Causes

Most cases of osteomyelitis are caused by staphylococcus bacteria, types of germs commonly found on the skin or in the nose of even healthy individuals.

Germs can enter a bone in a variety of ways, including:

• The bloodstream. Germs in other parts of your body — for example, in the lungs from pneumonia or in the bladder from a urinary tract infection — can travel through your bloodstream to a weakened spot in a bone.
• Injuries. Severe puncture wounds can carry germs deep inside your body. If such an injury becomes infected, the germs can spread into a nearby bone. Germs can also enter the body if you have broken a bone so severely that part of it is sticking out through your skin.
• Surgery. Direct contamination with germs can occur during surgeries to replace joints or repair fractures.