Temporal trends and epidemiology of Staphylococcus aureus surgical site infection in the Swiss surveillance network: a cohort study

Summary Background Staphylococcus aureus is the leading pathogen in surgical site infections (SSI). Aim To explore trends and risk factors associated with S. aureus SSI. Methods Risk factors for monomicrobial S. aureus SSI were identified from the Swiss multi-centre SSI surveillance system using multi-variate logistic regression. Both in-hospital and postdischarge SSI were identified using standardized definitions. Findings Over a six-year period, data were collected on 229,765 surgical patients, of whom 499 (0.22%) developed monomicrobial S. aureus SSI; 459 (92.0%) and 40 (8.0%) were due to meticillin-susceptible S. aureus (MSSA) and meticillin-resistant S. aureus (MRSA), respectively. There was a significant decrease in the rate of MSSA SSI ( P  = 0.007), but not in the rate of MRSA SSI ( P  = 0.70). Independent protective factors for S. aureus SSI were older age [≥75 years vs S. aureus SSI compared with other procedures. Conclusions SSI due to S. aureus are decreasing and becoming rare events in Switzerland. High-risk procedures that may benefit from specific preventive measures were identified. Unfortunately, many of the independent risk factors are not easily modifiable.