FIG. 7.

Roles of Rgg and AhpCF in virulence. (A) Rgg-deficient GAS is more virulent than wt GAS. Ten mice divided into two cages were challenged intraperitoneally with wt (7.3 × 10⁸ CFU; wt-1), Δrgg (6.7 × 10⁸ CFU; Δrgg-1), twofold-diluted Δrgg-1 (Δrgg-2), or fivefold-diluted Δrgg-1 (Δrgg-5) bacteria. The survival of the mice was monitored daily for up to 7 days. The survival data are presented as a Kaplan-Meier plot. (B) Up-regulation of AhpCF expression in Δrgg does not account for the increased virulence of Δrgg. Ten mice divided into two cages were challenged intraperitoneally with Δrgg (1.5 × 10⁸ CFU) or Δrgg ΔahpCF (1.6 × 10⁸ CFU) bacteria. The survival of the mice was monitored daily up to 14 days. The survival data are presented as a Kaplan-Meier plot. All mice were weighed daily to get a readout of the general condition of the infected animals as weight indexes.