Acute osteomyelitis is a bone infection, occurring predominantly in children and often seeded hematogenously (Carek, Dickerson and Sack, 2001). In adults, osteomyelitis is most often a subacute or chronic bone infection following injury to a bone or the surrounding soft tissues. Several types of bacteria produce osteomyelitis, and are grouped according to common clinical scenarios: Staphylococcus aureus is the most common bacteria in patients with acute hematogenous osteomyelitis; S. epidermis, S. aureus, Pseudomonas aeruginosa, Serratia marcescens, and Escherichia coli are the most common bacteria found in chronic osteomyelitis.
Osteomyelitis is a complex disease, and a number of classification systems have emerged, e.g. the Waldvogel system, which divides osteomyelitis into hematogenous, contiguous and chronic (Carek, Dickerson and Sack, 2001, 2413). In this system, contiguous osteomyelitis is secondary to a contiguous focus of infection and either has no generalized vascular disease, or there is generalized vascular disease present. Chronic osteomyelitis in this system has necrotic bone. The newer Cierny-Mader classification system is based on the disease status, not its chronicity, etiology, or other factors. The terms "acute" and "chronic are not used in this system, and the stages are dynamic, changing with the patient's medical condition, successful antibiotic treatment, and other treatments. There may be special circumstances under which neither classification system applies, e.g. infections involving prosthetic joints, implanted materials, special infections such as vertebral osteomyelitis, and infections involving small bones.
Other infectious agents as well as those mentioned above may cause osteomyelitis, such as the mycobacterium tuberculosis, one type of Salmonella bacteria in patients with sickle cell anemia, organisms usually present in the gastrointestinal tract in the elderly, and P. aeruginosa in dru...