This is a prospective, multicenter, randomized, double-blinded, placebo-controlled Phase 3 study of a microbiota suspension of intestinal microbes. The primary assessments for this study are (i) efficacy of RBX2660 as compared to a Placebo in preventing recurrent episodes of CDI and (ii) safety via assessment of adverse events. Follow-up office visits occur at weeks 1-, 4- and 8 after completing the blinded study treatment. Telephone assessments for adverse events occur during weeks 2, 3 and 6 after the study enema and at months 3 and 6. Patients who have had at least two recurrences after a primary episode and have completed at least two rounds of standard-of-care oral antibiotic therapy or have had at least two episodes of severe CDI resulting in hospitalization within the last year may be eligible for the study. Study Subjects who are deemed failures following the blinded treatment per the pre-specified treatment failure definition may elect to receive an unblinded RBX2660 enema.