Decolonization of Patients Carrying S. Aureus Before Cardiac Surgery: Study of the Risk Factors Associated With Failure

Staphylococcus aureus nasal carriage is a well-known risk factor for S. aureus surgical site infections (SSI). According to a recent study demonstrating 60% reduction risk of SSI due this bacterium after patients' screening and decolonization, recent French and WHO guidelines recommend in cardiac surgery the decolonization of nasal S. aureus carriers before surgery. In practice the decolonization procedures are not well-defined according notably to the duration and time of delivery before surgery and doses of topical antimicrobial drugs. The aim of the proposed study is to investigate the factors associated with failures of S. aureus decolonization: carriage state, compliance with treatment, S. aureus capacity of internalization in nasal epithelial cells, resistance to antimicrobial drugs used. This study will allow (i) to measure the frequency of patients with residual S. aureus carriage just before surgery, whatever they have been decolonized or not, (ii) to characterize the S. aureus nasal carriage state of patients before surgery, and (iii) to investigate the adding value of mupirocin dosage in the nose and urines of decolonized patients as a marker of compliance and efficacy of the decolonization process.