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

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Genomics

Background:

• Facultative anaerobic cocci are common human commensals and potential pathogens.
• Accurate bacterial identification is crucial for understanding disease pathogenesis and developing targeted therapies.

Purpose of the Study:

• To characterize a novel bacterial strain isolated from a human postoperative maxillary cyst.
• To determine the taxonomic placement of the novel strain using polyphasic characterization.

Main Methods:

• Phenotypic characterization including Gram staining, motility, and spore formation.
• Phylogenetic analysis based on 16S ribosomal RNA gene sequencing.
• Genomic analysis including DNA G+C content, Average Nucleotide Identity (ANI), and Genome-to-Genome Distance (GGD).

Main Results:

• Strain ChDC B353^T is a Gram-positive, non-spore forming, non-motile coccus.
• 16S rDNA sequence analysis showed highest similarity to Streptococcus pseudopneumoniae, Streptococcus mitis, and Streptococcus pneumoniae.
• ANI and GGD values were below the thresholds for species delineation, supporting its classification as a novel species.
• The major fatty acids were C_16:0 and C_{18:1 ω6c}/C_{18:1 ω7c}, and the DNA G+C content was 40.2%.

Conclusions:

• Strain ChDC B353^T represents a novel species of the genus Streptococcus.
• The proposed name for this new species is Streptococcus chosunense sp. nov.
• This finding expands the known diversity within the Streptococcus genus and highlights potential novel bacteria in clinical settings.