New Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus strains: well tolerated and improve infant microbiota

BACKGROUND: Different microorganisms from the environment will begin to colonise the infant during and immediately after the delivery. It could be advantageous to influence the microbiome early on by giving infants probiotic bacteria. The aim of the study was to investigate the tolerance of two probiotic lactobacilli in infants. The effect on the microbiota was also followed. METHODS: Thirty-six healthy infants, aged 4–83 days at the start of the study, were given a daily supplementation of probiotics (Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus rhamnosus 271, 10(9) CFU (colony-forming units)) or placebo for 8 weeks. Adverse events, growth parameters, the faecal microbiome and intestinal performance were followed. RESULTS: No differences between the groups in growth parameters, adverse events and intestinal performance were observed. The faecal levels of L. plantarum, L. rhamnosus and lactobacilli increased after the intake of probiotics and were significantly higher compared with the placebo group after 4 and 8 weeks of intake. The faecal microbial diversity was similar in the two groups at the end of the study. CONCLUSIONS: The intervention with the probiotic formulation was well tolerated and increased the level of lactobacilli in the intestine. The developed probiotic formulation will be further evaluated for clinical efficacy in infants. IMPACT: New data for the development of the gut function and the microbiome in breastfed and/or formula-fed young infants over time and the effect of adding two probiotic strains are presented. Lactiplantibacillus plantarum is a species that seldom has been analysed in infants, but it could be detected in 25% of the subjects before administration (mean age 41 days). Lactiplantibacillus plantarum and L. rhamnosus establish well in the intestine of infants and are well tolerated. The microbiota was positively affected by the intake of probiotics.