Infant Microbiota Research Articles

Maternal prebiotic supplementation during pregnancy and lactation modifies the microbiome and short chain fatty acid profile of both mother and infant

Background & AimsImproving maternal gut health in pregnancy and lactation is a potential strategy to improve immune and metabolic health in offspring and curtail the rising rates of inflammatory diseases linked to alterations in gut microbiota. Here, we investigate the effects of a maternal prebiotic supplement (galacto-oligosaccharides and fructo-oligosaccharides), ingested daily from <21 weeks’ gestation to six months’ post-partum, in a double-blinded, randomised placebo-controlled trial. MethodsStool samples were collected at multiple timepoints from 74 mother-infant pairs as part of a larger, double-blinded, randomised controlled allergy intervention trial. The participants were randomised to one of two groups; with one group recieving 14.2 g per day of prebiotic powder (galacto-oligosaccharides GOS and fructo-oligosaccharides FOS in ratio 9:1), and the other receiving a placebo powder consisting of 8.7 g per day of maltodextrin. The faecal microbiota of both mother and infants were assessed based on the analysis of bacterial 16S rRNA gene (V4 region) sequences, and short chain fatty acid (SCFA) concentrations in stool. ResultsSignificant differences in the maternal microbiota profiles between baseline and either 28-weeks’ or 36-weeks’ gestation were found in the prebiotic supplemented women. Infant microbial beta-diversity also significantly differed between prebiotic and placebo groups at 12-months of age. Supplementation was associated with increased abundance of commensal Bifidobacteria in the maternal microbiota, and a reduction in the abundance of Negativicutes in both maternal and infant microbiota. There were also changes in SCFA concentrations with maternal prebiotics supplementation, including significant differences in acetic acid concentration between intervention and control groups from 20 to 28-weeks’ gestation. ConclusionMaternal prebiotic supplementation of 14.2 g per day GOS/FOS was found to favourably modify both the maternal and the developing infant gut microbiome. These results build on our understanding of the importance of maternal diet during pregnancy, and indicate that it is possible to intervene and modify the development of the infant microbiome by dietary modulation of the maternal gut microbiome.

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.

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. 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. 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 4months (mean age (± SD) 12.3 ± 5.09weeks; 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 (2 × 108 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. Infants with colic receiving supplementary L. reuteri NCIMB 30351 for 25days 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) and numbers of crying cases and mean duration of crying (decrease from baseline - 144 (70.7) minutes, lower in the diarrhea subgroup than in constipation infants, compared with - 80 (58.9) in placebo, P < 0.0001), as well as regurgitation 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 gene in the collected samples showed that L. reuteri positively influences the proportions of prevalent species, while it 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. Conclusion: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. Trial registration: ClinicalTrials.gov : NCT04262648. What is Known: • Infantile functional gastrointestinal disorders, such as colic, constipation, diarrhea, and gastroesophageal reflux (regurgitation), often occur in early infancy and, represent one of the causes of significant parental anxiety. • A number of studies have shown that both the composition and diversity of the intestinal microbiota play important roles in the development and function of the gastrointestinal tract. What is New: • 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. • L. reuteri positively influences the proportions of prevalent species, while it negatively affects both conditionally pathogenic and commensal microbes in gut microbiota.

Intestinal microbiota features of children born by cesarean section and its correction

Introduction. Studying the gut microbiota of C-section newborns and its correction is a topical problem at present.Aim. To study the process of gut microbiota formation in healthy C-section infants, and the option for its correction using a Lactobacillus reuteri strain DSM 17938 probiotic.Materials and methods. A total of 80 healthy newborns were included in the study. Of these, 59 completed the study: the treatment group consisted of 36 elective caesarean (EC)-section infants and the control group was made up of 23 vaginally delivered infants. Newborns of the treatment study group were randomized into subgroups, one of which received the L. reuteri strain DSM 17938 (L subgroup) probiotic, and the second one did not receive it (0 subgroup). During the entire period of the study, infants were exclusively breastfed. The gut microbiota was analysed with the 16S rRNA sequencing method, and the metabolic activity of the gut microbiota was additionally assessed using gas-liquid chromatography.Results and discussion. The metagenomic analysis showed that the taxonomic richness and biological diversity of the gut microbiota in L subgroup infants increased in time interval 3, which indicated the active effect of the strain on the infant microbiota by Exposure Day 30. The gas-liquid chromatography analysis showed more pronounced changes in short-chain fatty acids in infants of the L subgroup: they were more similar to the findings in the control group (vaginal delivery). Also, bowel problems and allergies occurred less frequently in infants of this subgroup and they less frequently suffered from respiratory diseases during the year. The study showed the association between the mode of delivery and changes in anthropometric measurements.Conclusion. The use of L. reuteri strain DSM 17938 probiotic had a significant effect on the formation of the microbiota by the 30th day of age. A daily long-term addition of a L. reuteri strain DSM 17938 probiotic can prevent early microbiota dysbiosis and have a protective effect in later age period.

