Eubacterium /yo̅o̅′baktir″ē·əm/ , a large genus of nonsporulating gram-positive anaerobic rod-shaped bacteria normally found in soil and water. The organisms are also found in the skin and cavities of humans and other mammals, where they may cause soft-tissue infections. One species has been found in dental tartar; another synthesizes vitamin B12. Eubacterium is susceptible to penicillin, cliridamycin, and metronidazole.