Streptococcus chosunense sp. nov., Isolated from Human Postoperative Maxillary Cyst

Abstract

A novel facultative anaerobic, non-spore forming, non-motile, and Gram-stain-positive coccus, designated strain ChDC B353^T, was isolated from human postoperative maxillary cyst. The 16S ribosomal RNA gene (16S rDNA) sequence of the strain was most closely related to those of Streptococcus pseudopneumoniae ATCC BAA-960^T (99.4%), Streptococcus mitis NCTC 12261^T (99.3%), and Streptococcus pneumoniae NCTC 7465^T (99.2%). The major fatty acids of the strain were C_16:0 (43.2%) and C_{18:1 ω6c}/C_{18:1 ω7c} (20.2%). The genome of strain ChDC B353^T was composed of 1,902,053 bps. The DNA G+C content of the strain was 40.2 mol%. Average nucleotide identity (ANI) values between strain ChDC B353^T and S. pseudopneumoniae ATCC BAA-960^T, S. mitis NCTC 12261^T, and S. pneumoniae NCTC 7465^T were 91.9%, 93.5%, and 91.3%, respectively. Genome-to-genome distance (GGD) values between strain ChDC B353^T and S. pseudopneumoniae ATCC BAA-960^T, S. mitis NCTC 12261^T, or S. pneumoniae NCTC 7465^T were 46.6% (44.0-49.2%), 53.2% (50.5-55.9%), and 46.0% (43.5-48.7%), respectively. The threshold values of ANI and GGD for species discrimination are 95-96% and 70%, respectively. These results reveal that strain ChDC B353^T (= KCOM 1699^T = JCM 33453^T) is a novel species belonging to genus Streptococcus, for which a name of Streptococcus chosunense sp. nov. is proposed.