Ruminococcus is a genus of bacteria in the class Clostridia

Clostridia

The Clostridia are a class of Firmicutes, including Clostridium and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them. Species of the genus Clostridium are all Gram-positive and have the ability to...

. They are anaerobic, gram-positive gut microbes

Gut flora

Gut flora consists of microorganisms that live in the digestive tracts of animals and is the largest reservoir of human flora. In this context, gut is synonymous with intestinal, and flora with microbiota and microflora....

. 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

Paraphyly

A group of taxa is said to be paraphyletic if the group consists of all the descendants of a hypothetical closest common ancestor minus one or more monophyletic groups of descendants...

, and some or all members of Ruminococcus being reassigned to a new genus Blautia on the basis of 16S rRNA

16S ribosomal RNA

16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...

 gene sequences.

Species

• Ruminococcus albus
• Ruminococcus bromii
• Ruminococcus callidus
• Ruminococcus flavefaciens
• Ruminococcus gauvreauii
• Ruminococcus gnavus
• Ruminococcus lactaris
• Ruminococcus obeum
• Ruminococcus torques