[1] Univ Med Greifswald, Inst Hyg & Environm Med, Greifswald, Germany
[2] Med Univ Vienna, Vienna Gen Hosp, Clin Inst Hosp Hyg, Waehringer Guertel 18-20, A-1090 Vienna, Austria
[3] DAK Gesundheit, Hamburg, Germany
[4] Vivantes Humboldt Klinikum, Clin Surg Visceral & Vasc Surg, Berlin, Germany
[5] Techniker Krankenkasse, Hamburg, Germany
[6] Wannsee Akad, Berlin, Germany