title: Trigger factor of Streptococcus suis is involved in stress tolerance and virulence.
abstract: Streptococcus suis serotype 2 is an important zoonotic pathogen that causes serious diseases such as meningitis, septicemia, endocarditis, arthritis and septic shock in pigs and humans. Little is known about the regulation of virulence gene expression in S. suis serotype 2. In this study, we cloned and deleted the entire tig gene from the chromosome of S. suis serotype 2 SC21 strain, and constructed a mutant strain (Δtig) and a complementation strain (CΔtig). The results demonstrated that the tig gene, encoding trigger factor from S. suis serotype 2 SC21, affects the stress tolerance and the expression of a few virulence genes of S. suis serotype 2. Deletion of the tig gene of S. suis serotype 2 resulted in mutant strain, ΔTig, which exhibited a significant decrease in adherence to cell line HEp-2, and lacked hemolytic activity. Tig deficiency diminishes stresses tolerance of S. suis serotype 2 such as survive thermal, oxidative and acid stresses. Quantification of expression levels of known S. suis serotype 2 SC21 virulence genes by real-time polymerase chain reaction in vitro revealed that trigger factor influences the expression of epf, cps, adh, rpob, fbps, hyl, sly, mrp and hrcA virulence-associated genes. ΔTig was shown to be attenuated in a LD50 assay and bacteriology, indicating that trigger factor plays an important part in the pathogenesis and stress tolerance of. S. suis serotype 2 infection. Mutant ΔTig was 100% defective in virulence in CD1 mice at up to 107 CFU, and provided 100% protection when challenged with 107 CFU of the SC21 strain.
authors.affiliation: Hubei Key Laboratory of Animal Nutrition and Feed Science, School of Animal Science and Nutritional Engineering, Wuhan Polytechnic University, Wuhan 430023, PR China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Zhanqin
authors.initials: Z
authors.lastname: Zhao
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Hongwei
authors.initials: H
authors.lastname: Ma
authors.forename: Ka
authors.initials: K
authors.lastname: Lu
authors.forename: Wen
authors.initials: W
authors.lastname: Ren
authors.forename: Zhengya
authors.initials: Z
authors.lastname: Liu
authors.forename: Haitao
authors.initials: H
authors.lastname: Chang
authors.forename: Weicheng
authors.initials: W
authors.lastname: Bei
authors.forename: Yinsheng
authors.initials: Y
authors.lastname: Qiu
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response / Q000235:genetics*; D006801:Humans; D051379:Mice; D019696:Peptidylprolyl Isomerase / Q000235:genetics / Q000378:metabolism*; D013290:Streptococcal Infections / Q000382:microbiology; D017011:Streptococcus suis / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology; D013552:Swine; D014774:Virulence; D037521:Virulence Factors
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D019696:Peptidylprolyl Isomerase