Probiotic lactobacilli in breast milk and infant stool in relation to oral intake during the first year of life

Vertical mother-neonate transfer of maternal gut bacteria via breastfeeding

Breast milk has recently been recognized as source of commensal and potential probiotic bacteria. The present study investigated whether viable strains of gut-associated obligate anaerobes are shared between the maternal and neonatal gut ecosystem via breastfeeding. Maternal faeces, breast milk and corresponding neonatal faeces collected from seven mothers-neonate pairs at three neonatal sampling points were analyzed by culture-independent (pyrosequencing) and culture-dependent methods (16S rRNA gene sequencing, pulsed field gel electrophoresis, random amplified polymorphic DNA and repetitive extragenic palindromic polymerase chain reaction. Pyrosequencing allowed identifying gut-associated obligate anaerobic genera, like Bifidobacterium, Bacteroides, Parabacteroides and members of the Clostridia (Blautia, Clostridium, Collinsella and Veillonella) shared between maternal faeces, breast milk and neonatal faeces. Using culture, a viable strain of Bifidobacterium breve was shown to be shared between all three ecosystems within one mother-neonate pair. Furthermore, pyrosequencing revealed that several butyrate-producing members of the Clostridia (Coprococcus, Faecalibacterium, Roseburia and Subdoligranulum) were shared between maternal faeces and breast milk. This study shows that (viable) obligate gut-associated anaerobes may be vertically transferred from mother to neonate via breastfeeding. Thus, our data support the recently suggested hypothesis of a novel way of mother-neonate communication, in which maternal gut bacteria reach breast milk via an entero-mammary pathway to influence neonatal gut colonization and maturation of the immune system.

No effect of probiotics on respiratory allergies: a seven-year follow-up of a randomized controlled trial in infancy

BACKGROUND

Supplementation with the probiotic Lactobacillus reuteri reduced the incidence of IgE-associated allergic disease in infancy. This treatment might therefore also reduce the risk of asthma and allergic rhinoconjunctivitis in school age.

OBJECTIVE

To evaluate whether perinatal and infant supplementation with L. reuteri reduced the prevalence of respiratory allergic disease in school age and to explore whether this supplementation was associated with any long-term side effects.

METHODS

A randomized, placebo-controlled trial with oral supplementation with L. reuteri ATCC 55730 (1 × 10(8) CFU) during the last month of gestation and through the first year of life comprising 232 families with allergic disease, of whom 184 completed a 7-yr follow-up. The primary outcomes at 7 yr of age were allergic disease and skin prick test reactivity (ClinicalTrials.gov ID NCT01285830).

RESULTS

The prevalence of asthma (15% in the probiotic vs. 16% in placebo group), allergic rhinoconjunctivitis (27% vs. 20%), eczema (21% vs. 19%) and skin prick test reactivity (29% vs. 26%) was similar in the probiotic and placebo group. Growth indices and gastrointestinal symptoms were similar in the two groups. No severe adverse events were reported.

CONCLUSION

The effect of L. reuteri on sensitization and IgE-associated eczema in infancy did not lead to a lower prevalence of respiratory allergic disease in school age. Thus, the effect of L. reuteri on the immune system seems to be transient. Administration of L. reuteri during the last weeks of gestation and in infancy was not associated with any long-term side effects.

Assessment of bacterial diversity in breast milk using culture-dependent and culture-independent approaches

Initial neonatal gut colonisation is a crucial stage for developing a healthy physiology, beneficially influenced by breast-feeding. Breast milk has been shown not only to provide nutrients and bioactive/immunological compounds, but also commensal bacteria, including gut-associated anaerobic Bifidobacterium spp. The aim of the present study was to investigate bacterial diversity in breast milk, with emphasis on identifying gut-associated obligate anaerobes. Breast milk collected from seven mothers at three sampling points (days 3-6, 9-14 and 25-30 postpartum) was analysed by combined culture-dependent and state-of-the-art, culture-independent methods (Sanger sequencing and 454-pyrosequencing). In addition to the predominance of facultative anaerobes such as Staphylococcus, Streptococcus and Propionibacterium (>90% of isolated strains and 23·7% relative abundance using pyrosequencing), significant populations of obligate anaerobes, including Bifidobacterium and Veillonella, were detected using pyrosequencing and confirmed by the isolation of viable strains (3·4% of isolates and 1·4% relative abundance). Pyrosequencing also revealed the presence of DNA of multiple major gut-associated obligate anaerobes (6·2% relative abundance) such as Bacteroides and, for the first time, several members of the Clostridia, including butyrate producers, such as Faecalibacterium and Roseburia, which are important for colonic health. The present study suggests that breast milk may be a major source of bacterial diversity to the neonatal gut, including gut-associated obligate anaerobes, and may thus significantly influence gut colonisation and maturation of the immune system.

