Cohort study of probiotics in a North American neonatal intensive care unit

Contemporary use of prophylactic probiotics in NICUs in the United States: a survey update

OBJECTIVE

In 2015, 14.0% of US NICUs administered probiotics to very low birth weight infants. Current probiotic use prior to and after the Fall of 2023 (when FDA warnings were issued) remains unknown.

STUDY DESIGN

A survey was distributed to the American Academy of Pediatrics Section on Neonatal and Perinatal Medicine (August-November/2022) and Neonatology Solutions' Level III/IV NICUs (January-April/2023). Probiotic administration practices were investigated.

RESULTS

In total, 289 unique NICUs and 406 providers responded to the survey. Of those, 29.1% of NICUs administered prophylactic probiotics to premature neonates, however, this decreased considerably after FDA warnings were issued. Additionally, 71.4% of providers stated willingness to administer probiotics to premature infants if there was an FDA-approved formulation.

CONCLUSIONS

Probiotic use in US NICUs increased between 2015 and the Fall of 2023 and then dropped dramatically following warning letters from the FDA. The introduction of an FDA-approved probiotic may further expand administration.

Care from Birth to Discharge of Infants Born at 22 to 23 Weeks' Gestation

The clinical care of infants born at 22 weeks' gestation must be well-designed and standardized if optimal results are to be expected. Although several approaches to care in this vulnerable population are possible, protocols should be neither random nor inconsistent. We describe the approach taken at the University of Iowa Stead Family Children's Hospital neonatal intensive care unit with respect to preterm infants born at 22 weeks' gestation. We have chosen to present our standardize care plan with respect to prenatal, neurologic, nutritional, gastrointestinal, and skin management. Respiratory and cardiopulmonary care will be briefly reviewed, as these strategies have been published previously.

Age of onset of necrotising enterocolitis (NEC) and focal intestinal perforation (FIP) in very preterm and low birthweight infants: a systematic review

OBJECTIVE

Review of age of onset of necrotising enterocolitis (NEC) and focal intestinal perforation (FIP) in very preterm (≤32 weeks) and/or very low birthweight (VLBW, ≤1500 g) infants.

DESIGN

Preregistered review undertaken according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses in July 2021 and updated October 2021.

DATA SOURCES

MEDLINE/ PubMed, Embase, CINAHL and Cochrane Central Register of Controlled Trials.

ELIGIBILITY

Eligible studies reported age of onset of NEC and/or FIP in randomised controlled trials of >200 or observational studies of >500 infants.

DATA EXTRACTION AND SYNTHESIS

Titles/abstracts were screened; eligible articles underwent data extraction. Age of onset as day of life (DOL) and/or corrected gestational age (CGA) were extracted alongside study information, such as NEC definition, included population, intervention, location and dates studied. Weighted means were used to compare onset by birth gestation, study type, NEC definition, trial intervention, location and dates studied. Comparison was done by Mann-Whitney U test or one-way analysis of variance.

RESULTS

Of the 747 screened studies 188 were eligible. Removal of duplicates, studies without onset data and ineligible populations left 10 RCTs and 14 observational studies contributing 51 NEC cohorts; 49 reported onset DOL and 14 CGA. 2984 cases of NEC had average DOL onset of 16.7 (15.5 in RCTs, 16.9 in observational studies), and CGA onset of 30.1 weeks. Gestation did not impact DOL onset. No other demographic feature impacted NEC onset. Few studies included data on FIP.

CONCLUSIONS

Average onset of NEC in exclusively very preterm/very low birthweight infants is in the third week of life and unlike in cohorts including more mature or heavier infants is not impacted by birth gestation.

A systematic review on selection characterization and implementation of probiotics in human health

Probiotics are live bacteria found in food that assist the body's defence mechanisms against pathogens by reconciling the gut microbiota. Probiotics are believed to aid with gut health, the immune system, and brain function, among other factors. They've furthermore been shown to help with constipation, high blood pressure, and skin issues. The global probiotics market has been incrementally growing in recent years, as consumers' demand for healthy diets and wellness has continued to increase. This has prompted the food industry to develop new probiotic-containing food products, as well as researchers to explore their specific characteristics and impacts on human health. Although most probiotics are fastidious microorganisms that are nutritionally demanding and sensitive to environmental conditions, they become less viable as they are processed and stored. In this review we studied the current literature on the fundamental idea of probiotic bacteria, their medical benefits, and their selection, characterization, and implementations.

Graphical Abstract

Enteral supplementation with probiotics in preterm infants: A retrospective cohort study and 6-year follow-up

The objective of this retrospective cohort study was to assess the impact of an enteral probiotics supplementation protocol on the incidence of necrotizing enterocolitis (NEC) in infants born <33 weeks gestational age (GA) or birth weight (BW) <1,500 g. In addition, a 6-year follow-up is presented after instigation of probiotic use. In October 2014, our NICU introduced an enteral probiotics supplementation protocol for infants born <33 weeks GA or BW <1,500 g. Infants received 0.5 g of Bifidobacterium breve HA-129, Lacticaseibacillus rhamnosus HA-111, Bifidobacterium bifidum HA-132, Bifidobacterium longum subsp. infantis HA-116, and Bifidobacterium longum subsp. longum HA-135 (FloraBABY^Ⓡ) daily until discharge or transfer from hospital. The incidence of NEC was compared among infants for 2 years pre- and post implementation of the protocol then 6-years following continuous implementation of the probiotic use. In total, 370 infants not treated with probiotics between 2012 and 2014 were included with an incidence of NEC at 4.9%. In comparison, the 367 infants who received had a 67% reduction (4.9-1.6%, p = 0.01) in our Neonatal Intensive Care Unit (NICU). The results remained significant (aOR = 0.26; 95% CI: 0.09, 0.72; p < 0.01) after adjusting for GA, small for gestational age, and antenatal corticosteroid use. Data from the Canadian Neonatal Network not only showed a consistently high rate of NEC in October 2014, but also identified exceedingly high rates (8.7-15.6%) in some hospitals up to 2021, while our rates have been consistently low with using the probiotic as standard therapy for low BW premature babies, with no serious side effects reported. In conclusion, the introduction of a five-strain probiotic natural health product has coincided with a reduced incidence and complications of NEC in our NICU setting.

