Enterocloster clostridioformis

Enterocloster clostridioformis, formerly known as "Clostridium clostridioforme", is an anaerobic, motile, Gram-positive bacterium .
Description.
"E. clostridioformis" are rod-shaped bacteria which cannot grow in the presence of oxygen. While "Clostridium" species have cell walls that resemble gram-positive bacteria, "E. clostridioformis" often appears negative by Gram stain.
History.
The organism now classified as "E. clostridioformis" was first identified in the 1950s in human and animal feces and assigned to the genus of Gram-negative non-spore-forming bacteria "Bacteroides". In subsequent years, these bacteria were shown to form spores, causing them to be reclassified in the genus "Clostridium". Most recently this species has been reclassified as "E. clostridioformis" based on phylogeny.