Influence of maternal bifidobacteria on the development of gut bifidobacteria in infants

Relationship between maternal consumption of fermented foods and the development of the offspring at the age of 3 years: The Japan Environment and Children's Study

BACKGROUND

It is well known that maternal diet affects the development of offspring. Herein, the relationship between maternal intake of fermented foods during pregnancy and offspring development was investigated.

METHODS

The diet of 103,060 pregnant women at >4 months of gestation who were enrolled in the Japan Environment and Children's Study was analyzed. Their intake levels of fermented soybeans (miso and natto), yogurt, and cheese were investigated. The developmental status of the offspring at 3 years of age was assessed using the Ages and Stages Questionnaires (ASQ-3). Multivariable logistic regression analysis was performed to determine the risk of maternal intake levels of the fermented foods associated with subsequent developmental delay in the offspring.

RESULTS

Intake of cheese was associated with a reduced risk of child developmental delay in all intake level groups from the second quartile onward. Intakes of miso and yogurt were associated with a reduced risk of developmental delay in communication skills in the fourth quartile. There was no association between intake of natto and developmental delay.

CONCLUSION

Maternal consumption of fermented foods during pregnancy may reduce the risk of later developmental delay in offspring. It is therefore important to review the mother's diet for fermented foods during pregnancy. However, further studies are warranted to evaluate the factors influencing the association between diet and offspring development.

A Stress Reduction Intervention for Lactating Mothers Alters Maternal Gut, Breast Milk, and Infant Gut Microbiomes: Data from a Randomized Controlled Trial

BACKGROUND

This secondary analysis of data from a randomized controlled trial (RCT) investigated how the maternal gut, breast milk, and infant gut microbiomes may contribute to the effects of a relaxation intervention, which reduced maternal stress and promoted infant weight gain.

METHODS

An RCT was undertaken in healthy Chinese primiparous mother-infant pairs (340/7-376/7gestation weeks). Mothers were randomly allocated to either the intervention group (IG, listening to relaxation meditation) or the control group (CG). Outcomes were the differences in microbiome composition and the diversity in the maternal gut, breast milk, and infant gut at 1 (baseline) and 8 weeks (post-intervention) between IG and CG, assessed using 16S rRNA gene amplicon sequencing of fecal and breastmilk samples.

RESULTS

In total, 38 mother-infant pairs were included in this analysis (IG = 19, CG = 19). The overall microbiome community structure in the maternal gut was significantly different between the IG and CG at 1 week, with the difference being more significant at 8 weeks (Bray-Curtis distance R2 = 0.04 vs. R2 = 0.13). Post-intervention, a significantly lower α-diversity was observed in IG breast milk (observed features: CG = 295 vs. IG = 255, p = 0.032); the Bifidobacterium genera presented a higher relative abundance. A significantly higher α-diversity was observed in IG infant gut (observed features: CG = 73 vs. IG = 113, p < 0.001).

CONCLUSIONS

The findings were consistent with the hypothesis that the microbiome might mediate observed relaxation intervention effects via gut-brain axis and entero-mammary pathways; but confirmation is required.

Shaping Microbiota During the First 1000 Days of Life

Given that the host-microbe interaction is shaped by the immune system response, it is important to understand the key immune system-microbiota relationship during the period from conception to the first years of life. The present work summarizes the available evidence concerning human reproductive microbiota, and also, the microbial colonization during early life, focusing on the potential impact on infant development and health outcomes. Furthermore, we conclude that some dietary strategies including specific probiotics and other-biotics could become potentially valuable tools to modulate the maternal-neonatal microbiota during this early critical window of opportunity for targeted health outcomes throughout the entire lifespan.

