Delineation of Streptococcus dysgalactiae, Its Subspecies, and Its Clinical and Phylogenetic Relationship to Streptococcus pyogenes
Delineation of Streptococcus dysgalactiae, Its Subspecies, and Its Clinical and Phylogenetic Relationship to Streptococcus pyogenes
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DOI：
10.1128/jcm.05900-11
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发表时间：
2012-01-01
影响因子：
9.4
通讯作者：
Kilian, Mogens
中科院分区：
文献类型：
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作者：
Jensen, Anders;Kilian, Mogens
停乳链球菌的分类地位和结构一直是很混乱的对象。在临床环境中，属于该种属的细菌通常被称为兰斯菲尔德C组或G组链球菌，尽管这些术语缺乏精确性，并且无法识别这些细菌的确切临床相关性。本研究的目的是为临床微生物实验室中化脓性链球菌群的各个种的划分和鉴定建立一个改进的基础，特别关注链球菌。停乳我们批判性地重新审视了物种S的遗传关系。通过基于多位点序列分析（MLSA）和16 S rRNA基因序列的系统发育重建以及通过emm分型与表型表征相结合，对可能共享兰斯菲尔德群抗原的停乳链球菌、化脓链球菌、犬链球菌和马链球菌进行了鉴定。先前用于检测草绿色链球菌的七个基因的串联序列的分析区分了稳健和连贯的簇。S.停乳症由两个独立的集群组成，与两个公认的停乳症亚种和似乳症亚种一致。这两个类群与S.在几个管家基因中发现化脓性链球菌，这使得基于单基因座测序的鉴定无效。S. dysgalactiae、S. canis和S.化脓性链球菌构成链球菌属内的密切相关的分支，表明最近从共同祖先传来，而链球菌。马链球菌与化脓性链球菌属的其它种类有很大差异。这些结果为临床上重要的化脓性链球菌的鉴定提供了更好的依据，并解释了与人类相关的物种引起的重叠感染谱。
The taxonomic status and structure of Streptococcus dysgalactiae have been the object of much confusion. Bacteria belonging to this species are usually referred to as Lancefield group C or group G streptococci in clinical settings in spite of the fact that these terms lack precision and prevent recognition of the exact clinical relevance of these bacteria. The purpose of this study was to develop an improved basis for delineation and identification of the individual species of the pyogenic group of streptococci in the clinical microbiology laboratory, with a special focus on S. dysgalactiae. We critically reexamined the genetic relationships of the species S. dysgalactiae, Streptococcus pyogenes, Streptococcus canis, and Streptococcus equi, which may share Lancefield group antigens, by phylogenetic reconstruction based on multilocus sequence analysis (MLSA) and 16S rRNA gene sequences and by emm typing combined with phenotypic characterization. Analysis of concatenated sequences of seven genes previously used for examination of viridans streptococci distinguished robust and coherent clusters. S. dysgalactiae consists of two separate clusters consistent with the two recognized subspecies dysgalactiae and equisimilis. Both taxa share alleles with S. pyogenes in several housekeeping genes, which invalidates identification based on single-locus sequencing. S. dysgalactiae, S. canis, and S. pyogenes constitute a closely related branch within the genus Streptococcus indicative of recent descent from a common ancestor, while S. equi is highly divergent from other species of the pyogenic group streptococci. The results provide an improved basis for identification of clinically important pyogenic group streptococci and explain the overlapping spectrum of infections caused by the species associated with humans.