Table 1.

Summary of studies investigated links between gut microbiota and intestinal diseases

	Increase	Decrease	Pathological features
IBD	Proteobacteria	Firmicutes	Disruption of intestinal barrier
			Intestinal mucosal inflammation
			Bacterial antigen translocation increased
PI-IBD	Escherichia, Veillonella, Megasphera and Lachnospiraceae	Prevotella	Bacterial adhesion
		Roseburia bacteroidetes Lactobacillus	Inflammatory autoimmune disease
IBS	Methane bacteria	Lactobacillus	Gastrointestinal infections
		Bifidobacterium	Intestinal bacterial overgrowth (SIBO)
			Coliform and pathogen translocation increased
Chronic constipation	Bacteroides	Firmicutes, Clostridium, Lactobacillus, Desulfovibrio, and Methylobacterium	Intestinal SERT
	Akkermansia muciniphila Bacteroides		Decrease the level of 5-HT
Osmotic diarrhea	Bacteroides	S24-7 bacteria	Changes in intestinal osmotic pressure
		Y deformation bacteria
CRC	Fusobacterium nucleatum, P. anaerobius, Peptostreptococcus stomatis, Solobacterium moorei, Gemella morbillorum and Parvimonas micra		Transform the microbiome
			Create a tumour environment
			Tumour cell proliferation
			The inflammatory response