Native vertebral osteomyelitis — fellow's quick read

Personal study digest for a new ID fellow. Recommendations are from the 2015 IDSA NVO guideline (Berbari et al.) and the local Michigan CPG. The "What's changed since 2015" section is reviewer synthesis of newer evidence, each claim cited. Not a substitute for the full guideline.

In one line

NVO is hematogenous seeding of the disc/endplate — usually monomicrobial and usually S. aureus. Back pain + fever or ↑ESR/CRP is the trigger; MRI confirms. Get a microbiologic diagnosis before antibiotics (hold abx if stable), treat ~6 weeks, and follow ESR/CRP — not imaging — for response.

◆When to suspect / diagnose

New or worsening back/neck pain plus any of: fever, ↑ESR or CRP, or bloodstream infection / endocarditis (each strong, low). New spinal pain after a recent S. aureus bacteremia is NVO until proven otherwise.
MRI of the spine is the diagnostic test (strong, low) — plain films are insensitive early. Use gallium/Tc-99 bone scan, CT, or PET only when MRI can't be done (devices, claustrophobia).
Most cases are monomicrobial, S. aureus most common. Add Brucella blood cultures + serology if endemic/subacute, and a PPD/IGRA if TB risk; fungal cultures if host risk.

◆Workup the fellow drives

2 sets of blood cultures + baseline ESR and CRP in everyone (strong, low).
Image-guided aspiration/biopsy when no organism is identified — but you can SKIP the biopsy when blood cultures already grow S. aureus, S. lugdunensis, or Brucella with compatible MRI (the bacteremia names the bug).
If the first biopsy is nondiagnostic: add fungal/mycobacterial/Brucella cultures and bacterial nucleic-acid amplification (16S/broad-range PCR), and repeat the biopsy (or PEDD/open biopsy).
Hold empiric antibiotics until a microbiologic diagnosis if the patient is neurologically intact and hemodynamically stable — empiric abx lower culture yield.

◆Empiric & definitive therapy

Scenario	Drug / dose / route	Notes
Empiric (only if septic / neuro deficit)	Vancomycin (AUC-guided) + a gram-negative agent (e.g., cefepime 2 g IV q8–12h)	Otherwise HOLD until cultures. Covers MRSA + GNR pending data
MSSA	Nafcillin/oxacillin 1.5–2 g IV q4–6h · or cefazolin 1–2 g IV q8h · or ceftriaxone 2 g IV q24h	Ceftriaxone convenient for OPAT
MRSA	Vancomycin 15–20 mg/kg IV q12h (AUC-guided)	Alt: daptomycin 6–8 mg/kg IV q24h or linezolid 600 mg q12h
Gram-negative (Enterobacterales)	Cefepime 2 g IV q12h or ertapenem 1 g IV q24h	Ciprofloxacin 500–750 mg PO q12h if susceptible (excellent PO bioavailability)
Brucella	Doxycycline + rifampin (or doxycycline + an aminoglycoside)	3 months (strong, moderate)

Oral β-lactams should NOT be used for initial therapy (poor bioavailability). Highly bioavailable oral agents — fluoroquinolones, linezolid, metronidazole — permit an early oral switch once improving and any abscess is drained.

◆Duration & stopping

~6 weeks of parenteral OR highly bioavailable oral therapy for most bacterial NVO (strong, low) — backed by the DTS/Bernard RCT (6 wk = 12 wk).
Brucella: 3 months (strong, moderate). Extend bacterial NVO only for undrained abscess, hardware, or slow response.
Follow ESR/CRP + clinical status at ~4 weeks. Do NOT routinely repeat MRI in a patient improving clinically (strong) — pain and imaging lag behind cure.

◆Key decisions a fellow owns

Hold vs treat empirically: start empiric abx before a diagnosis only for sepsis/hemodynamic instability or progressive/severe neuro deficit; otherwise hold and biopsy.
Surgery for progressive neurologic deficit, progressive deformity, or spinal instability (strong, low); also for persistent/recurrent bacteremia or worsening pain despite appropriate therapy.
Don't over-call failure: residual pain, persistently elevated markers, or radiographic findings alone do not equal treatment failure. Rising ESR/CRP after 4 weeks should raise suspicion.

What's changed since 2015

Reviewer synthesis of newer evidence — not the guideline. Each claim cited; flags where the 2015 IDSA NVO guideline lags current practice.

Still no newer IDSA NVO guideline — the 2015 document remains the operative US reference. The newest major society guidance is the French SPILF 2022 disco-vertebral infection guideline. Berbari, CID 2015;61:e26-46 · Lacasse, Infect Dis Now 2023;53:104647 (doi:10.1016/j.idnow.2023.01.007)
OVIVA gave the oral switch its RCT proof. The 2015 guideline already permitted "highly bioavailable oral" therapy but on weak data; OVIVA showed oral noninferior to IV for the first 6 weeks of bone/joint infection (incl. vertebral osteo): failure 13.2% PO vs 14.6% IV, fewer catheter complications (1.0% vs 9.4%) and shorter stay. Quinolones were the most-used oral agents; oral β-lactams were little used. OVIVA, NEJM 2019;380:425-436 (PMID 30699315)
6 weeks is now RCT-backed, not expert opinion. DTS/Bernard: 6 wk noninferior to 12 wk in pyogenic vertebral osteomyelitis, ~91% cure in both arms (351 patients, 71 French centers). SPILF: go beyond 6 wk only if the infection is complicated. Bernard, Lancet 2015;385:875-882 (PMID 25468170)
SPILF 2022 dropped several old habits — no ESR, PCT, or scintigraphy for diagnosis/follow-up; no antibiotics before a microbiologic diagnosis (except emergencies); whole-spine MRI in ≥2 orthogonal planes; and several disc samples when blood cultures are negative. Lacasse, Infect Dis Now 2023
Molecular diagnostics are increasingly used when cultures are negative — the guideline endorses adding bacterial nucleic-acid amplification (16S/broad-range PCR) to nondiagnostic biopsy specimens. IDSA NVO 2015, recs 18–19

◆Anki cards minted this run

Duration of bacterial NVO = 6 weeks (DTS/Bernard, Lancet 2015).
When you can SKIP the image-guided biopsy (S. aureus/S. lugdunensis/Brucella bacteremia + MRI).
Brucellar NVO = 3 months (doxycycline + rifampin or aminoglycoside).
The two situations that justify empiric abx before a diagnosis (sepsis; progressive neuro deficit).
Held as duplicates — already in deck: OVIVA result, levofloxacin as the OVIVA oral agent, ESR for follow-up, S. aureus as most common organism, "hold antibiotics" in stable disease.

Sources: IDSA NVO guideline (Berbari, CID 2015;61:e26-46, doi:10.1093/cid/civ482); OVIVA (Li, NEJM 2019;380:425-436, PMID 30699315, doi:10.1056/NEJMoa1710926); DTS/Bernard duration RCT (Lancet 2015;385:875-882, PMID 25468170); SPILF 2022 disco-vertebral infection (Lacasse, Infect Dis Now 2023); Michigan Bone & Joint CPG (rev. 2023).