Members of the haloarchaeal genera Halosarcina and Halogeometricum (family Halobacteriaceae ) are closely related to each other and show 96.6–98 % 16S rRNA gene sequence similarity. This is higher than the accepted threshold value (95 %) to separate two genera, and a taxonomic study using a polyphasic approach of all four members of the two genera was conducted to clarify their relationships. Polar lipid profiles indicated that Halogeometricum rufum RO1-4T, Halosarcina pallida BZ256T and Halosarcina limi RO1-6T are related more to each other than to Halogeometricum borinquense CGMCC 1.6168T. Phylogenetic analyses using the sequences of three different genes (16S rRNA gene, rpoB′ and EF-2) strongly supported the monophyly of these four species, showing that they formed a distinct clade, separate from the related genera Halopelagius , Halobellus , Haloquadratum , Haloferax and Halogranum . The results indicate that the four species should be assigned to the same genus, and it is proposed that Halosarcina pallida and Halosarcina limi be transferred to the genus Halogeometricum as Halogeometricum pallidum comb. nov. (type strain, BZ256T = KCTC 4017T = JCM 14848T) and Halogeometricum limi comb. nov. (type strain, RO1-6T = CGMCC 1.8711T = JCM 16054T).
Phylogenies generated from whole genome sequence (WGS) data provide definitive means of bacterial isolate characterization for typing and taxonomy. The species status of strains recently defined with conventional taxonomic approaches as representing Neisseria oralis was examined by the analysis of sequences derived from WGS data, specifically: (i) 53 Neisseria ribosomal protein subunit (rps) genes (ribosomal multi-locus sequence typing, rMLST); and (ii) 246 Neisseria core genes (core genome MLST, cgMLST). These data were compared with phylogenies derived from 16S and 23S rRNA gene sequences, demonstrating that the N. oralis strains were monophyletic with strains described previously as representing ‘ Neisseria mucosa var. heidelbergensis’ and that this group was of equivalent taxonomic status to other well-described species of the genus Neisseria . Phylogenetic analyses also indicated that Neisseria sicca and Neisseria macacae should be considered the same species as Neisseria mucosa and that Neisseria flavescens should be considered the same species as Neisseria subflava . Analyses using rMLST showed that some strains currently defined as belonging to the genus Neisseria were more closely related to species belonging to other genera within the family; however, whole genome analysis of a more comprehensive selection of strains from within the family Neisseriaceae would be necessary to confirm this. We suggest that strains previously identified as representing ‘ N. mucosa var. heidelbergensis’ and deposited in culture collections should be renamed N. oralis . Finally, one of the strains of N. oralis was able to ferment lactose, due to the presence of β-galactosidase and lactose permease genes, a characteristic previously thought to be unique to Neisseria lactamica , which therefore cannot be thought of as diagnostic for this species; however, the rMLST and cgMLST analyses confirm that N. oralis is most closely related to N. mucosa .
The 16S rRNA gene sequences of Pasteurella lymphangitidis , Yersinia pseudotuberculosis and Yersinia pestis were found to be identical and multilocus sequence analysis could not discriminate between the three species. The susceptibility to a Y. pseudotuberculosis phage and the presence of the Y. pseudotuberculosis -specific invasin gene in P. lymphangitidis indicate that the latter should be reclassified as Y. pseudotuberculosis .