Flagellin is essential for initial attachment to mucosal surfaces .

Mucins are glycoproteins which can be found in host cell membranes and as a gelatinous surface formed from secreted mucins. Mucosal surfaces in mammals form a barrier to invasive microbes, particularly bacteria, but are a point of attachment for others. is anaerobic bacterium which colonizes the mammalian GI tract and is a common cause of acute GI inflammation leading to a variety of negative outcomes. Although toxicity stems from secreted toxins, colonization is a prerequisite for disease. While is known to associate with the mucus layer and underlying epithelium, the mechanisms underlying these interactions that facilitate colonization are less well-understood. To understand the molecular mechanisms by which interacts with mucins, we used mucosal surfaces to test the ability of to bind to mucins from different mammalian tissues. We found significant differences in adhesion based upon the source of mucins, with highest levels of binding observed to mucins purified from the human colonic adenocarcinoma line LS174T and lowest levels of binding to porcine gastric mucin. We also observed that defects in adhesion by mutants deficient in flagella, but not type IV pili. These results imply that interactions between host mucins and flagella facilitate the initial host attachment of to host cells and secreted mucus.