FIG. 4.
Expression of vapA fails to rescue the PAI mutant of R. equi from clearance in SCID mice. SCID mice were injected intravenously with 5 × 106 CFU of R. equi 103+, 103−, 103−/vapA, 103+ ΔvapA, 103+ ΔvapA/vapA, ΔPAI, and ΔPAI/vapA. At 0, 2, 7, and 14 days postinfection, mice were humanely sacrificed and organs removed aseptically. The total numbers of bacteria in the spleens (A), lungs (B), and livers (C) were determined by dilution plating of organ homogenates. Each point on the graph represents the mean ± standard deviation of bacterial counts for four mice.