Microbes and mucosal immune responses in asthma

The substantial increase in the worldwide prevalence of asthma and atopy has been attributed to lifestyle changes that reduce exposure to bacteria. A recent insight is that the largely bacterial microbiome maintains a state of basal immune homoeostasis, which modulates immune responses to microbial pathogens. However, some respiratory viral infections cause bronchiolitis of infancy and childhood wheeze, and can exacerbate established asthma; whereas allergens can partly mimic infectious agents. New insights into the host’s innate sensing systems, combined with recently developed methods that characterise commensal and pathogenic microbial exposure, now allow a unified theory for how microbes cause mucosal inflammation in asthma. The respiratory mucosa provides a key microbial interface where epithelial and dendritic cells interact with a range of functionally distinct lymphocytes. Lymphoid cells then control a range of pathways, both innate and specific, which organise the host mucosal immune response. Fundamental to innate immune responses to microbes are the interactions between pathogen-associated molecular patterns and pattern recognition receptors, which are associated with production of type I interferons, proinflammatory cytokines, and the T-helper-2 cell pathway in predisposed people. These coordinated, dynamic immune responses underlie the differing asthma phenotypes, which we delineate in terms of Seven Ages of Asthma. An understanding of the role of microbes in the atopic march towards asthma, and in causing exacerbations of established asthma, provides the rationale for new specific treatments that can be assessed in clinical trials. On the basis of these new ideas, specific host biomarkers might then allow personalised treatment to become a reality for patients with asthma.

The role of the manipulation of the gut microbiota in obesity

The manipulation of the gut microbiota by diet, antibiotics, or probiotics could promote, prevent, or reverse the development of specific diseases, including obesity. A link has been proposed between obesity and the growth promoters (probiotics and antibiotics) that have been used in animals for more than 40 years to induce weight gain. Several species of the Lactobacillus genus that are frequently used as probiotics for human consumption merit particular attention because they are increased in the gut microbiota under high-fat diets, are more abundant in obese humans, and are selected by growth-promoter antibiotics; moreover, the administration of these bacteria in experimental models is linked to the development of obesity. However, other species or strains of the same genus are associated with an antiobesity effect. Newborns and infants are a particularly susceptible population in which the administration of antibiotics or probiotics could be related to the development of obesity in adulthood.

Immunological programming by breast milk creates an anti-inflammatory cytokine milieu in breast-fed infants compared to formula-fed infants

Breast milk provides important maturational stimuli to an infant's developing immune system. However, data concerning the role of breast-feeding in reducing the risk of allergic disease remain contradictory. Previous studies have centred on comparative analyses of breast milk and formula compositions. We chose a slightly different angle, whereby we focused on the effects of the chosen diet on the infant himself, comparing the immune development of formula-fed and breast-fed children. The objective of the present study was to determine how the mode of feeding affects infant immunology. Altogether, eighteen formula-fed infants with limited breast-feeding for ,3 months and twenty-nine infants who were exclusively breast-fed for .3 months were included in the study. Concentrations of interferon g, TNF-a IL-10, IL-5, IL-4 and IL-2 were measured simultaneously from the same serum sample through use of a multiplexed flow cytometric assay at the ages of 1, 3, 6 and 12 months. Transforming growth factor β2 (TGF-β2) was measured using ELISA at the same time points. Serum TNF-a and IL-2 concentrations were significantly higher in formula-fed than in breast-fed infants during the first year of life (ANOVA, P=0·002). The serum concentrations of TGF-b were significantly lower in formula-fed than in breast-fed infants throughout the first year of life (ANOVA, P≤0·0001). Exclusive breast-feeding promotes an anti-inflammatory cytokine milieu, which is maintained throughout infancy. Such an immunological environment limits hyper-responsiveness and promotes tolerisation, possibly prohibiting the onset of allergic disease.

Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant

BACKGROUND

Probiotics have shown promising potential in reducing the risk of eczema in infants. Optimal probiotic intervention regimen remains to be determined.

OBJECTIVE

We investigated whether maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of developing eczema in high-risk infants.

METHODS

This was a parallel, double-blind placebo-controlled trial of 241 mother-infant pairs. Mothers with allergic disease and atopic sensitization were randomly assigned to receive (1) Lactobacillus rhamnosus LPR and Bifidobacterium longum BL999 (LPR+BL999), (2) L paracasei ST11 and B longum BL999 (ST11+BL999), or (3) placebo, beginning 2 months before delivery and during the first 2 months of breast-feeding. The infants were followed until the age of 24 months. Skin prick tests were performed at the ages of 6, 12, and 24 months.

RESULTS

Altogether 205 infants completed the follow-up and were included in the analyses. The risk of developing eczema during the first 24 months of life was significantly reduced in infants of mothers receiving LPR+BL999 (odds ratio [OR], 0.17; 95% CI, 0.08-0.35; P < .001) and ST11+BL999 (OR, 0.16; 95% CI, 0.08-0.35; P < .001). The respective ORs for chronically persistent eczema were 0.30 (95% CI, 0.12-0.80; P = .016) and 0.17 (95% CI, 0.05-0.56; P = .003). Probiotics had no effect on the risk of atopic sensitization in the infants. No adverse effects were related to the use of probiotics.

CONCLUSION

Prevention regimen with specific probiotics administered to the pregnant and breast-feeding mother, that is, prenatally and postnatally, is safe and effective in reducing the risk of eczema in infants with allergic mothers positive for skin prick test.

Microbial contact during pregnancy, intestinal colonization and human disease

Interaction with colonizing intestinal bacteria is essential for healthy intestinal and immunological development in infancy. Advances in understanding early host-microbe interactions indicate that this early microbial programming begins in utero and is substantially modulated by mode of birth, perinatal antibiotics and breastfeeding. Furthermore, it has become evident that this stepwise microbial colonization process, as well as immune and metabolic programming by the microbiota, might have a long-lasting influence on the risk of not only gastrointestinal disease, but also allergic, autoimmune and metabolic disease, in later life. Modulating early host-microbe interaction by maternal probiotic intervention during pregnancy and breastfeeding offers a promising novel tool to reduce the risk of disease. In this Review, we describe the current body of knowledge regarding perinatal microbial contact, initial intestinal colonization and its association with human disease, as well as means of modulating early host-microbe interaction to reduce the risk of disease in the child.

Probiotics to improve outcomes of colic in the community: protocol for the Baby Biotics randomised controlled trial

BACKGROUND

Infant colic, characterised by excessive crying/fussing for no apparent cause, affects up to 20% of infants under three months of age and is a great burden to families, health professionals and the health system. One promising approach to improving its management is the use of oral probiotics. The Baby Biotics trial aims to determine whether the probiotic Lactobacillus reuteri DSM 17938 is effective in reducing crying in infants less than three months old (<13.0 weeks) with infant colic when compared to placebo.

METHODS/DESIGN

DESIGN

Double-blind, placebo-controlled randomised trial in Melbourne, Australia.

PARTICIPANTS

160 breast and formula fed infants less than three months old who present either to clinical or community services and meet Wessel's criteria of crying and/or fussing.

INTERVENTION

Oral once-daily Lactobacillus reuteri (1x108 cfu) versus placebo for one month.

PRIMARY OUTCOME

Infant crying/fussing time per 24 hours at one month.

SECONDARY OUTCOMES

i) number of episodes of infant crying/fussing per 24 hours and ii) infant sleep duration per 24 hours (at 7, 14, 21, 28 days and 6 months); iii) maternal mental health scores, iv) family functioning scores, v) parent quality adjusted life years scores, and vi) intervention cost-effectiveness (at one and six months); and vii) infant faecal microbiota diversity, viii) infant faecal calprotectin levels and ix) Eschericia coli load (at one month only).

ANALYSIS

Primary and secondary outcomes for the intervention versus control groups will be compared with t tests and non-parametric tests for continuous data and chi squared tests for dichotomous data. Regression models will be used to adjust for potential confounding factors. Intention-to-treat analysis will be applied.

