Intestinal Microbiota as Modulators of the Immune System and Neuroimmune System: Impact on the Host Health and Homeostasis

Table 1

Profile of alterations in the gut microbiota in IBS, IBD, colorectal cancer, obesity, and type 2 diabetes.

Disease	Microbial alteration	Reference
Irritable bowel syndrome	Increased presence of Firmicutes, specifically Ruminococcus sp., Clostridium sp., and Dorea sp.; reduction in Bifidobacterium and Faecalibacterium spp.; decrease of Bacteroides in afflicted children; increased presence of Dorea sp., Ruminococcus sp., Haemophilus sp. and parainfluenzae sp. in paediatric patients.	[9–11]
Inflammatory bowel disease	Reduced complexity of Firmicutesand Bacteroidetes, with decrease in the abundance of Clostridium leptum and Clostridium coccoides; increase in bacteria of the Gammaproteobacteriaclass; presence of adherent and invasive Escherichia coli; decreased presence of Faecalibacterium prausnitzii; altered abundance of members of the families Enterobacteriaceae, Ruminococcaceae, and Leuconostocaceae,with increased presence of Clostridium and reduced presence of Roseburia and Phascolarctobacterium.	[12–14]
Colorectal cancer	Members of the genus Fusobacterium appear increased on colorectal cancerous tissue; reduction in bacteria of the phyla Firmicutesand Bacteroidetes; alterations in number of butyrate producing bacteria (Coprococcus spp.; Eubacterium rectale; Roseburia spp.; and Faecalibacterium prausnitzii), related to the protective effect of butyrate for the enterocytes.	[15, 16]
Obesity	Decreased presence of Bacteroidetes; increased presence of Actinobacteria.	[3, 17]
Type 2 diabetes	Overall alterations of the microbiota; increased presence of Clostridium spp.; Akkermansia muciniphila; Bacteroides spp.; and Desulfovibrio spp.	[18]
Ulcerative colitis	Decreased presence of Firmicutes, Lentisphaerae, and Verrucomicrobia; increased presence of Proteobacteria, Fusobacteria, and Spirochaetes.	[19]