Distribution of S. holeraesuis in BALB/c mice. Four groups of mice were orally infected with doses of 1 × 10C9 CFU of rSC0016(pYA3493), rSC0016(pS-SaoA), rSC0016(pS-Eno) and rSC0016(pS-SE). Bacterial counts were recovered from Peyer’s patches (A), spleen (B), and liver (C) tissues at 3, 7, 14, and 21 days post-infection. Colonies were recorded as CFU/g for organ samples. Data are expressed as the mean ± standard deviations of the five infected mice. (ns) means that there is no significant difference between rSC0016(pS-SE) and rSC0016(pS-SaoA) or rSC0016(pS-Eno) treated groups.