Capturing the antibiotic resistome of preterm infants reveals new benefits of probiotic supplementation

BACKGROUND

Probiotic use in preterm infants can mitigate the impact of antibiotic exposure and reduce rates of certain illnesses; however, the benefit on the gut resistome, the collection of antibiotic resistance genes, requires further investigation. We hypothesized that probiotic supplementation of early preterm infants (born < 32-week gestation) while in hospital reduces the prevalence of antibiotic resistance genes associated with pathogenic bacteria in the gut. We used a targeted capture approach to compare the resistome from stool samples collected at the term corrected age of 40 weeks for two groups of preterm infants (those that routinely received a multi-strain probiotic during hospitalization and those that did not) with samples from full-term infants at 10 days of age to identify if preterm birth or probiotic supplementation impacted the resistome. We also compared the two groups of preterm infants up to 5 months of age to identify persistent antibiotic resistance genes.

RESULTS

At the term corrected age, or 10 days of age for the full-term infants, we found over 80 antibiotic resistance genes in the preterm infants that did not receive probiotics that were not identified in either the full-term or probiotic-supplemented preterm infants. More genes associated with antibiotic inactivation mechanisms were identified in preterm infants unexposed to probiotics at this collection time-point compared to the other infants. We further linked these genes to mobile genetic elements and Enterobacteriaceae, which were also abundant in their gut microbiomes. Various genes associated with aminoglycoside and beta-lactam resistance, commonly found in pathogenic bacteria, were retained for up to 5 months in the preterm infants that did not receive probiotics.

CONCLUSIONS

This pilot survey of preterm infants shows that probiotics administered after preterm birth during hospitalization reduced the diversity and prevented persistence of antibiotic resistance genes in the gut microbiome. The benefits of probiotic use on the microbiome and the resistome should be further explored in larger groups of infants. Due to its high sensitivity and lower sequencing cost, our targeted capture approach can facilitate these surveys to further address the implications of resistance genes persisting into infancy without the need for large-scale metagenomic sequencing. Video Abstract.

Efficacy of Direct or Indirect Use of Probiotics for the Improvement of Maternal Depression during Pregnancy and in the Postnatal Period: A Systematic Review and Meta-Analysis

The mother and infant form a unique bond, with maternal mental health affecting the interactions with the infant and infant behaviours impacting maternal mental health. One of the possible mechanisms influencing maternal mental health is the manipulation of the gut-brain axis by consuming probiotic supplements. Probiotics can also have an indirect influence on maternal mental health via the modulation of the infant microbiome and consequently improving the infant’s health and thus, indirectly leading to an improvement in maternal mood. This systematic review evaluated the efficacy of probiotics on maternal mental health by searching for randomised controlled trials via international databases: Cochrane Library, PubMed, Scopus, ScienceDirect, and Web of Science until January 2022. A meta-analysis was performed using the Cochrane Collaboration methodology where possible. We found seven clinical trials that included the word probiotics and addressed maternal depression and/or anxiety. Of these, five trials investigated the influence of maternal probiotic supplementation on the gut-brain axis. Two trials investigated the indirect influence of probiotics on maternal depression via supplementation of probiotics by infants and subsequent influence on the crying of colicky infants. Meta-analysis of two studies of pregnant and postnatal women and two studies of infants consuming probiotics on the outcome of the Edinburgh Postnatal Depression Scale for mothers showed no statistical difference. The findings indicate that maternal depression is very complex and is influenced by various bidirectional factors. One of the factors that can improve maternal mental health is probiotics, however, careful consideration must be given to correct strain selection as strain-specific effectiveness was observed. Further well-designed, robust clinical studies are warranted.

Clinical implications of preterm infant gut microbiome development

Perturbations to the infant gut microbiome during the first weeks to months of life affect growth, development and health. In particular, assembly of an altered intestinal microbiota during infant development results in an increased risk of immune and metabolic diseases that can persist into childhood and potentially into adulthood. Most research into gut microbiome development has focused on full-term babies, but health-related outcomes are also important for preterm babies. The systemic physiological immaturity of very preterm gestation babies (born earlier than 32 weeks gestation) results in numerous other microbiome-organ interactions, the mechanisms of which have yet to be fully elucidated or in some cases even considered. In this Perspective, we compare assembly of the intestinal microbiome in preterm and term infants. We focus in particular on the clinical implications of preterm infant gut microbiome composition and discuss the prospects for microbiome diagnostics and interventions to improve the health of preterm babies.

The effect of daily probiotics on the incidence and severity of necrotizing enterocolitis in infants with very low birth weight

Background:

Necrotizing enterocolitis remains a leading cause of morbidity and mortality in premature infants. The role of prophylactic probiotics in its prevention is unclear. This study evaluates the effect of routine probiotics on the incidence and severity of necrotizing enterocolitis in infants with very low birth weight in the neonatal intensive care unit.

Methods:

This retrospective cohort study compared infants cared for at a single institution before and after implementation of routine probiotic administration (2014– 2018). Babies born after July 2016 received probiotics containing Bifidobacterium and Lactobacillus daily until 35 weeks corrected gestational age. Baseline characteristics, necrotizing enterocolitis incidence and severity, infections, mortality, and length of stay were compared between groups.

Results:

Of the 665 infants included in the study, 310 received probiotics and 355 did not. The 2 groups did not differ with regard to gestational age, birth anthropometrics, mode of delivery, comorbidities, and type of enteral feed. The incidence of necrotizing enterocolitis (Bell’s stage 2 of 3) was similar between groups (4% v. 5%, p = 0.35), as was its severity (p = 0.10). In addition, there were no significant differences in mortality and length of stay between the groups. Significantly fewer infants receiving probiotics developed infections (27% v. 34%, p = 0.046), with the rate of urinary tract infections having the largest reduction.

Conclusion:

The routine use of Bifidobacterium and Lactobacillus probiotics in infants with very low birth weight did not significantly affect the incidence and severity of necrotizing enterocolitis. However, the use of probiotics was associated with fewer overall infections.

Probiotics, Prebiotics, and Synbiotics for the Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in preterm infants. The exact mechanism by which NEC develops is poorly understood however there is growing evidence to suggest that perturbations in the early-life gut microbiota composition increase the risk for NEC. Modulation of the gut microbiota with probiotics, prebiotics, or in combination (synbiotics) is an area which has attracted intense interest in recent years. In this narrative review, we present an overview of the role of the gut microbiota in the pathogenesis of NEC. We also examine the evidence currently available from randomized controlled trials, observational studies, systematic reviews, and meta-analysis examining the role of probiotics, prebiotics, and synbiotics in reducing the risk of or preventing NEC. Current clinical practice guidelines with recommendations on the routine administration of probiotics to preterm infants for NEC are also explored.

