1. Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas.
2. Public Health Laboratory, Oklahoma State Department of Health, Oklahoma City, Oklahoma.
3. Department of Microbiology & Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland.
4. Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas.
5. Department of Pathology, University of Texas Medical Branch, Galveston, Texas.