Effect of administration of bifidobacteria on intestinal microbiota in low-birth-weight infants and transition of administered bifidobacteria: A comparison between one-species and three-species administration

Probiotics in the New Era of Human Milk Oligosaccharides (HMOs): HMO Utilization and Beneficial Effects of Bifidobacterium longum subsp. infantis M-63 on Infant Health

A healthy gut microbiome is crucial for the immune system and overall development of infants. Bifidobacterium has been known to be a predominant species in the infant gut; however, an emerging concern is the apparent loss of this genus, in particular, Bifidobacterium longum subsp. infantis (B. infantis) in the gut microbiome of infants in industrialized nations, underscoring the importance of restoring this beneficial bacterium. With the growing understanding of the gut microbiome, probiotics, especially infant-type human-residential bifidobacteria (HRB) strains like B. infantis, are gaining prominence for their unique ability to utilize HMOs and positively influence infant health. This article delves into the physiology of a probiotic strain, B. infantis M-63, its symbiotic relationship with HMOs, and its potential in improving gastrointestinal and allergic conditions in infants and children. Moreover, this article critically assesses the role of HMOs and the emerging trend of supplementing infant formulas with the prebiotic HMOs, which serve as fuel for beneficial gut bacteria, thereby emulating the protective effects of breastfeeding. The review highlights the potential of combining B. infantis M-63 with HMOs as a feasible strategy to improve health outcomes in infants and children, acknowledging the complexities and requirements for further research in this area.

Early Probiotic Supplementation of Healthy Term Infants with Bifidobacterium longum subsp. infantis M-63 Is Safe and Leads to the Development of Bifidobacterium-Predominant Gut Microbiota: A Double-Blind, Placebo-Controlled Trial

Bifidobacteria are important intestinal bacteria that provide a variety of health benefits in infants. We investigated the efficacy and safety of Bifidobacterium longum subsp. infantis (B. infantis) M-63 in healthy infants in a double-blind, randomized, placebo-controlled trial. Healthy term infants were given B. infantis M-63 (n = 56; 1 × 109 CFU/day) or placebo (n = 54) from postnatal age ≤ 7 days to 3 months. Fecal samples were collected, and fecal microbiota, stool pH, short-chain fatty acids, and immune substances were analyzed. Supplementation with B. infantis M-63 significantly increased the relative abundance of Bifidobacterium compared with the placebo group, with a positive correlation with the frequency of breastfeeding. Supplementation with B. infantis M-63 led to decreased stool pH and increased levels of acetic acid and IgA in the stool at 1 month of age compared with the placebo group. There was a decreased frequency of defecation and watery stools in the probiotic group. No adverse events related to test foods were observed. These results indicate that early supplementation with B. infantis M-63 is well tolerated and contributes to the development of Bifidobacterium-predominant gut microbiota during a critical developmental phase in term infants.

Therapeutic Potential of Gut Microbiota and Its Metabolite Short-Chain Fatty Acids in Neonatal Necrotizing Enterocolitis

Short chain fatty acids (SCFAs), the principle end-products produced by the anaerobic gut microbial fermentation of complex carbohydrates (CHO) in the colon perform beneficial roles in metabolic health. Butyrate, acetate and propionate are the main SCFA metabolites, which maintain gut homeostasis and host immune responses, enhance gut barrier integrity and reduce gut inflammation via a range of epigenetic modifications in DNA/histone methylation underlying these effects. The infant gut microbiota composition is characterized by higher abundances of SCFA-producing bacteria. A large number of in vitro/vivo studies have demonstrated the therapeutic implications of SCFA-producing bacteria in infant inflammatory diseases, such as obesity and asthma, but the application of gut microbiota and its metabolite SCFAs to necrotizing enterocolitis (NEC), an acute inflammatory necrosis of the distal small intestine/colon affecting premature newborns, is scarce. Indeed, the beneficial health effects attributed to SCFAs and SCFA-producing bacteria in neonatal NEC are still to be understood. Thus, this literature review aims to summarize the available evidence on the therapeutic potential of gut microbiota and its metabolite SCFAs in neonatal NEC using the PubMed/MEDLINE database.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Effect of single versus multistrain probiotic in extremely preterm infants: a randomised trial

OBJECTIVE

Evidence indicates that multistrain probiotics benefit preterm infants more than single-strain (SS) probiotics. We assessed the effects of SS versus triple-strain (TS) probiotic supplementation (PS) in extremely preterm (EP) infants.

DESIGN

EP infants (gestational age (GA) <28 weeks) were randomly allocated to TS or SS probiotic, assuring blinding. Reference (REF) group was EP infants in the placebo arm of our previous probiotic trial. PS was commenced with feeds and continued until 37 weeks' corrected GA. Primary outcome was time to full feed (TFF: 150 mL/kg/day). Secondary outcomes included short-chain fatty acids and faecal microbiota collected at T1 (first week) and T2 (after 3 weeks of PS) using 16S ribosomal RNA gene sequencing.

