Fusobacterium nucleatum. Coloured transmission electron micrograph of a cross-section through Fusobacterium nucleatum bacteria. It is associated with gum disease (gingivitis) in humans. These bacteria are anaerobic, rod-shaped, Gram-negative bacilli. Typically their shape is tapered at both ends. The cell wall and the granular cell contents are visible. Fusobacterium nucleatum occur in the mouth. They adhere to oral epithelium, and occur in dental plaque that forms on teeth. Plaque is a cause of periodontal disease and tooth decay, and may cause gingivitis (gum inflammation). Treatment includes antibacterial drugs. Magnification: x44,000 at 5x7cm size.