Comparing Culture-Positive and -Negative Pyogenic Vertebral Osteomyelitis

The goal of this study is to investigate the antimicrobial therapy, therapeutic response, and outcome of culture-negative PVO compared with culture-positive PVO.

Culture-positive (CP) pyogenic vertebral osteomyelitis (PVO) was commonly identifiable by an epidural abscess, and patients who were CP required longer parenteral antibiotic therapy. These findings from a retrospective study were published in BMC Infectious Diseases.

Patients (N=73) diagnosed with lumbar PVO at 1 tertiary-care university hospital in South Korea between 2014 and 2018 were retrospectively included in this study. Patients were stratified into CP and culture-negative (CN) groups on the basis of tomography-guided needle biopsy or open surgery.

Patients were 60.3% male with a mean age of 64.73 plus or minus 11.61 years. Patients who were CN or CP differed significantly for instance of epidural abscess (43.9% vs 84.4%; P =.001), extent of affected lesion (1.49±0.93 vs 2.09±1.28; P =.022), and hospital stay (50.32±19.96 vs 62.88±26.04 days; P =.022), respectively.

Bacterial infections manifested in tissue culture (46.9%), blood culture (25%), and both cultures (28.1%). Causative microorganisms were Staphylococcus aureus (40.6%), coagulase-negativestaphylococci (12.5%), Escherichia coli (6.3%), Acinetobacter baumannii (6.3%), Klebsiella pneumoniae (3.1%), Enterobacter (3.1%), Streptococcus (18.8%), and Enterococcus (9.4%) species.

All patients were administered parenteral antibiotics and most were given oral antibiotics (60.5%). Patients who were CN or CP differed significantly for nafcillin (2.4% vs 18.8%; P =.039) and quinolone (22.0% vs 3.1%; P =.036), respectively. Patients who were CN were given parenteral antibiotics for a shorter time (45.88±16.14 vs 57.31±24.39 days; P =.019) and oral antibiotics for a longer time (55.29±47.40 vs 26.84±41.10 days; P =.009).

Predictors of bacterial infection included epidural abscess (odds ratio [OR], 6.90; 95% CI, 2.22-21.49; P =.001), baseline back visual analog scale (OR, 2.00; 95% CI, 1.21-3.33; P =.007), baseline C-reactive protein (OR, 1.08; 95% CI, 1.02-1.14; P =.009), open-surgery biopsy (OR, 3.31; 95% CI, 1.26-8.71; P =.015), and extent of lesion (OR, 1.65; 95% CI, 1.06-2.58; P =.027).

At the 3-month follow-up, the patient groups did not differ significantly for back pain, C-reactive protein concentrations, or erythrocyte sedimentation rate.

This study was limited by its sample size, as it was too underpowered to assess any differences between patient groups for recurrence.

The study authors concluded patients with CN or CP PVO had similar clinical outcomes at 3 months. Patients who were CN received shorter courses of parenteral antibiotics and CP was associated with epidural abscesses.


Yu D, Kim S W, Jeon I. Antimicrobial therapy and assessing therapeutic response in culture-negative pyogenic vertebral osteomyelitis: a retrospective comparative study with culture-positive pyogenic vertebral osteomyelitis. Published online December 9, 2020. BMC Infect Dis. 2020;20(1):939. doi:10.1186/s12879-020-05669-1