Reappraisal of the taxonomy of the Streptococcus bovis/Streptococcus equinus complex and related species: description of Streptococcus gallolyticus subsp. gallolyticus subsp. nov., S. gallolyticus subsp. macedonicus subsp. nov. and S. gallolyticus subsp. pasteurianus subsp. nov

1 Centre National de Référence des Streptocoques, Service de Microbiologie, Hôtel Dieu, AP-HP, Université Paris VI, 1 place du Parvis Notre-Dame, F-75181 Paris 04, France 2 Unité Biodiversité des Bactéries Pathogènes Emergentes, INSERM U389, Institut Pasteur, Paris, France Correspondence Anne Bouvet anne.bouvet{at}htd.ap-hop-paris.fr ‘ Streptococcus bovis / Streptococcus equinus ’ is a large bacterial complex including different species frequently isolated from infections of humans ( Streptococcus gallolyticus , Streptococcus infantarius ) or animals ( S. bovis , S. equinus , Streptococcus alactolyticus ). The separation of S. bovis into three different biotypes has been partially correlated with genetic differentiation. In addition, recent advances in bacterial phylogeny have led to the inclusion of Streptococcus macedonicus and Streptococcus waius in this complex. The aim of this study was to improve physiological differentiation between species related to the complex and to clarify their respective phylogenetic positions. In this study, physiological, genetic and phylogenetic analyses of a set of 88 streptococcal strains were performed. The diversity of strains of S. bovis biotype II was analysed, and it was confirmed that they belong to different species, either S. equinus or S. infantarius . It was demonstrated that S. gallolyticus , S. bovis biotype II.2, S. macedonicus and S. waius form a single DNA cluster separated into three different subspecies. They are delineated by different biochemical traits, limited DNA–DNA relatedness and noticeable divergence in 16S rDNA sequences. According to the current definition of species, the names S. gallolyticus subsp. gallolyticus subsp. nov., S. gallolyticus subsp. pasteurianus subsp. nov. and S. gallolyticus subsp. macedonicus subsp. nov. are proposed for these three subspecies. Published online ahead of print on 11 October 2002 as DOI 10.1099/ijs.0.02361-0. The GenBank accession numbers for the 16S rRNA gene sequences determined in this study are AF429762 – AF429766 .