College of Veterinary Medicine, China Agricultural University, Beijing 100094, P. R. China;
College of Veterinary Medicine, China Agricultural University, Beijing 100094, P. R. China;
College of Veterinary Medicine, China Agricultural University, Beijing 100094, P. R. China;
College of Veterinary Medicine, China Agricultural University, Beijing 100094, P. R. China;
College of Veterinary Medicine, China Agricultural University, Beijing 100094, P. R. China;
Digoxigenin; Plasmid probe; E. coli; Kanamycin resistance; Surveillance;