1. Department of Diagnosis, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, PR China
2. Chinese Center for Disease Control and Prevention, Beijing, PR China
3. Branch for Enteric Disease Control and Prevention, Institute for Infectious Disease Control and Prevention, Henan Center for Disease Control and Prevention, PR China
4. Department of Microbiology, Zhoukou Center for Disease Control and Prevention, PR China
5. Department of Clinical Laboratory, Shangqiu Center for Disease Control and Prevention, PR China