Increased mortality associated with methicillin-resistant Staphylococcus aureus (MRSA) infection in the intensive care unit: results from the EPIC II study

Int J Antimicrob Agents. 2011 Oct;38(4):331-5. doi: 10.1016/j.ijantimicag.2011.05.013. Epub 2011 Jul 28.


Controversy continues regarding whether the presence of meticillin resistance increases mortality risk in Staphylococcus aureus infections. In this study, we assessed the role of meticillin resistance in survival of patients with S. aureus infection included in the EPIC II point-prevalence study of infection in critically ill patients performed on 8 May 2007. Demographic, physiological, bacteriological and therapeutic data were collected for 13796 adult patients in 1265 participating Intensive Care Units (ICUs) from 75 countries on the study day. ICU and hospital outcomes were recorded. Characteristics of patients with meticillin-sensitive S. aureus (MSSA) and meticillin-resistant S. aureus (MRSA) infections were compared. Co-morbidities, age, Simplified Acute Physiology Score (SAPS) II, site of infection, geographical region and MRSA/MSSA were entered into a multivariate model, and adjusted odds ratios (ORs) [95% confidence interval (CI)] for ICU and hospital mortality rates were calculated. On the study day, 7087 (51%) of the 13796 patients were classified as infected. There were 494 patients with MRSA infections and 505 patients with MSSA infections. There were no significant differences between the two groups in use of mechanical ventilation or haemofiltration/haemodialysis. Cancer and chronic renal failure were more prevalent in MRSA than in MSSA patients. ICU mortality rates were 29.1% and 20.5%, respectively (P<0.01) and corresponding hospital mortality rates were 36.4% and 27.0% (P<0.01). Multivariate analysis of hospital mortality for MRSA infection showed an adjusted OR of 1.46 (95% CI 1.03-2.06) (P=0.03). In ICU patients, MRSA infection is therefore independently associated with an almost 50% higher likelihood of hospital death compared with MSSA infection.

Publication types

  • Clinical Trial
  • Multicenter Study

MeSH terms

  • Adult
  • Aged
  • Anti-Bacterial Agents / therapeutic use
  • Comorbidity
  • Cross-Sectional Studies
  • Female
  • Gram-Negative Bacteria / drug effects
  • Gram-Negative Bacteria / isolation & purification
  • Gram-Negative Bacterial Infections / drug therapy
  • Gram-Negative Bacterial Infections / microbiology
  • Gram-Negative Bacterial Infections / mortality
  • Hemofiltration
  • Hospital Mortality
  • Hospitals
  • Humans
  • Intensive Care Units
  • Male
  • Methicillin / therapeutic use
  • Methicillin Resistance / drug effects
  • Methicillin Resistance / physiology*
  • Methicillin-Resistant Staphylococcus aureus / metabolism
  • Methicillin-Resistant Staphylococcus aureus / pathogenicity*
  • Middle Aged
  • Renal Dialysis
  • Respiration, Artificial / mortality
  • Risk Factors
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / microbiology
  • Staphylococcal Infections / mortality*
  • Staphylococcus aureus


  • Anti-Bacterial Agents
  • Methicillin