title: Probing genomic diversity and evolution of Streptococcus suis serotype 2 by NimbleGen tiling arrays.
abstract: BACKGROUND
  Our previous studies revealed that a new disease form of streptococcal toxic shock syndrome (STSS) is associated with specific Streptococcus suis serotype 2 (SS2) strains. To achieve a better understanding of the pathogenicity and evolution of SS2 at the whole-genome level, comparative genomic analysis of 18 SS2 strains, selected on the basis of virulence and geographic origin, was performed using NimbleGen tiling arrays.
  
  
  RESULTS
  Our results demonstrate that SS2 isolates have highly divergent genomes. The 89K pathogenicity island (PAI), which has been previously recognized as unique to the Chinese epidemic strains causing STSS, was partially included in some other virulent and avirulent strains. The ABC-type transport systems, encoded by 89K, were hypothesized to greatly contribute to the catastrophic features of STSS. Moreover, we identified many polymorphisms in genes encoding candidate or known virulence factors, such as PlcR, lipase, sortases, the pilus-associated proteins, and the response regulator RevS and CtsR. On the basis of analysis of regions of differences (RDs) across the entire genome for the 18 selected SS2 strains, a model of microevolution for these strains is proposed, which provides clues into Streptococcus pathogenicity and evolution.
  
  
  CONCLUSIONS
  Our deep comparative genomic analysis of the 89K PAI present in the genome of SS2 strains revealed details into how some virulent strains acquired genes that may contribute to STSS, which may lead to better environmental monitoring of epidemic SS2 strains.
authors.affiliation: CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: Zuowei
authors.initials: Z
authors.lastname: Wu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Changjun
authors.initials: C
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Na
authors.initials: N
authors.lastname: Lu
authors.forename: Ruifen
authors.initials: R
authors.lastname: Zhang
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Jiang
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.forename: Cuihua
authors.initials: C
authors.lastname: Liu
authors.forename: Hui
authors.initials: H
authors.lastname: Liao
authors.forename: George F
authors.initials: GF
authors.lastname: Gao
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Tang
authors.forename: Baoli
authors.initials: B
authors.lastname: Zhu
mesh_terms: D000818:Animals; D058872:Epidemics; D019143:Evolution, Molecular; D017353:Gene Deletion; D014644:Genetic Variation / Q000235:genetics*; D044404:Genomic Islands / Q000235:genetics; D023281:Genomics / Q000379:methods*; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D010802:Phylogeny; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D017011:Streptococcus suis / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D037521:Virulence Factors / Q000235:genetics
chemical_list: D037521:Virulence Factors