Probiotics, Prebiotics and Epithelial Tight Junctions: A Promising Approach to Modulate Intestinal Barrier Function

Disruptions in the intestinal epithelial barrier can result in devastating consequences and a multitude of disease syndromes, particularly among preterm neonates. The association between barrier dysfunction and intestinal dysbiosis suggests that the intestinal barrier function is interactive with specific gut commensals and pathogenic microbes. In vitro and in vivo studies demonstrate that probiotic supplementation promotes significant upregulation and relocalization of interepithelial tight junction proteins, which form the microscopic scaffolds of the intestinal barrier. Probiotics facilitate some of these effects through the ligand-mediated stimulation of several toll-like receptors that are expressed by the intestinal epithelium. In particular, bacterial-mediated stimulation of toll-like receptor-2 modulates the expression and localization of specific protein constituents of intestinal tight junctions. Given that ingested prebiotics are robust modulators of the intestinal microbiota, prebiotic supplementation has been similarly investigated as a potential, indirect mechanism of barrier preservation. Emerging evidence suggests that prebiotics may additionally exert a direct effect on intestinal barrier function through mechanisms independent of the gut microbiota. In this review, we summarize current views on the effects of pro- and prebiotics on the intestinal epithelial barrier as well as on non-epithelial cell barrier constituents, such as the enteric glial cell network. Through continued investigation of these bioactive compounds, we can maximize their therapeutic potential for preventing and treating gastrointestinal diseases associated with impaired intestinal barrier function and dysbiosis.

Effects of neonatal nutrition interventions on neonatal mortality and child health and development outcomes: A systematic review

Background

The last two decades have seen a significant decrease in mortality for children <5 years of age in low and middle-income countries (LMICs); however, neonatal (age, 0-28 days) mortality has not decreased at the same rate. We assessed three neonatal nutritional interventions that have the potential of reducing morbidity and mortality during infancy in LMICs.

Objectives

To determine the efficacy and effectiveness of synthetic vitamin A, dextrose oral gel, and probiotic supplementation during the neonatal period.

Search Methods

We conducted electronic searches for relevant studies on the following databases: PubMed, CINAHL, LILACS, SCOPUS, and CENTRAL, Cochrane Central Register for Controlled Trials, up to November 27, 2019.

Selection Criteria

We aimed to include randomized and quasi-experimental studies. The target population was neonates in LMICs. The interventions included synthetic vitamin A supplementation, oral dextrose gel supplementation, and probiotic supplementation during the neonatal period. We included studies from the community and hospital settings irrespective of the gestational age or birth weight of the neonate.

Data Collection and Analysis

Two authors screened the titles and extracted the data from selected studies. The risk of bias (ROB) in the included studies was assessed according to the Cochrane Handbook of Systematic Reviews. The primary outcome was all-cause mortality. The secondary outcomes were neonatal sepsis, necrotizing enterocolitis (NEC), prevention and treatment of neonatal hypoglycaemia, adverse events, and neurodevelopmental outcomes. Data were meta-analyzed by random effect models to obtain relative risk (RR) and 95% confidence interval (CI) for dichotomous outcomes and mean difference with 95% CI for continuous outcomes. The overall rating of evidence was determined by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

Main Results

Sixteen randomized studies (total participants 169,366) assessed the effect of vitamin A supplementation during the neonatal period. All studies were conducted in low- and middle-income (LMIC) countries. Thirteen studies were conducted in the community setting and three studies were conducted in the hospital setting, specifically in neonatal intensive care units. Studies were conducted in 10 different countries including India (four studies), Guinea-Bissau (three studies), Bangladesh (two studies), and one study each in China, Ghana, Indonesia, Nepal, Pakistan, Tanzania, and Zimbabwe. The overall ROB was low in most of the included studies for neonatal vitamin A supplementation. The pooled results from the community based randomized studies showed that there was no significant difference in all-cause mortality in the vitamin A (intervention) group compared to controls at 1 month (RR, 0.99; 95% CI, 0.90-1.08; six studies with 126,548 participants, statistical heterogeneity I 2 0%, funnel plot symmetrical, grade rating high), 6 months (RR, 0.98; 95% CI, 0.89-1.07; 12 studies with 154,940 participants, statistical heterogeneity I 2 43%, funnel plot symmetrical, GRADE quality high) and 12 months of age (RR, 1.04; 95% CI, 0.94-1.14; eight studies with 118,376 participants, statistical heterogeneity I 2 46%, funnel plot symmetrical, GRADE quality high). Neonatal vitamin A supplementation increased the incidence of bulging fontanelle by 53% compared to control (RR, 1.53; 95% CI, 1.12-2.09; six studies with 100,256 participants, statistical heterogeneity I 2 65%, funnel plot symmetrical, GRADE quality high). We did not identify any experimental study that addressed the use of dextrose gel for the prevention and/or treatment of neonatal hypoglycaemia in LMIC. Thirty-three studies assessed the effect of probiotic supplementation during the neonatal period (total participants 11,595; probiotics: 5854 and controls: 5741). All of the included studies were conducted in LMIC and were randomized. Most of the studies were done in the hospital setting and included participants who were preterm (born < 37 weeks gestation) and/or low birth weight (<2500 g birth weight). Studies were conducted in 13 different countries with 10 studies conducted in India, six studies in Turkey, three studies each in China and Iran, two each in Mexico and South Africa, and one each in Bangladesh, Brazil, Colombia, Indonesia, Nepal, Pakistan, and Thailand. Three studies were at high ROB due to lack of appropriate randomization sequence or allocation concealment. Combined data from 25 studies showed that probiotic supplementation reduced all-cause mortality by 20% compared to controls (RR, 0.80; 95% CI, 0.66-0.96; total number of participants 10,998, number needed to treat 100, statistical heterogeneity I 2 0%, funnel plot symmetrical, GRADE quality high). Twenty-nine studies reported the effect of probiotics on the incidence of NEC, and the combined results showed a relative reduction of 54% in the intervention group compared to controls (RR, 0.46; 95% CI, 0.35-0.59; total number of participants 5574, number needed to treat 17, statistical heterogeneity I 2 24%, funnel plot symmetrical, GRADE quality high). Twenty-one studies assessed the effect of probiotic supplementation during the neonatal period on neonatal sepsis, and the combined results showed a relative reduction of 22% in the intervention group compared to controls (RR, 0.78; 95% CI, 0.70-0.86; total number of participants 9105, number needed to treat 14, statistical heterogeneity I 2 23%, funnel plot symmetrical, GRADE quality high).

