The microbiome compositional and functional differences between rectal mucosa and feces

Area of Science:

• Microbiome research
• Gut health
• Colorectal cancer pathogenesis

Background:

• Previous gut microbiome studies predominantly used fecal samples, neglecting the intestinal mucosal microbiome.
• The microbial communities residing on the rectal mucosa remain relatively unexplored, creating a knowledge gap.

Purpose of the Study:

• To comprehensively map and compare the microbial communities in rectal mucosa versus matched fecal samples.
• To investigate the unique microecological characteristics of the rectal mucosa and their association with colorectal cancer risk factors.
• To identify potential gut microbiome biomarkers for health and disease states.

Main Methods:

• Shotgun metagenomics was employed to analyze microbial composition.
• Samples included normal rectal mucosa and matched feces from 20 patients with colonic polyps.
• KEGG Orthology (KO) annotation was used to explore functional pathways.

Main Results:

• Significant distinctions were observed between mucosal and fecal microbiomes.
• The mucosal microbiome exhibited fewer genera, with Burkholderia being a key discriminating genus.
• Novel biomarkers, including Clostridium ramosum and Enterobacter cloacae, were identified in association with age.
• Enrichment of pathways related to sugar transport and short-chain fatty acid metabolism was noted in the mucosal microbiota.

Conclusions:

• The rectal mucosal microbiome possesses unique characteristics distinct from fecal microbiomes.
• These findings highlight the specificity of gut microbial communities and their potential role in colorectal cancer.
• The study provides a foundation for developing new microbiome-based strategies for colorectal cancer prevention and treatment.