The effect of early colonized gut microbiota on the growth performance of suckling lambs

The early colonized gut microbiota during the newborn period has been reported to play important roles in the health and immunity of animals; however, whether they can affect the growth performance of suckling lambs is still unclear. In this study, a total of 84 newborn lambs were assigned into LF-1 (top 15%), LF-2 (medium 70%), and LF-3 (bottom 15%) groups according to their average body weight gain at 30 days of age. Fecal samples of lambs (LF) as well as feces (MF), vagina (VAG), colostrum (COL), teat skin (TEAT) samples of ewes, and the air sediment (AIR) in the delivery room were collected 72 h after birth, and then the 16S rRNA gene was sequenced on the Illumina MiSeq platform. The results showed that the early colonized gut microbiota had a significant effect on the growth performance of suckling lambs with alpha and beta diversity (p < 0.05), and we observed that the contribution of early colonized bacteria on the growth performance of lambs increased with age (from BW30 at 25.35% to BW45 at 31.10%; from ADG30 at 33.02% to ADG45 at 39.79% by measuring the relative effects of factors that influence growth performance). The early colonized gut microbiota of suckling lambs with high growth performance was similar to that in VAG, MF, and AIR (p < 0.05). With the RandomForest machine learning algorithm, we detected 11, 11, 6, and 4 bacterial taxa at the genus level that were associated with BW30, BW45, ADG30, and ADG45 of suckling lambs, respectively, and the correlation analysis showed that Butyricicoccus, Ruminococcus_gnavus_group, Ruminococcaceae_Other, and Fusobacterium could significantly affect the growth performance (BW30, BW45, ADG30, and ADG45) of suckling lambs (p < 0.05). In conclusion, the early colonized gut microbiota could significantly affect the growth performance of suckling lambs, and targeting the early colonized gut microbiota might be an alternative strategy to improve the growth performance of suckling lambs.

Impact of Gut Microbiota on Host Aggression: Potential Applications for Therapeutic Interventions Early in Development

Aggression in the animal kingdom is a necessary component of life; however, certain forms of aggression, especially in humans, are pathological behaviors that are detrimental to society. Animal models have been used to study a number of factors, including brain morphology, neuropeptides, alcohol consumption, and early life circumstances, to unravel the mechanisms underlying aggression. These animal models have shown validity as experimental models. Moreover, recent studies using mouse, dog, hamster, and drosophila models have indicated that aggression may be affected by the "microbiota-gut-brain axis." Disturbing the gut microbiota of pregnant animals increases aggression in their offspring. In addition, behavioral analyses using germ-free mice have shown that manipulating the intestinal microbiota during early development suppresses aggression. These studies suggest that treating the host gut microbiota during early development is critical. However, few clinical studies have investigated gut-microbiota-targeted treatments with aggression as a primary endpoint. This review aims to clarify the effects of gut microbiota on aggression and discusses the therapeutic potential of regulating human aggression by intervening in gut microbiota.

Influence of Geographical Location on Maternal-Infant Microbiota: Study in Two Populations From Asia and Europe

Early gut microbial colonization is driven by many factors, including mode of birth, breastfeeding, and other environmental conditions. Characters of maternal-neonatal microbiota were analyzed from two distinct populations in similar latitude but different continents (Oriental Asia and Europe). A total number of 120 healthy families from China (n=60) and Spain (n=60) were included. Maternal and neonatal microbiota profiles were obtained at birth by 16S rRNA gene profiling. Clinical records were collected. Geographical location influenced maternal-neonatal microbiota. Indeed, neonatal and maternal cores composed by nine genera each one were found independently of location. Geographical location was the most important variable that impact the overall structure of maternal and neoantal microbiota. For neonates, delivery mode effect on neonatal microbial community could modulate how the other perinatal factors, as geographical location or maternal BMI, impact the neoantal initial seeding. Furthermore, lower maternal pre-pregnancy BMI was associated with higher abundance of Faecalibacterium in maternal microbiota and members from Lachnospiraceae family in both mothers and infants. At genus-level, Chinese maternal-neonate dyads possessed higher number of phylogenetic shared microbiota than that of Spanish dyads. Bifidobacterium and Escherichia/Shigella were the genera most shared between dyads in the two groups highlighting their importance in neonatal colonization and mother-infant transmission. Our data showed that early gut microbiota establishment and development is affected by interaction of complex variables, where environment would be a critical factor.

