Table 3.

Bacteria-mediated changes in the mucosal barrier in IBD.

Animal Model/Clinic Data Analysis	Mucosal Bacteria	Outcome	References
345 colonic biopsies samples from bowel inflammation patients (305) and controls (40)	High concentrations of bacteria attached to mucosa in patients, no translocation	Mucosal bacteria increased with the severity of inflammation	[121]
Biopsy specimens from 72 UC, 12 CD patients and 65 healthy controls	Harmful bacterial groups increased, while beneficial bacterial species declined	Components of mucosal flora changed in IBD patients	[122]
MDCK1 cells infected with Campylobacter jejuni	—	Monolayer integrity changed, affected tight junction protein ZO-1 distribution	[123]
Mucosal biopsies from CD, UC, disease and healthy controls (n = 63)	Active mucosa-attached microbiota changed in IBD patients	Altered inflammation status	[124]
120 biopsies from controls (20), self-limiting colitis (SLC, 20), UC (20) and randomly individual (60)	Bacteria found within mucus in UC, SLC	Bacterial migration, adherence to and invasion of the mucosa	[125]
Mucosal and submucosal samples from CD and controls	4 and 13 bacterial species were found within submucosa at the center and margin of disease	Changed bacteria might drive or inhibit certain organisms in CD	[126]
35 ilea mucosal and submucosal tissues from CD patients (n = 20) and healthy controls (n = 15)	Ruminococcus spp., Oscillospira spp., Pseudobutyrivibrio spp., and Tumebacillus spp increased in subjacent submucosa	Bacterial migration to submucosal resulting from mucosal barrier injury	[127]
Intestinal biopsies from IBD patients (inflammation, non-inflammation) and from controls	Streptococcus spp. accounted for 80% in the inflamed mucosa of CD; mucus layer in the inflamed IBD patients was remarkably thinner	Streptococcus spp. increased with the severity of IBD	[128]