A 44-year-old male patient complained of "a 20-day history of neck pain with quadriplegia for 2 days". Cervical spine CT (Figure 1A-D) at a local hospital showed abnormalities in his C6-7 cervical segment, and conservative treatment was performed with poor results. Two days before admission, he experienced numbness and weakness in his limbs, difficulty urinating, and a fever with a body temperature up to 38  C. Cervical magnetic resonance examination found: C6/7 abnormal signals of the vertebral body and intervertebral disc, abscess formation under the anterior longitudinal ligament and spinal canal, compression of the spinal cord, and infectious lesions (Figure 2A-C). On the day of admission, the physical examination showed limited flexion and extension of the cervical spine, weak bilateral upper extremity muscle strength (bilateral triceps muscle strength class I, bilateral biceps muscle strength class II, grip strength grade 0), and loss of tendon reflexes. Both lower limb muscles had a strength level of 0 and low muscle tone. Additional physical examination findings included: bilateral Achilles tendon reflex (-), knee tendon reflex (-), Hoffmann's sign (-), sphincter contraction without touch, bilateral ankle burn, heavy right side, and second-degree scald (Figure 3A and B). Laboratory tests, including the Brucella antibody test, tuberculosis antibody test, and Mycobacterium tuberculosis T-cell test, were negative, and serology showed inflammation (Table 1).   
Two days after admission, the patient underwent posterior cervical spine decompression and fixation under general anesthesia. Preoperative X-ray examination showed C6-7 cervical vertebral body abnormalities and cervical spine degeneration (Figure 4A and B), and the operation went smoothly and the decompression was adequate. Postoperative examination of the internal fixation position was good, as seen in perspective (Figure 4C and D), but there was no significant improvement in limb mobility immediately after the operation. On the first day after surgery, the patient indicated a significant recovery in the strength of both upper limbs, and the physical examination showed that the grip strength of both hands was restored to grade 3 and the sensation of both lower limbs was restored, yet the muscle strength was not significantly improved. On the second day after surgery, the patient complained of an increase in body temperature at night, up to 38.5  C, and an increase in his inflammatory factors compared to preoperatively. Blood culture findings showed Streptococcus constellatus infection, and antimicrobial susceptibility test results indicated that blood isolates were sensitive to vancomycin, penicillin G, cefepime, cefotaxime, levofloxacin, chloramphenicol, and linezolid. Considering that the patient had severe symptoms, the patient was given systemic antibiotic therapy (vancomycin injection 1000 mg, q12h, IV drip; Cefzoxime sodium 1 g, q8h, IV drip) and symptomatic treatments such as fluid replacement, maintenance of water-electrolyte balance, and nutritional support. 
After 2 weeks of vancomycin and cephalosporin treatment, the patient's blood culture reexamination results were negative, the serological inflammatory indicators showed a downward trend (Table 1), the body temperature remained stable at 38  C, and the sensory and muscle strength of both lower limbs recovered more than before, the left side was obvious and the right side was weak (Supplementary Video 1); however, there was a neck rash. The dermatology department and clinical pharmacy department considered that the neck rash was related to the previous use of vancomycin, so we changed the antibiotic (linezolid 0.6 g, q12h, IV drip) for symptomatic treatment. After 3 weeks of systemic antibiotic treatment, the patient's condition tended to be stable, and the muscle strength and sensory motor function of both lower limbs were significantly improved compared with those before surgery (Supplementary Video 2). The muscle strength of the left lower limb was grade 4, and that of the right lower limb was grade 3. Inflammatory indicators showed a good downward trend (Table 1). The MRI reexamination results showed that the cervical spine infection was relieved compared with the previous observation (Figure 5A-D). CT reexamination of the cervical spine showed that the C6/7 vertebral body was severely damaged and the bone defect was obvious (Figure 6A-F). Therefore, the patient underwent a second operation under general anesthesia for an anterior infection lesion removal and internal fixation of the cervical spine. During the operation, it was found that the lower edge of the C6 vertebral body, the upper edge of the C7 vertebral body, and the C6/7 intervertebral space were obviously damaged, cavities were formed, and some blood gushed out of the cavity (Figure 7A-C). The infection lesion was carefully removed, and the tissue was removed for routine pathological culture. A fibular allogeneic bone of appropriate length (Figure 7D and E) was selected and placed between the C5-7 vertebral bodies, and an anterior cervical titanium plate was fixed in front of C5 and C7 (Figure 7F). The results of pathological culture during the operation showed acute and chronic inflammatory cell infiltration and granulation tissue formation, and the clinical results were consistent with inflammatory lesions (Figure 8A and B). According to all the test results, tuberculosis infection and Brucella infection were excluded, and the patient was finally diagnosed with SEA caused by Streptococcus constellatus.    
Within a week of the second operation, the patient continued to receive systemic antibiotics, and the serological inflammatory index gradually decreased to normal. Bacterial culture and anaerobic culture of the puncture fluid were both negative (Table 1), indicating that systemic antibiotic therapy was effective. The patient's CT (Figure 9A-D) and X-ray (Figure 9G and H) review images showed that the internal fixation position was good, the intervertebral space and C6-7 vertebral bone mass were filled on the CT review image (Figure 9E and F), and the patient was discharged. Two weeks after discharge, the patient's serological examination showed that the inflammatory indicators tended to be normal, and there was no significant change (Table 1).