Heat-sterilized Bifidobacterium breve prevents depression-like behavior and interleukin-1β expression in mice exposed to chronic social defeat stress

Major depressive disorder (MDD) is a common and serious psychiatric disease that involves brain inflammation. Bifidobacterium breve is commonly used as a probiotic and was shown to improve colitis and allergic diseases by suppressing the inflammatory response. Heat-sterilized B. breve has beneficial effects on inflammation. We hypothesize, therefore, that this probiotic might reduce depression symptoms. We tested this is a mouse model of social defeat stress. C57BL/6J mice exposed to chronic social defeat stress (CSDS) for five consecutive days developed a mild depression-like behavior characterized by a social interaction impairment. CSDS also altered the gut microbiota composition, such as increased abundance of Bacilli, Bacteroidia, Mollicutes, and Verrucomicrobiae classes and decreased Erysipelotrichi class. The prophylactic effect of heat-sterilized B. breve as a functional food ingredient was evaluated on the depression-like behavior in mice. The supplementation started two weeks before and lasted two weeks after the last exposure to CSDS. Two weeks after CSDS, the mice showed deficits in social interaction and increased levels of inflammatory cytokines, including interleukin-1β (IL-1β) in the prefrontal cortex (PFC) and hippocampus (HIP). Heat-sterilized B. breve supplementation significantly prevented social interaction impairment, suppressed IL-1β increase in the PFC and HIP, and modulated the alteration of the gut microbiota composition induced by CSDS. These findings suggest that heat-sterilized B. breve prevents depression-like behavior and IL-1β expression induced by CSDS through modulation of the gut microbiota composition in mice. Therefore, heat-sterilized B. breve used as an ingredient of functional food might prevent MDD.

The Gut Microbiome and Cardiovascular Disease

Cardiovascular disease (CVD) is currently the leading cause of death worldwide. Although many well-known conditions cause CVD, recent research has suggested that alterations to the gut microbiome may also promote CVD. The gastrointestinal tract houses trillions of bacteria, some of which in large numbers are considered to be part of a healthy gut microbiome profile. These "good" bacteria have the ability to process and digest complex carbohydrates into short-chain fatty acids (SFCA). These SCFA serve as signaling molecules, immune-modulating molecules, and sources of energy. However, with gut dysbiosis, there is an overgrowth of certain bacteria and these bacteria overly produce phosphatidylcholine, choline, and carnitine into the waste product trimethylamine-N-oxide (TMAO). Elevated TMAO levels are associated with an increased risk of atherosclerosis, myocardial infarction, thrombosis, and stroke. Therefore, introducing therapeutic interventions that alter a dysbiotic gut profile back to a healthy gut microbiome may be the key to reducing the incidence of cardiovascular disease in some conditions. The purpose of this review is to critically examine and consolidate the relevant information bearing on this concept. Our goal is to provide the informational framework for the possible use of microbiome modification as an optional therapeutic modality.

The Composition and Concordance of Lactobacillus Populations of Infant Gut and the Corresponding Breast-Milk and Maternal Gut

The maternal gut is the principal source of commensal bacteria in the infant gut during the lactation stage, where breast milk acts as an intermediary for the transfer of potential probiotic bacteria consortia, including Lactobacillus. This study aimed to characterize the bacterial communities in human milk, maternal, and infant feces in a small yet very homogeneous cohort of 25 healthy mother–infant pairs in northwestern China (n = 25, infant age from 7 days to 2 years), with special emphasis on the cooccurrence and vertical transfer of Lactobacillus phylotypes at the species or strain level in mother-breast milk-infant triads. Accurate sequencing analysis revealed that among 73 Lactobacillus zero-radius operational classification units (ZOTUs) identified, 58 belonging to 18 recognized species or species groups were distributed in all three types of samples. Lactobacillus ruminis, L. mucosae and L. gasseri-johnsonii as true residents were the most represented in all three ecosystems, whereas the content of Lactobacillus phylotypes commonly developed as probiotics was not dominant. While the numbers of Lactobacillus species in breast milk and infant feces were greater than that in maternal feces, principal coordinates analysis (PCoA) based on beta diversity, coupled with the frequency of isolates determined by culture methods, showed that the Lactobacillus community in the infant gut was more similar to that in the maternal gut than to that in breast milk, suggesting that the gut is niche selective for Lactobacillus populations. In addition, identical strains of L. ruminis, L. paracasei, L. mucosae and L. salivarius were isolated from multiple mother–infant pairs, supporting the hypothesis that vertical transfer of bacteria via breastfeeding contributes to the initial establishment of the microbiota in the developing infant intestine.

