Streptococcus dysgalactiae subsp. equisimilis (SDSE) causes severe invasive streptococcal infections, especially in elderly people. Between 2013 and 2018, 88 streptococci were isolated from clinical blood culture in a hospital in Toyama prefecture, Japan. The collection included six Group A SDSE (ASD) strains, which are rarely isolated. Multilocus sequence typing categorized five of the six strains into ST128 and the remaining strain into a new type. Maximum-likelihood phylogenetic analysis revealed that the six ASD strains had highly similar genome sequences. Bayesian analysis indicated that the most recent common ancestor of the strains appeared 39 years ago. The ASD strains possessed carbohydrate synthase genes that are conserved in Streptococcus pyogenes strains, whereas one strain featured a different arrangement of the gene cluster. The carbohydrate synthase genes varied by Lancefield type (A, C, and G).

中文翻译：

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甲型链球菌dysgalactiae亚种的流行和基因组学特征。从日本富山县的侵入性感染患者中分离出的equimisimilis。

链球菌dysgalactiae亚种。equisimilis（SDSE）引起严重的侵袭性链球菌感染，尤其是在老年人中。在2013年至2018年之间，在日本富山县的一家医院从临床血液培养物中分离出88株链球菌。该集合包括六种A组SDSE（ASD）菌株，这些菌株很少分离。多基因座序列分型将六个菌株中的五个分为ST128，其余菌株归为新类型。最大似然系统发育分析表明，这六个ASD菌株具有高度相似的基因组序列。贝叶斯分析表明，该菌株的最新祖先出现在39年前。ASD菌株拥有化脓性链球菌菌株中保守的碳水化合物合酶基因，而一种菌株的基因簇排列方式却不同。