1. Institute for Medical Microbiology, University of Berne, CH-3010 Berne, Switzerland1;
2. Division of Infectious Diseases, Department of Medicine, University of California, San Francisco, California 94143-06542; and
3. Meningitis and Special Pathogens Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 303333