Vertebral osteomyelitis and a forgotten dog bite in an immunocompetent patient

A woman in her 60s presented with a three-week history of progressive subacute back pain without neurological deficits. MRI of the lumbar spine demonstrated necrosis at the L3-L4 disc and adjacent vertebral bodies, raising suspicion for malignancy or infection. Two image-guided bone biopsies were nondiagnostic. A peripheral infectious disease workup was similarly unremarkable. Owing to the persistent concern for infection, 16S ribosomal RNA sequencing was performed on biopsy samples, which identified <i>Capnocytophaga canimorsus</i>. Only after receiving this result did the patient recall a minor dog bite sustained six weeks prior to symptom onset. She was managed with an extended course of oral antibiotics with complete clinical recovery. This case illustrates the capacity of <i>C. canimorsus</i> to cause insidious vertebral osteomyelitis in immunocompetent individuals, underscores the diagnostic utility of 16S rRNA sequencing in culture-negative infections, and highlights the critical importance of a detailed exposure history in atypical clinical presentations.