1. Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
2. Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
3. Department of Epidemiology and Public Health, The University of Maryland School of Medicine, Baltimore, Maryland
4. Division of Infectious Diseases, Department of Medicine, The University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
5. Division of Infectious Diseases, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland