Fig. 9

Adjuvant effect in hamster challenge model studies. Panel a, five groups of hamsters (n = 6) were gastrically inoculated with 100 CFU. of C. difficile (the dose can kill >50 % of hamsters) at 2 weeks after the third immunization with either PBS, A-rRBD + B-rRBD, rlipoA-RBD + B-rRBD, or A-rRBD + B-rRBD formulated with alum (300 μg) or Pam3CSK4 (10 μg). The final survival rates were reported. Panel b, The number of C. difficile colonies (CFU) grown in TCCFA selective medium. Bacterial colonies obtained from the faeces (~100 mg) of survived hamsters were determined every two days after challenge. The number of CFU shown in the figure represented the geometric mean of CFU per 100 mg of feacal pellets obtained from survived hamsters in each group after the spore challenge