Anaerobic Infections Health Article

Definition

An anaerobic infection is an infection caused by bacteria (called anaerobes) which cannot grow in the presence of oxygen. Anaerobic bacteria can infect deep wounds, deep tissues, and internal organs where there is little oxygen. These infections are characterized by abscess formation, foul-smelling pus, and tissue destruction.

Description

Anaerobic means "life without air." Anaerobic bacteria grow in places which completely, or almost completely, lack oxygen. 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.

Anaerobic bacteria can cause an infection when a normal barrier (such as skin, gums, or intestinal wall) is damaged due to surgery, injury, or disease. Usually, the immune system kills any invading bacteria, but sometimes the bacteria are able to grow and cause an infection. Body sites that have tissue destruction (necrosis) or a poor blood supply are low in oxygen and favor the growth of anaerobic bacteria. The low oxygen condition can result from blood vessel disease, shock, injury, and surgery.

Anaerobic bacteria can cause infection practically anywhere in the body. For example:

• Mouth, head, and neck. Infections can occur in the root canals, gums (gingivitis), jaw, tonsils, throat, sinuses, and ears.
• Lung. Anaerobic bacteria can cause pneumonia, lung abscesses, infecton of the lining of the lung (empyema), and dilated lung bronchi (bronchiectasis).
• Intraabdominal. Anaerobic infections within the abdomen include abscess formation, peritonitis, and appendicitis.
• Female genital tract. Anaerobic bacteria can cause pelvic abscesses, pelvic inflammatory disease, inflammation of the uterine lining (endometritis), and pelvic infections following abortion, childbirth, and surgery.
• Skin and soft tissue. Anaerobic bacteria are common causes of diabetic skin ulcers, gangrene, destructive infection of the deep skin and tissues (necrotizing fascitis), and bite wound infections.
• Central nervous system. Anaerobic bacteria can cause brain and spinal cord abscesses.
• Bloodstream. Anaerobic bacteria can be found in the bloodstream of ill patients (a condition called bacteremia).