To evaluate the clinical characteristics and outcomes of patients with hematogenous vertebral osteomyelitis (HVO) caused by gram-negative bacteria (GNB).

We conducted a retrospective chart review of adult patients with HVO from three tertiary-care hospitals over a 7-year period.

Of the 313 microbiologically diagnosed HVO cases, GNB was responsible for 65 (20.8%) cases. Compared with patients with MSSA HVO, patients with GNB HVO were more likely to be female (P = 0.03) and have diabetes (P = 0.03), but less likely to have epidural abscess (P = 0.02) and paravertebral abscess (P = 0.003). Clinical outcomes were similar between the GNB and MSSA groups, including in-hospital mortality (4.6% vs. 7.8%; P = 0.53), recurrence (9.7% vs. 4.3%; P = 0.20), and sequelae (31.7% vs. 32.2%; P = 0.95). Among GNB-infected patients, recurrence rates differed according to the total duration of antibiotic treatment: 40.0% (4–6 weeks), 33.3% (6–8 weeks), and 2.1% (≥8 weeks) (P = 0.002).

GNB HVO was responsible for 20.8% of adult cases of HVO. Despite some differences in clinical and radiological presentation, clinical outcomes were similar between GNB and MSSA HVO. Antibiotic therapy for ≥8 weeks may benefit patients with GNB HVO.