Complete genome sequence of Streptococcus periodonticum strain CRC221 isolated from human colorectal tumor tissue

Streptococcus periodonticum is a facultative anaerobic, Gram-positive coccus originally isolated from human periodontitis lesions and implicated in colorectal cancer pathogenesis. This study aimed to comprehensively characterize the genome of strain CRC221, isolated from human colorectal tumor tissue, to support future research on its potential role in tumorigenesis.

Genomic DNA from strain CRC221 was sequenced using Illumina NovaSeq 6000 and PacBio platforms. The final assembly yielded a complete circular chromosome of 1,851,769 bp with 38.81% GC content. Structural annotation predicted 1,837 genes, comprising 1,707 protein-coding sequences (CDSs), 12 rRNAs, 59 tRNAs, 3 non-coding RNAs, and 56 pseudogenes. Functional annotation associated most CDSs with core bacterial survival pathways, particularly carbohydrate and amino acid metabolism. Notably, 94 genes were annotated as virulence factors, 68 as antibiotic resistance genes, and 319 as pathogen-host interaction factors. Comparative genomics revealed an ANI of 97.51% and a dDDH value of 71.8% against the reference S. periodonticum genome (GCA_003963555.1). Pan-genome analysis indicated an open genome architecture containing 199 conserved core genes. These genomic data provide a foundation for investigating the biological characteristics of intratumoral S. periodonticum and its potential relevance to colorectal cancer.