LAUSR

Akkermansia muciniphila is a promising probiotic in the gut. This study aimed to determine the presence and abundance of Akkermansia in patients with inflammatory bowel disease (IBD) who underwent washed microbiota transplantation (WMT) in order to elucidate the relationship between its level and patients' clinical data and outcomes. A cohort of Chinese volunteers including 80 healthy controls (HC), 43 patients with ulcerative colitis (UC), and 57 patients with Crohn's disease (CD) were recruited. Akkermansia presented a low colonization rate of 48.8% and a relative abundance of 0.07% in a healthy Chinese population. Compared with HC, significantly lower colonization and abundance of Akkermansia were found in UC and CD (p < 0.01, p < 0.001, respectively). The combination of Akkermansia and twelve other gut commensal bacteria significantly enriched in healthy individuals could be conductive to discriminate IBD from HC. Co-occurrence of Akkermansia-Faecalibacterium prausnitzii was at a lower level in IBD. Patients' age could affect the abundance of Akkermansia in CD. After WMT, 53.7% of patients achieved clinical response, and the colonization rate of Akkermansia increased significantly than that pre-WMT (p < 0.01). There was a positive correlation between patients and donors in the abundance of Akkermansia after WMT. Different from Europeans, the healthy Chinese population is characterized by a low presence of intestinal Akkermansia. Compared with healthy people, its colonization and abundance in IBD decreased more significantly. The efficacy of WMT for IBD was closely correlated with Akkermansia. ClinicalTrials.gov , pooled registered trials, NCT01790061, NCT01793831. Registered February 13, 2013, 18 February 2013. KEY POINTS: • Akkermansia showed a lower colonization and abundance in Chinese than Europeans. • Akkermansia could distinguish IBD from healthy people with a reduced abundance. • IBD patients achieved response from WMT through an increased Akkermansia level. Graphical abstract.