Anaerobes are the classification of bacteria that can survive without oxygen. These organisms are able to go through metabolic processes with very little or no oxygen and some will even die in the presence of oxygen. Anaerobes can be classified as facultative anaerobes which are able to survive with or without oxygen obligate anaerobes which require environments without oxygen.
Aerobes are bacteria that require oxygen for survival. They cannot undergo metabolic processes without oxygen.
Facultative anaerobes are well adapted and able to survive in a variety of environments whereas the obligate anaerobes and aerobic bacteria are limited in the types of environments that they can survive in.
Bacteria that do not need oxygen to survive are called anaerobic bacteria. They may also live in places that have very little oxygen. A couple examples of diseases that are caused by anaerobic bacteria are tetanus and botulism.
These bacteria live in the mouth, gastrointestinal tract, and on the skin. They can also live in the ears and sinuses as well as several other places on and in the human body.
Some people are at risk for becoming very sick due to anaerobic bacteria. These are people who have had recent surgery and have blood vessel disease.