1. Division of Risk Surveillance I, China National Center for Food Safety Risk Assessment, Beijing, China.
2. Institute for Communicable Disease Control and Prevention, Shandong Provincial Center for Disease Control and Prevention, Jinan, China.
3. Institute for Communicable Disease Control and Prevention, Heilongjiang Provincial Center for Disease Control and Prevention, Harbin, China.
4. Microbiology Department, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China.
5. Microbiology Laboratory, Gansu Provincial Center for Disease Control and Prevention, Lanzhou, China.