Vertebral osteomyelitis caused by non-tuberculous mycobacteria: case reports and review

There are currently few reports of vertebral osteomyelitis caused by non-tuberculous mycobacteria. To date, only 38 cases, excluding human immunodeficiency virus patients, have been reported. We describe 3 patients with vertebral osteomyelitis caused by Mycobacterium avium-intracellulare complex or Mycobacterium kansasii, and review previous reports of vertebral osteomyelitis caused by non-tuberculous mycobacteria. Case 1 is a 50-year-old man who presented with lower back pain. Radiologic examination revealed L1–L5 enhancement and paravertebral abscess. The surgical specimen was positive for Mycobacterium avium-intracellulare complex. The patient was successfully treated by surgical excision and antibiotic administration. Case 2 is a 68-year-old woman who presented with upper back pain. Spine MRI revealed multiple lesions at T9–T12, L2, L4, and L5. Her back pain worsened, and repeated MRI revealed extensive bone lesions. Mycobacterium kansasii was isolated from a T5 vertebral body specimen. Surgery was not performed. Case 3 is a 38-year-old woman who had been taking prednisolone for systemic lupus erythematosus. We diagnosed her condition as suppurative knee arthritis caused by M. avium-intracellulare complex. Vertebral MRI revealed T9 vertebral body enhancement and a paravertebral abscess at T8–T9. Tissue culture of a T9 specimen yielded M. avium-intracellulare complex. Her clinical condition improved following posterior thoracic spinal fusion. In conclusion, vertebral osteomyelitis caused by non-tuberculous mycobacteria should be included in the differential diagnosis, even in immunocompetent patients.