FIG. 1.

The SLS⁻ mutant is attenuated in the adult zebrafish model of necrotic myositis. Groups of zebrafish were challenged intramuscularly with 10⁵ CFU of mutant (SLS⁻) or wild-type (WT) S. pyogenes. Significant differences are indicated by an asterisk. (A) Percentage of fish with lesions at 6, 12, and 24 h. The data represent the average of 10 fish per experiment over three separate experiments at the indicated time points. There were significantly fewer lesions (P < 0.02) in the mutant group at each time point. (B) Numbers of CFU recovered from infected tissue at 6 and 12 h. Data represent the mean and standard deviation of three separate experiments. A significant difference was seen at 6 h but not at 12 h. (C) Survival data presented as a Kaplan-Meier plot. Data are pooled from three independent experiments, each of which was conducted using 10 zebrafish per group. These data indicate that the mutant was significantly less lethal than the wild type (P < 0.0043).