FIG 5.

Mutants of mldA and mldB are attenuated in hamsters. Syrian hamsters inoculated orally with 10,000 viable spores were monitored for colonization for up to 4 days and morbidity for up to 30 days. (A) Time from inoculation to detection of C. difficile spores in fecal pellets. Each point represents one hamster, and the bar represents the mean. Colonization rates were 18/18 for the wild type (WT), 19/20 for the mldA::erm strain, and 9/10 for the mldB::erm strain. Data from the two hamsters that were not colonized were excluded from calculations of means. (B) Time from colonization to death. The surviving hamsters were sacrificed on day 30, and their data were included in calculations of means. (C) Kaplan-Meier survival plot indicating time from inoculation to death. Numbers in parentheses refer to the number of hamsters in each treatment group. Data for the wild-type and mldA::erm strains were pooled from two experiments; the mldB::erm mutant was assayed once. *, P ≤ 0.0003 for comparisons of data from the respective mutants and the wild type.