The progressive endemic diffusion of C. difficile, the continuous appearance of more virulent strains, and the ability to mutate the molecular domains of TcdB and TcdA involved in binding to the various Tcd receptors (chondroitin sulphate proteoglycan 4; frizzled proteins 1, 2 and 7; poliovirus receptor-like protein; sucrase isomaltase; and glycoprotein 96) differently expressed on various cell types [17,18,42], together favour greater pathogenicity, highlighting the need to develop more effective strategies to combat this serious infection. Here, SI is linked to infection.