Li Yu, Han Fei, Wu Yue, Li Weicheng, Ren Dongyan, Su Xin, Zhao Lixia, Menghe Bilige, Liu Wenjun
Key Laboratory of Dairy Biotechnology and Engineering (Inner Mongolia Agricultural University), Ministry of Education, Inner Mongolia Agricultural University, Hohhot, China, 010018, PR China.
Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Hohhot, China, 010018, PR China.
Int J Syst Evol Microbiol. 2024 May;74(5). doi: 10.1099/ijsem.0.006354.
Human breast milk contains lactic acid bacteria (LAB), which have an important influence on the composition of the intestinal microbia of infants. In this study, one strain of an α-hemolytic species of the genus , IMAU99199, isolated from the breast milk of a healthy nursing mother in Hohhot city PR China, was studied to characterise its taxonomic status using phenotypic and molecular taxonomic methods. The results indicated that it represented a member of the mitis-suis clade, pneumoniae subclade of the genus . It is a Gram-stain-positive, catalase-negative and oxidase-negative bacterium, and the cells are globular, paired or arranged in short chains. The results of a phylogenetic analysis of its 16S rRNA gene and two housekeeping genes ( and ) placed it in the genus . A phylogenetic tree based on 135 single-copy genes sequences indicated that IMAU99199 formed a closely related branch well separated from '' IMAU99125, '' Marseille Q6994, NCTC 12261, '' DM3B3, TP1632, ATCC BAA-960 and NCTC 7465. IMAU99199 and '' IMAU99125 had the highest average nucleotide identity (93.7 %) and digital DNA-DNA hybridisation (55.3 %) values, which were below the accepted thresholds for novel species. The DNA G+C content of the draft genome of IMAU99199 was 39.8 %. The main cellular fatty acids components of IMAU99199 were C and Cω7. It grew at a temperature range of 25-45 °C (the optimum growth temperature was 37 °C) and a pH range of 5.0-8.0 (the optimum growth pH was 7.0). These data indicate that strain IMAU99199 represents a novel species in the genus , for which the name sp. nov. is proposed. The type strain is IMAU99199 (=GDMCC 1.1874=KCTC 21155).
人乳中含有乳酸菌（LAB），其对婴儿肠道微生物的组成具有重要影响。在本研究中，从中国呼和浩特市一位健康哺乳期母亲的母乳中分离出一株α-溶血的属菌株IMAU99199，采用表型和分子分类学方法对其分类地位进行了研究。结果表明，它代表了属缓症-猪亚群、肺炎亚分支的一个成员。它是革兰氏阳性、过氧化氢酶阴性和氧化酶阴性细菌，细胞呈球形，成对或呈短链排列。对其16S rRNA基因和两个管家基因（和）进行系统发育分析的结果将其归入属。基于135个单拷贝基因序列构建的系统发育树表明，IMAU99199形成了一个与“IMAU99125”、“马赛Q6994”、NCTC 12261、“DM3B3”、TP1632、ATCC BAA - 960和NCTC 7465明显分开的紧密相关分支。IMAU99199与“IMAU99125”的平均核苷酸同一性（93.7%）和数字DNA - DNA杂交（55.3%）值最高，但均低于新物种的公认阈值。IMAU99199基因组草图的DNA G + C含量为39.8%。IMAU99199的主要细胞脂肪酸成分是C和Cω7。它在25 - 45°C的温度范围内生长（最适生长温度为37°C），在pH值5.0 - 8.0的范围内生长（最适生长pH为7.0）。这些数据表明，菌株IMAU99199代表了属中的一个新物种，为此提出新种名为sp. nov.。模式菌株为IMAU99199（=GDMCC 1.1874 = KCTC 21155）。
