TAXONOMY: Bacteria -> Terrabacteria group -> Firmicutes -> Clostridia -> Clostridiales -> Ruminococcaceae -> Ruminococcus
'Ruminococcus' is a genus of bacteria in the class Clostridia. They are anaerobic, Gram-positive gut microbes. One or more species in this genus are found in significant numbers in the intestines of humans. The type species is R. flavefaciens. 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. Cells are coccoid, usually 0.3–1.5 × 0.7–1.8 µm. Cells are in pairs and chains. A few are motile with 1–3 flagella. Gram-stain-positive cell-wall structure but many stain Gram-negative. Optimal temperature, 37–42°C. Chemo-organotrophic. Strictly anaerobic and require fermentable carbohydrates to grow. Fermentation of carbohydrate yields various proportions of acetate, formate, succinate, lactate, and ethanol. Amino acid and peptides are not fermented. Indole is not produced (Bryant, 1986). Isolated from rumen, large bowel, or cecum of many animals and humans. Some are isolated from human clinical specimens. Rumen fluid agar is effective to isolate and characterize strains (Holdeman et al., 1977). Some strains use cellulose on rumen fluid cellobiose agar plate (Holdeman et al., 1977) and require ammonia as a nitrogen source.
This genus contains microbial species that can reside in the human gastrointestinal tract. [PMC 4262072]
Blood group A-degrading activity; blood group H-degrading activity (R. torques). Blood group B-degrading activity; blood group H-degrading activity (R. gnavus) [PMC 4365749]