- Assume if no other information is available- S aureus -

- Sexually active - N gonorrhoeae (septic arthritis more common)

- Sickle cell disease - Salmonella and S aureus

- Prosthetic joint replacement - S aureus or S epidermidis

- Vertebral involvement - S aureus or Mycobacterium tuberculosis (Pott disease)

- MRI is best for detecting acute infection- Radiographs can be useful in chronic infection