The present invention is related to a new probiotic composition or food product wherein such a composition or product comprises Clostridim bifermentans. Such a composition or product can be advantageously used to prevent or treat a gut infection with Clostridium difficile.Also part of the invention is formed by methods for assaying for C. bifermentans, for establishing the infective state of a subject by assaying for the presence of C. bifermentans, and by predicting the risk of overgrowth of C. difficile resulting from an antibiotic treatment before start of that treatment.
