Necrotizing enterocolitis (NEC) is one of the most devastating gastrointestinal emergencies in preterm neonates and a leading cause of death and morbidity.

The pathogenesis of NEC remains largely unclear, but it is widely considered as a multifactorial disease. Prematurity, enteral feeding, bacterial colonisation of the gut and intestinal ischemia have been proposed as major risk factors.

Probiotics may prevent NEC by improving the maturity and function of the gut mucosal barrier, modulating the immune system, promoting colonization of the gut with beneficial organisms and preventing colonization by pathogens.

A variety of clinical trials have evaluated the effect of different probiotic preparations on the occurrence of NEC in preterm infants. The results of recent metaanalyses suggest a benefit of probiotic bacteria in reducing the incidence of NEC and propose a change of practice.

The aim of the study is to evaluate the efficacy of the probiotic preparation Infloran® in reducing the incidence of NEC after implementation in clinical routine in preterm (< 34 weeks gestational age) very low birth weight infants compared to a historical cohort.

Inclusion Criteria:

• Neonates admitted to the neonatal intensive care unit on day 1 of life
• Very low birth weight (<1500 gram)
• Prematurity < 34/0 weeks gestational age
• For group receiving probiotics: 230 infants born after the 20/Sep/2010 (i.e. date of introduction of Infloran in clinical routine)
• For control group (historical): 230 infants born before 2010

Exclusion Criteria:

• Malformation of the gut (omphalocele, gastroschisis, intestinal atresia)
• Death before seven days of life, except due to NEC
• Transfer to another hospital before 37 weeks of corrected gestational age, except those who were transferred to a partner clinic using the same protocol for probiotic supplementation
• For group receiving probiotics: Infants who did not receive Infloran® starting in the first week of life or stopped before 34 weeks gestational age, except infants who developed NEC (reason for discontinuation of Infloran)

Very low birth weight Infants (<1500g birth weight)