Effect of probiotics on the intestinal microbiota of preterm and low birth weight infants: systematic review

Premature infants have an immature intestinal microbiota when compared to a full-term baby, colonized with a reduced number of beneficial bacterial species and, therefore, are more likely to have their microbiota populated by pathogenic species. The administration of probiotics can positively influence the intestinal colonization of premature babies. Thus, this study aimed to systematically review evidences of the effect of administering probiotics on the microbiota of premature newborns and their safety. It was designed as follows: population (premature newborns), intervention (probiotics), comparison (placebo or no treatment), outcome (changes in the microbiota of premature newborns), study type (randomized clinical trials). The studies were searched in the Cochrane Library, Medline via PubMed and Embase databases and, in a complementary way, through manual searches on Google Scholar and the Brazilian CAPES journal portal (www.periodicos.capes.gov.br). We included 23 studies involving 3,670 preterm infants, of which 65.2% (n=15) were classified as having a low risk of bias, 17.4% (n=4) with some risk of bias and 17.4% (n= 4) with high risk of bias. Probiotics have been used in order to colonize the intestinal microbiota. Finally, some Lactobacillus and Bifidobacterium strains tested seem to have benefits and safety for the microbiota and health of premature newborns