DIAGNOSTIC APPROACHES TO NATIVE VERTEBRAL OSTEOMYELITIS (NVO) IN A SINGLE UK TERTIARY CENTRE: A RETROSPECTIVE REVIEW HIGHLIGHTING THE ROLE OF SPINAL BIOPSY AND PET-CT

Aim NVO is a rare but life-threatening infection, with an estimated 20% mortality rate. Prompt diagnosis and treatment is required to prevent neurological deficits and death. However, presentation is often non-specific, leading to diagnostic delays and adverse outcomes. i ii iii iv v We present a data set of NVO patients focusing on clinical presentation, diagnosis, management and outcomes. Method We retrospectively analysed patients aged >18 years diagnosed with NVO through clinical coding June 2022–September 2024. Clinical coding identified 81 patient records. Results Pain on admission was the commonest clinical presentation (79%), then neurological dysfunction (43%) and fever (37%). 93% of patients had a raised CRP (>5mg/L) or fever associated with pain or neurological dysfunction. Mean age was 64 years. 68% were male and 54% immunocompromised. All-cause mortality was 9% within 90 days. 98% had blood cultures taken (n=79), of which 52% were positive. Pathogens isolated were: MSSA (51%), Escherichia coli (15%), MRSA (10%), Streptococcus mitis/oralis (7%), Streptococcus anginosus (5%) Enterococcus faecalis (3%), Enterococcus faecalis plus MSSA (2%), Salmonella enteritidis (2%), Staphylococcus haemolyticus (2%), Staph epidermidis (2%). 44% underwent spinal biopsy (SB) (n=36), of which 81% were positive. Isolating: MSSA (45%), MRSA (10%), Klebsiella sp. (10%), Escherichia coli (7%), Cutibacterium acnes (3%),, Group G streptococci (3%), Streptococcus pneumoniae plus Cutibacterium acnes (3%), Mycobacterium xenopi plus MSSA (3%), Mycobacterium tuberculosis (3%), Micrococcus luteus (3%), Corynebacterium striatum (3%). Piperacillin-tazobactam and flucloxacillin were the commonest empirical antibiotics. 21 patients who underwent SB had no growth on peripheral blood cultures. 76% had positive SB results. MSSA was less common in this cohort (n=5, 31%). SB increased the percentage of patients with an isolated organism from 51% (n=41) with blood cultures alone to 70% (n=57) with SB. 5 patients underwent PET-CT; 100% demonstrating NVO. Conclusions Within this cohort the majority of patients presented with raised inflammatory markers or fever. PET-CT demonstrated a successful imaging technique to be considered for this infection. In addition, SB facilitated accurate pathogen identification and targeted antimicrobial therapy. Aligning with previous literature, empirical antibiotics should aim to cover MSSA , the commonest pathogen isolated. Although here we noted a higher-than-expected rate of MRSA , and thus if there are any risk factors, empirical MRSA cover should be considered in our patients. Clinicians are reminded to have a high index of suspicion for NVO and to consider advanced diagnostic tools (SB, PET-CT) to enable the best possible patient outcomes.