Baek Ju Hye, Han Dong Min, Choi Dae Gyu, Moon Chae Yeong, Lee Jae Kyeong, Kim Chul-Hong, Kim Jung-Woong, Jeon Che Ok
Department of Life Science, Chung-Ang University, Seoul 06974, Republic of Korea.
J Microbiol. 2025 Aug;63(8):e2503003. doi: 10.71150/jm.2503003. Epub 2025 Aug 31.
Strains Mo2-6T, S9, KG4-3T, and 50Mo3-2, identified as coagulase-negative, Gram-stain-positive, halotolerant, non-motile coccoid bacteria, were isolated from traditional Korean soybean foods. Strains Mo2-6T and S9 were both catalase- and oxidase-negative, whereas KG4-3T and 50Mo3-2 were catalase-positive but oxidase-negative. The optimal growth conditions for Mo2-6T and S9 were 30°C, 2% NaCl, and pH 7.0, while KG4-3T and 50Mo3-2 grew best at 35°C, 2% NaCl, and pH 7.0. All strains contained menaquinone-7 as the predominant isoprenoid quinone, with anteiso-C15:0 and iso-C15:0 as the major cellular fatty acids (> 10%). Additionally, anteiso-C13:0 was a major fatty acid in strain KG4-3T. The DNA G + C contents of strains Mo2-6T, S9, KG4-3T, and 50Mo3-2 were 33.4%, 33.3%, 32.5%, and 32.7%, respectively. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strains Mo2-6T and S9, as well as KG4-3T and 50Mo3-2, formed distinct lineages within the genus Staphylococcus. Digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses confirmed that strains Mo2-6T and S9, as well as KG4-3T and 50Mo3-2, belonged to the same species. Meanwhile, dDDH and ANI values between strains Mo2-6T and KG4-3T, as well as comparisons with other Staphylococcus type strains, were below the species delineation thresholds, indicating they represent novel species. Based on phenotypic, chemotaxonomic, and molecular data, we propose strain Mo2-6T as the type strain of Staphylococcus parequorum sp. nov. (=KACC 23685T =JCM 37038T) and strain KG4-3T as the type strain of Staphylococcus halotolerans sp. nov. (=KACC 23684T =JCM 37037T).
从传统韩国大豆食品中分离出了菌株Mo2-6T、S9、KG4-3T和50Mo3-2，它们被鉴定为凝固酶阴性、革兰氏染色阳性、耐盐、无运动性的球状细菌。菌株Mo2-6T和S9的过氧化氢酶和氧化酶均为阴性，而KG4-3T和50Mo3-2的过氧化氢酶为阳性但氧化酶为阴性。Mo2-6T和S9的最佳生长条件为30°C、2% NaCl和pH 7.0，而KG4-3T和50Mo3-2在35°C、2% NaCl和pH 7.0时生长最佳。所有菌株均以甲基萘醌-7作为主要的类异戊二烯醌，以anteiso-C15:0和iso-C15:0作为主要的细胞脂肪酸（>10%）。此外，anteiso-C13:0是菌株KG4-3T中的主要脂肪酸。菌株Mo2-6T、S9、KG4-3T和50Mo3-2的DNA G + C含量分别为33.4%、33.3%、32.5%和32.7%。基于16S rRNA基因和全基因组序列的系统发育分析表明，菌株Mo2-6T和S9，以及KG4-3T和50Mo3-2在葡萄球菌属内形成了不同的谱系。数字DNA-DNA杂交（dDDH）和平均核苷酸同一性（ANI）分析证实，菌株Mo2-6T和S9，以及KG4-3T和50Mo3-2属于同一物种。同时，菌株Mo2-6T和KG4-3T之间的dDDH和ANI值，以及与其他葡萄球菌模式菌株的比较，均低于物种划分阈值，表明它们代表新物种。基于表型、化学分类和分子数据，我们提议将菌株Mo2-6T作为副等量葡萄球菌新种（Staphylococcus parequorum sp. nov.）的模式菌株（=KACC 23685T =JCM 37038T），将菌株KG4-3T作为耐盐葡萄球菌新种（Staphylococcus halotolerans sp. nov.）的模式菌株（=KACC 23684T =JCM 37037T）。
