Microbiological and therapeutic challenges in infectious spondylodiscitis: a cohort study of 100 cases, 2006-2011

Background: The microbiological diagnosis of infectious spondylodiscitis is often difficult to establish and the disease requires prolonged antibiotic treatment. We analyzed the medical records of 100 patients admitted for infectious spondylodiscitis from 2006 to 2011 with an emphasis on (1) the diagnostic utility of blood cultures and invasive biopsies in the microbiological diagnosis, (2) clinical features differentiating Staphylococcus aureus infections from those with other aetiologies, and (3) evaluation of the outcome of the antimicrobial therapy. Methods: A retrospective chart review was performed. Results: Patients were diagnosed a median of 32 days after symptom onset and treated for a median of 91 days; 68% had abscesses, 65% experienced sequelae, and the 1-y crude mortality was 11%. Blood cultures yielded a diagnosis in 67%. Among blood culture-positive cases, no other culture or polymerase chain reaction results yielded further diagnoses. S. aureus infections comprised 58%. These cases compared to those with other aetiologies were younger, more frequently female, had a higher C-reactive protein, and more often had neutrocytosis, bacteraemia, and abscess formation. Presumed side effects mediated a change in treatment 33 times in 23 patients. Four patients experienced relapse. Conclusions: This contemporary case-series on infectious spondylodiscitis mostly concurs with previous studies. We emphasize the importance of thorough blood culture sampling before more invasive tests are considered. S. aureus infections exhibit, in particular, prominent pyogenic characteristics. Prospective studies evaluating the choice and duration of antimicrobial treatment are needed.