Capnocytophaga canimorsus spondylodiscitis: an unusual presentation of a zoonotic infection.

Capnocytophaga canimorsus is a slow-growing, Gram-negative bacterium commonly found as a part of the normal oral flora of dogs and cats, and it is associated with severe systemic infections following dog bites, especially in immunocompromised patients. Although spondylodiscitis due to Capnocytophaga species has been reported in the literature, cases involving previously operated spinal segments are extremely rare. A 52-year-old woman working as a dog trainer presented with fever, headache, photophobia, and lumbar back pain. Her medical history included an L5-S1 hemilaminectomy performed 9-year prior to admission. Following an initial concern for meningitis, imaging studies revealed L4-L5 spondylodiscitis. Microbiological diagnosis was obtained through computed tomography-guided biopsy. Biopsy cultures isolated C. canimorsus after 72 h of anaerobic incubation, subsequently confirmed by MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. The patient was successfully treated with amoxicillin/clavulanic acid, achieving complete resolution of symptoms. Hematogenous seeding, rather than direct surgical site contamination, should be emphasized in patients with a history of prior spinal surgery. Furthermore, C. canimorsus should be included in the differential diagnosis of spinal infections in patients with animal exposure, even in the absence of overt bite wounds.