Risk of Infective Endocarditis in Patients with Spinal Surgical Site Infection and Staphylococcus aureus Bacteremia

Context: Surgical site infection (SSI) is responsible for significant morbidity, prolonged hospital stays, and increased costs. Infectious endocarditis (IE) is a rare but serious complication of bacteremia, particularly that resulting from Staphylococcus aureus SSI. The VIRSTA score predicts the risk of IE and determines the priority of transthoracic echocardiography (TTE) in patients with S. aureus bacteremia. The aim of the study was to (1) assess the performance of the VIRSTA score and (2) determine the usefulness of TTE in S. aureus bacteremia related to spinal SSI. Materials and Methods: We carried out a retrospective study of consecutive patients with spinal SSI and S. aureus bacteremia at two university hospitals in France (Bordeaux and Tours) from January 2009 to January 2023. We collected the patients' clinical and surgical characteristics at baseline, VIRSTA score items, TTE results, and medicosurgical management. The associations of these parameters with IE were assessed using the chi-square test and logistic regression models. Results: Of 82 patients with spinal SSI and S. aureus bacteremia, only 1 (1.21%) developed IE. Thirteen patients did not benefit from TTE during hospitalization and were considered free of IE after clinical follow-up. Diabetes mellitus (p < 0.04) and the presence of severe sepsis or septic shock (p < 0.03) were significantly associated with the presence of IE in this population. Conclusions: Incidence of IE in patients with spinal SSI and S. aureus bacteremia is low. The VIRSTA score has high sensitivity but is not accurate for identifying patients at high risk for IE and systematic performance of TTE is complex and not useful in this setting. Level of Evidence: IV.