Copyright: ©Author(s) 2026. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial (CC BY-NC 4.0) license. No commercial re-use. See permissions. Published by Baishideng Publishing Group Inc.
World J Clin Pediatr. Dec 9, 2026; 15(4): 122122
Published online Dec 9, 2026. doi: 10.5409/wjcp.122122
Impact of Limosilactobacillus reuteri DSM 17938 on early-life gut microbial diversity
Tanawan Noicharoen, Duc Long Tran, Areewan Soontornsook, Chonnikant Visuthranukul, Thanita Thammarakcharoen, Pavit Klomkliew, Suthida Visedthorn, Kittima Phutthawong, Sunchai Payungporn, Palittiya Sintusek
Tanawan Noicharoen, Areewan Soontornsook, Palittiya Sintusek, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok 10330, Thailand
Duc Long Tran, Palittiya Sintusek, Center of Excellence in Thai Pediatric Gastroenterology, Hepatology and Immunology (TPGHAI), Division of Gastroenterology and Hepatology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok 10330, Thailand
Duc Long Tran, Faculty of Medicine, Can Tho University of Medicine and Pharmacy, Can Tho 90000, Viet Nam
Chonnikant Visuthranukul, Center of Excellence in Pediatric Nutrition, Division of Nutrition, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Thanita Thammarakcharoen, Department of Pediatrics, Bumrungrad International Hospital, Bangkok 10110, Thailand
Pavit Klomkliew, Suthida Visedthorn, Kittima Phutthawong, Sunchai Payungporn, Center of Excellence in Systems Microbiology, Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Author contributions: Noicharoen T, Visuthranukul C, and Sintusek P conceptualized and designed the study, designed the data collection instruments, collected data; Soontornsook A, Noicharoen T, Tran DL, Thammarakcharoen T and Sintusek P collected the data and stool samples; Klomkliew P, Visedthorn S, and Phutthawong K conducted the experiments, analyzed the data, and interpreted the results; Payungporn S conceptualized the study, designed and contributed to the experiments, confirmed the validity of the data, and critically reviewed and revised the manuscript; Noicharoen T drafted the manuscript; Sintusek P critically reviewed the manuscript. All authors read and approved the final manuscript.
AI contribution statement: The authors used AI-assisted editing tools (Chat-GPT) to improve spelling, grammar, and clarity during manuscript preparation and answering reviewers.
Supported by Ratchadapiseksompotch Fund, Faculty of Medicine, Chulalongkorn University, No. 67/026 and No. 67/027; the Second Century Fund (C2F) from Chulalongkorn University; and Thailand Science research and Innovation Fund, Chulalongkorn University, No. HEA_FF_69_225_3000_031.
Institutional review board statement: This study was approved by the Institutional Review Board of Chulalongkorn University (No. 0855/66).
Clinical trial registration statement: This study is registered at ClinicalTrials.gov. The registration identification number is No. NCT06309199.
Informed consent statement: All study participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement—checklist of items, and the manuscript was prepared and revised according to the CONSORT Statement—checklist of items.
Data sharing statement: The 16S bacterial sequencing datasets generated in the current study are publicly available in the NCBI Sequence Read Archive (SRA) under BioProject ID: No. PRJNA1464364. The technical appendix, statistical code, and other datasets used and analyzed during the current study are available from the corresponding author at
palittiya.s@chula.ac.th upon reasonable request. Participants gave informed consent for data sharing.
Corresponding author: Palittiya Sintusek, MD, PhD, Associate Professor, Center of Excellence in Thai Pediatric Gastroenterology, Hepatology and Immunology (TPGHAI), Division of Gastroenterology and Hepatology, Department of Pediatrics, Faculty of Medicine, Chulalong
korn University and King Chulalongkorn Memorial Hospital, 1873 Rama IV, Pathumwan, Bangkok 10330, Thailand.
palittiya.s@chula.ac.th
Received: April 10, 2026
Revised: June 1, 2026
Accepted: June 17, 2026
Published online: December 9, 2026
Processing time: 162 Days and 15.2 Hours
BACKGROUND
Gut microbiota dysbiosis plays an important role in functional gastrointestinal disorders. While the effectiveness of Limosilactobacillus reuteri (L. reuteri) DSM 17938 has been evidenced in several pediatric gastrointestinal conditions, its effects on gut microbiota modulation in exclusively breastfed infants remain unclear.
AIM
To evaluate the effect of L. reuteri DSM 17938 supplementation on gut microbiota diversity and gastrointestinal symptoms in healthy, exclusively breastfed infants.
METHODS
Healthy, term infants born at King Chulalongkorn Memorial Hospital (March 2024 to January 2025) were randomized to receive L. reuteri DSM 17938 or a placebo, five drops daily for up to 8 weeks. Fecal samples were collected at 1, 2, and 4 months. The stool microbiota was characterized using 16S rRNA sequencing (Nanopore technology) to assess taxonomic classification, microbial diversity, and relative abundance.
RESULTS
Stool samples from 34 exclusively breastfed infants (17 receiving probiotics, 17 placebo-treated) were analyzed. Baseline characteristics and gastrointestinal symptoms were comparable between groups. Gut microbiota diversity significantly differed with the mode of delivery during the first two months; a higher alpha diversity was observed in neonates born through normal delivery than in babies born through cesarean section (P = 0.028) (Chao 1 index, P = 0.07 and Shannon index, P = 0.01). By 2 months, the probiotic-treated group showed greater alpha diversity than the placebo, particularly in infants born by vaginal delivery (Chao 1 index, P = 0.38 and Shannon index, P = 0.05). In addition, beta diversity differed significantly between the groups (P = 0.04). However, no significant differences in alpha- or beta-diversity were observed at the 4-month time point. Probiotic supplementation was associated with an increased relative abundance of Bifidobacterium, regardless of delivery mode. Higher abundances of Parabacteroides and Hungatella hathewayi were observed in infants born via normal delivery or cesarean section, respectively. No differences in gastrointestinal symptoms were detected.
CONCLUSION
L. reuteri DSM 17938 supplementation during early infancy induced modest and transient changes in gut microbiota composition, particularly increasing Bifidobacterium abundance, without sustained microbiota alterations or significant effects on gastrointestinal symptoms.
Core Tip: While Limosilactobacillus reuteri (L. reuteri) DSM 17938 has demonstrated benefits in several pediatric gastrointestinal conditions, its effects on gut microbiota modulation in exclusively breastfed infants remain unclear. In this prospective sub-study of a randomized controlled trial, L. reuteri DSM 17938 supplementation during the first two months of life was associated with an increased Bifidobacterium abundance and, independently of the delivery modes, higher Parabacteroides and Hungatella hathewayi were the most distinctive species identified in vaginally- and cesarean-delivered infants, respectively. L. reuteri DSM 17938 administration induced only modest and transient microbiota changes, with no evidence of sustained colonization.
