Fecal samples of 30 hospitalized infants who previously received probiotics and 30 not receiving
probiotics were analyzed.We find that the two groups showed differences in gut microbial strains composition
and richness. Infant treated with probiotics have a lower total anaerobic gramnegative counts (p=0.03) and a
higher total anaerobic gram-positive counts (p = 0.02). Enterobacteriaceae and enterococci were significantly
higher (p = 0.04) in the control group. No significant differences were observed for total aerobic counts,
lactobacilli and bifidobacteria. C. sakazaki was found only in one infant recruited in the control group. Infants
not previously treated with probiotics showed a higher colonization by diarrheagenic E. coli (EPEC) (p=0.04).
Conclusions: Our findings enhanced our understanding of the effects of probiotics on gut health in pediatric subjects.
Early administration of L. reuteri in infancy could improve gut health by reducing pathogens colonization.