Clostridium difficile infections (CDI), in particular due to hypervirulent strains, are a major cause of healthcare-associated infections. Surveillance of CDI according to the surveillance protocol is compulsory for acute care hospitals since 2007. For at least 6 months per year (first or last 6 months of the year), hospitals have to register all cases of CDI in the institution. This is a patient-based surveillance (as opposed to aggregated data): the unit of the database is the infection. These data are used to compute incidence rates at hospital and national level.