Figure 2. Deletion of hha does not impair long-term cecal colonization of MT15. Groups of C57BL/6 mice were vaccinated with 5 × 10⁷ cfu of Salmonella Typhimurium MT12 (ssaV mutant; n = 10) and MT15 (ssaV and hha double mutant; n = 10) by oral gavage. Control mice group was treated with PBS (n = 10). (A) Fecal shedding of different Salmonella strains as analyzed by plating at various time-points. (B) Mice from each vaccinated group were sacrificed (n = 5) at day 30 post-vaccination (p.v.) to assess the bacterial densities at different host sites. Graph shows the enumeration of bacterial loads at various host sites. Broken lines in the graphs shows minimum detection limit. n.s., not significant; *statistically significant (P < 0.05, t test).