Figure 1.

Infection of hCD46Ge transgenic mice with MC58 and its Δapp, ΔmspA and ΔappΔmspA mutant derivatives. Groups of 10 mice were infected intraperitoneally with 1.2 × 10⁹ CFU of bacteria.

A. Survival rates tended to be higher in groups infected with Δapp, Δmsp A or ΔappΔmsp A (P < 0.05, Fisher's exact test, MC58 compared with MC58 Δapp‐infected groups or MC58ΔappΔmsp A strain at 72 h). A negative control group (n = 7), which received re‐suspension fluid alone, showed 100% survival at all time points (not shown).

B. CFU counts were determined after plating out serial dilutions of blood. Significantly fewer bacteria were found in the blood of animals infected with MC58Δmsp A and MC58ΔappΔmsp A at 6 h post‐challenge, and in animals infected with MC58ΔappΔmsp A at 48 h post‐infection. Mean CFU (± SEM) from surviving animals shown. *P < 0.05; **P < 0.01; Kruskal–Wallis and Dunn's test.