Association between Intestinal Microbiota in Infants and their Neurodevelopment: Systematic Literature Review on Scoping Review Methodology

Background. The long-term effects of large intestine microbiota or its disorders on human health remain largely unexplored. Particularly the issue of an association between the intestinal microbiota in newborns and infants with their further neurodevelopment remains unclear. Objective. The aim of the study is to systematically summarize studies' results on the association of large intestine microbiota (its normal composition and in case of any disorders) in newborns and infants and their neurodevelopment until the age of 1 year. Methods. The search of publications was performed in the following databases: Medline, Web of Science (WoS), Scientific electronic library (eLIBRARY.RU), and CyberLeninka. The publication period was dated from January 2001 to May 2022 (until December 2021 for WoS). The review included studies that examined the an association of large intestine microbiota in newborns and infants with their neurodevelopment until the age of 1 year, the presence of nervous system pathology, behavioral and/or emotional disorders. Languages of analyzed publications were Russian and English. Results. The review includes data from 9 studies. Data on the association of the intestine microbiota (its composition and/or the number of microorganisms) with neurodevelopment at the early age is summarized. Conclusion. Large intestine microbiota of infants is regarded as new non-invasive biomarker of their neurodevelopment. Differences in the design of published original studies included in the systematic literature review do not allow us to assess the role of individual microbiota components in infant’s neurodevelopment.

Maternal short chain fructo-oligosaccharides supplementation during late gestation and lactation influences milk components and offspring gut metabolome: a pilot study

Breast milk composition is influenced by maternal diet. This study aimed to evaluate if supplementation of maternal diet with a prebiotic fibre, through its potential effect on milk composition, can be a leverage to orientate the gut microbiota of infants in a way that would be beneficial for their health. Twelve sows received a diet supplemented with short chain fructo-oligosaccharides or maltodextrins during the last month of gestation and the lactation. Oligosaccharidic and lipidomic profiles of colostrum and mature milk (21 days), as well as faecal microbiota composition and metabolomic profile of 21 day-old piglets were evaluated. The total porcine milk oligosaccharide concentration tended to be lower in scFOS-supplemented sows, mainly due to the significant reduction of the neutral core oligosaccharides (in particular that of a tetrahexose). Maternal scFOS supplementation affected the concentration of 31 lipids (mainly long-chain triglycerides) in mature milk. Faecal short-chain fatty acid content and that of 16 bacterial metabolites were modified by scFOS supplementation. Interestingly, the integrative data analysis gave a novel insight into the relationships between (i) maternal milk lipids and PMOs and (ii) offspring faecal bacteria and metabolites. In conclusion, scFOS-enriched maternal diet affected the composition of mature milk, and this was associated with a change in the colonisation of the offspring intestinal microbiota.

Associations between gut microbiota and adverse neurodevelopmental outcomes in preterm infants: a two-sample Mendelian randomization study.

Gut microbiota are associated with adverse neurodevelopmental outcomes in preterm infants; however, the precise causal relationship remains unclear. In this study, we conducted a two-sample Mendelian randomization (MR) analysis to comprehensively study the relationship between gut microbiota and adverse neurodevelopmental outcomes in preterm infants and identify specific causal bacteria that may be associated with the occurrence and development of adverse neurodevelopmental outcomes in preterm infants. The genome-wide association analysis (GWAS) of the MiBioGen biogroup was used as the exposure data. The GWAS of six common adverse neurodevelopmental outcomes in premature infants from the FinnGen consortium R9 was used as the outcome data. Genetic variations, namely, single nucleotide polymorphisms (SNPs) below the locus-wide significance level (1 × 10-5) and genome-wide statistical significance threshold (5 × 10-8) were selected as instrumental variables (IVs). MR studies use inverse variance weighting (IVW) as the main method. To supplement this, we also applied three additional MR methods: MR-Egger, weighted median, and weighted mode. In addition, the Cochrane's Q test, MR-Egger intercept test, Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO), and leave-one-out methods were used for sensitivity analysis. Our study shows a causal relationship between specific gut microbiota and neurodevelopmental outcomes in preterm infants. These findings provide new insights into the mechanism by which gut microbiota may mediate adverse neurodevelopmental outcomes in preterm infants.