RESULTS

173 EP (SS: 86, TS: 87) neonates with similar GA and birth weight (BW) were randomised. Median TFF was comparable (11 (IQR 8-16) vs 10 (IQR 8-16) days, p=0.92). Faecal propionate (SS, p<0.001, and TS, p=0.0009) and butyrate levels (TS, p=0.029) were significantly raised in T2 versus T1 samples. Secondary clinical outcomes were comparable. At T2, alpha diversity was comparable (p>0.05) between groups, whereas beta-diversity analysis revealed significant differences between PS and REF groups (both p=0.001). Actinobacteria were higher (both p<0.01), and Proteobacteria, Firmicutes and Bacteroidetes were lower in PS versus REF. Gammaproteobacteria, Clostridia and Negativicutes were lower in both PS versus REF.

CONCLUSION

TFF in EP infants was similar between SS and TS probiotics. Both probiotics were effective in reducing dysbiosis (higher bifidobacteria and lower Gammaproteobacteria). Long-term significance of increased propionate and butyrate needs further studies.

TRIAL REGISTRATION NUMBER

ACTRN 12615000940572.

Safety and efficacy of probiotics in the prevention of necrotizing enterocolitis in premature and/or low-birthweight infants: a systematic review and meta-analysis

BACKGROUND

Neonatal necrotizing enterocolitis (NEC) is a serious pediatric gastrointestinal disease and a cause of death in neonates, especially in premature infants. The addition of probiotics to the diet can reduce the incidence and severity of neonatal NEC. This meta-analysis explored the preventive effect of probiotics on NEC.

METHODS

Endnote X9 software was used to search for relevant studies in the Ovid, Embase, PubMed, and Web of Science databases. The search terms were "probiotics" and "necrotizing enterocolitis". After retrieval, screening, and quality evaluation of the studies, Stata 16.0 software was used to analyze the data.

RESULTS

A total of 10 studies, which collectively included 3,227 patients, were selected for analysis. Of them, 5 used a multiple-strain probiotics, and 5 used single-strain probiotic. Meta-analysis showed that treatment with probiotics could reduce the incidence of severe NEC [risk ratio (RR) =0.66; 95% confidence interval (CI): (0.50, 0.87); Z=-2.978; P=0.003], reduce mortality in underweight premature children [RR =0.81; 95% CI: (0.70, 0.94); Z=-2.864; P=0.004], and reduce the incidence of feeding intolerance [RR =0.78; 95% CI: (0.67, 0.90); Z=-3.280; P=0.001].

DISCUSSION

The addition of probiotics to the diet of low-birthweight and premature infants can reduce the incidence of severe NEC and reduce related mortality rates.

Phylogenetic, Functional and Safety Features of 1950s B. infantis Strains

Strains of Bifidobacterium longum subsp. infantis (B. infantis) are amongst the first to colonize the infant gut, partly due to their capacity to metabolize complex human milk oligosaccharides (HMO), and are proposed to play a key role in the development of the infant gut. Since early life, B. infantis supplementation is of high interest, and detailed phylogenetic, functional and safety characterization of the selected strains should be pursued. Using a combination of long and short-read sequencing technologies, we first decipher the genetic distance between different isolates of the same B. infantis strain. Using the same approach, we show that several publicly available genomes recapitulate this strain-level distance as compared to two of the first strains obtained in the 1950s. Furthermore, we demonstrate that the two 1950s B. infantis strains display different functional and safety attributes, as ATCC 15697 is resistant to streptomycin and shows a preference towards lacto-N-tetraose LNT and sialylated HMOs, while LMG 11588 is sensitive to all tested antibiotics and shows a preference towards fucosylated HMOs. Overall, our work highlights that the current diversity observed in B. infantis is likely underestimated and that strain selection within this subspecies must be the subject of scientific pursuit and associated evaluation.

A systematic review of the factors influencing microbial colonization of the preterm infant gut

Prematurity coupled with the necessary clinical management of preterm (PT) infants introduces multiple factors that can interfere with microbial colonization. This study aimed to review the perinatal, physiological, pharmacological, dietary, and environmental factors associated with gut microbiota of PT infants. A total of 587 articles were retrieved from a search of multiple databases. Sixty studies were included in the review after removing duplicates and articles that did not meet the inclusion criteria. Review of this literature revealed that evidence converged on the effect of postnatal age, mode of delivery, use of antibiotics, and consumption of human milk in the composition of gut microbiota of PT infants. Less evidence was found for associations with race, sex, use of different fortifiers, macronutrients, and other medications. Future studies with rich metadata are needed to further explore the impact of the PT exposome on the development of the microbiota in this high-risk population.

