Clostridioides difficile stimulates CCL20 expression in human colonoid monolayers in a transwell-based co-culture system that supports its anaerobic growth

The pathogenic bacterium Clostridioides difficile is a major cause of antibi-otic-associated diarrheal disease. Treatment of the disease is challenging because anti-biotics used for treatment may also perpetuate the conditions that contributed to initial susceptibility. Elucidating the mechanisms of C. difficile/intestinal epithelium interaction is needed to facilitate the development of new therapeutic options. The studies described in this communication demonstrate the development of a tissue culture system that supported the growth of C. difficile in co-culture with a model of the human intestinal epithelium produced from colonoids, organoids derived from human colonic biopsies. Epithelial cell responses to C. difficile included upregulation of CCL20, encoding a chemokine. Glucosylating toxin production by the bacteria was required for upregulation of CCL20. Additionally, bacteria associated with the monolayer in a non-toxin dependent manner. This system will support future investigation of epithelium/C. difficile interac-tions during CDI and identification of mechanisms that drive pathogenesis by C. difficile in the human intestine.