Taxonomy of the Anginosus group of the genus Streptococcus and description of Streptococcus anginosus subsp. whileyi subsp. nov. and Streptococcus constellatus subsp. viborgensis subsp. nov

• Published in: International journal of systematic and evolutionary microbiology Vol. 63; no. Pt_7; pp. 2506 - 2519
• Main Authors: Jensen, Anders, Hoshino, Tomonori, Kilian, Mogens
• Format: Journal Article
• Language: English
• Published: England International Union of Microbiological Societies 01.07.2013
• Subjects: alleles; Bacterial Typing Techniques; DNA; DNA, Bacterial - genetics; essential genes; Genes, Bacterial; Humans; microbiology; Molecular Sequence Data; Multilocus Sequence Typing; new subspecies; nucleotide sequences; patients; pharyngitis; Pharyngitis - microbiology; Phylogeny; ribosomal RNA; RNA, Ribosomal, 16S - genetics; Sequence Analysis, DNA; Streptococcus anginosus; Streptococcus anginosus - classification; Streptococcus anginosus - genetics; Streptococcus anginosus - isolation & purification; Streptococcus constellatus - classification; Streptococcus constellatus - genetics; Streptococcus constellatus - isolation & purification; Streptococcus constellatus subsp. constellatus; Streptococcus viridans
• ISSN: 1466-5034; 1466-5026; 1466-5034
• DOI: 10.1099/ijs.0.043232-0

The Anginosus group of the genus Streptococcus has been the subject of much taxonomic confusion, which has hampered the full appreciation of its clinical significance. The purpose of this study was to critically re-examine the taxonomy of the Anginosus group, with special attention to β-haemolytic, Lancefield group C strains, using multilocus sequence analysis (MLSA) combined with 16S rRNA gene sequence and phenotypic analyses. Phylogenetic analysis of concatenated sequences of seven housekeeping genes previously used for examination of viridans streptococci distinguished seven distinct and coherent clusters in the Anginosus group. Analyses of 16S rRNA gene sequences and phenotypic characters supported the MLSA clustering and currently recognized taxa of the Anginosus group. Single gene analyses showed considerable allele sharing between species, thereby invalidating identification based on single-locus sequencing. Two novel clusters of β-haemolytic, Lancefield group C strains within the Streptococcus constellatus and Streptococcus anginosus species and isolated from patients with sore throat showed sufficient phylogenetic distances from other clusters to warrant status as novel subspecies. The novel cluster within S. anginosus was identified as the previously recognized DNA homology cluster, DNA group 2. The names S. anginosus subsp. whileyi subsp. nov. (type strain CCUG 39159T = DSM 25818T = SK1267T) and S. constellatus subsp. viborgensis subsp. nov. (type strain SK1359T = CCUG 62387T = DSM 25819T) are proposed.