University of Cologne - Division of Infectious Diseases, University of Cologne - Department of Hospital Hygiene and Infection Control, University of Cologne - Department of Neurology, University of Cologne - Center for Neurosurgery, University of Cologne - Center for Neurosurgery, University of Cologne - Department of Orthopedics and Trauma Surgery, University of Cologne - Department of Orthopedics and Trauma Surgery, University of Cologne - Division of Infectious Diseases, University of Cologne - Division of Infectious Diseases, University of Cologne - Division of Infectious Diseases, Bonn University - Institute of Hygiene and Public Health, Gesundheitsamt der Stadt Köln - Abteilung Infektions- und Umwelthygiene, University Hospital of Cologne - Institute for Medical Microbiology, Immunology and Hygiene, University Hospital of Cologne - Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne - Division of Infectious Diseases, University of Cologne - Department of Hospital Hygiene and Infection Control and University of Cologne - Division of Infectious Diseases