2571. Norovirus Infection and Gut Microbiota in Transplant Recipients

BACKGROUND: In vitro studies have shown that enteric viruses require the gut microbiota (specific members of the Enterobacteriaceae family) for efficient infection of the gastrointestinal tract. Human norovirus (NV) infection in transplant recipients may be chronic and severe. The role of gut microbiota has not been defined in this setting. We hypothesized that gut microbiota diversity and composition are different in norovirus-infected transplant patients. METHODS: We performed a single-center, pilot, prospective cohort study of adult solid-organ transplant and hematopoietic stem cell transplant recipients with diarrhea. Serial fecal samples were collected and processed for gDNA. Norovirus levels were quantified by PCR and gut microbiota profiling determined by 16S rRNA gene sequencing. RESULTS: Twenty-five transplant recipients were included: 9 with NV infection and 16 without. Age (61 ± SEM 2.3 years vs. 54 ± 3.5 years; P = 0.172), duration of diarrhea prior to diagnosis (105 ± 43 days vs. 20 ± 7 days; P = 0.146), prior cumulative antibiotic use (42 ± 12 days vs. 46 ± 17 days; P = 0.646), anti-anaerobic antibiotic use (7 ± 3 days vs. 11 ± 6 days; P = 0.643) and length of hospitalization (12 ± 6 days vs. 12 ± 3 days; P = 0.624) were not different between transplant recipients with and without NV infection. Interestingly, the relative abundance of Enterobactericeae was significantly higher in NV-infected transplant recipients compared with those without NV infection (26 ± 5.8% vs. 6.2 ± 2.8%; P = 0.017, Mann–Whitney) (Figure 1). In contrast, the abundance of the Phyla Bacteroidetes (11.2 ± 5.2% vs. 26.3 ± 6.5%; P = 0.191), and Firmicutes (26.8 ± 7.6% vs. 24.9 ± 4.7%; P = 0.803), were not significantly different between those who were NV and not NV-infected. Of note, the diversity metrics of Shannon (3.5 ± 0.4 vs. 3.8 ± 0.3; P = 0.637) and inverse Simpson indices (1.3 ± 0.1 vs. 1.1±0.1; P = 0.419) were not significantly different between the two groups. CONCLUSION: Norovirus-infected transplant recipients had a significantly higher relative abundance of Enterobactericeae in their gut microbiota compared with transplant recipients without norovirus infection. Future studies are needed to explore if this association is mechanistically important for norovirus infection. [Image: see text] DISCLOSURES: All authors: No reported disclosures.