Authors' Conclusions

Vitamin A supplementation during the neonatal period does not reduce all-cause neonatal or infant mortality in LMICs in the community setting. However, neonatal vitamin A supplementation increases the risk of Bulging Fontanelle. No experimental or quasi-experimental studies were available from LMICs to assess the effect of dextrose gel supplementation for the prevention or treatment of neonatal hypoglycaemia. Probiotic supplementation during the neonatal period seems to reduce all-cause mortality, NEC, and sepsis in babies born with low birth weight and/or preterm in the hospital setting. There was clinical heterogeneity in the use of probiotics, and we could not recommend any single strain of probiotics for wider use based on these results. There was a lack of studies on probiotic supplementation in the community setting. More research is needed to assess the effect of probiotics administered to neonates in-home/community setting in LMICs.

Prophylactic Probiotic Supplementation for Preterm Neonates-A Systematic Review and Meta-Analysis of Nonrandomized Studies

Systematic review and meta-analyses of randomized controlled trials (RCTs) show that probiotics reduce the risk of necrotizing enterocolitis (NEC ≥ Stage II), late onset sepsis (LOS), all-cause mortality, and feeding intolerance in preterm neonates. Data from observational studies is important to confirm probiotic effects in clinical practice. We aimed to compare outcomes before and after implementing routine probiotic supplementation (RPS) in preterm neonates (<37 weeks of gestation) by performing a systematic review of non-RCTs using Cochrane methodology. Databases including PubMed, The Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Cochrane Central library, and Google Scholar were searched in May 2020. A meta-analysis was performed using a random effects model. Categorical measure of effect size was expressed as OR and 95% CI. Statistical heterogeneity was assessed by the chi-squared test, I2 statistic. The level of evidence (LOE) was summarized using GRADE (Grading of Recommendations Assessment, Development, and Evaluation) guidelines. Primary outcomes were NEC ≥ Stage II, LOS, and all-cause mortality. Secondary outcomes included probiotic sepsis. Thirty good-quality non-RCTs (n = 77,018) from 18 countries were included. The meta-analysis showed RPS was associated with significantly reduced: 1) NEC ≥ Stage II (30 studies, n = 77,018; OR: 0.60; 95% CI: 0.50, 0.73; P <0.00001, I2: 65%; LOE: Moderate), 2) LOS: (21 studies, n = 65,858; OR: 0.85; 95% CI: 0.74, 0.97; P = 0.02, I2: 74%; LOE: Low), and 3) all-cause mortality (27 non-RCTs, n = 70,977; OR: 0.77; 95% CI: 0.68, 0.88; P = 0.0001, I2: 49%; LOE: Low). Subgroups: 1) extremely low birth weight (ELBW: birth weight <1000 g) neonates: RPS was associated with significantly reduced NEC ≥ Stage II (4.5% compared with 7.9%). However, there was no difference in LOS and mortality. 2) Multistrain RPS was more effective than single strain. One study reported 3 nonfatal cases of probiotic sepsis. In summary, moderate- to low-quality evidence indicates that RPS was associated with significantly reduced NEC ≥ Stage II, LOS, and all-cause mortality in neonates <37 weeks of gestation and NEC ≥ Stage II in ELBW neonates.

Current and Future Perspectives on the Role of Probiotics, Prebiotics, and Synbiotics in Controlling Pathogenic Cronobacter Spp. in Infants

Cronobacter species, in particular C. sakazakii, is an opportunistic bacterial pathogen implicated in the development of potentially debilitating illnesses in infants (<12months old). The combination of a poorly developed immune system and gut microbiota put infants at a higher risk of infection compared to other age groups. Probiotics and prebiotics are incorporated in powdered infant formula and, in addition to strengthening gut physiology and stimulating the growth of commensal gut microbiota, have proven antimicrobial capabilities. Postbiotics in the cell-free supernatant of a microbial culture are derived from probiotics and can also exert health benefits. Synbiotics, a mixture of probiotics and prebiotics, may provide further advantages as probiotics and gut commensals degrade prebiotics into short-chain fatty acids that can provide benefits to the host. Cell-culture and animal models have been widely used to study foodborne pathogens, but sophisticated gut models have been recently developed to better mimic the gut conditions, thus giving a more accurate representation of how various treatments can affect the survival and pathogenicity of foodborne pathogens. This review aims to summarize the current understanding on the connection between Cronobacter infections and infants, as well as highlight the potential efficacy of probiotics, prebiotics, and synbiotics in reducing invasive Cronobacter infections during early infancy.

Routine Administration of a Multispecies Probiotic Containing Bifidobacterium and Lactobacillus to Very Low Birth Weight Infants Had No Significant Impact on the Incidence of Necrotizing Enterocolitis

Background: Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity in preterm infants, and prevention and treatment strategies have remained largely unchanged over the past several decades. As understanding of the microbiome has increased, probiotics have been hypothesized as a possible strategy for decreasing rates of NEC, and several studies have noted significant decreases in rates of NEC after initiation of probiotics in preterm infants. However, a recent AAP report cited caution on the use of probiotic use in part because studies of probiotic use in ELBW infants are lacking. As our unit began routine use of probiotics for all infants <33 weeks in 2015 and we are a leading institution for intact survival of ELBW infants, we attempted to answer if probiotic use can impact the rate of NEC in VLBW and ELBW infants. Methods: We conducted a single-center retrospective chart review of infants with modified Bell's stage ≥2a NEC for the 4 years prior to and 5 years after initiation of a protocol involving routine supplementation of a multispecies probiotic to premature infants at the University of Iowa, Stead Family Children's Hospital. The primary outcome measures were rates of modified Bell's stage ≥2a NEC and all-cause pre-discharge mortality at our institution before and after initiation of routine probiotic supplementation in 2015. Results: In our institution, neither the rates of modified Bell's stage ≥2a NEC, nor the rates of all-cause mortality were significantly altered in very low birth weight (VLBW) infants by the initiation of routine probiotic use (NEC rates pre-probiotic 2.1% vs. post-probiotic 1.5%; all-cause mortality rates pre-probiotic 8.4% vs. post-probiotic 7.4%). Characteristics of our two cohorts were overall similar except for a significantly lower 5-minute APGAR score in infants in the post-probiotic epoch (pre-probiotic 8 vs. post-probiotic 6 p = 0.0316), and significantly more infants in the post-probiotic epoch received probiotics (pre-probiotics 0% vs. post-probiotics 65%; p < 0.0001). Similarly, probiotic use had no impact on the incidence of NEC when we restricted our data to only extremely low birth weight (ELBW) infants (pre-probiotics 1.6% vs post-probiotics 4.1%). When we restricted our analysis to only inborn infants, probiotics still had no impact on NEC rates in VLBW infants (1.5% pre- and 1.1% post-probiotic, p = 0.61) or ELBW infants (2% pre- and 2.1% post-probiotic, p = 0.99) Conclusions: Contrary to other studies, we found no significant difference in rates of modified Bell's stage ≥2a NEC or all-cause pre-discharge mortality in VLBW infants following routine administration of a multispecies probiotic supplement.