Role of Bifidobacteria on Infant Health

Bifidobacteria are among the predominant microorganisms during infancy, being a dominant microbial group in the healthy breastfed infant and playing a crucial role in newborns and infant development. Not only the levels of the Bifidobacterium genus but also the profile and quantity of the different bifidobacterial species have been demonstrated to be of relevance to infant health. Although no definitive proof is available on the causal association, reduced levels of bifidobacteria are perhaps the most frequently observed alteration of the intestinal microbiota in infant diseases. Moreover, Bifidobacterium strains have been extensively studied by their probiotic attributes. This review compiles the available information about bifidobacterial composition and function since the beginning of life, describing different perinatal factors affecting them, and their implications on different health alterations in infancy. In addition, this review gathers exhaustive information about pre-clinical and clinical studies with Bifidobacterium strains as probiotics in neonates.

The Potential of Probiotics to Eradicate Gut Carriage of Pathogenic or Antimicrobial-Resistant Enterobacterales

Probiotic supplements have been used to decrease the gut carriage of antimicrobial-resistant Enterobacterales through changes in the microbiota and metabolomes, nutrition competition, and the secretion of antimicrobial proteins. Many probiotics have shown Enterobacterales-inhibiting effects ex vivo and in vivo. In livestock, probiotics have been widely used to eradicate colon or environmental antimicrobial-resistant Enterobacterales colonization with promising efficacy for many years by oral supplementation, in ovo use, or as environmental disinfectants. In humans, probiotics have been used as oral supplements for infants to decease potential gut pathogenic Enterobacterales, and probiotic mixtures, especially, have exhibited positive results. In contrast to the beneficial effects in infants, for adults, probiotic supplements might decrease potentially pathogenic Enterobacterales, but they fail to completely eradicate them in the gut. However, there are several ways to improve the effects of probiotics, including the discovery of probiotics with gut-protection ability and antimicrobial effects, the modification of delivery methods, and the discovery of engineered probiotics. The search for multifunctional probiotics and synbiotics could render the eradication of “bad” Enterobacterales in the human gut via probiotic administration achievable in the future.

Anticancer effects of bifidobacteria on colon cancer cell lines

Background

Colorectal cancer (CRC), with a growing incidence trend worldwide, is resistant to apoptosis and has uncontrolled proliferation. It is recently reported that probiotic microorganisms exert anticancer effects. The genus Bifidobacterium, one of the dominant bacterial populations in the gastrointestinal tract, has received increasing attention because of widespread interest in using it as health-promoting microorganisms. Therefore, the present study aimed to assess the apoptotic effects of some bifidobacteria species on colon cancer cell lines.

Methods

The cytotoxicity evaluations performed using MTT assay and FACS-flow cytometry tests. Also, the effects of five species of bifidobacteria secretion metabolites on the expression level of anti- or pro-apoptotic genes including BAD, Bcl-2, Caspase-3, Caspase-8, Caspase-9, and Fas-R studied by real-time polymerase chain reaction (RT-PCR) method.

Results

The cell-free supernatant of all studied bifidobacteria significantly decreased the survival rates of colon cancer cells compared with control groups. Flow cytometric and RT-PCR results indicated that apoptosis is induced by bifidobacteria secretion metabolites and the mechanism for the action of bifidobacteria species in CRC prevention could be down-regulation and up-regulation of anti-apoptotic and, pro-apoptotic genes.

Conclusions

In the present study, different bifidobacteria species showed anticancer activity on colorectal cancer cells through down-regulation and up-regulation of anti-apoptotic and pro-apoptotic genes. However, further studies are required to clarify the exact mechanism of apoptosis induction by bifidobacteria species.

Colonization of Supplemented Bifidobacterium breve M-16V in Low Birth Weight Infants and Its Effects on Their Gut Microbiota Weeks Post-administration

The colonization and persistence of probiotics introduced into the adult human gut appears to be limited. It is uncertain, however, whether probiotics can successfully colonize the intestinal tracts of full-term and premature infants. In this study, we investigated the colonization and the effect of oral supplementation with Bifidobacterium breve M-16V on the gut microbiota of low birth weight (LBW) infants. A total of 22 LBW infants (12 infants in the M-16V group and 10 infants in the control group) were enrolled. B. breve M-16V was administrated to LBW infants in the M-16V group from birth until hospital discharge. Fecal samples were collected from each subject at weeks (3.7-9.3 weeks in the M-16V group and 2.1-6.1 weeks in the control group) after discharge. qPCR analysis showed that the administrated strain was detected in 83.3% of fecal samples in the M-16V group (at log₁₀ 8.33 ± 0.99 cell numbers per gram of wet feces), suggesting that this strain colonized most of the infants beyond several weeks post-administration. Fecal microbiota analysis by 16S rRNA gene sequencing showed that the abundance of Actinobacteria was significantly higher (P < 0.01), whereas that of Proteobacteria was significantly lower (P < 0.001) in the M-16V group as compared with the control group. Notably, the levels of the administrated strain and indigenous Bifidobacterium bacteria were both significantly higher in the M-16V group than in the control group. Our findings suggest that oral administration of B. breve M-16V led to engraftment for at least several weeks post-administration and we observed a potential overall improvement in microbiota formation in the LBW infants' guts.

