1. Department of Medicine, Division of Infectious Diseases, Johns Hopkins University School of Medicine , Baltimore, Maryland , USA
2. Division of Anti-Infectives, Center for Drug Evaluation and Research, US Food and Drug Administration , Silver Spring, Maryland , USA
3. Department of Pediatrics, Division of Infectious Diseases, Johns Hopkins University School of Medicine , Baltimore, Maryland , USA
4. Department of Emergency Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland , USA