1. Section of Infectious Diseases, Baylor College of Medicine , Houston, Texas , USA
2. Department of Internal Medicine, Baylor College of Medicine , Houston, Texas , USA
3. Department of Pathology and Immunology, Baylor College of Medicine , Houston, Texas , USA
4. Department of Pathology, Baylor College of Medicine , Houston, Texas , USA
5. Center for Quality, Effectiveness, and Safety, Michael E. DeBakey Veterans Affairs Medical Center , Houston, Texas , USA