1. Institute of Hygiene and the National Consulting Laboratory on Hemolytic Uremic Syndrome, University of Münster, Robert Koch Str. 41, 48149 Münster, Germany
2. Governmental Institute of Public Health of the Lower Saxony, Roesebeckstr. 4-6, 30449 Hannover, Germany
3. Institute of Medical Microbiology, University of Münster, Domagkstr. 10, 48149 Münster, Germany