Their ability to adapt and persist in changing gut environments allows abundance and stability,^8,21-23 providing long-term associations with human hosts and enabling functions that include⁸:

• Immunomodulatory effects^8,a
• Inhibitory activities against C. difficile and reduction of colonization^24,a,b

^aSome Bacteroides.
^bIn preclinical studies.

Composed of helpful and harmful bacteria,^2,11 Firmicutes are the most abundant and diverse bacterial gut species,² with functions that include:

• Anti-inflammatory effects^25-27,a
• Fortification of gut barrier (along with other bacteria)^28-30,b

^aIn preclinical studies.
^bDemonstrated in Crohn’s disease, inflammatory bowel disease, and ulcerative colitis studies.