Development of intestinal dysbiosis and necrotizing enterocolitis in infants and the treatment of enterocolitis

Abstract

The human gut microbiota is a complex ecosystem of trillions of microorganisms that provide health benefits to the host. Gut colonization begins at birth and is affected by five primary factors – mode of delivery, antibiotic exposure, hygiene, mode of feeding, and prematurity. These colonization factors are also associated with gut microbiota dysbiosis and the development of necrotizing enterocolitis (NEC). NEC is an inflammatory gastrointestinal disease, mainly affecting premature infants. Development of NEC is associated with a distinct bacterial population, an immature immune system and contributes to an exaggerated immune response. This altered microbiota, or dysbiosis, isthought to lead to the chronic inflammation associated with NEC. Breast milk reduces the risk of NEC in preterm infants; however, not all infants will have access to breast milk. The protective effects of break milk are elicited by various components that promote colonization of the infant gut with protective bacteria. These effects may be mimicked by supplementing feedings with pre-, pro-, or synbiotics, promoting the establishment of a healthy microbiota in formula-fed infants. This review summarizes our understanding of the functions and development of the gut microbiota, and its association with dysbiosis and related diseases, with emphasis on NEC and its treatment.