the majority being capsular type II. In the mouse avirulent strains, capsular type antigen production was demostrated in 263 of 273 strains examined and mono- and polyvalent capsular types comprised 52.3 and 44.0%, respectively. Capsular type I, II and III strains and non-typable strains occurred at frequencies of 15.0, 95.2, 34.9 and 3.7%, respectively, the majority of mouse avirulent strains also being capsular type II. Thus, most ordinary S. epidermidis produce capsular type antigens, although the capability is quantitatively different according to strain.