Difficulties in developmental follow-up of preterm neonates in a randomised-controlled trial of Bifidobacterium breve M16-V - Experience from Western Australia

BACKGROUND

Probiotics may be neuroprotective for preterm neonates due to their anti-inflammatory effects and ability to facilitate nutrition.

AIM

To assess long-term effects of early probiotic supplementation on neuropsychological development in preterm infants.

STUDY DESIGN

Follow up study.

SUBJECTS

Children at age 3 to 5 years who had participated as preterm infants (<33 week) in the randomised controlled trial.

OUTCOMES

Primary: Continuous early learning composite measure derived from the Mullen's Scale of Early Learning (MSEL). Other outcomes were assessed by the Developmental, Dimensional and Diagnostic Interview, Developmental NEuroPSYchological assessment-2nd Edition, Parental questionnaires using children's communication checklist-2nd edition, social responsiveness scale, and Vineland Adaptive Behavioural Scales-2nd edition.

MEASURES

Continuous scores derived from all the measures.

RESULTS

67 children of the 159 participants (42%) (Probiotic: 36/79, Placebo: 31/80) were followed-up for at least one neuropsychological assessment. All six assessments were completed in 18/31 (58.1%) of the control vs. 11/36 (30.6%) probiotic group children. Multivariable analysis of MSEL composite score showed no evidence of probiotic effect univariately, or after adjustment for gestation, intrauterine growth restriction, Apgar <7 at 5 min and age at assessment (adjusted mean effect in probiotic group: -2.7, 95% CI -8.5-3.0, p = 0.349).

CONCLUSION

There was no significant effect on neurodevelopment of children assessed at the age of 3 to 5 years who participated as preterm neonates in the RCT of B. breve M-16V. The validity of these results is limited by the reduced sample size due to high rate of loss to follow up.

Succession of Bifidobacterium longum Strains in Response to a Changing Early Life Nutritional Environment Reveals Dietary Substrate Adaptations

Diet-microbe interactions play a crucial role in modulation of the early life microbiota and infant health. Bifidobacterium dominates the breast-fed infant gut and may persist in individuals during transition from a milk-based to a more diversified diet. Here, we investigated adaptation of Bifidobacterium longum to the changing nutritional environment. Genomic characterization of 75 strains isolated from nine either exclusively breast- or formula-fed (pre-weaning) infants in their first 18 months revealed subspecies- and strain-specific intra-individual genomic diversity with respect to carbohydrate metabolism, which corresponded to different dietary stages. Complementary phenotypic studies indicated strain-specific differences in utilization of human milk oligosaccharides and plant carbohydrates, whereas proteomic profiling identified gene clusters involved in metabolism of selected carbohydrates. Our results indicate a strong link between infant diet and B. longum diversity and provide additional insights into possible competitive advantage mechanisms of this Bifidobacterium species and its persistence in a single host.

Bifidobacterium breve UCC2003 Induces a Distinct Global Transcriptomic Program in Neonatal Murine Intestinal Epithelial Cells

The underlying health-driving mechanisms of Bifidobacterium during early life are not well understood, particularly how this microbiota member may modulate the intestinal barrier via programming of intestinal epithelial cells (IECs). We investigated the impact of Bifidobacterium breve UCC2003 on the transcriptome of neonatal murine IECs. Small IECs from two-week-old neonatal mice administered B. breve UCC2003 or PBS (control) were subjected to global RNA sequencing, and differentially expressed genes, pathways, and affected cell types were determined. We observed extensive regulation of the IEC transcriptome with ∼4,000 genes significantly up-regulated, including key genes linked with epithelial barrier function. Enrichment of cell differentiation pathways was observed, along with an overrepresentation of stem cell marker genes, indicating an increase in the regenerative potential of the epithelial layer. In conclusion, B. breve UCC2003 plays a central role in driving intestinal epithelium homeostatic development during early life and suggests future avenues for next-stage clinical studies.

