Wei wang1,2, Junzhang Zhao1,2, Tao Liul1,2, Zhiyin Gao1,2, Ni Ding1,2, Xiang Gao1,2

1Department of Gastroenterology, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China, 2Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, the Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, PR China

Background/Aims: Few studies investigated the microbiota compostion between complicated and non-complicated Crohn’s disease. In this study, we investigated the difference of microbiota profile between complicated and non-complicated CD.

Methods: Thirty-five individuals with complicated Crohn’s disease (CD2) and forty-nine individuals of Crohn’s disease with no complication (CD1) and twenty-nine healthy control (HC) were included in this study. No antibiotics was used in one month before samples collected. Bacteria 16S sequencing targeting V4 region was accomplished by BGI, and Linear Discriminant Analysis Effect Size (LEfSe) pipeline was used for biomarker discovery.

Results: Patients with Crohn’s disease had significantly decreased microbial diversity in comparison with HC in alpha diversity, however there was no difference between CD1 and CD2 groups. The microbiota composition of patents with CD1 and CD2 were significantly different from that of healthy control, but there was no difference between CD1 and CD2 based on the microbiota composition. The relative abundance of Verrucomicrobia and Fusobacteria were higher in CD2 compared to CD1. LEfSe analysis identified 12 discriminant genera. In patients with CD2, an enrichment in three taxa of Proteobacteria, Fusobacteria and Verrucomicrobia were observed, including its dominant genus Escherichia, Fusobacterium and Akkermansia respectively. The order Lactobacillales belonging to the Firmicutes phylum and its dominant genus Enterococcus and Lactobacillus enriched in CD2 and CD1, respectively. And the genus Blautia belonging to the order Costridiales in Firmicutes phylum enriched in CD1. We included the 12 most relevant taxa characterized in each group of patients and calculated the microbial dysbiosis index (MDI). The CD1 had a higher MDI than that of patients with CD1. And the MDI showed an inverse correlation with Shannon index .

Conclusion: Complicated Crohn’s disease patients captured severe dysbiosis than patients with no complication. Akkermansia sp.’s function requres further validation.

Keywords: complicated Crohn’s disease, microbiota, Akkermansia, Fusobacteria