Streptococcus chenjunshii sp. nov. isolated from feces of Tibetan antelopes

Abstract

Three Gram-stain-positive, catalase-negative, a-haemolytic, chain-forming and coccus-shaped microorganisms (strains Z15 T , Z1 and Z2) were isolated from feces of Tibetan antelopes collected from the Qinghai-Tibet plateau, PR China. The results of 16S rRNA gene sequence studies indicated that Z15 T shared 94.5, 93.1 and 92.2 % similarity with Streptococcus pantholopis DSM 102135 T , Streptococcus ursoris NUM 1615 T and Streptococcus dentapri NUM 1529 T , respectively. rpoB and groEL-based sequence analysis of our three novel isolates revealed interspecies divergence of 16.7 and 14.3 % from Streptococcus pantholopis DSM 102135 T. The genomic DNA G+C content of Z15 T is 42.48 mol%. Z15 T has an average nucleotide identity (ANI) value of 81.19 % with S. pantholopis DSM 102135 T and a DNA-DNA relatedness value of less than 70 % in the in-silico DNA-DNA hybridization (isDDH) with other species of genus Streptococcus deposited in the GenBank database. A wholegenome phylogenetic tree based on 246 core genes of 78 genomes of members of the genus Streptococcus indicated that Z15 T represents a member of genus Streptococcus but one well separated from the currently recognized species. Z15 T contains C 18 : 1 !7c (25.5 %), C 18 : 1 !9c (19.6 %), C 16 : 0 (17.5 %) and C 16 : 1 !9c (13.3 %) as its major cellular fatty acids. According to the morphological, biochemical and molecular phylogenetic features of the three novel isolates, they represent a novel species of the genus Streptococcus, and Streptococcus chenjunshii sp. nov. is thus proposed. The type strain is Z15 T (=CGMCC 1.16529=DSM 106182).