Predicted toxicity correlates with disease severity in vivo. Using high and low doses (7.8–8.0 and 3.7–4.1 × 10⁷ CFU, respectively), mice were inoculated intravenously with the high and low toxic isolates (HU13 and MU9, respectively), and survival of the mice, the development of septic arthritis, and weight loss were recorded as indications of disease severity. In each case the highly toxic HU13 isolate caused the most severe disease symptoms. (A) n = 10–15. (B) n = 8–10. (C) n = 10–20. (D) n = 10. (E) n = 10–19. (F) n = 10. Significant P-values (<0.05) are indicated (*).