1. Institute of Medical Microbiology and Hygiene, University Hospital of Ulm, Albert-Einstein-Allee 23, D-89081 Ulm, Germany
2. German National Reference Laboratory for Multidrug-Resistant Gram-negative Bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Universitätsstraße 150, D-44801 Bochum, Germany