Sakamoto, Mitsuo

The genus Lactococcus was proposed by Schleifer et al. by separating Lactococcus lactis from the genus Streptococcus. Although the family Streptococcaceae consists of four genera, each genus contains a relatively small number of species, with the exception of the genus Streptococcus, which contains more than 100 species. The genera Lactococcus and Lactovum currently comprise 26 species and a single species, respectively. This study evaluated the taxonomy of the genus Lactococcus based on the 16S rRNA gene phylogeny, core-genome phylogeny and (conserved) pairwise average amino acid identity. These evaluations clearly indicated that the genus Lactococcus could be divided into two genus-level clusters, and we propose to reclassify this genus into two; the authentic Lactococcus, which includes the L. lactis group, and a novel genus for which the name Pseudolactococcus is proposed. Three lactic acid bacterial strains, RyT2T, OfM1T and OfM2, were isolated from the gut of termites in Okinawa, Japan. Based on the combination of genetic and phenotypic data, we conclude that these isolates represent two novel species of the genera Pseudolactococcus and Lactovum, respectively, for which we propose the names Pseudolactococcus yaeyamensis sp. nov. (RyT2T=JCM 36015T=DSM 118067T) and Lactovum odontotermitis sp. nov. (OfM1T=JCM 34431T=DSM 118066T, OfM2=JCM 34432), respectively.

Small, obligately anaerobic strains 13CB8CT, 13CB11CT, 13CB18CT and 13GAM1GT were isolated from a faecal sample in a patient with Parkinson’s disease with a history of duodenal resection. After conducting a comprehensive polyphasic taxonomic analysis including genomic analysis, we propose the establishment of one new genus and four new species. The novel bacteria are Desulfovibrio falkowii sp. nov. (type strain JCM 36128T = DSM 116810T), Porphyromonas miyakawae sp. nov. (type strain JCM 36129T = DSM 116947T), Mediterraneibacter flintii sp. nov. (type strain JCM 36130T = DSM 116866T) and Owariibacterium komagatae gen. nov. sp. nov. (type strain JCM 36131T = DSM 116982T), respectively.

Six strains (CB7T, CB18, CB23, CB26, CB28 and CB35T) were isolated from human faeces. Based on phylogenetic analysis, phenotypic characteristics, cellular fatty acid profiles and menaquinone profiles, these strains could be included within the genusPrevotellaand made up two clusters. 16S rRNA gene sequence analysis indicated that five strains were most closely related toPrevotella veroralis, sharing about 92 % sequence similarity; the remaining strain was most closely related toPrevotella shahii, sharing about 90 % sequence similarity. All six strains were obligately anaerobic, non-pigmented, non-spore-forming, non-motile, Gram-negative rods. The cellular fatty acid compositions of the six strains differed significantly from those of otherPrevotellaspecies. Five strains (CB7T, CB18, CB23, CB26 and CB28) contained dimethyl acetals and the major menaquinones of these strains were MK-11, MK-12 and MK-13. The major menaquinones of CB35Twere MK-12 and MK-13. Based on phenotypic and phylogenetic findings, two novel species,Prevotella coprisp. nov. andPrevotella stercoreasp. nov., are proposed, representing the two different strain clusters. The DNA G+C contents of strains CB7Tand CB35Twere 45.3 and 48.2 mol%, respectively. The type strains ofP. copriandP. stercoreaare CB7T(=JCM 13464T=DSM 18205T) and CB35T(=JCM 13469T=DSM 18206T), respectively.