FIG. 2.

Survival rates of vegetative C. difficile after 1 h of exposure to unadjusted gastric contents (GC), to gastric contents adjusted to pH 4 to 7, or to PBS. Pooled data from four strains of C. difficile are shown. Gastric contents that were grossly bilious were excluded. Error bars indicate SDs. *, P < 0.0001 versus survival rate in gastric contents at pH 4; †, P < 0.0001 versus survival rate in gastric contents at pH 5; ‡, P < 0.0001 versus survival rates in gastric contents at pH 6 and 7 and in PBS.