Figure 5.

ΔInvC Salmonella is only mildly attenuated in vivo. (a) Mice infected with ΔInvC Salmonella showed extended survival as compared to mice infected with wild-type (WT) Salmonella. C57BL/6 mice were orally infected with 10⁵ bacteria and survival was registered daily. Mice treated with vehicle were included as controls. (b) Mice infected with ΔInvC Salmonella showed reduced organ colonization at 4 and 7 days post-infection, as compared to mice infected with WT Salmonella. To determine organ colonization capacity, mice were killed at day 4 or 7 after infection and their liver, spleen and mesenteric lymph nodes were lysed and plated for intracellular bacterial count. (c, d) Bacterial colonization for individual organs at 4 days (c) and 7 days (d) post-infection with either WT or ΔInvC Salmonella. Survival and organ colonization experiments were repeated at least three times for each strain. At least four mice per group were included in each experiment. Bars represent SE (Student’s t-test: *P < 0·05; **P < 0·01).