Institute of Medical Microbiology, Justus-Liebig-University Frankfurter Strasse 107, D-35392 Giessen, Germany. Andre.Billion@mikrobio.med.uni-giessen.de|Institute of Medical Microbiology, Justus-Liebig-University Frankfurter Strasse 107, D-35392 Giessen, Germany. Andre.Billion@mikrobio.med.uni-giessen.de|Institute of Medical Microbiology, Justus-Liebig-University Frankfurter Strasse 107, D-35392 Giessen, Germany. Andre.Billion@mikrobio.med.uni-giessen.de|Institute of Medical Microbiology, Justus-Liebig-University Frankfurter Strasse 107, D-35392 Giessen, Germany. Andre.Billion@mikrobio.med.uni-giessen.de