Alterations of gut microbiota in infants with biliary atresia identified by 16S rRNA-sequencing

BackgroundBiliary atresia (BA) is a severe neonatal disease with progressive intra- and extra-hepatic bile ducts inflammation and hepatic fibrosis. Characterization of gut microbiome profiles in infants with biliary atresia can provide valuable information and potential disease biomarkers. Our study aims to explore the relationship between gut microbiota and biliary atresia.Methods16 S ribosomal RNA (rRNA) gene sequencing was carried out to identify the differences in composition and diversity of gut microbiota between infants with BA and healthy subjects. A total of 31 infants with biliary atresia and 20 healthy subjects were recruited.ResultsThe composition of gut microbiota in BA group was significantly different with the normal control group (P < 0.05) and the abundance ratio of Klebsiella/Bifidobacterium showed great potential for identification of BA (P < 0.01). In addition, the differential bacterial taxa were involved in lipid and vitamins metabolism.ConclusionOur results could provide potential non-invasive biomarker for identification of biliary atresia and contribute to the treatment in terms of ameliorating microbiota dysbiosis.

The Effect of Oral Iron Supplementation/Fortification on the Gut Microbiota in Infancy: A Systematic Review and Meta-Analysis.

(1) Background: Iron is an essential metal for the proper growth and neurodevelopment of infants. To prevent and treat iron deficiency, iron supplementation or fortification is often required. It has been shown, though, that it affects the synthesis of gut microbiota. (2) Methods: This paper is a systematic review and meta-analysis of the effect of oral iron supplementation/fortification on the gut microbiota in infancy. Studies in healthy neonates and infants who received per os iron with existing data on gut microbiota were included. Three databases were searched: PUBMED, Scopus, and Google Scholar. Randomized controlled trials (RCTs) were included. Quality appraisal was assessed using the ROB2Tool. (3) Results: A total of six RCTs met inclusion criteria for a systematic review, and four of them were included in the meta-analysis using both the fixed and random effects methods. Our results showed that there is very good heterogeneity in the iron group (I2 = 62%), and excellent heterogeneity in the non-iron group (I2 = 98%). According to the meta-analysis outcomes, there is a 10.3% (95% CI: -15.0--5.55%) reduction in the bifidobacteria population in the iron group and a -2.96% reduction for the non-iron group. There is a confirmed difference (p = 0.02) in the aggregated outcomes between iron and non-iron supplement, indicative that the bifidobacteria population is reduced when iron supplementation is given (total reduction 6.37%, 95%CI: 10.16-25.8%). (4) Conclusions: The abundance of bifidobacteria decreases when iron supplementation or fortification is given to infants.

Gut microbiota of preterm infants in the neonatal intensive care unit: a study from a tertiary care center in northern India.

Disruptions of the gut microbiota of preterm infants admitted to the neonatal intensive care unit (NICU) during the first 2 weeks of life are of critical importance. These infants are prone to various complications, including necrotizing enterocolitis (NEC) and sepsis. Studying the gut microbiota will improve outcomes in preterm infants. In the present study, we examined the gut microbiota of preterm infants admitted to the NICU in the first month of life. Neonates admitted to the NICU were recruited, and stool samples were collected weekly from the seventh day of the infant's life until the 30th day of life. DNA was extracted using a DNeasy Powersoil DNA isolation kit. 16S rRNA gene sequencing targeting the V3-V4 region was performed using the MiSeq platform. Sequenced reads were processed on DADA2 pipeline to obtain an amplicon sequence variant (ASV) table. All bioinformatic and statistical analyses were performed using different packages in the R statistical framework. Fourteen preterm infants were recruited, and 48 samples were collected. Alpha diversity metrics, observed ASV count, and Shannon index were found to have no differences in any clinical variables. Permutational multivariate analysis of variance (PERMANOVA) showed discrimination of neonates by gestational age and administration of probiotics. Differential abundance analysis showed a decreased abundance of Bifidobacterium Breve in extremely preterm infants (gestational age <28 weeks) compared to moderate preterm infants (gestational age 29-32 weeks). Supplementation with probiotics decreased Acinetobacter and increased Bifidobacterium in the gut of preterm neonates regardless of gestational age. Gestational age and probiotic supplementation alter the gut microbiota of preterm infants admitted to the NICU.

