Table 1.

Cluster IV (Clostridium leptum group) and Cluster XIVa (Clostridium coccoides group) probiotic properties.

Cluster		Species	Beneficial Properties	Literature
Cluster IV (Clostridium leptum group)		C. leptum C. sporosphaeroides C. cellulosi Faecalibacterium prausnitzii	Production of SCFAs, especially butyrate; Regulates intestinal epithelial function; Performs an anti-inflammatory role in the gastrointestinal tract (blocking NF-κB and IL-8 production); Induces Treg cell accumulation in the colon; Attenuates allergic diarrhea and colitis; Triggers the secretion of IL-10 and IL-12 which attenuate inflammation.	[2,7,8,9,10,11,14,15,19,20,21,22,23,26,27,30,31,32]
Cluster XIVa (Clostridium coccoides group)	Spore-formers	C. clostridiiforme C. coccoides C. aerotolerans C. aminophilum C. aminovalericum C. celecrescens C. nexile C. oroticum C. polysaccharolyticum C. populeti C. symbiosum C. spheroids C. xylanolyticum Clostridium spp. DSM 6877	Produces SCFAs; Prevents vancomycin-resistant Enterococcus (VRE) colonization; Performs an anti-inflammatory role in the gastrointestinal tract (blocking NF-κB and IL-8 production); Induces Treg cell accumulation in the colon.	[2,8,9,10,11,13,14,17,18]
	Asporulating	Acetitomaculum ruminis Coprococcus eutactus Eubacterium cellulosolvent Peptostreptococcus productus Roseburia cecicola Ruminococcus torques Streptococcus hasenii