1. National Center for Biological Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
2. Food and Drug Administration, Center for Veterinary Medicine, Office of Research, Laurel, Maryland, USA
3. USDA Food Safety and Inspection Service, Office of Public Health Science, Eastern Laboratory, Athens, Georgia, USA
4. Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA