- Clostridium difficile is an important nosocomial pathogen that has become a major cause of antibiotic-associated diarrhea.
There is a general consensus that C. difficile spores play an important role in C. difficile pathogenesis, contributing to infection,
persistence, and transmission. Evidence has demonstrated that C. difficile spores have an outermost layer, termed the exosporium,
that plays some role in adherence to intestinal epithelial cells. Recently, the protein encoded by CD1067 was shown to be
present in trypsin-exosporium extracts of C. difficile 630 spores. In this study, we renamed the CD1067 protein Clostridium difficile
exosporium cysteine-rich protein (CdeC) and characterized its role in the structure and properties of C. difficile spores.
CdeC is expressed under sporulation conditions and localizes to the C. difficile spore. Through the construction of an ΔcdeC
isogenic knockout mutant derivative of C. difficile strain R20291, we demonstrated that (i) the distinctive nap layer is largely
missing in ΔcdeC spores; (ii) CdeC is localized in the exosporium-like layer and is accessible to IgGs; (iii) Δ cdeC spores were
more sensitive to lysozyme, ethanol, and heat treatment than wild-type spores; and (iv) despite the almost complete absence of
the exosporium layer, Δ cdeC spores adhered at higher levels than wild-type spores to intestinal epithelium cell lines (i.e., HT-29
and Caco-2 cells). Collectively, these results indicate that CdeC is essential for exosporium morphogenesis and the correct assembly
of the spore coat of C. difficile.
- Keywords: Spore surface,
Bacillus anthracis exosporium,
- Barra-Carrasco, J., Olguín-Araneda, V., Plaza-Garrido, A., Miranda-Cárdenas, C., Cofré-Araneda, G., Pizarro-Guajardo, M., . . . Paredes-Sabja, D. (2013). The clostridium difficile exosporium cysteine (CdeC)-rich protein is required for exosporium morphogenesis and coat assembly. Journal of Bacteriology, 195(17), 3863-3875. doi:10.1128/JB.00369-13
|Funding Statement (additional comments about funding)
- This work was supported by grants from MECESUP UAB0802, Fondo Nacional de Ciencia y Tecnología de Chile (FONDECYT grant 1110569), by a grant from the Research Office of Universidad Andres Bello (DI-275-13/R 2013) (to D.P.-S), and by grants from the N. L. Tartar Foundation of Oregon State University, Agricultural Research Foundation of Oregon State University, and the Department of Defense Multi-disciplinary University Research Initiative (MURI) award through the U.S. Army Research Laboratory and the U.S. Army Research Office under contract number W911NF-09-1-0286 (to M.R.S.).