Bifidobacterium bifidum activates toll-like receptor-2 (TLR2) in the intestinal epithelium and enhances cyclooxygenase-2 (COX-2) expression, leading to increased production of prostaglandin E2 (PGE2) in the ileum, which helps protect against intestinal apoptosis associated with NEC [21]. Here, PTGS2 is linked to necrotizing enterocolitis.