Risk factors for mortality in patients with nosocomial Staphylococcus aureus bacteremia

Aim: Bloodstream infections (BSIs) due to Staphylococcus aureus have become increasingly common in hospitals worldwide. The aim of this study was to evaluate the risk factors for mortality of nosocomial BSI due to S. aureus. Materials and methods: We analyzed risk factors for mortality of methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA) bacteremia in a prospective case control study in a 1196-bed tertiary referral medical center. Logistic regression analyses were used to determine risk factors and prognostic factors of mortality. Results: Between July 2006 and January 2009, 176 patients were identified with clinically significant and microbiologically confirmed nosocomial bacteremia due to S. aureus. After controlling potential risk factors for mortality on multivariate logistic regression analysis, age equal to and greater than 60 years, hospitalization in intensive care unit, total parenteral nutrition support, and methicillin resistance were found as independent risk factors for mortality. The mortality with MRSA bacteremia was revealed to be 3.02 times higher than that of MSSA bacteremia (P = 0.008, RR = 3.02, 95% CI = 1.34–6.8). Conclusion: S. aureus BSI is a serious condition and methicillin resistance leads to higher mortality rates