Methods for exploring the faecal microbiome of premature infants: a review

The premature infant gut microbiome plays an important part in infant health and development, and recognition of the implications of microbial dysbiosis in premature infants has prompted significant research into these issues. The approaches to designing investigations into microbial populations are many and varied, each with its own benefits and limitations. The technique used can influence results, contributing to heterogeneity across studies. This review aimed to describe the most common techniques used in researching the preterm infant microbiome, detailing their various limitations. The objective was to provide those entering the field with a broad understanding of available methodologies, so that the likely effects of their use can be factored into literature interpretation and future study design. We found that although many techniques are used for characterising the premature infant microbiome, 16S rRNA short amplicon sequencing is the most common. 16S rRNA short amplicon sequencing has several benefits, including high accuracy, discoverability and high throughput capacity. However, this technique has limitations. Each stage of the protocol offers opportunities for the injection of bias. Bias can contribute to variability between studies using 16S rRNA high throughout sequencing. Thus, we recommend that the interpretation of previous results and future study design be given careful consideration.

Bifidobacterium longum Subspecies infantis (B. infantis) in Pediatric Nutrition: Current State of Knowledge

Abstract: Since originally isolated in 1899, the genus Bifidobacterium has been demonstrated to predominate in the gut microbiota of breastfed infants and to benefit the host by accelerating maturation of the immune response, balancing the immune system to suppress inflammation, improving intestinal barrier function, and increasing acetate production. In particular, Bifidobacterium longum subspecies infantis (B. infantis) is well adapted to the infant gut and has co-evolved with the mother-infant dyad and gut microbiome, in part due to its ability to consume complex carbohydrates found in human milk. B. infantis and its human host have a symbiotic relationship that protects the preterm or term neonate and nourishes a healthy gut microbiota prior to weaning. To provide benefits associated with B. infantis to all infants, a number of commercialized strains have been developed over the past decades. As new ingredients become available, safety and suitability must be assessed in preclinical and clinical studies. Consideration of the full clinical evidence for B. infantis use in pediatric nutrition is critical to better understand its potential impacts on infant health and development. Herein we summarize the recent clinical studies utilizing select strains of commercialized B. infantis.

Exploring the Science behind Bifidobacterium breve M-16V in Infant Health

Probiotics intervention has been proposed as a feasible preventative approach against adverse health-related complications in infants. Nevertheless, the umbrella concept of probiotics has led to a massive application of probiotics in a range of products for promoting infant health, for which the strain-specificity, safety and efficacy findings associated with a specific probiotics strain are not clearly defined. Bifidobacterium breve M-16V is a commonly used probiotic strain in infants. M-16V has been demonstrated to offer potential in protecting infants from developing the devastating necrotising enterocolitis (NEC) and allergic diseases. This review comprehends the potential beneficial effects of M-16V on infant health particularly in the prevention and treatment of premature birth complications and immune-mediated disorders in infants. Mechanistic studies supporting the use of M-16V implicated that M-16V is capable of promoting early gut microbial colonisation and may be involved in the regulation of immune balance and inflammatory response to protect high-risk infants from NEC and allergies. Summarised information on M-16V has provided conceptual proof of the use of M-16V as a potential probiotics candidate aimed at promoting infant health, particularly in the vulnerable preterm population.

Effects of pidotimod and bifidobacteria mixture on clinical symptoms and urinary metabolomic profile of children with recurrent respiratory infections: a randomized placebo-controlled trial

BACKGROUND

Many preschool children develop recurrent respiratory tract infections (RRI). Strategies to prevent RRI include the use of immunomodulators as pidotimod or probiotics, but there is limited evidence of their efficacy on clinical features or on urine metabolic profile.

OBJECTIVE

To evaluate whether pidotimod and/or bifidobacteria can reduce RRI morbidity and influence the urine metabolic profile in preschool children.

MATERIALS AND METHODS

Children aged 3-6 years with RRI were enrolled in a four-arm, exploratory, prospective, randomized, double-blinded, placebo-controlled trial. Patients were randomly assigned to receive pidotimod plus bifidobacteria, pidotimod plus placebo, bifidobacteria plus placebo or double placebo for the first 10 days of each month over 4 consecutive months. Respiratory symptoms and infections were recorded with a daily diary by parents during the study. Metabolomic analyses on urine samples collected before and after treatment were performed.

