They are normally found in the mouth, gastrointestinal tract, and vagina, and on the skin. Commonly known diseases caused by anaerobic bacteria include gas gangrene, tetanus, and botulism. Nearly all dental infections are caused by anaerobic bacteria. Usually, the immune system kills any invading bacteria, but sometimes the bacteria are able to grow and cause an infection. The low oxygen condition can result from blood vessel disease, shock, injury, and surgery.
Anaerobic bacteria can cause infection practically anywhere in the body.
Anaerobic infections within the abdomen include abscess formation, peritonitis, and appendicitis. Female genital tract. Skin and soft tissue. Central nervous system. Anaerobic bacteria can cause brain and spinal cord abscesses.