Spinal infection caused by Coxiella burnetii and surgical treatments: a case report.

Q fever is a rare global zoonosis caused by Coxiella burnetii, with bone and joint involvement being an uncommon manifestation that poses significant diagnostic challenges. This article reports a case of persistent focal spinal infection caused by C. burnetii in an elderly female without a clear epidemiological exposure history, who was initially misdiagnosed with vertebral compression fractures. The diagnosis was confirmed by third-generation nanopore-based metagenomic next-generation sequencing (mNGS), which detected 12,170 reads of C. burnetii with a relative abundance of 98.27%. The patient was initially treated with oral doxycycline (0.1 g q12h) and rifampin capsules (0.45 g daily) for 4 weeks, resulting in decreased inflammatory markers and reduced paravertebral abscess size. After clinical stabilization, surgical intervention (posterior approach T12-L1 vertebral lesion resection, intervertebral bone graft fusion, and pedicle screw rod fixation) was performed under general anaesthesia. Postoperative follow-up for 3 months showed a significant improvement in the patient's low back pain [visual analogue scale (VAS) score from 6 preoperatively to 1 at 3 months] and functional status [Oswestry Disability Index (ODI) from 65% preoperatively to 10% at 3 months], with normalized inflammatory markers and a reduced C. burnetii IgG antibody titre (from 1:256 to 1:128). Serological follow-up revealed persistent negative IgM antibodies throughout the treatment course. This case highlights the diagnostic value of third-generation mNGS for rare spinal infections caused by C. burnetii and the efficacy of a multimodal treatment approach combining targeted antimicrobial therapy and surgical intervention. The rationale for antibiotic selection and surgical management is discussed, along with the limitations of the present case and clinical insights for managing similar cases.