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.

Persistence of Suspected Probiotic Organisms in Preterm Infant Gut Microbiota Weeks After Probiotic Supplementation in the NICU

Probiotics are becoming a prevalent supplement to prevent necrotizing enterocolitis in infants born preterm. However, little is known about the ability of these live bacterial supplements to colonize the gut or how they affect endogenous bacterial strains and the overall gut community. We capitalized on a natural experiment resulting from a policy change that introduced the use of probiotics to preterm infants in a single Neonatal Intensive Care Unit. We used amplicon sequence variants (ASVs) derived from the v3 region of the 16S rRNA gene to compare the prevalence and abundance of Bifidobacterium and Lactobacillus in the gut of preterm infants who were and were not exposed to a probiotic supplement in-hospital. Infants were followed to 5 months corrected age. In the probiotic-exposed infants, ASVs belonging to species of Bifidobacterium appeared at high relative abundance during probiotic supplementation and persisted for up to 5 months. In regression models that controlled for the confounding effects of age and antibiotic exposure, probiotic-exposed infants had a higher abundance of the suspected probiotic bifidobacteria than unexposed infants. Conversely, the relative abundance of Lactobacillus was similar between preterm groups over time. Lactobacillus abundance was inversely related to antibiotic exposure. Furthermore, the overall gut microbial community of the probiotic-exposed preterm infants at term corrected age clustered more closely to samples collected from 10-day old full-term infants than to samples from unexposed preterm infants at term age. In conclusion, routine in-hospital administration of probiotics to preterm infants resulted in the potential for colonization of the gut with probiotic organisms post-discharge and effects on the gut microbiome as a whole. Further research is needed to fully discriminate probiotic bacterial strains from endogenous strains and to explore their functional role in the gut microbiome and in infant health.

Bovine Lactoferrin Supplementation Does Not Disrupt Microbiota Development in Preterm Infants Receiving Probiotics

OBJECTIVE

The aim of the study was to assess whether bovine lactoferrin (bLf) supplementation disrupts intestinal microbiota development in preterm infants less than 31 weeks gestational age receiving prophylactic probiotic administration.

METHODS

Subjects were recruited from the LACUNA trial (ISRCTN66482337), designed to assess bLf safety. These subjects were randomized to daily receive either probiotic supplements or probiotics supplemented with 100 mg bLf mixed with their feeds (human milk or formula). Stools were collected weekly from enrolled infants for 1 month and the microbiota characterized using V6-16S rRNA gene amplicon profiling.

RESULTS

Infants' microbiomes did not increase in alpha diversity over time in both feeding interventions. Infants receiving bLf supplementation had overall higher species richness as compared with those not receiving these supplements and lactoferrin supplementation had differing effects on infant microbiota species richness depending on the infant's gestational age. Principal co-ordinate analysis revealed that the infant microbiotas did not separate by intervention group, gestational age bracket at birth or sampling time and the main factor dictating sample clustering was infant identity. There were very few detectable differences in taxa relative abundance or functional gene content between the microbiotas in the 2 study groups.

CONCLUSIONS

Bovine lactoferrin supplementation has minimal impact on microbiota composition/function in preterm infants receiving probiotics, and therefore, is unlikely to disrupt microbiota development.

Probiotic Supplementation During the Perinatal and Infant Period: Effects on Gut Dysbiosis and Disease

The perinatal period is crucial to the establishment of lifelong gut microbiota. The abundance and composition of microbiota can be altered by several factors such as preterm delivery, formula feeding, infections, antibiotic treatment, and lifestyle during pregnancy. Gut dysbiosis affects the development of innate and adaptive immune responses and resistance to pathogens, promoting atopic diseases, food sensitization, and infections such as necrotizing enterocolitis (NEC). Recent studies have indicated that the gut microbiota imbalance can be restored after a single or multi-strain probiotic supplementation, especially mixtures of Lactobacillus and Bifidobacterium strains. Following the systematic search methodology, the current review addresses the importance of probiotics as a preventive or therapeutic tool for dysbiosis produced during the perinatal and infant period. We also discuss the safety of the use of probiotics in pregnant women, preterm neonates, or infants for the treatment of atopic diseases and infections.

Prophylactic antenatal N-Acetyl Cysteine administration combined with postnatal administration can decrease mortality and injury markers associated with necrotizing enterocolitis in a rat model

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of neonates, especially premature neonates. To date, there is no prophylactic treatment against NEC, except breast milk and slow increase in enteral feeding, and there is no antenatal prophylaxis.

AIMS

To assess possible protective effects of antenatal N-Acetyl Cysteine (NAC) against the intestinal pathophysiological changes associated with NEC in a rat model of NEC and against its associated mortality.

METHODS

Newborn Sprague-Dawley rats were divided into 5 groups: control (n = 33); NEC (n = 32)-subjected to hypoxia and formula feeding for 4 days to induce NEC; NEC-NAC (n = 34)-with induced NEC and concomitant postnatal NAC administration; NAC-NEC (n = 33)-born to dams treated with NAC for the last 3 days of pregnancy starting at gestational age of 18 days, and then subjected to induced NEC after birth; NAC-NEC-NAC (n = 36)-subjected to induced NEC with both prenatal and postnatal NAC treatment. At day of life 5, weight and survival of pups in the different groups were examined, and pups were euthanized. Ileal TNF-α, IL-6, IL-1β, IL-10, NFkB p65, iNOS and cleaved caspase 3 protein levels (western blot) and mRNA expression (RT-PCR) were compared between groups.

RESULTS

Pup mortality was significantly reduced in the NAC-NEC-NAC group compared to NEC (11% vs. 34%, P<0.05). Ileal protein levels and mRNA expression of all injury markers tested except IL-10 were significantly increased in NEC compared to control. These markers were significantly reduced in all NAC treatment groups (NEC-NAC, NAC-NEC, and NAC-NEC-NAC) compared to NEC. The most pronounced decrease was observed in the NAC-NEC NAC group.

CONCLUSIONS

Antenatal NAC decreases injury markers and mortality associated with NEC in a rat model. Antenatal administration of NAC may present a novel approach for NEC prophylaxis in pregnancies with risk for preterm birth.

