Fig. 6. BclA3 is involved in C. difficile spore adherence to the intestinal mucosa and delays the onset of diarrhea during R-CDI.

a–g Intestinal loops of approximately ~1.5 cm of the ileum and colon were injected with 5 × 10⁸ C. difficile spores wild type (ileum n = 12; colon n = 10), ΔbclA3 (ileum n = 12; colon n = 12), and ΔbclA3/bclA3⁺ (ileum n = 12; colon n = 11). a–c Representative confocal micrographs. C. difficile spores are shown in red, F-actin is shown in green, and nuclei in blue (fluorophores colors were digitally reassigned for a better representation). The white arrows and empty arrows denote internalized and adhered C. difficile spores. Number of the spots (spores) per 10⁵ µm² relatives to wild type of d adhered and the percentage of internalized spores in the d, e ileum, and in the f, g colonic mucosa, respectively. h Schematics of the experimental design. Mice were infected with 5 × 10⁷ C. difficile spores strain, wild type (n = 10), ΔbclA3 (n = 16), or ΔbclA3/bclA3⁺ (n = 14) and were treated with vancomycin from days 3 to 7 and were monitored daily for i relative weight during and j onset of diarrhea during the R-CDI. k Spore adherence to the medium colon was evaluated on day 11. Error bars indicate the mean ± S.E.M. Statistical analysis was performed by d–g, k by two-tailed Mann–Whitney test; i Kruskal–Wallis test, Dunn multiple comparison, j log-rank (Mantel–Cox) test; ns, p > 0.05.