title: Identification of a cell wall-associated subtilisin-like serine protease involved in the pathogenesis of Streptococcus suis serotype 2.
abstract: Streptococcus suis is an important swine and human pathogen, and also an emerging zoonotic agent. A surface-associated subtilisin-like serine protease (SspA) of S. suis was identified by screening a genomic expression library as fragments of this protein reacted most strongly with convalescent-phase pig sera. The sspA gene is present in 29 of 33 S. suis serotypes reference strains and is expressed on the surface of S. suis. Relative real-time quantitative PCR assay demonstrated that sspA mRNA expression in vivo was several thousand fold of that in vitro. A sspA(-) mutant was generated from a S. suis serotype 2 strain SC19 by allelic exchange. The mutant was not different from the wild type strain in subcellular structures and in hemolytic phenotype. However, the virulence of the sspA(-) mutant was markedly lower than the wild type in pigs as demonstrated in experimental infections. These data indicated that the surface-associated protein SspA is a conserved virulence factor of S. suis and is involved in the pathogenesis of S. suis.
authors: College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
authors: Qiaoyun
authors: Q
authors: Hu
authors: Peng
authors: P
authors: Liu
authors: Zhengjun
authors: Z
authors: Yu
authors: Gang
authors: G
authors: Zhao
authors: Jun
authors: J
authors: Li
authors: Liu
authors: L
authors: Teng
authors: Mingguang
authors: M
authors: Zhou
authors: Weicheng
authors: W
authors: Bei
authors: Huanchun
authors: H
authors: Chen
authors: Meilin
authors: M
authors: Jin
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000201:enzymology*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D005798:Genes, Bacterial; D006801:Humans; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D016254:Mutagenesis, Insertional; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000382:microbiology / Q000662:veterinary*; D017011:Streptococcus suis / Q000201:enzymology* / Q000302:isolation & purification / Q000472:pathogenicity*; D020860:Subtilisin / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism*; D016019:Survival Analysis; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D020860:Subtilisin