A Quality Improvement Intervention to Reduce Necrotizing Enterocolitis in premature infants with Probiotic Supplementation

Supplemental Digital Content is available in the text.

Necrotizing Enterocolitis (NEC) is a severe intestinal inflammatory disease due to multifactorial causes that present in preterm infants. Compared with similar neonatal intensive care units, our NEC rate was increasing and prompted reduction by a quality improvement (QI) intervention.

Necrotizing Enterocolitis Reduction Using an Exclusive Human-Milk Diet and Probiotic Supplementation in Infants With 1000-1499 Gram Birth Weight

BACKGROUND

Necrotizing enterocolitis (NEC) is a major complication confronting clinicians caring for premature infants. This investigation compares clinical outcomes before and after quality improvement-program interventions in a population of premature infants at intermediate risk for NEC.

METHODS

This study is a retrospective single-center chart review of infants admitted with a birth weight of 1000-1499 g, excluding major congenital anomalies, over a 6-year period, beginning with implementation of a donor breast-milk program when mother's own milk was not available. Infants were separated into 2 epochs, before (July 2012-December 2013) and after (April 2014-June 2018) introduction of human milk-derived fortifier (Prolacta) and a daily probiotic (FloraBABY) supplement.

RESULTS

Comparing 140 preintervention infants with 265 postintervention infants, NEC was significantly lower in the postintervention group: 5.2% vs 1.1% (P = 0.046). Somatic growth was similar in both epochs.

CONCLUSIONS

Quality-improvement initiatives utilizing an exclusive human-milk diet and daily probiotic supplementation were associated with a decreased incidence of NEC in infants with a birth weight of 1000-1499 g. Implementation of the NEC reduction bundle did not affect infant growth.

Implementation of a probiotic protocol to reduce rates of necrotizing enterocolitis

OBJECTIVE

To utilize a probiotic protocol to achieve a 50% reduction in rates of necrotizing enterocolitis (NEC) ≥ Bell Stage 2 within 2 years of protocol implementation.

STUDY DESIGN

Literature review guided probiotic selection and protocol design. A driver diagram identified key drivers to achieve our aim. A U chart followed monthly NEC ≥ Bell Stage 2 per 100 patient days and per monthly admissions. The process measure was protocol compliance and the balancing measure was probiotic sepsis.

RESULTS

NEC ≥ Bell Stage 2 decreased from 0.14 to 0.04 per 100 patient days in infants < 33 weeks gestation or <1500 g, or a yearly rate of 7-2%. Protocol compliance was 98% and there were no cases of probiotic sepsis.

CONCLUSION

Implementation of a probiotic protocol was associated with a decrease in rates of NEC.

A national survey of the enteral feeding practices in Canadian neonatal intensive care units

Aim

Nutrition affects the growth and neurodevelopmental outcomes of preterm infants, yet controversies exist about the optimal enteral feeding regime. The objective of this study was to compare enteral feeding guidelines in Canadian neonatal intensive care units (NICUs).

Method

The research team identified key enteral feeding practices of interest. Canadian Neonatal Network site investigators at 30 Level 3 NICUs were contacted to obtain a copy of their 2016 to 2017 feeding guidelines for infants who weighed less than 1,500 g at birth. Each guideline was reviewed to compare recommendations around the selected feeding practices.

Results

Five of the 30 NICUs did not have a feeding guideline. The other 25 NICUs used 22 different enteral feeding guidelines. The guidelines in 40% of those NICUs recommend commencing minimal enteral nutrition (MEN) within 24 hours of birth and maintaining that same feeding volume for 24 to 96 hours. In 40% of NICUs, the guideline recommended that MEN be initiated at a volume of 5 to 10 mL/kg/day for infants born at <1,000 g. Guidelines in all 25 NICUs recommend the use of bovine-based human milk fortifier (HMF), and in 56% of NICUs, it is recommended that HMF be initiated at a total fluid intake of 100 mL/kg/day. Guidelines in only 16% of NICUs recommended routine gastric residual checks. Donor milk and probiotics are used in 76% and 72% of the 25 NICUs, respectively.

Conclusion

This study revealed substantial variability in recommended feeding practices for very low birth weight infants, underscoring the need to establish a national feeding guideline for this vulnerable group.

Historical aspects of probiotic use to prevent necrotising enterocolitis in preterm babies

Over the last few decades, numerous studies have evaluated probiotic use for the prevention of necrotising enterocolitis in preterm babies. Early 'proof of concept' studies evaluating whether probiotics are capable of colonising the preterm gut have translated into multiple observational studies, small and large randomised controlled trials. Some show evidence of benefit while others have produced disappointing results. In this paper, we review the history of probiotic use in preterm babies for NEC prevention in an attempt to explain why uncertainty exists and why this intervention has not been universally adopted into routine neonatal practice.

To start or not: Factors to consider when implementing routine probiotic use in the NICU

Supplementation of probiotics to very low birth weight (VLBW) infants has been extensively studied, with multiple meta-analyses reporting probiotics decrease the risk of necrotizing enterocolitis (NEC) and death. Despite availability of this evidence, the decision to initiate routine probiotic supplementation to preterm infants continues to be a complex one. There are uncertainties regarding the use of probiotics, including selecting the appropriate product, dose and target population. Additionally, availability of specific probiotic products and regulatory oversight varies by country, raising concerns regarding the safety and efficacy of specific probiotic products. In this review, we summarize the latest evidence on probiotic use in preterm infants and discuss considerations that may help guide clinicians who are considering routine probiotic supplementation.

Types, Frequency, Duration, and Dosage of Probiotics to Prevent Necrotizing Enterocolitis in Preterm Infants Among Countries

BACKGROUND

Probiotic use in the neonatal intensive care unit (NICU) has been linked to reduced rates of necrotizing enterocolitis in preterm infants. Currently, in the United States, probiotic use within the NICU is limited despite being commonly used in other countries.

PURPOSE

To provide an overview of the current practices of using probiotics in preterm infants for the prevention of NEC in the NICU in preselected countries.

METHODS

A comprehensive literature search was conducted on PubMed and clinicaltrials.gov. Also, studies from 2 recent meta-analyses on the topic were reviewed for inclusion. Selection criteria were as follows: studies involving preterm infants using probiotics in the NICU, reporting on the impact of probiotic use on the incidence of necrotizing enterocolitis, published within the last 10 years and in the English language, and originating from the United States, Canada, or any European country.

