Design of a surveillance system of antibiotic use and bacterial resistance in German intensive care units (SARI)

Background: Data on antibiotic consumption and bacterial resistance are important for benchmarking, ensuring quality of antibiotic treatment and helping to understand the relationship between the use of antibiotics and the emergence of resistance. Methods: The SARI project is an ecological study that has established Laboratory-based surveillance in German intensive care units (ICU). Resistance rates of 13 sentinel pathogens are reported and certain alert organisms are sent for genotyping and retesting of antimicrobial resistance. Results: The project, initiated in February 2000, now includes 35 ICUs generating a total of 266,013 patient days, 354,356 defined daily doses (DDD) and providing susceptibility data on 21,354 isolates. Pooled antibiotic usage density (AD = DDD/1,000 patient days) was highest for penicillins with lactamase inhibitor (AD 338.3) followed by quinolones (AD 155.5) and second-generation cephalosporins (AD 124.6). Total AD was calculated as 1,337 DDD/1,000 patient days. Resistance rates (RR) for Laboratories testing according to the German Industrial Standard (DIN) were 19.3% for methicillin-resistant Staphylococcus aureus(MRSA), 9.5% for ciprofloxacin-resistant Escherichia coli and 25.4% for imipenem-resistant Pseudomonas aeruginosa. 40% of the Laboratories did not identify the extended spectrum betalactamase production of a Klebsiella pneumoniae strain. Conclusion: Focusing on German ICUs, the SARI surveillance system provides a concept that produces a benchmark for the link between antibiotic resistance and consumption.