FIG 5.

Deletion of CD1492 results in decreased virulence in the hamster model of infection. (A) Kaplan-Meier survival plot of the survival times of Syrian golden hamsters infected with 5,000 spores of C. difficile strain 630Δerm (n = 12) or MC674 (ΔCD1492; n = 12). The mean times to morbidity were as follows: 630Δerm, 45.5 ± 3.5 h; ΔCD1492, 107.9 ± 52.5 h. (P < 0.01, log rank test). The total number of CFU of C. difficile recovered from feces at 24 h postinfection (B) or per milliliter of cecal content recovered postmortem (C) is shown. The solid lines in panels B and C represent the median CFU count of each strain, and the dotted lines denote the limit of detection (LOD; 2 × 10¹ CFU/g or CFU/ml). Statistical significance was assessed by one-way ANOVA. Animals infected with 630Δerm served as positive infection controls that were shown in a parallel study (22).