Q: What organism is most frequently involved in vertebral osteomyelitis? What is the antibiotic of choice for this organism? (choose one)

A- Pseudomonas aeruginosa

B- Klebsiella

C- Bacteroides fragilis

D- Staphylococcus aureus

E- E.Coli

Answer: D

The most common microorganism in vertebral osteomyelitis is Staphylococcus aureus, followed by E. Coli. The antibiotic of choice for vertebral osteomyelitis (without implant) is beta-lactam at high dose (e.g., nafcillin or oxacillin 2 g IV every 6 hours or cefazolin 1-2 g IV every 8 hours).