Inclusion Criteria:

• Ability to provide written informed consent.
• Men or women 18 years of age or older.
• Previously enrolled in PRISM3: Subjects who had a CDI recurrence within 8 weeks of receiving CP101 or placebo and have completed their PRISM3 end of study visit. The definition of CDI recurrence for subjects previously enrolled in PRISM3 includes:
  • Diarrhea (> 3 unformed stools [Bristol Stool Scale score of 6 or 7] per day) for 2 or more consecutive days; 
    • A stool specimen testing positive for Clostridium difficile (C. difficile) by the testing algorithm. At the discretion of the Medical Monitor, an  equivalent CDI testing algorithm per clinical guidelines may be accepted; and
    • Requiring a course of standard-of-care CDI antibiotics; AND
  • Subject has received a course of standard-of-care CDI antibiotics for the most recent CDI episode (for 10-42 days, with exact duration, antibiotic type, and dose at the discretion of the Investigator); AND
  • Subject has had an adequate clinical response, defined as ≤ 3 unformed stools in 24 hours for 2 or more consecutive days during standard-of-care CDI antibiotics prior to Treatment; OR
• Direct Study Entry: Recurrent CDI* defined as ≥ 2 episodes of CDI occurring within the previous 6 months (inclusive of the current episode);

*NOTE: CDI for direct study entry is defined by:

• History of diarrhea (≥ 3 unformed stools per day) for 2 or more consecutive days; AND
• A stool specimen documented as testing positive for C. difficile within 60 days prior to treatment.
• Testing for CDI may include:
  • Presence of toxin A and/or B of C. difficile in the stool determined by any locally available Food and Drug Administration (FDA)-cleared test of C. difficile toxin including the Alere© C. DIFF QUIK CHEK COMPLETE rapid test, enzyme immunoassay for cytotoxin, or toxigenic culture; AND/OR
  • Presence of a toxigenic strain of C. difficile determined by a locally available FDA cleared nucleic acid amplification test (NAAT) to detect the presence of either toxin genes or the pathogenicity locus, or non-FDA-cleared tests that have been approved by the Sponsor; AND
• Has received a course of standard-of-care CDI antibiotics for the most recent CDI episode (for 10-42 days, with exact duration, antibiotic type, and dose at the discretion of the Investigator); AND
  • Has an adequate clinical response, defined as ≤ 3 unformed stools in 24 hours for 2 or more consecutive days during standard-of-care CDI antibiotics prior to Treatment.
• Willingness to abstain from consuming non-dietary probiotics through Week 8 after Treatment;
• Women must fulfill at least 1 of the following criteria:
  • Post-menopausal, defined as amenorrhea ≥ 1 year;
  • Surgically sterile: hysterectomy, bilateral oophorectomy, or tubal ligation; or
  • Abstinent or willing to use adequate contraception from Screening through the Week 24 visit; and
• Deemed to have life expectancy of 8 weeks or greater.

Exclusion Criteria:

• Admitted to, or expected to be admitted to, an intensive care unit for any medical reason.
  • NOTE: Residents of long term care facilities, such as nursing homes and rehabilitation centers, are eligible for study entry;
  • NOTE: Patient visits to clinics, urgent care centers, acute care hospitals, or emergency departments are allowed; however, subject must be an outpatient prior to Treatment.
• Stools known to be positive for ova and/or parasite(s), or other enteric pathogens (e.g., Salmonella, Shigella, and/or Campylobacter) within 28 days prior to Screening.
• Inability to ingest capsules (e.g., severe nausea, vomiting, and/or dysphagia).
• Known or suspected toxic megacolon and/or known small bowel ileus.
• Prior history, evidence, or diagnosis of inflammatory bowel disease (e.g., Crohn’s disease, ulcerative colitis, indeterminate colitis, or microscopic colitis).
• Recent diagnosis (< 6 months prior to Screening) of diarrhea-predominant irritable bowel syndrome (post-infection or not related to an enteric infection). Subjects with diarrhea-predominant irritable bowel syndrome ≥ 6 months prior to Screening may be treated after consultation with the Medical Monitor.
• Current diagnosis of chronic diarrheal illness with pre-CDI baseline diarrhea (≥ 3 loose stools in a 24-hour period). This includes but is not limited to celiac disease, bile salt diarrhea, chronic pancreatitis, and short gut syndrome.
• Past administration of bezlotoxumab (Zinplava™), or past enrollment in a C. difficile vaccine study within 12 months of Treatment.
• Initiation of any systemic cancer treatment (e.g., chemotherapy, radiotherapy, biologic, other) for active malignancy that is planned 8 weeks prior to Treatment or during the 8 weeks following Treatment. Subjects on maintenance treatment for malignancy may be treated after consultation with the Medical Monitor.
• Initiation or escalation of immunosuppressive agents, at the discretion of the Investigator, for any condition during the 8 weeks prior to Treatment or planned during the 8 weeks following Treatment.  Subjects on stable immunosuppressive agents or short-courses may be treated after consultation with the Medical Monitor.
  • NOTE: Solid organ transplant recipients are excluded.
• Compromised immune system, including, but not limited to, a known history of human immunodeficiency virus infection and a cluster of differentiation 4 count that is unknown or documented to be < 200 cells/mm^3 within the last year, or an acquired immunodeficiency syndrome-defining illness; or at the discretion of the Investigator.
• Fecal transplant for any condition, regardless of route of administration in the last year or plans to undergo during the study.
  • NOTE: CP101 use in PRISM3 is not exclusionary.

Treatment (Day 1) Inclusion Criteria:

• An outpatient prior to Treatment.
  • NOTE: Subject may be enrolled while an inpatient in an acute care facility, but must be discharged prior to Treatment on Day 1. Subjects residing in an assisted living center, long-term care facility, or rehabilitation center may be treated.
• Has received a course of standard-of-care CDI antibiotics for the most recent CDI episode (for 10-42 days, with exact duration, antibiotic type, and dose at the discretion of the Investigator).
• Has an adequate clinical response defined as ≤ 3 unformed stools in 24 hours for 2 or more consecutive days during standard-of-care CDI antibiotics prior to Treatment.
• Subject has completed a washout (i.e., a minimum of 2 and a maximum of 6 days after cessation of standard-of-care CDI antibiotics). If the subject experiences diarrhea for 2 or more consecutive days during the washout period, the Investigator should contact the Medical Monitor.