The aim of this Phase I/II trial is to assess the efficacy and safety of oral administration of EXL01, a single isolated unmodified strain of F. prausnitzii, in preventing CDI recurrence in high-risk patients at W8. The study will be conducted in 2 parts. The phase I (Part A) is planned to include 6 patients. The phase II (Part B) will include 50 patients in two arms (25 patients respectively in the placebo and EXL01 arm). conditions: Clostridioides Difficile Infection conditions: Recurrent Infection studyType: INTERVENTIONAL phases: PHASE1 phases: PHASE2 allocation: RANDOMIZED interventionModel: PARALLEL interventionModelDescription: Part A = Single Arm open label. Part B = Randomised, placebo-controlled, double-blind. primaryPurpose: TREATMENT masking: QUADRUPLE maskingDescription: Part A: None (Open-label). Part B: Double-blind. whoMasked: PARTICIPANT whoMasked: CARE_PROVIDER whoMasked: INVESTIGATOR whoMasked: OUTCOMES_ASSESSOR count: 56 type: ESTIMATED name: EXL01 name: EXL01 name: Placebo measure: Incidence of Treatment-Emergent Adverse Events measure: Evaluation of the efficacy of EXL01 in preventing recurrence of C. difficile infection in patients at high risk of recurrence measure: Evaluation of the efficacy of EXL01 in preventing recurrence of C. difficile infection in patients at high risk of recurrence measure: Evaluation of the safety and tolerability profile of oral EXL01 measure: Number of stools per day over the past 24 hours measure: Stool consistency, as assessed by the Bristol scale, over the past 24 hours measure: Abdominal discomfort assessed by a validated irritable bowel syndrome scale measure: Number of stools per day over the past 24 hours measure: Stool consistency, as assessed by the Bristol scale, over the past 24 hours measure: Abdominal discomfort assessed by a validated irritable bowel syndrome scale measure: Assessment of patient quality of life during treatment and follow-up measure: Assessment of recurrence of C. difficile infection measure: Evaluation of the presence of EXL01 in the fecal microbiota measure: Assessment of EXL01 persistence in the intestinal microbiota measure: 16S rRNA sequencing or shotgun measure: 16S rRNA sequencing or shotgun measure: Assessment of the persistence of toxigenic C. difficile in the stool of patients in clinical remission during the study. measure: Assessment of the persistence of toxigenic C. difficile in the stool of patients in clinical remission during the study. measure: Assessment of recurrences of C. difficile infection requiring hospitalization measure: Assessment of recurrences of C. difficile infection requiring hospitalization measure: Assessment of recurrences of C. difficile infection requiring surgery measure: Assessment of recurrences of C. difficile infection requiring surgery sex: ALL minimumAge: 18 Years stdAges: ADULT stdAges: OLDER_ADULT facility: Service d'hépato-gastroentérologie - CHU Estaing city: Clermont-Ferrand zip: 63003 country: France name: Julien SCANZI, MD role: CONTACT phone: 04 73 75 02 35 email: jscanzi@chu-clermontferrand.fr name: Julien SCANZI, MD role: PRINCIPAL_INVESTIGATOR lat: 45.77966 lon: 3.08628 facility: Service d'Hépato-gastroentérologie Hôpital de la Croix Rousse city: Lyon zip: 69004 country: France name: Nicolas BENECH, MD role: CONTACT phone: 04 26 10 94 35 phoneExt: +33 email: nicolas.benech@chu-lyon.fr name: Fanny JOUBERT role: CONTACT phone: 04 26 73 27 27 phoneExt: +33 email: Fanny.joubert@chu-lyon.fr name: Nicolas BENECH, MD role: PRINCIPAL_INVESTIGATOR lat: 45.74848 lon: 4.84669 facility: Service d'hépato-gastroentérologie - Hôpital Saint Antoine (APHP) city: Paris zip: 75012 country: France name: Paul MCLELLAN, MD role: CONTACT phone: 01 49 28 20 00 phoneExt: +33 email: Paul.mclellan@aphp.fr name: Paul MCLELLAN, MD role: PRINCIPAL_INVESTIGATOR lat: 48.85341 lon: 2.3488 facility: Service d'infectiologie - Hôpital Nord / CHU Saint Etienne city: Saint-Étienne zip: 42100 country: France name: Elisabeth BOTHELO-NEVERS, Pr role: CONTACT phone: 04 77 12 77 89 phoneExt: +33 email: elisabeth.botelho-nevers@chu-st-etienne.fr name: Elisabeth BOTHELO-NEVERS, Pr role: PRINCIPAL_INVESTIGATOR lat: 45.43389 lon: 4.39 facility: Service de médecine interne - Pôle des maladies de l'appareil digestif - CHU de Toulouse city: Toulouse zip: 31059 country: France name: Laurent ALRIC, Pr role: CONTACT phone: 05 61 32 37 54 email: Alric.l@chu-toulouse.fr name: Laurent ALRIC, Pr role: PRINCIPAL_INVESTIGATOR lat: 43.60426 lon: 1.44367 facility: Service de Maladies Infectieuses - CH de Valence city: Valence zip: 26000 country: France name: Julien SAISON, MD role: CONTACT phone: 04 75 62 57 32 phoneExt: +33 email: jsaison@ch-valence.fr name: Julien SAISON, MD role: PRINCIPAL_INVESTIGATOR lat: 44.93333 lon: 4.9 hasResults: False