Table 1.

The main bacteria involved in dysbiosis in Inflammatory Bowel Disease patients.

Family/Species	In IBD	Protective Action on Intestinal Tissue	Pathogenic Action on Intestinal Tissue	References
Escherichia coli (adherent-invasive)	Increase		It triggers the worsening of IBD symptoms	[60]
Bacteroides	Decrease	Obligatory anaerobe, regulate the intestinal inflammation		[20]
Faecalibacterium prausnitzii	Decrease	It resists inflammation and can inhibit the NF-κB and induced the production of IL-10		[68,70]
Ruminococcus gnavus	Increase		It affects the balance of the intestinal mucus layer, which may increase the intestinal permeability	[58]
Bifidobacterium	Decrease	It is important producer of SCFA		[55]
Lactobacillus	Decrease	Limited biosynthetic abilities and ferment sugars, generating lactic acid as major product		[55]
Clostridium	Decrease	It is indispensable regulator of intestinal homeostasis		[55]
Akkermansia muciniphila	Decrease	it is a mucus-colonizing bacterium, studies have demonstrated an anti- inflammatory effect		[38,55]
Roseburia	Decrease	SCFA producer with anti- inflammatory effects		[55]
Fusobacterium nucleatum	Increase		Obligatory anaerobic, but can cause opportunistic infections after ileocecal resection	[55]
Disulfovibrio piger	Increase		It harms intestinal epithelial cells and induces mucosal inflammation	[55]

Relationship of the bacteria with protective and pathogenic action in Inflammatory Bowel Disease (IBD). In IBD, bacteria with protective action are decreased while pathogenic bacteria are increased, resulting in dysbiosis. NF-κB: nuclear factor κB; SCFA: short-chain fatty acids.