Streptococcus xiaochunlingii sp. nov. E24 Isolated From the Oropharynx of Healthy Chinese Children

A Gram-positive, α-hemolytic, catalase-negative, facultative anaerobic and non-motile coccus was isolated form throat swabs taken from the oropharynx of healthy children. The genome was shown to be 1.950,659 bp long and contained 42.03 mol% G + C bases with 1,942 protein-coding and 53 RNA coding genes. The results of 16S rRNA gene sequencing strongly suggested that the strain is a member of the Streptococcus genus, with 98.04, 98.11, and 97.34% similarities to Streptococcus australis ATCC 700641(T), Streptococcus rubneri LMG 27207(T) and Streptococcus parasanguinis ATCC 15912(T), respectively. A sodA gene comparison exhibited a sequence identity of 92.6% with the closest strain Streptococcus australis ATCC 700641(T). In silico DNA-DNA hybridization showed a highest DNA similarity value of 52% with Streptococcus australis ATCC 700641(T). Comparing 18 biochemical traits, the similarities of the Streptococcus strain E24 were 72% with Streptococcus rubneri LMG 27207(T), 78% with Streptococcus australis ATCC 700641(T) and 44% with Streptococcus parasanguinis ATCC 15912(T). We suggest that based on the genotypic and phenotypic results that the strain E24 is a novel species of the Streptococcus genus and propose the name Streptococcus xiaochunlingii sp. nov. E24.