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.