Bifidobacterium and Lactobacillus Composition at Species Level and Gut Microbiota Diversity in Infants before 6 Weeks

Our objective was to investigate the effects of different delivery and feeding modes on the gut microbiota composition of early infants with special emphasis on Bifidobacterium and Lactobacillus profiles at species level. 16S rRNA V3-V4 regions, bifidobacterial, and lactobacilli groEL genes from infant feces were sequenced by Illumina MiSeq. Gut microbiota abundance was significantly different, where standard vaginally delivered (SVD) and breast-fed (BF) groups were higher in comparison with caesarean section (CS), milk-powder-fed (MPF), and mixed-fed (MF) groups. The genus unclassified Enterobacteriaceae was dominant, followed by Bifidobacterium, which was highly abundant in SVD and BF groups. The dominant Bifidobacterium species in all groups were B. longum subsp. longum, B. longum subsp. infantis and B. animalis subsp. lactis. B. dentium and the diversity of Bifidobacterium in SVD and BF groups were significantly higher. For Lactobacillus profiles, L. rhamnosus and L. gasseri were dominant among all the groups, while Lactobacillus species in CS and MPF groups were more diverse. Functional predictions showed significant differences between delivery mode and feeding groups, such as phosphotransferase system as well as taurine and hypotaurine metabolism. In early infants with different delivery and feeding methods, gut microbiota-particularly bifidobacteria and lactobacilli communities-showed significant differences, with strong implications for physiological functions.

Bifidobacterium breve M-16V as a Probiotic for Preterm Infants: A Strain-Specific Systematic Review

INTRODUCTION

Bifidobacterium breve M-16V has been used as a probiotic in preterm infants. Probiotic strain-specific data are essential to guide clinical practice.

OBJECTIVE

To assess effects of B breve M-16V in preterm neonates.

DESIGN

A systematic review of randomized controlled trials (RCTs) and non-RCTs of B breve M-16V in preterm infants was conducted. Multiple databases, proceedings of Pediatric Academy Society, and other relevant conferences were searched in September 2016 and on January 5, 2017.

RESULTS

Five RCTs (n = 482) and 4 non-RCTs (n = 2496) were included. Of the 5 RCTs, 4 carried high/unclear risk of bias in many domains. Meta-analysis (fixed effects model) of RCTs showed no significant benefits on stage ≥2 necrotizing enterocolitis, late-onset sepsis, mortality, and postnatal age at full feeds. Meta-analysis of non-RCTs showed significant benefits on (1) late-onset sepsis-3 studies (n = 2452), odds ratio = 0.56 (95% CI, 0.45-0.71), P < .0001; (2) mortality-2 studies (n = 2319), odds ratio = 0.61 (95% CI, 0.44-0.84), P = .002; and (3) postnatal age at full feeds (days)-2 studies (n = 361), mean difference, -2.42 (95% CI, -2.55 to -2.3), P < .00001. There were no adverse effects from B breve M-16V. On Grading of Recommendations, Assessment, Development, and Evaluation analysis, the overall quality of evidence was deemed very low.

CONCLUSIONS

Current evidence is limited regarding the potential of B breve M-16V in preterm neonates. Adequately powered, preferably cluster RCTs are needed to confirm these findings.

