Primary sclerosing cholangitis (PSC) and ulcerative colitis (UC) are both long-term diseases of inflammation. Primary sclerosing cholangitis is characterized by the thickening and formation of fibrous tissue of bile ducts. Ulcerative colitis is an inflammatory bowel disease affecting the lining of the large intestine. So what do they have in common? They are both characterized by low levels of bacterial diversity.

A study has found that multiple identifiable bacteria species were overly abundant in PSC and UC. Rothia, Enterococcus, Streptococcus, Veillonella, were all overpopulated, while Adlercreutzia quolifaciens and Prevotella copri were both depleted. UC, in particular, found lowered levels of Akkermansia muciniphila, Butyricicoccus pullicaecorum, and Clostridium colinum. It is actually possible to clearly determine which inflammatory bowel disease phenotype is being expressed based on bacterial taxa. This further shows how the human microbiome and its diversity is connected to human health. UC and PSC are just more examples of how the microbiome can play into a disease.

Bajer, L., Kverka, M., Kostovcik, M., Macinga, P., Dvorak, J., Stehlikova, Z., … Drastich, P. (2017). Distinct gut microbiota profiles in patients with primary sclerosing cholangitis and ulcerative colitis. World Journal of Gastroenterology, 23(25), 4548–4558.