Reappraisal of the taxonomy of Streptococcus suis serotypes 20, 22, 26, and 33 based on DNA-DNA homology and sodA and recN phylogenies
Reappraisal of the taxonomy of Streptococcus suis serotypes 20, 22, 26, and 33 based on DNA-DNA homology and sodA and recN phylogenies
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DOI：
10.1016/j.vetmic.2012.11.001
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发表时间：
2013-03-23
影响因子：
3.3
通讯作者：
Osawa, Ro
中科院分区：
文献类型：
--
作者：
Le Hong Thuy Tien;Nishibori, Tomoyuki;Osawa, Ro
迄今为止，猪链球菌根据其多糖荚膜抗原分为33个血清型。尽管血清型20、22、26和33参考菌株与模式菌株NCTC 10234（T）的16 S rRNA序列相似性低于将其归类为S的阈值98.5%。猪种，没有强有力的证据支持重新分类。在这里，它们的分类身份确定的DNA-DNA杂交试验和部分测序的sodA和recN基因。结果表明，血清型20、22、26和33参考株与模式株NCTC 10234（T）和全序列株P1/7有较远的亲缘关系。猪。此外，血清型20、22和26的参考菌株彼此密切相关，但与血清型33参考菌株不同。对33株血清型参考株sodA和recN基因序列分析表明，血清20、22、26型参考株和血清33型参考株不仅与其它血清型不一致，而且与其它血清型也不一致。suis，而且还有其他链球菌物种（sodA为56个物种的63株，recN为55个物种的87株）。这些证据进一步证实了血清型20、22、26和33的参考菌株应从S.猪，虽然它们的分类名称和决定性的表型特征尚未得到解决。(C)2012爱思唯尔有限公司版权所有。
To date, Streptococcus suis was divided into thirty-three serotypes based on its polysaccharide capsular antigens. Although 16S rRNA sequence similarities of serotypes 20, 22, 26, and 33 reference strains to the type strain NCTC 10234(T) were below the threshold value of 98.5% to assign them to S. suis species, no strong evidence support to reclassification. Here, their taxonomic identities were determined by DNA-DNA hybridization assays and by partial sequencing of the sodA and recN genes. Our results confirmed that the serotype 20, 22, 26, and 33 reference strains were distantly related to the type strain NCTC 10234(T) and the whole sequence strain P1/7 of S. suis. Moreover, the reference strains of serotypes 20, 22, and 26 were closely related to each other but distinct from the serotype 33 reference strain. Sequencing analyses of sodA and recN of a total 33 serotype reference strains showed that the serotype 20, 22, and 26 reference strains and the serotype 33 reference strain did not fall with not only other serotypes of S. suis, but also other streptococcal species (63 strains of 56 species for sodA and 87 strains of 55 species for recN). The evidence further substantiates the view that the reference strains of serotypes 20, 22, 26 and 33 should be taxonomically removed from S. suis, although their taxonomic designations and determinative phenotypic characteristics are yet to be addressed. (C) 2012 Elsevier B.V. All rights reserved.