Gut microbiota in early life and its influence on health and disease: A position paper by the Malaysian Working Group on Gastrointestinal Health

The role of gut microbiota in early life and its impact on gut health and subsequent diseases remain unclear. There is a lack of research and awareness in this area, especially in the Asia-Pacific region, including Malaysia. This paper reports the position of a Malaysian Working Group on some key issues surrounding gut microbiota in early life and its role in gut health and diseases, as well as experts' stand on probiotics and prebiotics. The group reached a consensus that certain factors, including elective caesarean; premature deliveries; complementary feeding; use of antibiotics, prebiotics and/or probiotics; and exposure to the external environmental, have an impact on gut microbiota in early life. However, as evidence is lacking, especially from the Asia-Pacific region, further studies are needed to understand how gut microbiota in early life affects subsequent diseases, including allergy, inflammatory bowel disease, obesity and infantile colic. Lastly, although beneficial in acute diarrhoeal disease and probably allergic eczema, probiotics (and/or prebiotics) should be used cautiously in other gut dysbiotic conditions until more data are available.

Optimisation of 16S rRNA gut microbiota profiling of extremely low birth weight infants

BACKGROUND

Infants born prematurely, particularly extremely low birth weight infants (ELBW) have altered gut microbial communities. Factors such as maternal health, gut immaturity, delivery mode, and antibiotic treatments are associated with microbiota disturbances, and are linked to an increased risk of certain diseases such as necrotising enterocolitis. Therefore, there is a requirement to optimally characterise microbial profiles in this at-risk cohort, via standardisation of methods, particularly for studying the influence of microbiota therapies (e.g. probiotic supplementation) on community profiles and health outcomes. Profiling of faecal samples using the 16S rRNA gene is a cost-efficient method for large-scale clinical studies to gain insights into the gut microbiota and additionally allows characterisation of cohorts were sample quantities are compromised (e.g. ELBW infants). However, DNA extraction method, and the 16S rRNA region targeted can significantly change bacterial community profiles obtained, and so confound comparisons between studies. Thus, we sought to optimise a 16S rRNA profiling protocol to allow standardisation for studying ELBW infant faecal samples, with or without probiotic supplementation.

METHODS

Using ELBW faecal samples, we compared three different DNA extraction methods, and subsequently PCR amplified and sequenced three hypervariable regions of the 16S rRNA gene (V1 + V2 + V3), (V4 + V5) and (V6 + V7 + V8), and compared two bioinformatics approaches to analyse results (OTU and paired end). Paired shotgun metagenomics was used as a 'gold-standard'.

RESULTS

Results indicated a longer bead-beating step was required for optimal bacterial DNA extraction and that sequencing regions (V1 + V2 + V3) and (V6 + V7 + V8) provided the most representative taxonomic profiles, which was confirmed via shotgun analysis. Samples sequenced using the (V4 + V5) region were found to be underrepresented in specific taxa including Bifidobacterium, and had altered diversity profiles. Both bioinformatics 16S rRNA pipelines used in this study (OTU and paired end) presented similar taxonomic profiles at genus level.

CONCLUSIONS

We determined that DNA extraction from ELBW faecal samples, particularly those infants receiving probiotic supplementation, should include a prolonged beat-beating step. Furthermore, use of the 16S rRNA (V1 + V2 + V3) and (V6 + V7 + V8) regions provides reliable representation of ELBW microbiota profiles, while inclusion of the (V4 + V5) region may not be appropriate for studies where Bifidobacterium constitutes a resident microbiota member.

Allergic diseases among children: nutritional prevention and intervention

Allergic diseases comprise a genetically heterogeneous group of chronic, immunomediated diseases. It has been clearly reported that the prevalence of these diseases has been on the rise for the last few decades, but at different rates, in various areas of the world. This paper discusses the epidemiology of allergic diseases among children and their negative impact on affected patients, their families, and societies. These effects include the adverse effects on quality of life and economic costs. Medical interest has shifted from tertiary or secondary prevention to primary prevention of these chronic diseases among high-risk infants in early life. Being simple, practical, and cost-effective are mandatory features for any candidate methods delivering these strategies. Dietary therapy fits this model well, as it is simple, practical, and cost-effective, and involves diverse methods. The highest priority strategy is feeding these infants breast milk. For those who are not breast-fed, there should be a strategy to maintain beneficial gut flora that positively influences intestinal immunity. We review the current use of probiotics, prebiotics, and synbiotics, and safety and adverse effects. Other dietary modalities of possible potential in achieving this primary prevention, such as a Mediterranean diet, use of milk formula with modified (hydrolyzed) proteins, and the role of micronutrients, are also explored. Breast-feeding is effective in reducing the risk of asthma, allergic rhinitis, and atopic eczema among children. In addition, breast milk constitutes a major source of support for gut microbe colonization, due to its bifidobacteria and galactooligosaccharide content. The literature lacks consensus in recommending the addition of probiotics to foods for prevention and treatment of allergic diseases, while prebiotics may prove to be effective in reducing atopy in healthy children. There is insufficient evidence to support soy formulas or amino acid formulas for prevention of allergic disease. A healthy diet, such as the Mediterranean diet, may have a protective effect on the development of asthma and atopy in children. In children with asthma and allergic diseases, vitamin D deficiency correlates strongly with asthma, allergic rhinitis, and wheezing.

