1. Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria, Department of Hygiene, Microbiology and Social Medicine, Division of Hygiene and Medical Microbiology, Medical University of Innsbruck, Fritz-Pregl-Strasse 3, 6020 Innsbruck, Austria, and Bionorica AG, Kerschensteinerstrasse 11-15, 92318 Neumarkt, Germany