Poststernotomy mediastinitis due to Staphylococcus aureus: Comparison of methicillin-resistant and methicillin-susceptible cases

The objective of the study was to compare the outcome of poststernotomy med iastinitis (PSM) caused by methicillin-resistant and methicillin-susceptibl e Staphylococcus aureus (MRSA and MSSA, respectively). Hospital records of 41 patients with S. aureus PSM who were all treated by closed drainage from 1 April 1996 through 1 February 2000 were reviewed. PSM was caused by MRSA in 15 patients and by MSSA in 26. Followup (+/-SD) averaged 12.5 +/- 14.0 months per patient. Both groups had similar perioperative characteristics. Patients with MRSA PSM had a significantly lower actuarial survival rate th an did patients with MSSA PSM (60.0% +/- 12.6%, 52.5% +/- 3.4%, and 26.3% /- 19.7% versus 84.6% +/- 7.1%, 79.0% +/- 8.6% and 79.0% +/- 8.65 at 1 mont h, and at 1 and 3 years, respectively; values are +/- SD; P = .04). PSM-rel ated death and treatment failure were significantly higher in the MRSA grou p than in the MSSA group (P = .03 and .02, respectively). Logistic regressi on analysis revealed that MRSA was the only independent risk factor for ove rall mortality. In conclusion, the clinical outcome of PSM caused by MRSA i s poorer than that caused by MSSA.