title: Two Spx regulators modulate stress tolerance and virulence in Streptococcus suis serotype 2.
abstract: Streptococcus suis serotype 2 is an important zoonotic pathogen causing severe infections in pigs and humans. The pathogenesis of S. suis 2 infections, however, is still poorly understood. Spx proteins are a group of global regulators involved in stress tolerance and virulence. In this study, we characterized two orthologs of the Spx regulator, SpxA1 and SpxA2 in S. suis 2. Two mutant strains (ΔspxA1 and ΔspxA2) lacking the spx genes were constructed. The ΔspxA1 and ΔspxA2 mutants displayed different phenotypes. ΔspxA1 exhibited impaired growth in the presence of hydrogen peroxide, while ΔspxA2 exhibited impaired growth in the presence of SDS and NaCl. Both mutants were defective in medium lacking newborn bovine serum. Using a murine infection model, we demonstrated that the abilities of the mutant strains to colonize the tissues were significantly reduced compared to that of the wild-type strain. The mutant strains also showed a decreased level of survival in pig blood. Microarray analysis revealed a global regulatory role for SpxA1 and SpxA2. Furthermore, we demonstrated for the first time that Spx is involved in triggering the host inflammatory response. Collectively, our data suggest that SpxA1 and SpxA2 are global regulators that are implicated in stress tolerance and virulence in S. suis 2.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Chengkun
authors.initials: C
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Jiali
authors.initials: J
authors.lastname: Xu
authors.affiliation: College of Food Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Jinquan
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Luohong
authors.initials: L
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Jingyan
authors.initials: J
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Weina
authors.initials: W
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China; Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Weicheng
authors.initials: W
authors.lastname: Bei
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001769:Blood / Q000382:microbiology; D016207:Cytokines / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007249:Inflammation / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D012965:Sodium Chloride / Q000494:pharmacology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013290:Streptococcal Infections / Q000473:pathology; D017011:Streptococcus suis / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D013312:Stress, Physiological / Q000235:genetics*; D013552:Swine / Q000097:blood / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D014157:Transcription Factors; D012967:Sodium Dodecyl Sulfate; D012965:Sodium Chloride; D006861:Hydrogen Peroxide