Supplemented Infant Formula and Human Breast Milk Show Similar Patterns in Modulating Infant Microbiota Composition and Function In Vitro.

The gut microbiota of healthy breastfed infants is often dominated by bifidobacteria. In an effort to mimic the microbiota of breastfed infants, modern formulas are fortified with bioactive and bifidogenic ingredients. These ingredients promote the optimal health and development of infants as well as the development of the infant microbiota. Here, we used INFOGEST and an in vitro batch fermentation model to investigate the gut health-promoting effects of a commercial infant formula supplemented with a blend containing docosahexaenoic acid (DHA) (20 mg/100 kcal), polydextrose and galactooligosaccharides (PDX/GOS) (4 g/L, 1:1 ratio), milk fat globule membrane (MFGM) (5 g/L), lactoferrin (0.6 g/L), and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12) (106 CFU/g). Using fecal inoculates from three healthy infants, we assessed microbiota changes, the bifidogenic effect, and the short-chain fatty acid (SCFA) production of the supplemented test formula and compared those with data obtained from an unsupplemented base formula and from the breast milk control. Our results show that even after INFOGEST digestion of the formula, the supplemented formula can still maintain its bioactivity and modulate infants' microbiota composition, promote faster bifidobacterial growth, and stimulate production of SCFAs. Thus, it may be concluded that the test formula containing a bioactive blend promotes infant gut microbiota and SCFA profile to something similar, but not identical to those of breastfed infants.

Milk to mucus: How B. fragilis colonizes the gut

Human milk oligosaccharide (HMO) consumption by the infant microbiota is positively associated with immune health. In this issue of Cell Host & Microbe, Buzun etal. report a mechanism for HMO digestion by Bacteroides fragilis and demonstrate how the same pathway works on intestinal mucus to establish long-term gut residency.

The effect of in-hospital breast milk intake on the gut microbiota of preterm infants

The aim of this study was to explore the effect of in-hospital breast milk intake on the development of early gut microbiota in preterm infants in two dimensions: longitudinal over time and cross-sectional between groups. Researchers collected preterm infants' general data baseline characteristics, recorded their daily breast milk intake, probiotics, and antibiotics use, and collected their stool specimens at 1st week, 2ndweek, 3rd week and 4th week after birth. The researchers analyzed the effect of breast milk on gut microbiota of preterm infants by bioinformatics methods of intra-group longitudinal variation of gut microbiota structure and diversity in preterm infants and cross-sectional differences between >70% in-hospital breast milk intake (BM) group and ≤70% (PF) group. A total of 60 preterm infants were included in this study, and a total of 213 stool specimens were retained. BM had statistically different Shannon and Simpson indices between the first and fourth week after admission (P<0.05), both of them showed a lower diversity in the later week than in the previous week. The Shannon index and Simpson index of BM from week 3 onwards were statistically different from PF (P<0.05), and the Shannon index and Simpson index of BM were lower than those of PF. Significantly statistical differences (P<0.05) were found in the beta diversity of gut microbiota in preterm infants as time progressed, and both showed a lower beta diversity in the later week than in the preceding week. The dominant taxa of PF in the first postnatal week were Bifidobacterium animalis, etc., the dominant taxa of BM in the third postnatal week were Clostridium_sensu_stricto _1, etc. CONCLUSIONS: The development and evolution of gut microbiota in preterm infants' in-hospital period was a continuous, non-random process, and similar trends in species composition and changes in gut microbes emerged in preterm infants with different ratio of breast milk intake. In the NICU setting, alpha diversity was lower in preterm infants in the >70% breast milk intake group than in the ≤70% group when compared between groups at the same time, which may be related to delayed maturation of gut microbes and represents a more developmental gut time window.

Biomonitoring of Dietary Mycotoxin Exposure and Associated Impact on the Gut Microbiome in Nigerian Infants.

