Are blood cultures performed after disco-vertebral biopsy useful in patients with pyogenic infective spondylitis?

Sir, As the treatment of pyogenic infective spondylitis is based on appropriate antibiotic therapy, the identification of the causative micro‐organism is highly desirable. Thus, the investigations performed prior to initiation of therapy must include blood and, if negative, disco‐vertebral biopsy cultures [1]. Moreover, since it is thought that such biopsies can result in transient blood bacteriaemia, additional blood cultures in the minutes and hours following the biopsy are often recommended. However, to our knowledge, the usefulness of post‐biopsy blood cultures has never been assessed. The aim of this work was to evaluate the diagnostic value of such blood cultures. For this purpose, the data of every patient hospitalized in our rheumatology unit between 1991 and 2001 for pyogenic infective spondylitis were retrospectively reviewed. The diagnosis was made in the presence of clinical, laboratory and imaging (including bone scintigraphy and/or CT scan and/or magnetic resonance imaging) evidence of pyogenic infective spondylitis, and (i) the presence of micro‐organism on blood culture and/or disco‐vertebral biopsy, or (ii) the efficacy of empirical antibiotic treatment on clinical, laboratory and imaging parameters. Among these patients, the characteristics of those in whom a disco‐vertebral biopsy was performed were reviewed.