L. Reuteri SGL 01 in Nursing Mothers: Effects on Milk Microbiota and Neonatal Gut Colonization (Reuteri17)

Supplementation With L. Reuteri SGL 01 in Nursing Mothers: Evaluation of the Microbiota in Breast Milk and Intestinal Colonization in Newborns

The Reuteri17 study is a spontaneous, prospective, randomized intervention study designed to evaluate the effects of maternal supplementation with the probiotic Lactobacillus reuteri SGL 01 on the composition of the breast milk microbiota and subsequent intestinal colonization of the newborn.

The protocol involves the enrollment of 20 primiparous mothers of full-term, exclusively breastfed infants. Participants are divided into two groups: the first receives a daily supplement of 5 drops of Reuplus® (equivalent to 1 billion live cultures), while the second serves as a non-supplemented control group.

The effectiveness of the intervention is monitored through two sampling moments: at baseline (T0) and after 30 days of treatment (T1). Specifically, 20 ml samples of breast milk and fecal samples from the newborns are collected. Bacterial DNA is extracted from these biological matrices and analyzed using real-time PCR at the University of Bologna, with the aim of quantifying changes in the microbiota and the transfer of the probiotic strain.

To complete the investigation, mothers are given a nutritional questionnaire to correlate the results with dietary habits. The study aims to confirm that maternal oral supplementation can be an effective strategy for modulating the bacterial heritage of newborns during the first months of life.

Study Overview

• Status: Completed
• Conditions: Supplementation; Breastfeeding; Microbiota
• Intervention / Treatment: Dietary supplement: probiotic Lactobacillus reuteri SGL 01

• Study Type: Interventional
• Enrollment (Actual): 70
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • BO
    • Bologna, BO, Italy, 40131
      • Irccs Aoubo

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Primiparous women, mothers of full-term infants who are breastfed.
• Written informed consent;
• Age over 18 years.

Exclusion Criteria:

• Drug therapies that are contraindicated for breastfeeding
• Maternal conditions that are contraindicated for breastfeeding
• Neonatal formula milk feeding
• Antibiotic treatments

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Supplemented group; Daily oral supplementation with 1 × 10⁹ colony-forming units (CFU) of L. reuteri SGL 01 to breastfeeding mothers	Dietary supplement: probiotic Lactobacillus reuteri SGL 01; 5 drops of supplement based on lactic acid bacteria consisting exclusively of Lactobacillus Reuteri SGL 01
No Intervention: Non-supplemented group; Breastfeeding mothers who received no supplementation

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in maternal milk samples between T0 and T1	Bacterial DNA was extracted from 2 mL of milk samples, stored at -80 °C after collection, using the QIAamp DNA Mini Kit (Qiagen, West Sussex, UK). Bacterial counts (log CFU/ml milk) were based on rRNA gene copy numbers retrieved from the rRNA copy number database. Mann-Whitney U test was used to compare the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in milk samples at T0 and T1 between the study groups. Wilcoxon signed rank test was used to compare the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in milk samples between T0 and T1 within each study group. Significance level was set at P <0.05.	30 days
Changes in the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in neonatal fecal samples between T0 and T1	Bacterial DNA was extracted from 250 mg of neonatal fecal samples, stored at -80 °C after collection, using the QIAamp DNA Mini Kit (Qiagen, West Sussex, UK). Bacterial counts (log CFU/g feces) were based on rRNA gene copy numbers retrieved from the rRNA copy number database. Mann-Whitney U test was used to compare the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in neonatal fecal samples at T0 and T1 between the study groups. Wilcoxon signed rank test was used to compare the concentration of Lactobacillus, Bifidobacterium, Clostridium and Bacteroides spp. in fecal samples between T0 and T1 within each study group. Significance level was set at P <0.05.	30 days

Collaborators and Investigators

• Sponsor: IRCCS Azienda Ospedaliero-Universitaria di Bologna

Study record dates

Study Major Dates

• Study Start (Actual): October 16, 2017
• Primary Completion (Actual): January 31, 2021
• Study Completion (Actual): December 31, 2025

Study Registration Dates

• First Submitted: January 21, 2026
• First Submitted That Met QC Criteria: February 9, 2026
• First Posted (Actual): February 12, 2026

Study Record Updates

• Last Update Posted (Actual): February 12, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: breastfeeding; neonates; microbiota
• Additional Relevant MeSH Terms: Behavior; Feeding Behavior; Breast Feeding
• Other Study ID Numbers: Reuteri17

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No