Mycotoxins are toxic chemicals that adversely affect human health. Here, we assessed the influence of mycotoxin exposure on the longitudinal development of early life intestinal microbiota of Nigerian neonates and infants (NIs). Human biomonitoring assays based on liquid chromatography tandem mass spectrometry were applied to quantify mycotoxins in breast milk (n = 68) consumed by the NIs, their stool (n = 82), and urine samples (n = 15), which were collected longitudinally from month 1-18 postdelivery. Microbial community composition was characterized by 16S rRNA gene amplicon sequencing of stool samples and was correlated to mycotoxin exposure patterns. Fumonisin B1 (FB1), FB2, and alternariol monomethyl ether (AME) were frequently quantified in stool samples between months 6 and 18. Aflatoxin M1 (AFM1), AME, and citrinin were quantified in breast milk samples at low concentrations. AFM1, FB1, and ochratoxin A were quantified in urine samples at relatively high concentrations. Klebsiella and Escherichia/Shigella were dominant in very early life stool samples (month 1), whereas Bifidobacterium was dominant between months 3 and 6. The total mycotoxin levels in stool were significantly associated with NIs' gut microbiome composition (PERMANOVA, p < 0.05). However, no significant correlation was observed between specific microbiota and the detection of certain mycotoxins. Albeit a small cohort, this study demonstrates that mycotoxins may influence early life gut microbiome composition.

The Maternal Diet Index and Offspring Microbiota at 1 Month of Life: Insights from the Mediterranean Birth Cohort MAMI.

Background: Maternal diet during pregnancy may play a role in infant health outcomes via the maternal microbiota. We assessed the association of the maternal diet index for the Mediterranean area (MDI-med) with infant gut microbiota at 1 month of life. Methods: The MAMI study is a longitudinal birth cohort in the Mediterranean area. In this work, a cross-sectional study, including 120 mother-infant dyads with available maternal diet and infant microbiota at 1-month-old data, was undertaken. The MDI developed in the US (MDI-US) was adapted for the MAMI cohort (MDI-med). Stratification based on extreme values resulted (22 in the "lower" MDI-med group and 23 in the "upper" group from the mean). Relative microbial abundances and alpha (microbial richness and diversity indexes) and beta diversity (Bray-Curtis distance matrix) were compared between the groups. Results: Higher maternal daily vegetable intake and lower red meat intake were the characteristics of the "upper" MDI-med group. Significantly lower microbial diversity (Shannon and InvSimpson index (p = 0.01)), but no changes in richness (Chao1 index) nor in beta-diversity, using Bray-Curtis distance, were observed in the "upper" group, compared to the "lower" MDI-med group. A higher relative abundance of the Bifidobacterium genus (Actinomycetota phylum) was associated with maternal daily vegetable and yogurt intake. Conclusion: Reduced infant microbial diversity at 1 month of age was associated with "upper" MDI-med scores. Higher maternal intakes of vegetables and yogurt were associated with higher relative abundances of the Bifidobacterium genus in the infant gut. Further studies are needed to understand the link between pregnancy diet, infant microbiota, and health outcomes.

Human milk cream alters intestinal microbiome of preterm infants: a prospective cohort study.

In very low birth weight (VLBW) infants, human milk cream added to standard human milk fortification is used to improve growth. This study aimed to evaluate the impact of cream supplement on the intestinal microbiome of VLBW infants. Whole genome shotgun sequencing was performed on stool (n = 57) collected from a cohort of 23 infants weighing 500-1250 grams (control = 12, cream = 11). Both groups received an exclusive human milk diet (mother's own milk, donor human milk, and donor human milk-derived fortifier) with the cream group receiving an additional 2 kcal/oz cream at 100 mL/kg/day of fortified feeds and then 4 kcal/oz if poor growth. While there were no significant differences in alpha diversity, infants receiving cream significantly differed from infants in the control group in beta diversity. Cream group samples had significantly higher prevalence of Proteobacteria and significantly lower Firmicutes compared to control group. Klebsiella species dominated the microbiota of cream-exposed infants, along with bacterial pathways involved in lipid metabolism and metabolism of cofactors and amino acids. Cream supplementation significantly altered composition of the intestinal microbiome of VLBW infants to favor increased prevalence of Proteobacteria and functional gene content associated with these bacteria. We report changes to the intestinal microbiome associated with administration of human milk cream; a novel supplement used to improve growth rates of preterm very low birth weight infants. Since little is known about the impact of cream on intestinal microbiota composition of very low birth weight infants, our study provides valuable insight on the effects of diet on the microbiome of this population. Dietary supplements administered to preterm infants in neonatal intensive care units have the potential to influence the intestinal microbiome composition which may affect overall health status of the infant.

