Identification of a new protective antigen of Streptococcus canis.

Streptococcus canis(S.canis) is an important opportunistic pathogen that causes infections among a variety of animals including human.A new protective antigen(SPASc) was identified by screening a S.canis phage library of 3 kb-8 kb random DNA fragments.The sequence of the SPASc was determined by sequencing the rescued plasmids.The SPASc gene showed homology to that of Streptococcus equi subsp.zooepidemicus,Streptococcus pyogenes,and M protein of Streptococcus equi.Rabbit antiserum to recombinant SPASc was shown to protect mouse from S.canis challenge.