Firmicutes

The Firmicutes are a phylum of bacteria, most of which have the Gram-positive type of cell walls.

Firmicutes
Bacillus subtilis, Gram stained
Scientific classification
Domain:	Bacteria
Phylum:	Firmicutes
Classes
Bacilli Clostridia

Classes

The group is typically divided into the Clostridia, which are anaerobic, the Bacilli, which are aerobic, and the Mollicutes, a class of bacteria which do not have cell walls.

On phylogenetic trees, the first two groups show up as paraphyletic or polyphyletic, as do their main genera, Clostridium and Bacillus.^[1]

Health

Firmicutes make up the largest portion of the mouse and human gut microbiome.^[2] The division Firmicutes as part of the gut flora has been shown to be involved in energy resorption and obesity.^[3][4][5]