Administration of Non-Absorbable Antibiotics to Pregnant Mice to Perturb the Maternal Gut Microbiota Is Associated with Alterations in Offspring Behavior

There is increasing evidence that the gut microbiota plays a major role in host health and disease. In this study, we examined whether perturbation of the maternal gut microbiota during pregnancy, induced by administration of non-absorbable antibiotics to pregnant dams, influences the behavior of offspring. Terminal restriction fragment length polymorphism analyses of fecal bacterial composition showed that the relative abundance of the bacterial order Lactobacillales was lower in offspring born from antibiotic-treated dams (20.7±3.4%) than in control offspring (42.1±6.2%) at P24, while the relative abundance of the bacterial family Clostridium subcluster XIVa was higher in offspring born from antibiotic-treated dams (34.2±5.0%) than in control offspring (16.4±3.3%). Offspring born from antibiotic-treated dams exhibited low locomotor activity in both familiar and novel environments, and preferred to explore in the peripheral area of an unfamiliar field at postnatal week 4. At postnatal weeks 7–8, no difference was observed in the level of locomotor activity between control offspring and offspring from antibiotic-treated dams, while the tendency for the offspring from antibiotic-treated dams to be less engaged in exploring the inside area was still observed. The behavioral phenotypes of the offspring from antibiotic-treated dams at postnatal week 4 could be rescued to a considerable extent through fostering of these offspring by normal dams from postnatal day 1. Although the detailed underlying mechanisms are not fully elucidated, the present results suggest that administration of non-absorbable antibiotics to pregnant dams to perturb the maternal gut microbiota during pregnancy leads to alterations in the behavior of their offspring.

Impact of maternal bifidobacteria and the mode of delivery on Bifidobacterium microbiota in infants

The aim of this study is to examine the influence of maternal intestinal and vaginal bifidobacteria on the colonisation of bifidobacteria in the gut of infants. Faecal samples from 120 healthy pregnant mothers within 1 month of delivery and from their infants at 1 month of age and 98 vaginal swabs from the mothers at the time of delivery were collected at a maternity hospital in Chiang Mai, Thailand. The faecal and vaginal samples were assayed by real-time PCR assays to detect Bifidobacterium species and to estimate the bifidobacterial copy numbers. After adjusting for the numbers of each Bifidobacterium species, delivery mode, and antibiotic use in infants by the age of 1 month, total counts of bifidobacteria in the mothers' faeces were associated with increased copy numbers of bifidobacteria in the faeces of breastfed infants. A caesarean section was also significantly associated with a decrease in the copy numbers of bifidobacteria in the faeces of infants. No significant correlation was found between the bifidobacterial copies of the vaginal swabs and those of the infants' faeces. The intestinal bifidobacterial status of exclusively breastfed infants was significantly positive affected by vaginal delivery and high bifidobacterial copy numbers in their mothers' gut.

Multilocus sequence typing of bifidobacterial strains from infant’s faeces and human milk: are bifidobacteria being sustainably shared during breastfeeding?

