Protective efficacy by vaccination in mice. Mice were injected with S. equi
zooepidemicus ATCC35246 and mortality was recorded daily for 7 days. Mice in the non-immunized group died 24 to 48 h after the challenge, and the mortality rate reached 100%. Mice in the groups immunized with rGroEL or the inactivated S. equi spp. zooepidemicus vaccine died 48 to 72 h after the challenge with S. equi spp. zooepidemicus and 75% survived 7 days post-infection for these two groups. Significant differences in survival were noted, log rank test, P < 0.05. Compared with the non-immunized group, the mice in the groups immunized with rGroEL or the inactivated S. equi spp. zooepidemicus vaccine had higher survival rates (P < 0.05).