514. The Effect of Probiotics on the Incidence of Clostridium difficile

BACKGROUND: Currently there is conflicting evidence regarding probiotics affecting the incidence and/or severity of Clostridium difficile infection (CDI). According to the IDSA guidelines, there are insufficient data to support the use of probiotics as primary prophylaxis of CDI. The primary objective of this study was to evaluate whether the administration of probiotics is efficacious for CDI prophylaxis in patients who are on antibiotics making them at increased risk for contracting CDI. METHODS: The study is an Institutional Review Board approved retrospective cohort study looking at patients who were admitted to NYU Winthrop University Hospital and received at least one dose of antibiotics considered high-risk of inducing CDI. Patients were grouped according to concurrent probiotic use and the association between probiotic use and incident CDI was examined. A model for incident CDI adjusting for number of concurrent antibiotics, patient age, proton pump inhibitors, histamine receptor antagonists, presence of colitis, and chemotherapy was also estimated. Microbiology reports were analyzed for up to 12 weeks post initial administration of antibiotics to determine whether patient acquired CDI. If no CDI occurred during the admission or post discharge, data was censored at 12 weeks. RESULTS: Of 2,208 patients, 1,502 (68%) were included in the interim analysis. Ninety-six out of 1,502 patients (6.39%) had CDI within 12 weeks of antibiotics initiation. One hundred thirty-five (9%) were on probiotics during antibiotic use and 1,367 (91%) were not. Of those taking probiotics, 11.1% had an incident of CDI and of those not taking probiotics, 5.9% had an incident of CDI with a relative risk of 1.88 (1.11, 3.16) and a P = 0.02. After adjustment, although a positive association between probiotics and CDI was still observed, it was not statistically significant (P = 0.24) CONCLUSION: Based on the interim analysis, probiotics were associated with a higher risk of CDI in univariate analysis, however, when adjusted for several confounding factors this association, while still positive, was no longer statistically significant.Further data collection is ongoing to corroborate these results. [Image: see text] DISCLOSURES: All authors: No reported disclosures.