Whole-genome sequencing and analysis of a novel strain Streptococcus oralis CRC211 from colorectal tumor

This study provides a comprehensive genomic characterization of Streptococcus oralis CRC211, a novel bacterial strain isolated from colorectal tumor tissue, through whole-genome sequencing and comparative analysis. The high-quality assembled genome (15.03 Mb, 40.94% GC content) contains 2 prophage regions spanning 160.5 kb, which may facilitate horizontal transfer of virulence genes. Functional annotation identified 3,674 genes, with significant enrichment in metabolic pathways (amino acid and carbohydrate metabolism) and virulence factors (116 genes in VFDB), including adhesins and biofilm-associated proteins that likely promote tumor colonization. Comparative genomic analysis revealed CRC211 shares 92.29% average nucleotide identity with reference S. oralis strains, while pan-genome analysis demonstrated an open genome structure with 1,222 conserved core genes. The strain also carries 75 antimicrobial resistance genes, suggesting potential clinical relevance. Notably, the genomic profile indicates adaptations for nutrient acquisition and immune evasion in the tumor microenvironment. These findings establish CRC211 as a CRC-associated strain with distinct genomic features that may contribute to tumor progression, providing crucial insights for future investigations into its oncogenic mechanisms and potential applications in microbiota-based diagnostics or therapeutics for colorectal cancer. Overall design: Whole-genome sequencing and analysis of a novel strain Streptococcus oralis CRC211 from colorectal tumor