High Quality Content by WIKIPEDIA articles! Fusobacterium is a genus of filamentous, anaerobic, Gram-negative bacteria, similar to Bacteroides.Fusobacterium contribute to several human diseases, including periodontal diseases, Lemierre`s syndrome, and topical skin ulcers. Although older resources have stated that Fusobacterium is a common occurrence in the human oropharynx, the current consensus is that Fusobacterium should always be treated as a pathogen. In 2011, researchers discovered that this bacteria flourishes in colon cancer cells, and is often also associated with ulcerative colitis, although researchers have not determined if the organism actually causes these diseases or if it simply flourishes in the environment these diseases create.