RESULTS

Compared to placebo, children receiving pidotimod, alone or with bifidobacteria, had more symptom-free days (69 versus 44, p = 0.003; and 65 versus 44, p = 0.02, respectively) and a lower percentage of days with common cold (17% versus 37%, p = 0.005; and 15% versus 37%, p = 0.004, respectively). The metabolomic analysis showed that children treated with Pidotimod (alone or in combination with bifidobacteria) present, respect to children treated with placebo, a biochemical profile characterized by compounds related to the pathway of steroids hormones, hippuric acid and tryptophan. No significant difference in the metabolic profile was found between children receiving bifidobacteria alone and controls.

CONCLUSIONS

Preschool children with RRI treated with pidotimod have better clinical outcomes and a different urine metabolomic profile than subjects receiving placebo. Further investigations are needed to clarify the connection between pidotimod and gut microbiome.

Arguments against routine administration of probiotics for NEC prevention

PURPOSE OF REVIEW

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality among premature neonates. Although randomized trials have shown that probiotics may be efficacious in the prevention of NEC, their use has not been universally adopted in the neonatal intensive care unit (NICU). Caveats regarding routine probiotic supplementation for the prevention of NEC are summarized in this review.

RECENT FINDINGS

Accumulating evidence indicates that prophylactic probiotic supplementation in preterm infants can reduce the incidence of NEC. However, substantial knowledge gaps, regulatory issues, and implementation challenges should be addressed before probiotics are introduced as standard of care for all preterm neonates. Limitations of published trial data have made it challenging to define regimens that optimize efficacy and safety in specific patient subgroups. Moreover, the current probiotic market lacks rigorous regulatory oversight, which could raise concerns about the quality and safety of probiotic products. Finally, implementation pitfalls include risks of cross-colonization and resource requirements to monitor and mitigate potential adverse events.

SUMMARY

Probiotics have shown promise in the prevention of NEC. However, there is insufficient evidence to guide the selection of optimal regimens. Furthermore, issues related to regulatory and institutional oversight should be addressed before supplementation is routinely implemented in NICUs.

Bifidobacterium infantis M-63 improves mental health in victims with irritable bowel syndrome developed after a major flood disaster

Individuals in a community who developed irritable bowel syndrome (IBS) after major floods have significant mental health impairment. We aimed to determine if Bifidobacterium infantis M-63 was effective in improving symptoms, psychology and quality of life measures in flood-affected individuals with IBS and if the improvement was mediated by gut microbiota changes. Design was non-randomised, open-label, controlled before-and-after. Of 53 participants, 20 with IBS were given B. infantis M-63 (1×10⁹ cfu/sachet/day) for three months and 33 were controls. IBS symptom severity scale, hospital anxiety and depression scale, SF-36 Questionnaire, hydrogen breath testing for small intestinal bacterial overgrowth and stools for 16S rRNA metagenomic analysis were performed before and after intervention. 11 of 20 who were given probiotics (M-63) and 20 of 33 controls completed study as per-protocol. Mental well-being was improved with M-63 vs controls for full analysis (P=0.03) and per-protocol (P=0.01) populations. Within-group differences were observed for anxiety and bodily pain (both P=0.04) in the M-63 per-protocol population. Lower ratio of Firmicutes/Bacteroidetes was observed with M-63 vs controls (P=0.01) and the lower ratio was correlated with higher post-intervention mental score (P=0.04). B. infantis M-63 is probably effective in improving mental health of victims who developed IBS after floods and this is maybe due to restoration of microbial balance and the gut-brain axis. However, our conclusion must be interpreted within the context of limited sample size. The study was retrospectively registered on 12 October 2017 and the Trial Registration Number (TRN) was NCT03318614.

A randomised controlled trial of the probiotic Bifidobacterium breve BBG-001 in preterm babies to prevent sepsis, necrotising enterocolitis and death: the Probiotics in Preterm infantS (PiPS) trial

BACKGROUND

Necrotising enterocolitis (NEC) and late-onset sepsis remain important causes of death and morbidity in preterm babies. Probiotic administration might strengthen intestinal barrier function and provide protection; this is supported by published meta-analyses, but there is a lack of large well-designed trials.

OBJECTIVE

To test the use of the probiotic Bifidobacterium breve strain BBG-001 to prevent NEC, late-onset sepsis and death in preterm babies while monitoring probiotic colonisation of participants.

DESIGN

Double-blind, randomised, placebo-controlled trial.

SETTING

Recruitment was carried out in 24 hospitals, and the randomisation programme used a minimisation algorithm. Parents, clinicians and outcome assessors were blinded to the allocation.

PARTICIPANTS

Babies born between 23 and 30 weeks' gestation and randomised within 48 hours of birth. Exclusions included life-threatening or any gastrointestinal malformation detected within 48 hours of birth and no realistic chance of survival.

