A method for prediction of the susceptibility of an at risk patient to developing or redeveloping an infection with Clostridium difficile, having the determination by immunoassay, in a stool sample from said patient, of the level of antibody IgA anti-toxin B of Clostridium difficile, and comparing this level with a reference value S determined beforehand using two populations of patients exposed to the bacterium, one population not having developed or redeveloped such an infection and the other population having developed or redeveloped such an infection, —a level lower than said reference value S signifying that the patient is a patient with a heightened risk of developing or redeveloping a Clostridium difficile infection, and —a level higher than said reference value S signifying that the patient is not a patient with a heightened risk of developing or redeveloping a Clostridium difficile infection.