DISCUSSION

An effective, practical and acceptable intervention for infant colic would represent a major clinical advance. Because our trial includes breast and formula-fed babies, our results should generalise to most babies with colic. If cost-effective, the intervention's simplicity is such that it could be widely taken up as a new standard of care in the primary and secondary care sectors.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95287767.

In vitro and in vivo characterization and strain safety of Lactobacillus reuteri NCIMB 30253 for probiotic applications

Lactobacillus reuteri NCIMB 30253 was shown to have potential as a probiotic by reducing the proinflammatory chemokine interleukin-8. Moreover, this strain was evaluated, by in vitro and in vivo techniques, for its safety for human consumption. The identity of the strain was investigated by metabolic profiling and 16S rRNA gene sequencing, and in vitro safety evaluations were performed by molecular and metabolic techniques. Genetic analysis was confirmed by assessing the minimum inhibitory concentration to a panel of antibiotics, showing that the strain was susceptible to 8 antibiotics tested. The ability of the strain to produce potentially harmful by-products and antimicrobial compounds was evaluated, showing that the strain does not produce biogenic amines and does not show bacteriocin activity or reuterin production. A 28-day repeated oral dose study was conducted in normal Sprague–Dawley rats to support the in vivo strain safety. Oral administration of the strain resulted in no changes in general condition and no clinically significant changes to biochemical and haematological markers of safety relative to vehicle control treated animals. This comprehensive assessment of safety of L. reuteri NCIMB 30253 supports the safety of the strain for use as a probiotic.

Executive summary of the workshop "Nutritional Challenges in the High Risk Infant"

In 2009, the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) invited an expert panel to a workshop to address the current knowledge gaps and lack of evidence-based guidelines that preclude optimal nutritional care for infants in neonatal intensive care units. Since much research needs to be done in this complex area of science, the group was requested to propose new research to rectify current deficiencies in this field. This paper provides a summary of the workshop presentations and discussions.

A Th1/Th2-associated chemokine imbalance during infancy in children developing eczema, wheeze and sensitization

BACKGROUND

Analyses of circulating chemokines offer novel tools to investigate the T helper (Th)1/Th2 imbalance in allergic disease in vivo.

OBJECTIVE

To relate circulating Th1- and Th2-associated chemokines in infancy to allergic disease, sensitization and probiotic supplementation.

METHODS

Circulating levels of Th1-associated CXC-chemokine ligand (CXCL)9, CXCL10 and CXCL11 and Th2-associated CC-chemokine ligand (CCL)17 and CCL22 were assessed with Luminex and CCL18 with enzyme-linked immunosorbent assay at birth (n=109), 6 (n=104), 12 (n=116) and 24 months (n=123) in 161 infants completing a double-blind placebo-controlled allergy prevention trial with Lactobacillus reuteri during the last month of gestation and through the first year of life. The infants were followed regarding the development of allergic disease and sensitization until 2 years of age.

RESULTS

The Th2-associated chemokines CCL17 and CCL22 were the highest at birth and then decreased, whereas CCL18 and the Th1-associated chemokines increased with age. High Th2-associated chemokine levels were observed in children developing allergic disease. Sensitization was preceded by elevated levels of the Th2-associated CCL22 and reduced levels of the Th1-associated CXCL11 already at birth. The Th2-associated CCL17 was also elevated at birth in infants developing recurrent wheeze. A high Th2/Th1 ratio (CCL22/CXCL10) at birth associated with both sensitization and eczema development. The presence of L. reuteri in stool in the first week of life was associated with low CCL17 and CCL22 and high CXCL11 levels at 6 months of age. High Th1-associated chemokine levels were associated with day-care.

CONCLUSION AND CLINICAL RELEVANCE

Allergic disease and sensitization in infancy was associated with low circulating Th1- and high Th2-associated chemokine levels already from birth. Circulating chemokines are useful for investigating the Th1/Th2 imbalance in allergic disease in vivo. Elucidation of the role of chemokines in allergic diseases may lead to future treatments (ClinicalTrials.gov NCT01285830).

