1. Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
2. Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
3. School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
4. Center for Quantitative Sciences, Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
5. Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA