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* = Presenting author

P748 Potential role of Fusobacteria in Korean inflammatory bowel disease patients

C. S. Eun*, D. S. Han, A. R. Lee, Y. R. Lee

Hanyang University Guri Hospital, Gastroenterology, Guri, South Korea

Background

Fusobacteria has been suggested to play an important role in the colorectal cancer, as well as inflammatory bowel disease (IBD). Previously, we demonstrated that the proportion of phylum Fusobacteria were significantly higher in the faeces and mucosal tissues of active Crohn’s disease (CD) patients compared with those of healthy control and CD patients in remission using high-throughput sequencing method. We tried to isolate Fusobacteria strains from the mucosal tissues of Korean IBD patients and to evaluate whether the isolated strains induce pro-inflammatory expression signatures in vitro assay.

Methods

Colonic mucosal tissue samples were obtained from the active inflammation sites in 54 Korean IBD patients (29 CD and 24 ulcerative colitis [UC]). Tissue specimens were spread across the Fusobacteria-selective agar plates and incubated under anaerobic conditions. Isolates were identified on the basis of their growth on the selective medium and their identity was confirmed by use of 16S PCR and 16S rRNA sequencing analysis. Isolated bacterial strains were added to several colon cancer cell lines (HT-29, SW480, RKO, and HCT116) with near confluence and incubated for 4 hours. RNA was prepared from monolayered cell lines and RT-PCR for pro-inflammatory cytokines, and MUC26 genes were performed.

Results

All of 262 isolates were identified by 16S rRNA gene sequencing. In total, 10 Fusobacterium spp. (7 F. mortiferum, 2 F. varium, and 1 F. nucleatum) were isolated from active colonic mucosal tissues of 9 patients (16.7%) amongst 54 Korean IBD patients. Both F. mortiferum and F. varium strains increased pro-inflammatory cytokines and MUC2 RNA expressions in colon cancer cell lines infected with these strains.

Conclusion

Several Fusobacteria strains are isolated from the active colonic mucosal tissues of Korean IBD patients, and, these bacterial strains induce pro-inflammatory expression signatures in vitro assay, suggesting the potential role of Fusobacteria in Korean IBD patients.