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

Abstract

Aim: This study provides a comprehensive genomic characterization of Streptococcus oralis CRC211, a novel bacterial strain isolated from colorectal tumor tissue. Methods: Whole-genome sequencing and comparative genomic analyses were performed. Results: The high-quality assembled genome (15.03 Mb, 40.94% guanine-cytosine content) contains 2 prophage regions spanning 160.5 kb, which may facilitate the 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 Virulence Factors Batabase), including adhesins and biofilm-associated proteins that likely promote tumor colonization. Comparative genomic analysis revealed that CRC211 shares 92.29% average nucleotide identity with reference Streptococcus oralis strains, while pan-genome analysis demonstrated an open genome structure with 1,222 conserved core genes. In addition, the strain also carries 75 antimicrobial resistance genes, underscoring its potential clinical relevance. Notably, the genomic profile indicates adaptations for nutrient acquisition and immune evasion in the tumor microenvironment. Conclusion: These findings establish CRC211 as a colorectal cancer (CRC)-associated strain with distinct genomic features that may contribute to tumor progression. The study provides critical insights into its possible oncogenic mechanisms and highlights potential applications in mic ases,indels - changerobiota-based diagnostics or therapeutics for colorectal cancer.