Food-sensitized children with juvenile colorectal polyps exhibit a unique microbial signature related to inflammation and colorectal cancer-associated taxa

Juvenile colorectal polyps (JCP) are frequent in children and are associated with type 2 inflammation and local IgE synthesis. Our previous work showed that children with JCP from our cohort are sensitized to food allergens. Here, we characterized the bacterial microbiota in fecal samples from food-sensitized children with JCP (FSS) and healthy controls (CS), as well as in JCP tissues and surrounding control tissues (SCT), using 16S rRNA gene sequencing. Although alpha-diversity was comparable across groups, beta-diversity clearly separated fecal from tissue samples and distinguished FSS from CS. Fecal microbiota from FSS was enriched in Prevotella, Senegalimassillia, and Allisonella, and depleted in Bacteroides H and Phocaeicola A. Polyp tissues exhibited increased abundance of Escherichia fergusonii, Fusobacterium mortiferum, F. necrogenes, and Streptococcus, with reduced Prevotella, Roseburia A, and Anaerobutyricum. Microbiota in polyp samples formed two distinct subclusters, while surrounding biopsies displayed intermediate profiles. Several taxa enriched in JCP overlapped with bacteria previously linked to inflammation and colorectal cancer, suggesting an early carcinogenic microbial signature. This study provides the first comprehensive characterization of the JCP-associated microbiota in food-sensitized pediatric patients, highlighting a potential link between microbial dysbiosis, allergic inflammation, and early events in colorectal tumorigenesis.