PPIB and obesity due to melanocortin 4 receptor deficiency: B. fragilis abundance in the gut microbiome usually has a positive correlation with obesity, inflammatory bowel disease, and colorectal cancer [17,18,19,20,21] due to the pathogenesis of enterotoxigenic B. fragilis (ETBF) strains that harbor B. fragilis toxin (BFT) genes encoding BFT [22].