This study aimed to establish the excess number of deaths, bed-days, and hospital costs associated with blood stream infections (BSIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) and third-generation cephalosporin-resistant Escherichia coli (G3CREC) in 31 countries participating in the European Antimicrobial Resistance Surveillance System (EARSS).

Prevalence data for 2007 from the EARSS and data on the clinical impact of antimicrobial resistance throughout Europe was used to calculate the number of BSIs caused by MRSA and G3CREC. This was expressed as excess number of deaths, excess number of days in hospital, and excess costs. Statistical methods were used to predict the trajectories for MRSA and G3CREC prevalence until 2015 for the 31 participating countries in the European region. Overall, a total of 1,293 hospitals from the 31 countries, typically covering 47% of all available acute care hospital beds in most countries, were included in the analysis. The following findings are reported:

• In 2007, for S. aureus, the estimated number of blood stream infections totalled 108,434, of which 27,711 (25.6%) were methicillin-resistant. E. coli caused 163,476 blood stream infections, of which 15,183 (9.3%) were resistant to third-generation cephalosporins.

• The 27,711 episodes of MRSA BSIs were associated with 5,503 excess deaths and 255,683 excess hospital days in the participating countries, whereas the 15,183 episodes of G3CREC BSIs were associated with 2,712 excess deaths and 120,065 extra hospital days.

• The total costs attributable to excess hospital stays for MRSA and G3CREC BSIs were 44.0 and 18.1 million Euros (63.1 and 29.7 million international dollars), respectively.

• Based on prevailing trends, the number of BSIs caused by G3CREC is likely to rapidly increase, outnumbering the number of MRSA BSIs in the near future.

The researchers conclude, “Excess mortality associated with BSIs caused by MRSA and G3CREC is significant, and the prolongation of hospital stay imposes a considerable burden on health care systems. A foreseeable shift in the burden of antibiotic resistance from Gram-positive to Gram-negative infections will exacerbate this situation and is reason for concern.”