1. Division of Infectious Diseases, Department of Medicine, College of Medicine, Mayo Clinic , Rochester, Minnesota , USA
2. Division of Clinical Trials and Biostatistics, Department of Quantitative Health Sciences, College of Medicine, Mayo Clinic , Rochester, Minnesota , USA
3. Department of Cardiovascular Disease, College of Medicine, Mayo Clinic , Rochester, Minnesota , USA
4. Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine , Houston, Texas , USA