Burden of Resistance and Disease in European Nations (BURDEN): Mortality and extra hospital stay attributable to antibiotic resistance in Staphylococcus aureus and Escherichia coli bloodstream infections in Europe

Background: The relative importance of diseases in humans is conventionally assessed by cause-specific mortality, morbidity and economic impact. For infections caused by antibiotic resistant bacteria, current estimates are not supported by quantitative empirical data.

Objective: To determine the incident and expected excess number of deaths, bed-days and hospital costs attributable to meticillin-resistant Staphylococcus aureus (MRSA) and third generation cephalosporin-resistant E. coli (G3CREC) causing bloodstream infections (BSIs) in Europe.

Methods: The incidence of MRSA and G3CREC bacteraemia per 100,000 population was derived from prevalence data of the European Antimicrobial Resistance Surveillance System (EARSS) and national health care statistics. Prospective clinical outcome studies from a sample of EARSS participating hospitals provided the parameters for calculating the excess 30-day mortality and extra hospital days attributable to MRSA and G3CREC bloodstream infections. Hospital expenditure was derived from a publicly available cost model. Future trends were estimated by regression models based on EARSS data.

Results: In 2007, 4.8 (95% CI 4.5-5.0) episodes of MRSA bacteraemias per 100,000 capita caused 5,521 (95% CI 3,101-8,355) excess deaths and 254,947 (95% CI 142,602-374,208) extra hospital days across 31 countries in the European region, whereas 0.5 (95% CI 0.1-1.0) episodes of G3CREC bacteraemias per 100,000 capita lead to 2,729 (95% CI 610-5,736) excess deaths and 119,927 (95% CI 52,311-197,328) extra hospital days. The total cost attributable to extra hospital stay was 43.8 and 18.0 million Euros, equivalent to 53.3 and 22.7 million I$, respectively. Based on prevailing trends the annual number of excess deaths associated with bloodstream infections caused by MRSA is estimated to decrease to 1,668 but to increase to 8,563 for G3CREC by 2015.

Conclusions: Although the presented results underestimate the total burden of resistance in Europe, MRSA and G3CREC bacteraemias alone caused an equal number of deaths as HIV/AIDS and lead to high costs. At the same time, MRSA incidence is still more than six times lower in Europe than in the USA (Klevens, JAMA 2007). The foreseen shift in burden of resistance from gram-positive to gram-negative infections should be directive for future public health policy in Europe.