618. Do Clinical Factors Affect Microbial Engraftment After Fecal Microbiota Transplantation in Recurrent Clostridium difficile Infection?

BACKGROUND: Fecal microbiota transplantation (FMT) is an effective treatment for recurrent Clostridium difficile infection (rCDI). Few studies have evaluated clinical factors associated with microbial engraftment. We describe microbial changes post-FMT and clinical factors impacting engraftment. METHODS: Patients undergoing FMT for rCDI via colonoscopy were enrolled. Clinical data and stool were collected pre- and 8 weeks post-FMT. Microbial profiles were assessed by 16S rRNA sequencing. Difference in microbial alpha and β-diversity between groups was determined. Significance testing was assessed using Mann–Whitney–Wilcoxon and PERMANOVA tests. The Jensen Shannon divergence (JSD) between donor and their recipient post-FMT was used as a measure of engraftment. The association of clinical factors on engraftment was evaluated by linear regression. RESULTS: A total of 12 patients received an FMT from 12 unique donors. The efficacy rate was 92%. Mean recipient age was 60 years (range: 33–87) with more females (7/12). Recipients pre-FMT alpha diversity was significantly lower compare to donors (P = 0.04, Figure 1a). This difference dissipated post-FMT (P = 0.67). On β-diversity analysis, the recipients pre-FMT samples clustered separately from their post-FMT samples (P = 0.01, Figure 1b), with the post-FMT samples shifting closer to the donor samples. Proteobacteria was dominant in patients’ pre-FMT samples and were substantially reduced post-FMT, combined with an expansion in Bacteroidetes (Figure 2). On linear regression analysis, clinical factors (age, sex, previous recurrent CDI episodes, inflammatory bowel disease, proton pump inhibitor, immunosuppression, previous anti-CDI antibiotic courses, probiotics) were not significantly associated with engraftment outcomes. CONCLUSION: There is a significant and durable shift in recipients’ microbial profile to resemble their donor post-FMT. Recipients’ pre-FMT clinical factors did not significantly affect microbial engraftment. Future metagenomic studies may help elucidate whether clinical factors impact engraftment. DISCLOSURES: All authors: No reported disclosures.