1. Foodborne and Diarrheal Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia.
2. Bacteriology and Enteric Diseases Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
3. Statens Serum Institut, Copenhagen, Denmark.
4. Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Shek Kip Mei, Kowloon, Hong Kong.
5. Association of Public Health Laboratories, Washington, D.C.
6. Instituto Panamericano de Protección de Alimentos y Zoonosis (INPPAZ), Buenos Aires, Argentina.
7. Departamento de Bacteriologia, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. Carlos G. Malbran, Ministerio de Salud, Ciudad de Buenos Aires, Argentina.