Osteomyelitis is a bone infection, almost always caused by bacteria. Over time, the infection can destroy the bone.

Bone infections may occur at any age. Certain conditions increase the risk of developing such an infection, including sickle-cell anemia, injury, the presence of a foreign object (such as a bullet or a screw placed to hold together a broken bone), intravenous drug use (such as heroin), diabetes, kidney dialysis, surgical procedures to bony areas, and untreated infections of tissue near a bone (for example, extreme cases of untreated sinus infections have led to osteomyelitis of the bones of the skull).

Staphylococcus aureus is the type of bacterium usually involved in osteomyelitis. Others include the mycobacterium which causes tuberculosis, a type of Salmonella bacterium in patients with sickle cell anemia, and Pseudomonas aeurginosa in drug addicts. The viruses that cause chickenpox and smallpox can cause viral osteomyelitis, but this is...