INTERVENTIONS

Active intervention: 1 ml of B. breve BBG-001 in one-eighth-strength infant formula Neocate(®) (Nutricia Ltd, Trowbridge, UK), (6.7 × 10(7) to 6.7 × 10(9) colony-forming units) per dose administered enterally. Placebo: 1 ml of one-eighth-strength infant formula Neocate. Started as soon as practicable and continued daily until 36 weeks' postmenstrual age.

MAIN OUTCOME MEASURES

Primary outcomes were an episode of bloodstream infection, with any organism other than a skin commensal, in any baby between 72 hours and 46 weeks' postmenstrual age; an episode of NEC Bell stage ≥ 2 in any baby; and death before discharge from hospital. Secondary outcomes included stool colonisation with B. breve.

RESULTS

In total, 654 babies were allocated to receive probiotic and 661 to receive placebo over 37 months from July 2010. Five babies were withdrawn; 650 babies from the probiotic group and 660 from the placebo group were included in the primary analysis. Baseline characteristics were well balanced. There was no evidence of benefit for the primary outcomes {sepsis: 11.2% vs. 11.7% [adjusted relative risk (RR) 0.97, 95% confidence interval (CI) 0.73 to 1.29]; NEC Bell stage ≥ 2: 9.4% vs. 10.0% [adjusted RR 0.93, 95% CI 0.68 to 1.27]; and death: 8.3% vs. 8.5% [adjusted RR 0.93, 95% CI 0.67 to 1.30]}. B. breve colonisation status was available for 1186 (94%) survivors at 2 weeks' postnatal age, of whom 724 (61%) were positive: 85% of the probiotic group and 37% of the placebo group. There were no differences for subgroup analyses by minimisation criteria and by stool colonisation with B. breve at 2 weeks. No harms associated with the interventions were reported.

LIMITATIONS

Cross-colonisation of the placebo arm could have reduced statistical power and confounded results; analyses suggest that this did not happen.

CONCLUSIONS

This is the largest trial to date of a probiotic intervention. It shows no evidence of benefit and does not support routine use of probiotics for preterm infants.

FUTURE WORK RECOMMENDATIONS

The increasing understanding of the pathogenesis of NEC and sepsis will inform the choice of probiotics for testing and better define the target population. Future Phase III trials should incorporate monitoring of the quality and viability of the intervention and colonisation rates of participants; cluster design should be considered.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN05511098 and EudraCT 2006-003445-17.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 66. See the NIHR Journals Library website for further project information.

Maternal antimicrobial use at delivery has a stronger impact than mode of delivery on bifidobacterial colonization in infants: a pilot study

OBJECTIVE

To investigate factors related to bifidobacterial colonization in early infancy, with a focus on maternal antimicrobial use at delivery.

STUDY DESIGN

A cross-sectional pilot study was performed. Feces samples of 33 Japanese healthy infants were collected over 10 months and analyzed by next-generation sequencing to examine the diversity and abundance of the gut microbiota.

RESULTS

The beta diversity index of the gut microbiota differed significantly based on maternal antimicrobial use at delivery (P < 0.05). The most dominant genus was bifidobacteria, and the relative abundance of bifidobacteria in infants exposed to maternal antibiotics was significantly lower than in those who were not exposed (P < 0.05). In contrast, the delivery mode showed no significant relationship with gut microbiota diversity.

CONCLUSIONS

Maternal antimicrobial use at delivery has a stronger effect than delivery mode on the gut microbiota, especially for colonization of bifidobacteria.

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.

Microbial Therapeutics Designed for Infant Health

Acknowledgment of the gut microbiome as a vital asset to health has led to multiple studies attempting to elucidate its mechanisms of action. During the first year of life, many factors can cause fluctuation in the developing gut microbiome. Host genetics, maternal health status, mode of delivery, gestational age, feeding regime, and perinatal antibiotic usage, are known factors which can influence the development of the infant gut microbiome. Thus, the microbiome of vaginally born, exclusively breastfed infants at term, with no previous exposure to antibiotics, either directly or indirectly from the mother, is to be considered the "gold standard." Moreover, the use of prebiotics as an aid for the development of a healthy gut microbiome is equally as important in maintaining gut homeostasis. Breastmilk, a natural prebiotic source, provides optimal active ingredients for the growth of beneficial microbial species. However, early life disorders such as necrotising enterocolitis, childhood obesity, and even autism have been associated with an altered/disturbed gut microbiome. Subsequently, microbial therapies have been introduced, in addition to suitable prebiotic ingredients, which when administered, may aid in the prevention of a microbial disturbance in the gastrointestinal tract. The aim of this mini-review is to highlight the beneficial effects of different probiotic and prebiotic treatments in early life, with particular emphasis on the different conditions which negatively impact microbial colonisation at birth.

