Spinal infection by Enterobacter hormaechei: an unusual cause of spondylodiscitis: a case report

Abstract

Spondylodiscitis is an infectious condition involving the intervertebral disc and adjacent vertebral bodies. Although Staphylococcus aureus and Mycobacterium tuberculosis are the most common pathogens, cases caused by Gram-negative bacilli are relatively rare. Enterobacter hormaechei is an exceptionally uncommon etiologic agent in this context. A 69-year-old Turkish male with type 2 diabetes mellitus and a history of prostate adenocarcinoma in remission, with no active immunosuppression, presented with lower back pain and elevated inflammatory markers. Initially suspected to have metastatic spinal involvement, spinal MRI revealed spondylodiscitis at the T12–L1 level. Microbiological evaluation of the needle biopsy specimen yielded Enterobacter hormaechei . Species-level identification was established by culture and MALDI-TOF MS, with off-label syndromic PCR testing (BIOFIRE ® Joint Infection Panel) providing supportive concordant results. The patient was successfully managed with surgical intervention and appropriate antimicrobial therapy. Spondylodiscitis due to Enterobacter hormaechei remains exceedingly rare. This case highlights the importance of considering atypical Gram-negative organisms in spinal infections and underscores the value of advanced microbiological methods for accurate species-level identification.