The efficacy of oral supplementation with probiotic in preterm infants in the prevention of necrotizing enterocolitis: A randomized, double-blind, controlled study

Necrotizing enterocolitis (NEC) is a disease mostly seen in premature infants where part of their intestine undergoes tissue damage. Probiotics are considered attractive preventive potential to manipulate and normalize the intestinal flora of preterm neonates at risk of NEC. Probiotics exert their protective effect toward NEC prevention partly via immune-modulation, a mechanism that needs further elucidation and research. This clinical trial aims to evaluate the effect of supplementation with Bifidobacterium animalis subsp. lactis in preterm neonates on whole blood gene expression of inflammatory response associated genes, on the alterations of some gut microbiota groups present in the preterms fecal samples, and its overall effect on incidence and severity of NEC. The qPCR technique was used to test both the gene expression for RORC, NCR1, HIF1A and IL1RL1 in blood samples and the bacterial count and colonization in stool samples for Bifidobacterium genus, Enterococcus spp., Enterobacteriaceae, Lactobacillus group, and Candida albicans. Blood and stool samples were collected from preterm group supplied with B.lactis, a preterm control group and full-term healthy group at two time points. Results showed that progression to NEC stage III was prevented in the preterms supplied by B.lactis. The presence of B.lactis in the intestines of probiotic-supplied group has played a major role in altering the gut microbiota competing with other species such as Enterobacteriacae, which include many potential pathogens that are considered risk factors of NEC. Gene expression analysis showed significant alterations in the tested genes that may elucidate the beneficial effect of B.lactis on preterms at risk of NEC. It is the first study, so far, to test these genes in blood samples of preterms prone to NEC before and after probiotic administration.