Abstract

Objective: Staphylococcus aureus is the most common cause of hematogenous vertebral osteomyelitis in adults. To better define clinical features and therapeutic outcomes, the charts of 40 adult patients with S aureus hematogenous vertebral osteomyelitis were retrospectively reviewed.

Methods: Retrospective chart review using standardized data collection form.

Results: S aureus hematogenous vertebral osteomyelitis commonly occurred in the settings of recent invasive procedures (55% of patients), insulin use (28%), and hemodialysis (20%). Ten percent of patients had S aureus bacteremia or vascular catheter infection within the preceding 6 months. Median time from first symptom to diagnosis was 51.3 days. A portal of entry for S aureus was identified in 13 patients (32.5%); intravenous catheters were the likely origin in 9 of those 13 patients. Concurrent endocarditis was present in 4 patients. Forty-eight percent of patients had neurologic abnormalities and 60% of patients had an epidural, paraspinous, or psoas abscess demonstrated by neuroimaging. S aureus was isolated through fine-needle aspiration in 17 of 23 patients (74%) and from blood cultures in 23 of 34 patients (68%). Infection was due to methicillin-susceptible S aureus in 67.5% of patients. All patients received intravenous antibiotics for a mean duration of 58.6 days; 36 of 40 (90%) also received concomitant rifampin. Twenty-seven percent and 12.5% of patients underwent surgical debridement and CT-guided drainage of abscesses, respectively. After intravenous therapy, 19 of 30 eligible patients received oral continuation treatment. The mean duration of total antibiotic therapy was 142.2 days.

Conclusions: Cure of infection was achieved in 83% (24/29) of evaluable patients, but 50% of those achieving cure still had infection-related sequelae. Intravenous antibiotic therapy for at least 8 weeks was the only clinical factor associated with cure (P = 0.05, two-tailed Fisher exact test).

Key Points

* Vertebral osteomyelitis should be a diagnostic consideration in any patient with back pain and Staphylococcus aureus bacteremia.

* Vascular catheters are a frequent portal of entry for S aureus to gain access to the bloodstream before vertebral seeding.

* Neurologic findings are often present at the time of diagnosis and serve to identify patients who may have complicating abscesses that require drainage.

* Methicillin-resistant S aureus is the causative organism in approximately one third of patients.

* A minimum parenteral treatment duration of 8 weeks is usually warranted.