RT Journal Article SR Electronic(1) A1 Fernández, Elena A1 Blume, Verena A1 Garrido, Patricia A1 Collins, Matthew D. A1 Mateos, Ana A1 Domínguez, Lucas A1 Fernández-Garayzábal, José F.YR 2004 T1 Streptococcus equi subsp. ruminatorum subsp. nov., isolated from mastitis in small ruminants JF International Journal of Systematic and Evolutionary Microbiology, VO 54 IS 6 SP 2291 OP 2296 DO https://doi.org/10.1099/ijs.0.63145-0 PB Microbiology Society, SN 1466-5034, AB Six isolates of an unknown Gram-positive, catalase-negative, chain-forming, coccus-shaped organism isolated from ovine and caprine mastitis were characterized by phenotypic and molecular taxonomic methods. On the basis of cellular morphology and the results of biochemical tests, the organism was tentatively identified as a streptococcal species. Comparative 16S rRNA gene sequencing studies confirmed that the organism is a member of the genus Streptococcus, with Streptococcus equi as its closest phylogenetic relative (98·8 % similarity). DNA–DNA pairing studies showed that the unidentified organism displayed more than 70 % relatedness to the type strains of S. equi subsp. equi and subsp. zooepidemicus. Despite the relatively high DNA–DNA reassociation values, biotyping and ribotyping allowed clear differentiation of the unknown bacterium from the two recognized subspecies of S. equi. On the basis of phenotypic and molecular genetic evidence, it is proposed that the unknown Streptococcus isolates from ovine and caprine mastitis be classified as a novel subspecies, Streptococcus equi subsp. ruminatorum subsp. nov. The type strain is CECT 5772T (=CCUG 47520T=Mt 167T)., UL https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijs.0.63145-0