The Microbiome of Infants Recruited to a Randomised Placebo-controlled Probiotic Trial (PiPS Trial)

The microbial dysbiosis associated with necrotizing enterocolitis (NEC) in preterm infants suggests that early exposure to probiotics may decrease and antibiotics may increase NEC risk. However, administration of Bifidobacterium breve strain BBG-001 to preterm infants did not affect NEC incidence in a multicenter randomised controlled phase 3 trial (PiPS trial). Using a subset of these subjects we compared the fecal microbiome of probiotic and placebo groups and assessed the impact of early antibiotic treatment. Extracted DNA from 103 fecal samples collected at 36 weeks post-menstrual age underwent PCR amplification of a fragment of the 16S rRNA gene. Heatmaps were constructed showing the proportions of sequences from bacterial families present at > 1% of the community. Stepwise logistic regression assessed the association between early antibiotic exposure and microbiome group. There was no difference in the microbial richness and diversity of the microbiome of preterm infants following treatment with probiotic or a placebo. Conversely, early antimicrobial exposure was associated with different patterns of colonisation, specifically a relative abundance of Proteobacteria.

These findings highlight that the potential influence of probiotics on the microbiome of preterm infants remains unclear whereas the modulatory effect of antibiotic exposure on microbial colonisation requires further research.

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Microbial dysbiosis has been associated with the development of neonatal necrotizing enterocolitis in premature infants.

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Early administration of a probiotic compared to a placebo did not alter the microbiome of premature infants.

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Early life exposure to antibiotics was associated with different patterns of colonisation in premature infants.

The association of altered microbial gastrointestinal colonisation (dysbiosis) with neonatal necrotizing enterocolitis suggests that, through their effects on microbial colonisation, probiotics and antimicrobials may modulate necrotizing enterocolitis risk. We compared microbial colonisation patterns of premature infants administered a probiotic or placebo in the early stages of life. We found no significant effect of probiotic administration on microbial colonisation, a finding which disputes the suggestion that prophylactic use of probiotics prevents the dysbiosis associated with necrotizing enterocolitis. In contrast, antibiotic exposure did alter the pattern of colonisation, indicating the need for further research in order to clearly ascertain the nature of this relationship.

The role of early life nutrition in the establishment of gastrointestinal microbial composition and function

The development of the human infant intestinal microbiota is a sequential process that begins in utero and continues during the first 2 to 3 years of life. Microbial composition and diversity are shaped by host genetics and multiple environmental factors, of which diet is a principal contributor. An understanding of this process is of clinical importance as the microbiota acquired in early life influence gastrointestinal, immune and neural development, and reduced microbial diversity or dysbiosis during infancy is associated with disorders in infancy and later childhood. The goal of this article was to review the published literature that used culture-independent methods to describe the development of the gastrointestinal microbiota in breast- and formula-fed human infants as well as the impact of prebiotic and probiotic addition to infant formula, and the addition of solid foods.

Early Gut Microbiota Perturbations Following Intrapartum Antibiotic Prophylaxis to Prevent Group B Streptococcal Disease

The faecal microbiota composition of infants born to mothers receiving intrapartum antibiotic prophylaxis with ampicillin against group B Streptococcus was compared with that of control infants, at day 7 and 30 of life. Recruited newborns were both exclusive breastfed and mixed fed, in order to also study the effect of dietary factors on the microbiota composition. Massive parallel sequencing of the V3-V4 region of the 16S rRNA gene and qPCR analysis were performed. Antibiotic prophylaxis caused the most marked changes on the microbiota in breastfed infants, mainly resulting in a higher relative abundance of Enterobacteriaceae, compared with control infants (52% vs. 14%, p = 0.044) and mixed-fed infants (52% vs. 16%, p = 0.13 NS) at day 7 and in a lower bacterial diversity compared to mixed-fed infants and controls. Bifidobacteria were also particularly vulnerable and abundances were reduced in breastfed (p = 0.001) and mixed-fed antibiotic treated groups compared to non-treated groups. Reductions in bifidobacteria in antibiotic treated infants were also confirmed by qPCR. By day 30, the bifidobacterial population recovered and abundances significantly increased in both breastfed (p = 0.025) and mixed-fed (p = 0.013) antibiotic treated groups, whereas Enterobacteriaceae abundances remained highest in the breastfed antibiotic treated group (44%), compared with control infants (16%) and mixed-fed antibiotic treated group (28%). This study has therefore demonstrated the short term consequences of maternal intrapartum antibiotic prophylaxis on the infant faecal microbial population, particularly in that of breastfed infants.

