A 25-year-old intravenous drug user presents with low-grade fever and pain in the lumbar spine. MRI shows destruction of two adjacent vertebral bodies with disc space narrowing and paraspinal soft tissue swelling. The most likely causative organism is:

• A Staphylococcus aureus
• B Pseudomonas aeruginosa ✓
• C Mycobacterium tuberculosis
• D Escherichia coli

Explanation

Pseudomonas aeruginosa is the characteristic causative organism of vertebral osteomyelitis and disc space infection in intravenous drug users, because it is a common contaminant of needles and drug paraphernalia. The disc is involved early because of the rich vascular supply to the disc in young adults. In the general population, S. aureus would be most common, but the IV drug use context mandates thinking of Pseudomonas.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.