A rifampicin-containing antibiotic treatment improves outcome of staphylococcal deep sternal wound infections

Deep sternal wound infection (DSWI) is a severe complication after cardiac surgery, mostly caused by staphylococci. Little is known about the optimal antibiotic management. A 10 year retrospective analysis of 100 patients with staphylococcal DSWI after cardiac surgery in a tertiary hospital. Treatment failure was defined as sternal wound dehiscence or fistula at the end of the prescribed antibiotic therapy, 12 months later, or DSWI-related death. Most patients were male (83%) and the median age was 72 years [interquartile range (IQR) 63-76]. Coronary artery bypass was the most frequent preceding procedure (93%). The median time to diagnosis of DSWI was 13 days (IQR 10-18) after surgery. Clinical presentation consisted of wound discharge in 77% of patients. Coagulase-negative staphylococci were isolated in 54 and Staphylococcus aureus in 46 patients. All patients received antibiotics and 95% underwent surgical debridement. The median duration of antibiotic treatment was 47 days (IQR 41-78). During follow-up, 21 out of 100 patients experienced treatment failure. Of these, 8/21 patients (38%) died from DSWI after a median of 12 days (IQR 8-30). In the multivariate analysis, a rifampicin-containing antibiotic regimen was the only factor associated with lower risk of treatment failure (hazard ratio 0.26, 95% confidence interval 0.10-0.64, P = 0.004). Prolonged treatment (12 weeks instead of 6 weeks) did not alter outcome (P = 0.716) in patients without prosthetic valve endocarditis. Treatment of rifampicin-susceptible staphylococcal DSWI with a rifampicin-containing antibiotic regimen may improve the outcome. After surgical debridement an antibiotic treatment of 6 weeks may be adequate for staphylococcal DSWI.