[Colony morphology of Clostridium perfringens type A (author's transl)]

At least 4 different colony form of Clostridium perfringens on the surface of yeast extract blood agar after overnight incubation were demonstrated. A: glossy colonies with entire margins, mostly surrounded by narrow zones of complete hemolysis and a much wider zone of incomplete hemolysis (colonies typical for C. perfringens (Fig. 1), B: dwarf colonies, similar to A, but very small (Fig. 2), C:rough colonies slightly raised with lobate margins (Fig. 3-4), D: flat colonies with irregular surface and filamentous margins (Fig. 5). Three strains out of 126 gave rise to glossy and rough colony forms (Fig. 6).