1. Department of Chemistry and Pharmacy; University of Erlangen-Nürnberg; Schuhstrasse 19 91052 Erlangen Germany
2. Institute of Medical Microbiology and Hygiene; University of Regensburg; Franz-Josef-Strauss-Allee 11 93053 Regensburg Germany
3. Institute of Clinical Microbiology and Hygiene; University of Regensburg; Franz-Josef-Strauss-Allee 11 93053 Regensburg Germany