Clinical appearance of Staphylococcus aureus spondylodiscitis and molecular characterization of the isolates

Abstract

Infectious spondylodiscitis is diagnosed with increasing frequency. It is most commonly caused by Staphylococcus aureus. The aim of the present study was to determine clinical differences between S. aureus and non-S. aureus spondylodiscitis and, by using spa typing, to determine whether certain clones of S. aureus predominate. During the y 2002-2006, 70 patients (45 male, 25 female) were diagnosed with spondylodiscitis and treated at the Department of Infectious Diseases, University Medical Centre Ljubljana. The age range was 13-95 y (mean age 63.4 y). Cultures were positive in 59 (85%) patients; S. aureus was isolated from blood and/or vertebral disc in 42 (60%) and other bacteria were isolated in 17 (25%). In patients with S. aureus spondylodiscitis, the infection was more likely to be haematogenous. These patients were more likely at risk for epidural abscess. Thirty S. aureus isolates from blood were typed with the spa typing molecular method. All of them were methicillin-susceptible. We identified 20 spa types. Seven spa types (t005, t015, t026, t091, t116, t449 and t474) were identified more than once, while 13 were sporadic. Among the sporadic spa types, 6 were newly identified in this study and introduced as new types into the spa server database. A heterogeneity of S. aureus isolates from spondylodiscitis was detected in this study. Thus no specific clone was identified that might be more likely to cause infection of the spine.