Inhibition of adhesion of Clostridium difficile to human intestinal cells after treatment with serum and intestinal fluid isolated from mice immunized with nontoxigenic C. difficile membrane fraction

• Nontoxigenic Clostridium difficile membrane fraction (ntCDMF) generated an immune response.
• Serum and intestinal fluid of immunized mice hindered adhesion of parental strain.
• Serum and intestinal fluid also inhibited the adhesion of toxigenic strains.
• The ntCDMF has potential as a preventive measure against C. difficile infection.

Diarrhea and pseudomembrane colitis caused by Clostridium difficile infection is a global health concern because of the high recurrence rate after standard antibiotic therapy. Vaccination presents a powerful countermeasure against disease recurrence. In this study, mice vaccinated with the nontoxigenic C. difficile membrane fraction generated a marked immune response to the antigen, as demonstrated by the serum IgG and intestinal fluid IgA levels. Significantly, pretreatment with harvested IgG- and IgA-containing fluids was sufficient to prevent in vitro adhesion of C. difficile to human Caco-2 intestinal cells. These results highlight the potential of nontoxigenic C. difficile membrane fraction as a vaccine candidate for C. difficile infection.