title: A novel virulence-associated protein, vapE, in Streptococcus suis serotype 2.
abstract: Streptococcus suis serotype 2 (SS2) is an important pathogen that affects pigs. However, neither its virulence nor its pathogenesis of infection has yet to be fully elucidated. The present study identifies a novel virulence‑associated protein E gene (vapE) of SS2. To investigate the importance of vapE in SS2 infection, a vapE knock‑out mutant based on SS2 wild‑type strain ZY458 was designated 458ΔvapE. 458ΔvapE was generated through homologous recombination, using a combined plasmid with a vapE knock‑out fragment and a pSET4s suicide vector. Additionally, the 458ΔvapE strain was transformed by a pAT18 shuttle plasmid containing the vapE gene. A functionally complemented strain for the vapE gene [termed 458ΔvapE (pvapE)] was constructed. Animal experiments demonstrated that mice infected with ZY458 and 458ΔvapE (pvapE) exhibited severe clinical symptoms, including depression, apathy, fever, anorexia, emaciation, swollen eyes and neural disorders, and died within two days of infection. All mice infected with ZY458, and 85% of mice infected with 458ΔvapE (pvapE), died within 2 days of infection. In contrast, mice inoculated with 458ΔvapE exhibited only mild clinical symptoms in the first 2 days following infection, and recovered within a week. A bacterial colonization assay demonstrated the ability of the 458ΔvapE mutant SS2 strain to colonize the heart, liver, spleen, lung and kidney of infected mice. PCR analysis of the vapE gene revealed that functional vapE was detected in virulent strains, but not in avirulent and carrier strains of S. suis SS2. These findings indicate that vapE is important for the pathogenesis of SS2.
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Xue
authors.initials: X
authors.lastname: Ji
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Lingwei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Guo
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Xulong
authors.initials: X
authors.lastname: Lang
authors.affiliation: Molecular Bacteriology Department, Institute of Military Veterinary Science, Academy of Military Medical Sciences, Changchun, Jilin 130122, P.R. China.
authors.forename: Shuzhang
authors.initials: S
authors.lastname: Feng
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity; D013290:Streptococcal Infections / Q000382:microbiology*; D017011:Streptococcus suis / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D014774:Virulence
chemical_list: D001426:Bacterial Proteins