The Efficacy and Mechanisms of Oral Probiotics in Preventing Necrotizing Enterocolitis Among Very Low Birth Weight Infants With Formula-feeding

Necrotizing enterocolitis (NEC) remains the most catastrophic gastrointestinal emergencies in preterm very low birth weight (VLBW) infants.Although study showed it is a multifactorial disease, its pathogenesis is still not yet unclear currently. Prematurity and formula feeding is considered as the main risk factors.Gut microbiota disturbance and immature immune system is associated with NEC. A lot of studies had showed that oral probiotics can alter gut microbiota flora colonization and reduce the incidence of NEC,but the exact mechanism remains unclear.The aim of this study is to elucidate the clinical efficacy and possible molecular mechanism of oral mixture probiotics in preventing NEC among preterm VLBW infants.

Patient Registry procedures: First,randomized numbers was generated by the computer and sent to the principal investigator(PI) at each center when an infant was eligible for enrollment.Second, patient will be assigned randomly to experimental group or control group by PI.Finally,the PI at each center will be responsible for the accuracy,completeness or representativeness of medical records, registry forms,data collection.

Sample size determination: The incidence of death and NEC was around 20% recently.To reduce the incidence of NEC and death to 10% at discharge would require a 50% improvement.At 80% power at P = 0.05 (two-sided),the loss rate of 0.2, this would require 135 subjects per arm.