Composition of Microbiota in Transient and Mature Human Milk: Significant Changes in Large for Gestational Age Group.

The composition of the human milk (HM) microbiota and, consequently, the microorganisms that are passed on to the infant through breastfeeding, can be influenced by various factors such as the mother's health and diet, gestational age, delivery mode, lactation stage, method of infant feeding, and geographical location. The aim of the Human Milk-Gest Study was to compare the microbiota of transient (postpartum 7-15 days) and mature HM (postpartum 45-90 days) of 44 mothers, and to investigate any potential changes associated with preterm birth, mode of delivery, and birth weight in relation to gestational age. The data were classified into five study groups: normal spontaneous delivery-term (NS-T) newborns, cesarean delivery-term (CS-T) newborns, preterm (PT) newborns (with a gestational age of less than 37 weeks), small for gestational age (SGA) newborns, and large for gestational age (LGA) newborns. An analysis of differential abundance was conducted using ANCOM-BC to compare the microbial genera between transient and mature HM samples as well as between other study groups. A significant difference was detected between HM samples at different sampling times and between the study groups (p < 0.01). In transient HM samples, Ralstonia, Burkholderiaceae_uc, and Pelomonas were significantly dominant in the LGA group compared to the NS-T, CS-T, PT, and SGA groups. In mature HM samples, Burkholderiaceae_uc, Ralstonia, Pelomonas, and Klebsiella were significantly dominant in the LGA group compared to the NS-T, CS-T, and PT groups, while Ralstonia, Burkholderiaceae_uc, and Pelomonas were significantly dominant in the LGA group compared to the SGA group. Differences were also detected between the transient and mature HM samples in the CS-T, PT, SGA, and LGA groups, but no differences occurred in the NS-T groups. In conclusion, we showed that Ralstonia, Burkholderiaceae_uc, and Pelomonas were significantly dominant in the LGA group in transient HM and continued in mature HM. The body mass index (BMI) of the mothers in the LGA group was not >30 at conception, however, the maternal BMI at birth and maternal weight gain during pregnancy were higher than in the other groups. The nutritional composition of HM is specifically designed to meet infant nutritional requirements during early life. Evaluating the effects of HM microbiota on infant microbiota composition and short- and long-term health effects in larger studies would be useful.

A Lipopolysaccharide-Enriched Cow's Milk Allergy Microbiome Promotes a TLR4-Dependent Proinflammatory Intestinal Immune Response.

We have previously reported that the gut microbiota of healthy infants harbors allergy-protective bacteria taxa that are depleted in infants with cow's milk allergy (CMA). Few reports have investigated the role of the gut microbiota in promoting allergic responses. In this study we selected a CMA-associated microbiota with increased abundance of Gram-negative bacteria for analysis of its proinflammatory potential. LPS is the major component of the outer membrane of Gram-negative bacteria. Colonization of mice with a global or conditional mutation of the LPS receptor TLR4 with this CMA microbiota induced expression of serum amyloid A1 (Saa1) and other Th17-, B cell-, and Th2-associated genes in the ileal epithelium in a TLR4-dependent manner. In agreement with the gene expression data, mice colonized with the CMA microbiota have expanded populations of Th17 and regulatory T cells and elevated concentrations of fecal IgA. Importantly, we used both antibiotic-treated specific pathogen-free and germ-free rederived mice with a conditional mutation of TLR4 in the CD11c+ compartment to demonstrate that the induction of proinflammatory genes, fecal IgA, and Th17 cells is dependent on TLR4 signaling. Furthermore, metagenomic sequencing revealed that the CMA microbiota has an increased abundance of LPS biosynthesis genes. Taken together, our results show that a microbiota displaying a higher abundance of LPS genes is associated with TLR4-dependent proinflammatory gene expression and a mixed type 2/type 3 response in mice, which may be characteristic of a subset of infants with CMA.

Global Insights and Key Trends in Gut Microbiota Research for Premature Infants: A Bibliometric and Visualization Study.