Bifidobacteria are considered to be one of the most important beneficial intestinal bacteria for infants, contributing to the priming of the mucosal immune system. These microbes can also be detected in mother’s milk, suggesting a potential role of human milk in the colonisation of infant’s gut. However, little is known about the timing of bacteria appearance in human milk, and whether human milk is the first source of inoculation. Here, we investigated whether specific strains are shared sustainably between maternal milk and infant’s gut. Faecal samples and human milk were collected from 102 healthy mother-infant pairs (infant’s faeces: meconium, 7, 30 days of age; mother’s milk: once before delivery, colostrum, 7, 30 days after delivery). Bifidobacterial strains were isolated from these samples, and were discriminated by means of multilocus sequencing typing. No bifidobacteria were detected from human milk collected before delivery, or colostrum. Strains were isolated only from human milk samples obtained 7 days after birth or later. On the other hand, bifidobacterial strains were obtained from infant’s faeces throughout the study period, sometimes as early as the first day of life (meconium). We have found that bifidobacterial species belonging to Bifidobacterium bifidum, Bifidobacterium breve, and Bifidobacterium longum subsp. longum could be identified as monophyletic between infant’s faeces and their mother’s milk. These strains were confirmed to be sustainably shared between maternal milk and infant’s gut. Moreover, monophyletic strains were isolated at the same time point or earlier from infant’s faeces than from human milk, and none were isolated earlier from human milk than from infant’s faeces. Although it remains unclear whether human milk is the first source of microbes for infants, our results confirm that human milk is a reservoir of bifidobacteria, and specific strains are shared between infant’s intestine and human milk during breastfeeding.

Is a foetus developing in a sterile environment?

Novel findings in microbiology question the long-standing paradigm that a healthy pregnancy implies a sterile uterus. It now seems that the placenta is frequently colonized with bacteria, and a placental microbiome has been identified. Recent literature findings are summarized here, and an attempt is made to separate pathological bacterial presence from a naturally occurring microbiome.

Effect of Bifidobacterium breve M-16V supplementation on fecal bifidobacteria in preterm neonates--a randomised double blind placebo controlled trial

BACKGROUND

Probiotic supplementation significantly reduces the risk of necrotising enterocolitis (NEC) and all cause mortality in preterm neonates. Independent quality assessment is important before introducing routine probiotic supplementation in this cohort.

AIM

To assess product quality, and confirm that Bifidobacterium breve (B. breve) M-16V supplementation will increase fecal B. breve counts without adverse effects.

METHODS AND PARTICIPANTS

Strain identity (16S rRNA gene sequencing), viability over 2 year shelf-life were confirmed, and microbial contamination of the product was ruled out. In a controlled trial preterm neonates (Gestation <33 weeks) ready to commence or on feeds for <12 hours were randomly allocated to either B. breve M-16V (3×109 cfu/day) or placebo (dextrin) supplementation until the corrected age 37 weeks. Stool samples were collected before (S1) and after 3 weeks of supplementation (S2) for studying fecal B. breve levels using quantitative PCR (Primary outcome). Secondary outcomes included total fecal bifidobacteria and NEC≥Stage II. Categorical and continuous outcomes were analysed using Chi-square and Mann-Whitney tests, and McNemar and Wilcoxon signed-rank tests for paired comparisons.

RESULTS

A total of 159 neonates (Probiotic: 79, Placebo: 80) were enrolled. Maternal and neonatal demographic characteristics were comparable between the groups. The proportion of neonates with detectable B. breve increased significantly post intervention: Placebo: [S1:2/66 (3%), S2: 25/66 (38%), p<0.001] Probiotic: [S1: 29/74 (40%), S2: 67/74 (91%), p<0.001]. Median S1 B. breve counts in both groups were below detection (<4.7 log cells x g(-1)), increasing significantly in S2 for the probiotic group (log 8.6) while remaining <4.7 log in the control group (p<0.001). There were no adverse effects including probiotic sepsis and no deaths. NEC≥Stage II occurred in only 1 neonate (placebo group).

CONCLUSION

B. breve M-16V is a suitable probiotic strain for routine use in preterm neonates.

TRIAL REGISTRATION

Australia New Zealand Clinical Trial Registry ACTRN 12609000374268.