1 Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of Cologne, Cologne, Germany; DZIF (German Centre for Infection Research), partner site Bonn-Cologne, Germany. Electronic address: axel.hamprecht@uk-koeln.de.
2 Institute of Medical Microbiology and Infection Control, Hospital of Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.