Could bile acids explain why kids with colitis get more c. diff infections?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

For everyone : Inclusion Criteria: * Pediatric patients (\<18 years) consultant or hospitalized in the Gastroenterology department of Necker-Enfants Malades Hospital. * Information and consent of parents and the patient Exclusion Criteria: * Patient who received antibiotic or antifungal treatment in the 4 weeks prior to inclusion. * Patients colonized by C. difficile. * Pregnant or breastfeeding young girl. * Refusal of the protocol by parents or patient. For group 1: Patients with active UC Inclusion criteria: * Patient with UC, whatever the extent, except isolated proctitis (\<5 cm), diagnosed for more than 3 months according to the usual clinical, biological and endoscopic criteria. * UC in flare defined by a PUCAI score of between 35 and 65. Non-inclusion criteria: * Patient with IBD unclassified or Crohn's disease. * Patient with isolated proctitis (\<5 cm). * Colectomized patients. * Patients with sclerosing cholangitis associated with their UC or liver disease. Group 2: Patients in UC remission Inclusion criteria: * Patient with UC, whatever the extent, except isolated proctitis (\<5 cm), diagnosed for more than 3 months according to the usual clinical, biological and endoscopic criteria. * UC in remission defined by a PUCAI score \<10. Non-inclusion criteria: * Patient with IBD unclassified or Crohn's disease. * Patient with isolated proctitis (\<5 cm). * Colectomized patients. * Patients with sclerosing cholangitis associated with their UC or liver disease. Group 3: Healthy control subjects Inclusion criteria: \- Patients hospitalized for an endoscopic assessment to control for abdominal pain, gastroesophageal reflux or polyposis. Non-inclusion criteria: * Patient with chronic liver disease. * Patient with chronic digestive disease (celiac disease, IBD, chronic chronic).