Fig 8.

Evaluation of murine virulence of F. tularensis migR, trmE, and cphA mutants. Mice were infected with 3,000 CFU of wild-type strain LVS or with LVS migR::TrgTn, LVS ΔtrmE, or LVS ΔcphA mutant strains with two separate doses to evaluate the effect of each mutation on the virulence of the strain. As can be seen, all mice infected with 3,000 CFU of LVS died by day 6 postinfection. The LD₅₀ values of the migR and cphA mutants were >1 × 10⁵ CFU, since no mice died at the highest dose. The calculated LD₅₀ value for the trmE mutant was 9.5 × 10⁴ CFU, as no mice died at a dose of 14,000 CFU but 60% of mice died at the 140,000-CFU dose.