FIG. 4.

GBS CiaR is essential for bacterial fitness and overall virulence. Shown are analyses of bacterial counts in blood 24 h after intravenous injection with equal amounts of WT and ΔciaR mutant GBS strains (A) and in blood, spleen, and brain tissues at the experimental end point of 72 h (B). CFU were enumerated on THA plates or on THA plates supplemented with Cm to distinguish between WT and mutant bacteria. An overall ratio of 1 indicates equal numbers of WT and ΔciaR GBS CFU. *, P < 0.05; **, P < 0.01; ***, P < 0.001.