Preoperative carriage and postoperative same-species sternal wound infection after cardiac surgery.

Sternal wound infection (SWI) after cardiac surgery remains an important problem. Prediction of pathogens involved in such infection could guide antibiotics. From April 1, 2006 to December 31, 2008, retrospectively, we evaluated the diagnostic value of preoperative methicillin-sensible Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) or multi-drug resistant Gram-negative bacillus (MDRGNB) carriage to predict same-pathogens involved in postoperative SWI. All patients referred for elective cardiac surgery were screened using multisite (nares, axillae, rectal) sampling at admission to detect MSSA, MRSA, and MDRGNB. Of the 1895 patients addressed, 425 patients (22.4%) were colonized at admission. Preoperative carriers more frequently developed SWI than non-carriers, respectively, 11% vs. 5.5% (P<0.05). Because of the small sample, MDRGNB carriers could not be analyzed. For prediction of MSSA SWI with preoperative MSSA carriage, the area under the receiver operating characteristic (ROC) curve was 0.720 (95% confidence interval (CI), 0.364-0.796) and 0.710 (95% CI, 0.623-0.787) for prediction of MRSA SWI with preoperative MRSA carriage. Preoperative MSSA carriage is frequent but preoperative MRSA or MDRGNB carriage remains infrequent. The ability of preoperative carriage to predict a same-pathogen-postoperative SWI was low and should not be used to guide empirical antibiotherapy.