Clinical isolates of anaerobic gram-negative rods with a formate-fumarate energy metabolism: Bacteroides corrodens, Vibrio succionogenes, and unidentified strains.

Strains of anaerobic, gram-negative bacteria, isolated from human clinical specimens and from studies of human normal flora, that have energy metabolism similar to Vibrio succinogenes are described. Included are four human isolates of V. succinogenes, five similar strains of motile straight rods, three strains of Bacteroides corrodens, and two unidentified strains. All strains studied grew poorly in usual anaerobic broth media but produced good turbidity in overnight broth cultures in media containing fromate and fumarate, indicating that all have an energy metabolism similar to V. succinogenes: they gain energy by the transfer of electrons from formate or hydrogen to fumarate.