1. 1st Department of Internal Medicine, University of Cologne, 50924 Cologne, Germany
2. Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, 50924 Cologne, Germany
3. Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA
4. Department of Internal Medicine 1, Division of Infectious Diseases, University of Regensburg, 93042 Regensburg, Germany