Inclusion Criteria:  Ability to provide written informed consent Men or women over 18 years of age or older Current diagnosis of a recurrence of non-severe, non-complicated CDI Subject has a clinical response to standard-of-care CDI antibiotics for the most recent CDI episode  History of recurrent CDI defined as:  ≥ 3 episodes of CDI, with 2 episodes occurring within the previous 6 months (inclusive of the current episode); OR Patients with a history of 2 episodes of CDI occurring within the previous 6 months (inclusive of the current episode) may be eligible if 65 years of age or older.  For the Qualifying CDI episode, the following criteria must be satisfied:  History of diarrhea (> 3 unformed stools per day) for 2 or more consecutive days that is clinically consistent with CDI. AND Documented positive stool test by local laboratory for toxigenic C. difficile (toxin enzyme immunoassay [EIA] or polymerase chain reaction [PCR]-based testing) for the current CDI episode and within 45 days prior to Randomization. AND Received a course of SOC CDI antibiotics for the most recent CDI episode (for 10 to 21 days, with exact duration, antibiotic type, and dose at the discretion of the Investigator). AND Demonstrated an adequate clinical response, defined as ≤ 3 unformed stools in 24 hours for 2 or more consecutive days during SOC CDI antibiotics prior to Randomization.  Exclusion Criteria:  Known stool sample testing positive for enteric pathogen(s) (e.g., Salmonella, Shigella, diarrhoeagenic E. coli, Campylobacter, Giardia) within 28 days prior to Screening Pregnant, breast-feeding, or planning to become pregnant during the trial Historical or current diagnosis of inflammatory bowel disease Recent diagnosis (<6 months prior to screening) of diarrhea-predominant irritable bowel syndrome (post-infection or non-related to an enteric infection) Initiation of any systemic cancer treatment (e.g., chemotherapy, radiotherapy, biologic, immunotherapy, others) for active malignancy Major intra-abdominal surgery (e.g., bowel resection) Known primary or secondary immunodeficiency