Staphylococcal post-sternotomy mediastinitis: five year audit

Abstract

Background: The reported rate of post-sternotomy mediastinitis is between 0.8 and 2.3%, with up to 79% of cases caused by staphylococci. Mediastinitis is associated with significant morbidity and mortality. Obesity and diabetes are the only risk factors consistently identified. The aims of the present study were to determine the incidence and risk factors for staphylococci post-sternotomy mediastinitis and to audit its management.

Methods: The clinical records of patients with staphylococcal post-sternotomy mediastinitis between 1 January 1998 and 31 May 2003 were retrospectively reviewed. Information collected included patient demographics, comorbidities, operation type, microbiology findings, surgical and medical management, and outcome. Data collected on cases were compared with data collected in a prospective database of all patients undergoing cardiac surgery.

Results: The incidence of staphylococcal post-sternotomy mediastinitis was 1.2% (60 cases in 5176 median sternotomies). Staphylococcus aureus was isolated in 49 (82%) cases and coagulase-negative staphylococci in 11 (18%) cases. Eight (16%) S. aureus isolates were methicillin-resistant. Risk factors associated with mediastinitis were ethnicity, diabetes mellitus, emergency surgery, ejection fraction and length of preoperative hospital stay. In-hospital mortality was 15%. Eighteen per cent of cases were not cured by initial therapy.

Conclusion: Staphylococcal mediastinitis is a serious complication with significant rates of relapse and mortality. This audit has lead to an evaluation of our clinical pathways to ensure that prevention and management of surgical site infection is optimized.