Bosom Buddies: The Symbiotic Relationship Between Infants and Bifidobacterium longum ssp. longum and ssp. infantis. Genetic and Probiotic Features

The intestinal microbiota is a complex community that plays an important role in human health from the initial steps of its establishment. Its microbial composition has been suggested to result from selective pressures imposed by the host and is modulated by competition among its members. Bifidobacterium longum is one of the most abundant species of the Bifidobacterium genus in the gut microbiota of healthy breast-fed infants and adults. The recent advancements of 'omics techniques have facilitated the genetic and functional studies of different gut microbiota members. They have revealed the complex genetic pathways used to metabolize different compounds that likely contribute to the competitiveness and persistence of B. longum in the colon. The discovery of a genomic island in B. longum ssp. infantis that encodes specific enzymes for the metabolism of human milk oligosaccharides suggests a specific ecological adaptation. Moreover, B. longum is widely used as probiotic, and beneficial effects in infant health have been reported in several studies.

Probiotics in neonatal intensive care - back to the future

Survival of extremely preterm and critically ill neonates has improved significantly over the last few decades following advances in neonatal intensive care. These include antenatal glucocorticoids, surfactant, continuous positive airway pressure support, advanced gentle modes of ventilation and inhaled nitric oxide. Probiotic supplementation is a recent significant milestone in the history of neonatal intensive care. Very few, if any, interventions match the ability of probiotics to significantly reduce the risk of death and definite necrotising enterocolitis while facilitating enteral feeds in high-risk preterm neonates. Probiotics also have a potential to benefit neonates with surgical conditions with significant gastrointestinal morbidity. Current evidence for the benefits of probiotic supplementation for neonates in an intensive care unit is reviewed. The mechanisms for the benefits of probiotics in this population are discussed, and guidelines for clinicians are provided in the context of the regulatory framework in Australia.

Maternal fucosyltransferase 2 status affects the gut bifidobacterial communities of breastfed infants

BACKGROUND

Individuals with inactive alleles of the fucosyltransferase 2 gene (FUT2; termed the 'secretor' gene) are common in many populations. Some members of the genus Bifidobacterium, common infant gut commensals, are known to consume 2'-fucosylated glycans found in the breast milk of secretor mothers. We investigated the effects of maternal secretor status on the developing infant microbiota with a special emphasis on bifidobacterial species abundance.

RESULTS

On average, bifidobacteria were established earlier and more often in infants fed by secretor mothers than in infants fed by non-secretor mothers. In secretor-fed infants, the relative abundance of the Bifidobacterium longum group was most strongly correlated with high percentages of the order Bifidobacteriales. Conversely, in non-secretor-fed infants, Bifidobacterium breve was positively correlated with Bifidobacteriales, while the B. longum group was negatively correlated. A higher percentage of bifidobacteria isolated from secretor-fed infants consumed 2'-fucosyllactose. Infant feces with high levels of bifidobacteria had lower milk oligosaccharide levels in the feces and higher amounts of lactate. Furthermore, feces containing different bifidobacterial species possessed differing amounts of oligosaccharides, suggesting differential consumption in situ.

CONCLUSIONS

Infants fed by non-secretor mothers are delayed in the establishment of a bifidobacteria-laden microbiota. This delay may be due to difficulties in the infant acquiring a species of bifidobacteria able to consume the specific milk oligosaccharides delivered by the mother. This work provides mechanistic insight into how milk glycans enrich specific beneficial bacterial populations in infants and reveals clues for enhancing enrichment of bifidobacterial populations in at risk populations - such as premature infants.

Benefits of probiotics on enteral nutrition in preterm neonates: a systematic review

INTRODUCTION

The optimization of enteral nutrition is a priority in preterm neonates worldwide. Probiotics are known to improve gut maturity and function in preterm neonates. To our knowledge, previous systematic reviews have not adequately assessed the effects of probiotic supplementation on enteral nutrition in preterm neonates.

OBJECTIVE

We assessed the evidence on effects of probiotics on enteral nutrition in preterm neonates.

DESIGN

A systematic review of randomized controlled trials (RCTs) of probiotic supplementation in preterm (gestation <37 wk) or low-birth-weight (birth weight <2500 g) neonates was conducted. With the use of the Cochrane Neonatal Review Group strategy, we searched the Cochrane Central Register of Controlled Trials, PubMed, EMBASE, and Cumulative Index of Nursing and Allied Health Literature databases and proceedings of Pediatric Academic Society meetings in April 2014.

RESULTS

A total of 25 RCTs (n = 5895) were included in the review. A meta-analysis (random-effects model) of data from 19 of 25 trials (n = 4527) estimated that the time to full enteral feeds was shorter in the probiotic group (mean difference: -1.54 d; 95% CI: -2.75, -0.32 d; P < 0.00001, I(2) = 93%). Other benefits included fewer episodes of feed intolerance, better weight gain and growth velocity, decreased transition time from orogastric to breast feeds, and increased postprandial mesenteric flow. There were no adverse effects of probiotic supplementation.

CONCLUSIONS

Probiotics reduced the time to full enteral feeds in preterm neonates. Additional research is necessary to assess the optimal dose, duration, and probiotic strain or strains used specifically for facilitating enteral nutrition in this population.