Aetiology of osteomyelitis in adults

In adults, Staphylococcus aureus is the most common cause of osteomyelitis, regardless of the site of infection. Consider risk factors for infection with methicillin-resistant strains.

Around half of vertebral osteomyelitis cases and at least one-third of long-bone osteomyelitis cases are due to infection with other organisms (eg gram-negative bacteria). Other pathogens are more likely to be seen in patients with any of the following risk factorsPark 2014:

• history of injecting drug use
• long-term vascular access device in situ
• postoperative infection
• confirmed infection (either current or recent) of the hepatobiliary system, or urinary or gastrointestinal tract.

For aetiology of infection in adults with osteomyelitis associated with prosthetic material, seek expert advice.