Probing genomic diversity and evolution of Streptococcus suis serotype 2 by NimbleGen tiling arrays

Abstract

BackgroundOur 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.ResultsOur 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.ConclusionsOur 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.

Streptococcus suisinfection

“…The fact that non-SS2 serotypes of S. suis can affect humans and even lead to fatal infections, has put the situation of S. suis infection in a much more complicated and serious status in public health. This might be an alternate way to decode the genome sequences of all 35 kinds of different serotypes, providing new insights into evolution and diversity of heterogeneous species, as well as distinct clues for preventing and controlling severe infections by these pathogens 191 , 192 . Systematic proteomic approaches are also encouraged to further address this question, which can complement genomics-based explorations 138 …”

Biology of Three ICE Families: SXT/R391, ICE Bs1 , and ICE St1 /ICE St3

“…Lys , is a genuine ICE that self-transfers, can cis-mobilize a related element, and encodes a new CAMP factor implicated in the cohemolytic activity of the pathogenic strain of S. agalactiae (110,112,113 Finally, the ICE 89K of S. suis has been well characterized for its diversity and functionality (114,115).…”

Population Analysis of Streptococcus suis Isolates from Slaughtered Swine by Use of Minimum Core Genome Sequence Typing

“…However, little is known of the S. suis population structure. High genetic diversity within the species adds complexity to the understanding of the clonal relationships between strains, especially low-virulence strains (5)(6)(7). In a previous study, we developed a whole-genome sequencebased typing scheme to identify and classify S. suis populations as one of seven minimum core genome (MCG) groups (8).…”