Katja Wieland1, Patrick Chhatwal1, Ralf-Peter Vonberg2. 1. Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, D-30625 Hannover, Germany. 2. Institute for Medical Microbiology and Hospital Epidemiology, Hannover Medical School, D-30625 Hannover, Germany. Electronic address: Vonberg.Ralf@MH-Hannover.DE.