Bacterial composition analysis of colorectal tissue is affected by the degree of mucus adhesion

Abstract

The outer mucus layer of the colorectal epithelium is easily removable and colonized by commensal microbiota, while the inner mucus layer is firmly attached to the epithelium and devoid of bacteria. Although the specific bacteria penetrating the inner mucus layer can contact epithelial cells and trigger cancer development, most studies ignore the degree of mucus adhesion at sampling. Therefore, we evaluated whether bacteria adhering to tissues could be identified by removing the outer mucus layer. Our 16S rRNA gene sequencing analysis of 18 surgical specimens of human colorectal cancer revealed that Sutterella (P = 0.045) and Enterobacteriaceae (P = 0.045) were significantly enriched in the mucus covering the mucosa relative to the mucosa. Rikenellaceae (P = 0.026) was significantly enriched in the mucus covering cancer tissues compared with those same cancer tissues. Ruminococcaceae (P = 0.015), Enterobacteriaceae (P = 0.030), and Erysipelotrichaceae (P = 0.028) were significantly enriched in the mucus covering the mucosa compared with the mucus covering cancers. Fusobacterium (P = 0.038) was significantly enriched in the mucus covering cancers compared with the mucus covering the mucosa. Comparing the microbiomes of mucus and tissues with mucus removed may facilitate identifying bacteria that genuinely invade tissues and affect tumorigenesis.

Novel microbiota Mesosutterella faecium sp. nov. has a protective effect against inflammatory bowel disease

“…These research findings underscore the importance of maintaining gut integrity in suppressing additional inflammatory reactions. Furthermore, based on existing reports, due to the characteristic of the family Sutterellaceae adhering to the mucosa, more strains of the Sutterella genus are found in mucosa covered with mucus than in those without (Tajima et al, 2022). In summary, the destruction of the gut structure induces the detachment of Sutterella from the gut mucosa and triggers colonic inflammation.…”