1 Philips Institute of Oral Health Research, Richmond, VA, USA.
2 Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, USA.
3 Philips Institute of Oral Health Research, Richmond, VA, USA; Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA; Department of Biochemistry, Virginia Commonwealth University, Richmond, VA, USA. Electronic address: jplewis@vcu.edu.