RESULTS

Twenty-three studies were selected. The most common types of probiotics used were Bifidobacterium infantis and Lactobacillus rhamnosus. The most common frequency of administration was daily or twice day. Duration ranged from 10 days to the entire NICU stay. The dosage was commonly 1 billion colony-forming units daily but ranged from 12 million daily to 12 billion per kilogram daily.

IMPLICATIONS FOR PRACTICE

Examining the current practices of probiotic use in the NICU provides useful information as this adjunctive therapy rises in popularity.

IMPLICATIONS FOR RESEARCH

Refining methods of probiotic research for necrotizing enterocolitis prevention will improve safety and effectiveness and provide a framework for future clinical trials.

The impact of probiotics and lactoferrin supplementation on piglet gastrointestinal microbial communities

Probiotics and lactoferrin are currently being used in neonatal intensive care units in the hopes of reducing rates of sepsis and necrotizing enterocolitis (NEC). While studies have shown that these measures can be clinically beneficial to premature babies, and there are ongoing trials to measure their impact on NEC and sepsis rates, little is known about how they may impact microbiota development. We thus employed a newborn piglet model to assess the impact of feeding probiotics or a combination of probiotics and lactoferrin on development of the gastrointestinal microbiota. Healthy full-term piglets were fed either probiotics alone or probiotics and a bovine lactoferrin supplement over the first weeks of life, and their microbiota profiles were compared with unsupplemented controls. We found that both probiotic and probiotic plus lactoferrin treatments impacted the microbial composition within the gastrointestinal tract, with differing impacts on various regions within the gut. In addition, the impact of probiotics was often reversed by the presence of lactoferrin and both feeding interventions altered the microbiota's genetic propensity to use ferric versus ferrous ions. These results suggest that iron availability may be a key factor to consider when designing feeding interventions that target the microbiome.

Probiotics for preterm infants: A National Retrospective Cohort Study

OBJECTIVE

To evaluate the effect of prophylactic probiotic (PP) administration on rates of necrotizing enterocolitis (NEC), late-onset sepsis (LOS), and mortality in preterm infants.

STUDY DESIGN

We conducted a retrospective cohort study of infants < 29 weeks' gestation, admitted to neonatal intensive care units participating in the Canadian Neonatal Network between 1 January 2014 and 31 December 2015. Infants in the exposure group received PP. A multiple logistic regression model with generalized estimation equation was used.

RESULTS

A total of 3093 infants were included, 652 infants (21%) received PP. The adjusted odds ratios (aOR) of NEC (aOR 0.64, 95% confidence interval [CI] 0.410, 0.996), mortality (aOR 0.41, 95% CI 0.26, 0.63), and a composite of NEC or mortality were significantly lower in the PP group. There was no significant difference in the aOR of LOS.

CONCLUSION

Prophylactic probiotic administration is associated with a reduction in NEC and mortality in preterm infants.

Probiotics for preterm infants - time to end all controversies

Mortality, necrotising enterocolitis (NEC), late onset sepsis (LOS) and feeding intolerance are significant issues for very preterm (< 32 weeks) and extremely preterm (< 28 weeks) infants. The complications of ≥ Stage II NEC [e.g. Resection of the gangrenous gut, survival with intestinal failure, recurrent infections, prolonged hospital stay, and long-term neurodevelopmental impairment (NDI)] impose a significant health burden. LOS also carries significant burden including long-term NDI due to adverse effects of inflammation on the preterm brain during the critical phase of development. Frequent stopping of feeds due to feeding intolerance is a significant iatrogenic contributor to postnatal growth failure in extremely preterm infants. Over 25 systematic reviews and meta-analyses of RCTs (~12 000 participants) have reported that probiotics significantly reduce the risk of all-cause mortality, NEC ≥ Stage II, LOS and feeding intolerance in preterm infants. Systematic reviews and meta-analysis of non-RCTs have also shown that the benefits after adopting probiotics as a standard prophylaxis for preterm infants are similar to those reported in RCTs. No intervention comes close to probiotics when it comes to significant reduction in death, NEC, LOS and feeding intolerance at a cost of less than a dollar a day irrespective of the setting and baseline incidence of NEC. The common controversies that are preventing the rapid uptake of probiotics for preterm infants are addressed in this paper.

The availability of probiotics and donor human milk is associated with improved survival in very preterm infants

BACKGROUND

To determine whether the introduction of pasteurized donor human milk and probiotics for infants born < 32 weeks gestational age or < 1500 g birthweight is associated with a reduction in mortality and the incidence of necrotising enterocolitis (NEC) and sepsis.

METHODS

We performed a retrospective analysis of two cohorts: before and after the introduction of probiotics and pasteurised donor human milk. Univariate analysis of primary and secondary outcomes was performed; variables impacting outcomes were assessed using multivariate logistic regression.

RESULTS

There were 1791 infants: 1334 in the pre-donor milk/probiotic cohort and 457 in the post-donor milk/probiotic cohort. On univariate analysis, mortality (7.6 vs. 2.4%, P < 0.001) and incidence of sepsis (6.2 vs. 3.5%, P = 0.028) were statistically significantly lower in the post-donor milk/probiotic group. NEC (2.8 vs. 1.5%, P = 0.14) and non-NEC associated gastrointestinal perforation (1.6 vs. 0.4%, P = 0.052) were lower in the post-donor milk/probiotics cohort, but these were not statistically significant. The difference in mortality remained statistically significant on multivariate analysis in the post-donor milk/probiotic cohort compared to those in the pre-donor milk/probiotic cohort (odds ratio 0.31, 95% confidence interval 0.16-0.61). The decrease in the incidence of NEC was consistent with previous observational studies but the difference was not statistically significant.

CONCLUSION

The availability of probiotics and pasteurised donor human milk is associated with a reduction in mortality in very preterm infants.

Para-probiotics for Preterm Neonates-The Next Frontier

Current evidence supports the use of probiotics in preterm neonates for prevention of necrotizing enterocolitis, mortality and late onset sepsis. Despite the strong evidence, the uptake of this intervention has not been universal due to concerns including probiotic sepsis, pro-inflammatory response and transmission of antibiotic resistance. Critically ill extremely preterm neonates with potentially compromised gut integrity are at higher risk of probiotic sepsis due to translocation. In most countries, probiotics are sold as food supplements with poor quality control. The traditional definition of probiotics as &ldquo;live microorganisms&rdquo; has been challenged as many experts have questioned the importance of viability in the context of the beneficial effects of probiotics. Paraprobiotics (ghost probiotics), are defined as non-viable microbial cells (intact or broken) or crude cell extracts (i.e., with complex chemical composition), which, when administered (orally or topically) in adequate amounts, confer a benefit on the human or animal consumer. Current evidence indicates that paraprobiotics could be safe alternatives to probiotics in preterm neonates. High-quality pre-clinical and clinical studies including adequately powered randomised controlled trials (RCTs) are warranted in preterm neonates to explore this new frontier.

