Gram-Negative Anaerobic Spondylodiscitis Caused by Prevotella intermedia: A Case Report

Oral bacteria, such as Prevotella intermedia, can be a rare cause of spondylodiscitis, especially in patients who have recently undergone an esophagogastroduodenoscopy (EGD). Gram-positive bacteria are typically the most common infecting organisms in spondylodiscitis cases. However, if empirical antibiotic treatment fails, it is crucial to perform a biopsy of the infected disc and vertebral body to culture and identify any unusual pathogens, such as anaerobic bacteria. We report the case of a 43-year-old man with L5/S1 spondylodiscitis attributed to P. intermedia. Cauda equina syndrome developed two days later after initiation of empirical treatment with intravenous oxacillin, which prompted emergent decompression surgery. After initial decompression and debridement surgery, intravenous oxacillin was continued due to the negative intraoperative culture result. However, pus discharge from the surgical wound was noted six days after the first operation, and the C-reactive protein level was elevated. Re-operation for debridement was done, and P. intermedia was isolated from intraoperative tissue culture. According to antibiotic susceptibility testing, antibiotics were adjusted to intravenous metronidazole (7.5 mg/kg every six hours), and the patient's clinical symptoms and signs improved gradually. The patient had undergone an EGD four weeks prior, and the bacteremia could have originated from the breach of the mucocutaneous barrier that occurred during the EGD, allowing oral bacteria to access the bloodstream. This report highlights an unusual case of P. intermedia-associated spondylodiscitis and emphasizes the potential for rare pathogens to cause serious spinal infections. Additionally, it aims to draw attention to the possibility that procedures such as EGD might introduce oral bacteria into the bloodstream, leading to infections distant from the site of the procedure.