Intestinal colonization in premature and very low birth weight infants: Influencing factors and necrotizing enterocolitis (NEC)

Abstract

The intestinal microbiota has been recognized to influence metabolic, immune system and neurological development through host-microbe interactions. Preterm infants show aberrant intestinal colonization compared to infants born at term, implicated in development of gastrointestinal disorders, including necrotizing enterocolitis (NEC). Since the last decade interest for strategies to modulate the microbiota establishment in preterm infants has increased, in order to reduce the high morbidity and mortality among these infants. In order to modulate intestinal colonization, the regular colonization pattern and factors influencing this should be investigated in infants born preterm. The aim of this review is to describe associations between intestinal colonization and gestational age, delivery mode, antibiotic use, and type of nutrition. Compared to infants born at term, an increased proportion of preterm infants are born via caesarean section (CS) instead of vaginally, treated with broad-spectrum antibiotics, and formula-fed instead of human milk-fed. These factors negatively affect the establishment of a healthy intestinal microbiota in term infants and are believed to do the same in preterm infants. Indeed, this review shows that low gestational age and the use of broad-spectrum antibiotics induce an aberrant intestinal microbiota. Interestingly, intestinal microbiota does not seem significantly different between CS and vaginally delivered preterm infants and between formula-fed and human milk-fed preterm infants. However, preterm animal models demonstrate a clear difference due to delivery mode and type of nutrition in premature cases. Since above mentioned factors are involved in intestinal colonization, which is implicated in NEC development, they also have an effect on NEC. Several factors could possibly be modulated to decrease morbidity and mortality in preterm infants.