High resolution full-length 16S rRNA gene sequencing reveals distinct fecal microbial consortium associated with colorectal cancer in Saudi Arabia

= 1.71%, BH-FDR-adjusted q = 0.049). Differential abundance analysis identified Fusobacterium animalis as a CRC-specific species, undetectable in healthy cohorts. Species-level co-occurrence network analysis further demonstrated positive associations among F. animalis, Peptostreptococcus stomatis, Dialister pneumosintes, and Parvimonas micra. These anaerobes, typically recognized as oral bacteria, formed a tightly connected consortium unique to patients with CRC but absent in healthy cohorts. These results suggest a CRC-specific microbial signature with potential utility as a non-invasive biomarker for early detection. Future multi-omics studies are warranted to support the development of microbiota-based diagnostics for CRC management.