Premature infants, defined as those born before 37weeks of gestation, face numerous health challenges due to their underdeveloped systems. One critical aspect of their health is the gut microbiota, which plays a vital role in their immune function and overall development. This study provides a comprehensive bibliometric analysis of research trends, influential contributors, and evolving themes in the study of gut microbiota in premature infants over the past two decades. We conducted a bibliometric analysis using the Web of Science Core Collection database, covering publications from January 1, 2004, to June 17, 2024. We employed VOSviewer, the R package "bibliometrix", and Citespace for data visualization and analysis, focusing on co-authorship, co-citation, and keyword co-occurrence networks. The temporal analysis revealed a significant increase in research output on gut microbiota in premature infants, particularly in the last decade. Early research primarily focused on characterizing the gut microbiota of premature infants, identifying less diversity and a higher prevalence of pathogenic bacteria compared to full-term infants. Key research themes identified include probiotics, necrotizing enterocolitis (NEC), and breastfeeding. Probiotic studies highlighted the potential of strains like Bifidobacterium and Lactobacillus in reducing NEC and sepsis incidences. Breastfeeding research consistently showed the benefits of human milk in fostering a healthier gut microbiota profile. Co-authorship and co-citation analyses identified key contributors and influential studies, emphasizing strong international collaborations, particularly among researchers from the United States, China, and European countries. This bibliometric analysis underscores the growing recognition of the gut microbiota's crucial role in the health of premature infants. The field has seen significant advancements, particularly in understanding how interventions like probiotics and breastfeeding can modulate gut microbiota to improve health outcomes. Continued research and international collaboration are essential to further unravel the complexities of gut microbiota in premature infants and develop effective therapeutic strategies.

Dissecting and tracing the gut microbiota of infants with botulism: a cross sectional and longitudinal study.

Infant botulism is caused by botulinum neurotoxin (BoNT), which is mainly produced by Clostridium botulinum. However, there is a lack of longitudinal cohort studies on infant botulism. Herein, we have constructed a cross-sectional and longitudinal cohort of infants infected with C. botulinum. Our goal was to reveal the differences in the intestinal microbiota of botulism-infected and healthy infants as well as the dynamic changes over time through multi-omics analysis. We performed 16S rRNA sequencing of 20 infants' stools over a period of 3 months and conducted whole genome sequencing of isolated C. botulinum strains from these laboratory-confirmed cases of infant botulism. Through bioinformatics analysis, we focused on the changes in the infants' intestinal microbiota as well as function over time series. We found that Enterococcus was significantly enriched in the infected group and declined over time, whereas Bifidobacterium was significantly enriched in the healthy group and gradually increased over time. 18/20 isolates carried the type B 2 botulinum toxin gene with identical sequences. In silico Multilocus sequence typing found that 20°C. botulinum isolates from the patients were typed into ST31 and ST32. Differences in intestinal microbiota and functions in infants were found with botulism through cross-sectional and longitudinal studies and Bifidobacterium may play a role in the recovery of infected infants.

The skin microbiota of preterm infants and impact of diaper change frequency.

To evaluate the impact of diaper change frequency, clinical characteristics, and skin health metrics on development of the skin microbiota in preterm infants. A randomized controlled parallel design was used. Medically stable preterm infants born <33 weeks' gestation were randomized to receive diaper changes at a frequency of every 3-hours or every 6-hours. Skin swabs were collected longitudinally from the diapered skin (buttocks) and chest. Skin pH and transepidermal water loss were measured with each sample collection. Stool samples were collected from the diaper. The microbiome at each site was characterized by 16S rRNA gene sequencing. Associations between microbiome features, diaper change frequency, and other covariates were examined using mixed effect models and redundancy analysis. A total of 1179 samples were collected from 46 preterm infants, beginning at a median postnatal age of 44 days and continuing through hospital discharge. Alpha-diversity of the skin microbiota increased over time, but did not differ significantly between 3-hour (n = 20) and 6-hour (n = 26) diaper change groups. Alpha-diversity of the skin microbiota was inversely correlated with skin pH, but not transepidermal water loss. Microbiota community structure differed significantly between body sites (buttocks, chest, and stool) and between individuals. Among samples collected from the diapered skin, diaper change frequency, infant diet, antibiotic exposure, and delivery mode accounted for minor proportions of the variation in microbiota community structure between samples. Relative abundances of multiple genera differed between 3- and 6-hour diaper change groups over time. The diversity and composition of the diapered skin microbiota is dynamic over time and differs from other body sites. Multiple factors including interindividual effects, diaper change frequency, diet, and antibiotics contribute to variation in the diapered skin microbiota.