FIG. 1.

Skin lesion development in mice following subcutaneous infection. Groups of at least 10 female SKHI hairless mice received a subcutaneous injection of 10⁷ CFU of wild-type or GpoA mutant streptococci and were observed after 1 and 3 days (top and bottom panels, respectively) for the development of a visible ulcer, whose area was determined as described in Materials and Methods. At the time of maximal lesion development for the wild-type strain (3 days), the wild-type strain produced a significantly more severe disease in that the areas of the resulting ulcers were significantly larger (P < 0.01). Each symbol represents the area of ulcer observed in an individual mouse, and the horizontal bar indicates the mean value obtained for each group of 10 mice.