2421. Efficacy of Secondary Prophylaxis with Oral Vancomycin in Preventing Recurrent Clostridioides difficile Infections in Patients Receiving Systemic Antibiotics

BACKGROUND: One of the major challenges in Clostridioides difficile infection (CDI) is preventing recurrence, particularly in the setting of risk factors, such as systemic antibiotics that impact the gut microbiome. There are little data to demonstrate the impact of secondary prophylaxis with oral vancomycin and due to the lack of evidence, the IDSA guidelines do not make a recommendation. METHODS: This was a multi-site, retrospective cohort study of adult inpatients within the University of Rochester Medical Center who received either a high- or medium-risk systemic antibiotic between July 1, 2013 and September 30, 2018 and had a positive C. difficile test within one year prior to admission. The primary endpoint was incidence of recurrent CDI within 90 days from the start of antibiotics in patients who received oral vancomycin prophylaxis (OVP) vs. those who did not receive prophylaxis (control). RESULTS: Of 425 patients screened, 153 patients were included in the control and 78 patients in the OVP group. The OVP group was more likely to be immunosuppressed (P < 0.001), have increased hospital length of stay (P < 0.001), receive a proton pump inhibitor (P = 0.049), have a prior episode of CDI within the previous 90 days (P < 0.001), and have > 1 prior episode of CDI (P = 0.038). The control group was more likely to have received metronidazole for the most recent CDI episode (P < 0.001), likely reflecting mild-moderate severity. Recurrent CDI within 90 days was 10.3% in the OVP group compared with 17.6% in the control (P = 0.175). A subgroup analysis of the patients with recurrent CDI found the time to recurrence from initiation of systemic antibiotics was similar in the OVP group compared with control (43 vs 30 days, P = 0.223). CONCLUSION: While there was not a statistically significant difference in recurrent CDI within 90 days, the OVP group had numerous risk factors that made these patients at higher risk for recurrence compared with the control group. This may be clinically important and certain risk factors, such as timing of previous CDI episode, could be used to guide which patients should receive OVP. Prospective studies are needed to better elucidate the role of OVP and better define the patients that may benefit the most. DISCLOSURES: All authors: No reported disclosures.