1. College of Veterinary Medicine, Yangzhou University, Yangzhou, China
2. Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
3. MOE Joint International Research Laboratory of Animal Health and Food Safety, Key Lab of Animal Bacteriology, Ministry of Agriculture, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China