Taxonomic note on Kocuria and Rothia: taxogenomic insights for addressing misidentifications and proposing new combinations and new subspecies

Misidentifications of Kocuria and Rothia species often occur due to their overlapping traits, including similar cell shapes, biochemical characteristics and environmental preferences. These revisions aim to address significant overlaps and correct previous misidentifications. Phylogenetic analysis using 16S rRNA gene and core protein sequences has positioned Kocuria uropygioeca 257T and Kocuria uropygialis 36T within the genus Rothia. This reclassification is further substantiated by high 16S rRNA gene sequence similarities and average amino acid identity values, which align these species more closely with Rothia than with Kocuria. As a result, we propose the reclassification of 257T and 36T as Rothia uropygioeca comb. nov. and Rothia uropygialis comb. nov., respectively, to accurately reflect their taxonomic status. Additionally, average nucleotide identity and digital DNA–DNA hybridization values indicate that Kocuria marina KCTC 9943T and Kocuria indica DSM 25126T, as well as Kocuria rosea DSM 20447T and Kocuria polaris CMS 76orT, surpass the thresholds for subspecies classification. Therefore, we propose the recognition of four new subspecies: Kocuria marina subsp. marina comb. nov., Kocuria marina subsp. indica comb. nov., Kocuria rosea subsp. rosea comb. nov. and Kocuria rosea subsp. polaris comb. nov.