Effect of Lactobacillus reuteri NCIMB 30351 drops on symptoms of infantile functional gastrointestinal disorders and gut microbiota in early infants: results from a randomized, placebo-controlled clinical trial
Authors: Yu Tyrsin Oleg Yu , Yu Tyrsin Dmitry Yu , Daniil Nemenov Daniil G , Alexey Ruzov Alexey S , Vera Odintsova Vera E , Stanislav Koshechkin Stanislav I , D’Amico D’Amico Luciano 
Published: August 2023

Background
Infantile functional gastrointestinal disorders, such as colic, constipation, diarrhea, and gastroesophageal reflux (regurgitation), often occur in early infancy and, representing one of the causes of significant parental anxiety, lead to a significant strain on the healthcare resources.
Objectives
In this study, we aimed to evaluate the effects of Lactobacillus reuteri drops (L. Reuteri NCIMB 30351) on the symptoms of infantile colic, constipation, diarrhea, and gastroesophageal reflux, as well as on the levels of intestinal microbiota in full-term newborns during the first months of life.
Methods
A randomized, placebo-controlled, single-masked (blinded), post-marketing clinical study was conducted in two clinical units - Children's City Clinical Hospital of Moscow and Medical Center "St. Andrew's Hospitals - NEBOLIT" from March 2020 to May 2022 in 90 infants aged from 1 to 4 months (mean age (± SD) 12.3 ± 5.09 weeks; 53.3% females, 46.7% males). Patients with colic, regurgitation (single symptom or combination of several symptoms) and constipation or diarrhea were randomly allocated in two parallel arms to receive either 5 drops (2x10^8 colony forming unit) of L. Reuteri NCIMB 30351 (n = 60) or masked placebo (n = 30) for 25 consecutive days. Two treatment arms had equal numbers of patients with constipation and diarrhea (n = 30 each). Daily crying times and their duration, evacuations and regurgitations were recorded in a structured diary. The levels of gut microbiota were analyzed by deep sequencing of bacterial 16S rRNA gene .
Results
Infants with colic receiving supplementary L. reuteri NCIMB 30351 for 25 days had significant reduction in the numbers of colic (change from baseline − 6.3 (7.34) vs -3.0 (7.29) in placebo, p < 0.05), numbers of crying cases and mean duration of crying (decrease from baseline − 144 (70.7) minutes, lower in Diarrhea subgroup than in Constipation infants, compared with − 80 (58.9) in placebo, p < 0.0001), as well as regurgitations numbers (decreased by -4.8 (2.49) with L. reuteri vs -3 (7.74) with placebo). We also observed increased numbers of evacuations in infants with constipation (L. reuteri 2.2 (2.4) vs 0.9 (1.06) in placebo, p < 0.05). There was a remarkable reduction of evacuations in infants with diarrhea, while not statistically significant. The analysis of bacterial 16S rRNA genes in the collected samples showed that L. reuteri positively influences the proportions of prevalent species, while negatively affects both conditionally pathogenic and commensal microbes. Additional in vitro test for formation of Clostridium colonies in the presence of the probiotic demonstrated that L. reuteri effectively inhibits the growth of pathogenic Clostridium species. No adverse events were reported in this study.
Conclusions
The uptake of L. Reuteri NCIMB 30351 leads to a significant reduction in the number of regurgitations, feeding-induced constipations and diarrhea as well as mean daily numbers of crying and crying duration in infants during the first months of life. Our results suggest that L. Reuteri NCIMB 30351 represents a safe and effective treatment for colic in newborns. The clinical trial registration No.: ClinicalTrials.gov: NCT04262648 and the date of registration is 10/02/2020.