Uncovering the role of microbiota and fecal microbiota transplantation in Crohn’s disease: Current advances and future hurdles

Table 1 Gut microbiota in Crohn’s disease

Ref.	Participants	Key findings
Ma et al[13]	Prospective cohort study (18 early CD, 22 advanced CD, 30 healthy control)	Elevated levels of Lachnospiraceae incertae sedis and Parabacteroides in early CD. Escherichia/Shigella, Enterococcus, and Proteus were more prevalent in advanced cases. Higher levels of Roseburia, Gemmiger, Coprococcus, Ruminococcus, Butyricicoccus, Dorea, Fusicatenibacter, Anaerostipes, and Clostridioides. Steady decline in short chain fatty acid-producing bacteria as CD progresses
Zhou et al[9]	Meta-analysis (9 studies with 706 patients)	Bacteroides levels were significantly lower in patients with active CD compared to healthy controls. Reduced levels of Bacteroides were associated with CD activity
Gevers et al[15]	Observational case-control study (447 patients with CD, 221 healthy control)	Enterobacteriaceae, Bacteroidales, Clostridioides, Pasteurellaceae (including Haemophilus spp.), Veillonellaceae, Neisseriaceae, and Fusobacteriaceae showed a positive correlation with CD severity. Bacteroides, Faecalibacterium, Roseburia, Blautia, Ruminococcus, Coprococcus, and the families Ruminococcaceae and Lachnospiraceae negatively correlated with CD. Dysbiosis observed in CD patients. Antibiotics aggravated microbial dysbiosis
Prosberg et al[16]	Meta-analysis. Total 10 studies including CD and ulcerative colitis. 5 studies with 231 CD patients.	Reduced levels of Clostridioides, Faecalibacterium prausnitzii, and Bifidobacterium in CD patients. Dysbiosis may be involved in the activity of IBD

CD: Crohn’s disease; IBD: Inflammatory bowel disease.