1. Robert Koch Institute, Wernigerode Branch, Burgstr. 37, D-38855 Wernigerode, Germany
2. Robert Koch Institute, Advanced Light and Electron Microscopy (ZBS 4), Seestr. 11, D-13353 Berlin, Germany
3. Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue-Str. 13, D-60438 Frankfurt am Main, Germany
4. Division of Clinical Microbiology and Infection Biology, Institute of Bacteriology, Mycology and Hygiene, University of Veterinary Medicine, A-1210 Vienna, Austria