CO92Δ yopH is attenuated by several routes of infection. A) 6-8 week old CD-1 mice were infected IN with 2 × 104 CFU of CO92 or 1 × 107 CFU CO92ΔyopH. The mice were monitored for survival over a 10-day period. B) Mice were infected by intradermal injection with 2 × 104 CFU of CO92 or 1 × 107 CFU CO92ΔyopH and then monitored for survival. Data was analyzed by log-rank analysis and determined to be significant in both cases p = 0.00001. Data is representative of three independent experiments with 10/mice per experimental group.