Abstract: 【Objective】In order to clarify the features of the M-like gene of Streptococcus equi subsp. zooepidemicus isolates from Chinese pig for directing the selection of vaccine isolate.【Method】The M-like genes were amplified from 9 isolates of Streptococcus equi subsp. zooepidemicus from Chinese pig by PCR and the M-like gene of each isolate was cloned, sequenced and analyzed. 【Result】Nucleotide sequence analysis revealed one open reading frame in M-like protein gene of all isolates, with different length of 1 125 bp in CP-0104 isolate, 1 143 bp in CG-74-63 isolate, and 1 137 bp in the others. The nucleotide identities of M-like genes among 9 isolates except CP-0104 isolate were higher than 95.4%, while the identities between isolate CP-0104 and the remaining 8 strains were 87.1%-88.3%. W60 strain, an equine origin isolate, shared identities of 81.6%-87.0% with these 9 isolates from pig, and 25064 strain, a human origin isolate, shared identities of 81.7%-91.8% with these 9 isolates from pig. All the 9 isolates shared the common membrane anchor region and N-terminal signal peptide. 【Conclusion】The M-like gene of 9 isolates of Streptococcus equi subsp. zooepidemicus from Chinese pig share high identity.

Key words: Streptococcus equi subsp. zooepidemicus, M-like gene, Analysis