Isolation and Identification of a High-pathogenicity Strepto- coccus suis Serotype 7 Strain

In order to diagnose the diseased pigs in a certain large pig farm in Binzhou City, Shandong Province, the dead piglets with joint swelling were subjected to necroscopy, and the pathogenic bacterium was isolated and identified. One Gram-positive Streptococcus was isolated. The strain was subjected to characteristic culture, microscopic examination and molecular biological identification, and resistance detection, animal regression experiment and mouse pathogenicity test were carried out. The results showed that the isolate was identified to be Streptococcus suis serotype 7, which was resistant to multiple drugs; and the pathogenicity test showed that the strain had high pathogenicity to pigs, resulting in neurosis on partial pigs, and the strain had no pathogenicity to Kunming and BALB/c mice but certain pathogenicity to CD1 mice.