Secondary Prevention of Clostridioides Difficile Using Vancomycin

Inclusion Criteria: * Inpatient or outpatient adults (≥18 years old) treated at the participating institutions. * An episode of CDI within the preceding 120 days (rationale in 2.4), diagnosed by both a positive C. difficile assay (including PCR toxin gene detection47, toxin enzyme immunoassay, and/or cell cytotoxicity neutralization assay29) and the presence of either ≥3 unformed stools in \<24 hours with a duration \>24 hours, endoscopic/histologic evidence of pseudomembranous colitis, or ileus29. * Treatment of the qualifying CDI episode with vancomycin or fidaxomicin for ≥10 days, clinical cure (≤3 unformed stool per 24 hours in ≥2 days10) by the conclusion of therapy, and ≥1 day has elapsed since cessation of CDI treatment. * Receipt of ≤3 days of at least one oral or intravenous systemic antibiotic for the treatment of an intercurrent confirmed or suspected bacterial infection, for which therapy is planned for at least one additional consecutive day in duration. Exclusion Criteria: * Treatment of the qualifying episode of CDI with metronidazole monotherapy or intravenous immunoglobulins. * Planned treatment with or treatment of the qualifying episode of CDI with fecal microbiota transplantation (FMT), bezlotoxumab, VOWST, or REBYOTA. * Inability to take medications orally or crushed by nasogastric tube. * Prior total colectomy. * Severe intolerance or allergy to oral vancomycin. * Lack of achievement of clinical cure during the treatment of the qualifying CDI episode …