The gut as communicator between environment and host: immunological consequences

During human evolution, the mucosal immune system developed two anti-inflammatory mechanisms: immune exclusion by secretory antibodies (SIgA and SIgM) to control epithelial colonization of microorganisms and inhibit penetration of harmful substances; and immunosuppression to counteract local and peripheral hypersensitivity against innocuous antigens such as food proteins. The latter function is referred to as oral tolerance when induced via the gut. Similar mechanisms also control immunity to commensal bacteria. The development of immune homeostasis depends on "windows of opportunity" where adaptive and innate immunities are coordinated by antigen-presenting cells; their function is not only influenced by microbial products but also by dietary constituents, including vitamin A and lipids like polyunsaturated omega-3 fatty acids. These factors can in several ways exert beneficial effects on the immunophenotype of the infant. Also breast milk provides immune-modulating factors and SIgA antibodies - reinforcing the gut barrier. Mucosal immunity is most abundantly expressed in the gut, and the intestinal mucosa of an adult contains at least 80% of the body's activated B cells - terminally differentiated to plasmablasts and plasma cells (PCs). Most mucosal PCs produce dimeric IgA which is exported by secretory epithelia expressing the polymeric Ig receptor (pIgR), also called membrane secretory component (SC). Immune exclusion is therefore performed mainly by SIgA. Notably, pIgR knockout mice which lack SIgs show increased uptake of food and microbial antigens and they have a hyper-reactive immune system with disposition for anaphylaxis; but this untoward development is counteracted by cognate oral tolerance induction as a homeostatic back-up mechanism.

Exploring metabolic pathway reconstruction and genome-wide expression profiling in Lactobacillus reuteri to define functional probiotic features

The genomes of four Lactobacillus reuteri strains isolated from human breast milk and the gastrointestinal tract have been recently sequenced as part of the Human Microbiome Project. Preliminary genome comparisons suggested that these strains belong to two different clades, previously shown to differ with respect to antimicrobial production, biofilm formation, and immunomodulation. To explain possible mechanisms of survival in the host and probiosis, we completed a detailed genomic comparison of two breast milk–derived isolates representative of each group: an established probiotic strain (L. reuteri ATCC 55730) and a strain with promising probiotic features (L. reuteri ATCC PTA 6475). Transcriptomes of L. reuteri strains in different growth phases were monitored using strain-specific microarrays, and compared using a pan-metabolic model representing all known metabolic reactions present in these strains. Both strains contained candidate genes involved in the survival and persistence in the gut such as mucus-binding proteins and enzymes scavenging reactive oxygen species. A large operon predicted to encode the synthesis of an exopolysaccharide was identified in strain 55730. Both strains were predicted to produce health-promoting factors, including antimicrobial agents and vitamins (folate, vitamin B₁₂). Additionally, a complete pathway for thiamine biosynthesis was predicted in strain 55730 for the first time in this species. Candidate genes responsible for immunomodulatory properties of each strain were identified by transcriptomic comparisons. The production of bioactive metabolites by human-derived probiotics may be predicted using metabolic modeling and transcriptomics. Such strategies may facilitate selection and optimization of probiotics for health promotion, disease prevention and amelioration.

Lactobacillus reuteri DSM 17938 in infantile colic: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To test the efficacy of Lactobacillus reuteri on infantile colic and to evaluate its relationship to the gut microbiota.

STUDY DESIGN

Fifty exclusively breastfed colicky infants, diagnosed according to modified Wessel's criteria, were randomly assigned to receive either L reuteri DSM 17 938 (10(8) colony-forming units) or placebo daily for 21 days. Parental questionnaires monitored daily crying time and adverse effects. Stool samples were collected for microbiologic analysis.

RESULTS

Forty-six infants (L reuteri group: 25; placebo group: 21) completed the trial. Daily crying times in minutes/day (median [interquartile range]) were 370 (120) vs 300 (150) (P=.127) on day 0 and 35.0 (85) vs 90.0 (148) (P=.022) on day 21, in the L reuteri and placebo groups, respectively. Responders (50% reduction in crying time from baseline) were significantly higher in the L reuteri group versus placebo group on days 7 (20 vs 8; P=.006), 14 (24 vs 13; P=.007), and 21 (24 vs 15; P=.036). During the study, there was a significant increase in fecal lactobacilli (P=.002) and a reduction in fecal Escherichia coli and ammonia in the L reuteri group only (P=.001). There were no differences in weight gain, stooling frequency, or incidence of constipation or regurgitation between groups, and no adverse events related to the supplementation were observed.

CONCLUSION

L. reuteri DSM 17 938 at a dose of 10(8) colony-forming units per day in early breastfed infants improved symptoms of infantile colic and was well tolerated and safe. Gut microbiota changes induced by the probiotic could be involved in the observed clinical improvement.