Department of Biology, Kyung Hee University, Seoul, 02447, Republic of Korea.
Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul, 02447, Republic of Korea.
J Microbiol. 2024 Nov;62(11):973-983. doi: 10.1007/s12275-024-00178-1. Epub 2024 Nov 12.
We isolated three novel strains, S1, S2, and S5, from human oral cavities and identified them as distinct novel species. All these strains are facultatively anaerobic, Gram-stain-positive, and non-flagellated bacteria. Their optimal growth conditions for these strains were observed in Columbia broth (CB) at 37 °C, pH 7.0, and in the absence of NaCl. Phylogenetic analyses, employing the 16S rRNA gene and whole-genome sequencing, confirmed that all three strains belong to the genus Streptococcus. The 16S rRNA gene sequences of strains S1, S2, and S5 showed the highest similarities to Streptococcus parasanguinis, 98.57%, 99.05%, and 99.05%, respectively, and the orthologous average nucleotide identity (OrthoANI) values between the three strains and S. parasanguinis were 93.82%, 93.67%, and 94.04%, respectively. The pairwise OrthoANI values between the novel strains were 94.37% (S1-S2), 95.03% (S2-S5), and 94.71% (S1-S5). All strains had C ω9c and summed feature 8 (C ω7c and/or C ω6c) as major cellular fatty acids. Additionally, diphosphatidylglycerol (DPG) and hydroxyphosphatidylethanolamine (OH-PE) were identified as major polar lipids. Menaquinone was undetected in all strains. The results from the phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses collectively indicated that strains S1, S2, and S5 represent three distinct novel species within the genus Streptococcus, and we propose the names Streptococcus dentalis sp. nov. for strain S1 (= KCTC 21234 = JCM 36526), Streptococcus gingivalis sp. nov. for strain S2 (= KCTC 21235 = JCM 36527), and Streptococcus lingualis sp. nov. for strain S5 (= KCTC 21236 = JCM 36528).
我们从人类口腔中分离出了三个新型菌株，S1、S2 和 S5，并鉴定它们为不同的新型物种。所有这些菌株都是兼性厌氧、革兰氏阳性和无鞭毛的细菌。这些菌株的最佳生长条件是在哥伦比亚肉汤（CB）中于 37°C、pH7.0 且无 NaCl 的条件下。基于 16S rRNA 基因和全基因组测序的系统发育分析证实，所有这三个菌株均属于链球菌属。菌株 S1、S2 和 S5 的 16S rRNA 基因序列与口腔链球菌的相似度最高，分别为 98.57%、99.05%和 99.05%，这三个菌株与口腔链球菌的直系同源平均核苷酸同一性（OrthoANI）值分别为 93.82%、93.67%和 94.04%。新型菌株之间的成对 OrthoANI 值分别为 94.37%（S1-S2）、95.03%（S2-S5）和 94.71%（S1-S5）。所有菌株均以 Cω9c 和总和特征 8（Cω7c 和/或 Cω6c）为主要细胞脂肪酸。此外，还鉴定出双磷脂酰甘油（DPG）和羟基磷酯乙醇胺（OH-PE）为主要极性脂。所有菌株均未检测到menaquinone。系统发育、表型、化学分类和基因型分析的结果共同表明，菌株 S1、S2 和 S5 代表链球菌属中的三个不同的新型物种，我们提议将菌株 S1（=KCTC 21234=JCM 36526）命名为牙链球菌新种，将菌株 S2（=KCTC 21235=JCM 36527）命名为牙龈链球菌新种，将菌株 S5（=KCTC 21236=JCM 36528）命名为舌链球菌新种。
