Bacterial infections of the oral cavity can take many forms. Scarlet fever is caused by Streptococcus bacteria and presents with a red rash and strawberry tongue. Tuberculosis is caused by Mycobacterium tuberculosis and typically causes lesions in the lungs but can also cause oral ulcers, gingivitis, and osteomyelitis of the jaw. Diphtheria is caused by Corynebacterium diphtheriae and presents with a diphtheritic membrane that can cover the tonsils, soft palate, and throat.