One or more species in this genus are found in significant numbers in the human gut microbiota.
As usual, bacteria taxonomy is in flux, with Clostridia being paraphyletic, and some erroneous members of Ruminococcus being reassigned to a new genus Blautia on the basis of 16S rRNA gene sequences.
[3] In 1972, Ruminococcus bromii was reportedly found in the human gut, which was the first of several species discovered.
[5] One study found that R. albus, R. callidus, and R. bromii are less abundant in people with inflammatory bowel disease.
[6] Ruminococcus are also less abundant in patients with Parkinson's disease[7] and amyotrophic lateral sclerosis.