Standardized slow enteral feeding protocol reduces necrotizing enterocolitis in micropremies

BACKGROUND

Compared to early enteral feeds, delayed introduction and slow enteral feeding advancement to reduce necrotizing enterocolitis (NEC) is not well studied in micropremies (<750g birth weight).

METHODS

Pre-post case control study. Micropremies who followed a standardized slow enteral feeding (SSEF) protocol (September 2009 to March 2015) were compared with a similar group of historical controls (PreSSEF, January 2003 to July 2009). Enteral feeding withheld for first 10-14 days and advanced at <10 ml/kg/day in the SSEF group.

RESULTS

Ninety-two infants in the SSEF group were compared with 129 PreSSEF group. Birth weight and gestational age in SSEF and PreSSEF were similar. Breast milk initiation rate was higher in SSEF (87.0 vs. 72.0%, p = 0.01) compared to PreSSEF, but were similar at full enteral feeds. Compared with PreSSEF, feeding initiation day, full enteral feeding day, parenteral nutrition days, and total central line days were longer in SSEF. There was significant reduction in NEC (1.1 vs. 16.2%, p < 0.01), surgical NEC (0.0 vs. 7.8%, p < 0.01) and NEC/death (7.6 vs. 29.5%, p < 0.01), in SSEF compared to PreSSEF. SSEF, compared to PreSSEF, had more cholestasis (41.8 vs 28.8%, p = 0.04), higher peak serum alkaline phosphatase (638 vs. 534 IU/dL, p < 0.01), but similar rates of late-onset sepsis (39.1 vs 43.4%, p = 0.53). In infants who survived to discharge, SSEF had higher discharge weight, lower extra-uterine growth restriction, and similar length of stay, compared to PreSSEF.

CONCLUSIONS

A SSEF protocol significantly reduces the incidence of NEC and combined NEC/death in micropremies.

Systematic Review of the Effect of Enteral Feeding on Gut Microbiota in Preterm Infants

OBJECTIVE

To examine the effect of feeding type on microbial patterns among preterm infants and to identify feeding factors that promote the colonization of beneficial bacteria.

DATA SOURCES

PubMed, Cochrane Database of Systematic Reviews, Scopus, and the Cummulative Index of Nursing and Allied Health Literature were thoroughly searched for articles published between January 2000 and January 2017, using the keywords gut microbiome, gut microbiota, enteral microbiome, enteral microbiota, premature infant, preterm infant, extremely low birth weight infant, ELBW infant, very low birth weight infant, feeding, breast milk, breastfeeding, formula, prebiotic, probiotic, and long chain polyunsaturated fatty acid.

STUDY SELECTION

Primary studies written in English and focused on the association between enteral feeding and gut microbiome patterns of preterm infants were included in the review.

DATA EXTRACTION

We independently reviewed the selected articles and extracted information using predefined data extraction criteria including study design, study participants, type of feeding, type and frequency of biospecimen (e.g., feces, gastric aspirate) collection, microbiological analysis method, and major results.

DATA SYNTHESIS

In 4 of the 18 studies included in the review, researchers described the effects of milk products (mothers' own milk, donor human milk, and formula). In 5 studies, the effects of prebiotics were assessed, and in 9 studies, the effects of probiotics on the gut microbiome were described. Mothers' own breast milk feeding influenced the compositional structure of preterm infants' gut microbial community and increased diversity of gut microbiota compared with donor human milk and formula feeding. The results of the use of prebiotics and probiotics varied among studies; however, the majority of the researchers reported positive bifidogenic effects on the development of beneficial bacteria.

CONCLUSION

Mothers' own milk is considered the best form of nutrition for preterm infants and the gut microbial community. Variation in fatty acid composition across infant feeding types can affect microbial composition. The evidence for supplementation of prebiotics and probiotics to promote the gut microbial community structure is compelling; however, additional research is needed in this area.

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.

Probiotics and necrotizing enterocolitis

In this review, we summarize existing knowledge regarding the effects of probiotics on necrotizing enterocolitis (NEC). We review the role of the microbiome in NEC and pre-clinical data on mechanisms of probiotic action. Next, we summarize existing randomized controlled trials and observational studies of probiotics to prevent NEC. We also summarize findings from several recent meta-analyses and report a new cumulative meta-analysis of probiotic trials. Finally, we review data from cohorts routinely using commercially available probiotics. Our goal is to inform clinicians about the risks and benefits of probiotics, which may be helpful for those considering use in preterm infants to prevent NEC, death, or sepsis.

The Neurodevelopmental Perspective of Surgical Necrotizing Enterocolitis: The Role of the Gut-Brain Axis

This state-of-the-art review article aims to highlight the most recent evidence about the therapeutic options of surgical necrotizing enterocolitis, focusing on the molecular basis of the gut-brain axis in relevance to the neurodevelopmental outcomes of primary peritoneal drainage and primary laparotomy. Current evidence favors primary laparotomy over primary peritoneal drainage as regards neurodevelopment in the surgical treatment of necrotizing enterocolitis. The added exposure to inhalational anesthesia in infants undergoing primary laparotomy is an additional confounding variable but requires further study. The concept of the gut-brain axis suggests that bowel injury initiates systemic inflammation potentially affecting the developing central nervous system. Signals about microbes in the gut are transduced to the brain and the limbic system via the enteric nervous system, autonomic nervous system, and hypothalamic-pituitary axis. Preterm infants with necrotizing enterocolitis have significant differences in the diversity of the microbiome compared with preterm controls. The gut bacterial flora changes remarkably prior to the onset of necrotizing enterocolitis with a predominance of pathogenic organisms. The type of initial surgical approach correlates with the length of functional gut and microbiome equilibrium influencing brain development and function through the gut-brain axis. Existing data favor patients who were treated with primary laparotomy over those who underwent primary peritoneal drainage in terms of neurodevelopmental outcomes. We propose that this is due to the sustained injurious effect of the remaining diseased and necrotic bowel on the developing newborn brain, in patients treated with primary peritoneal drainage, through the gut-brain axis and probably not due to the procedure itself.

Benefits of probiotics in preterm neonates in low-income and medium-income countries: a systematic review of randomised controlled trials

OBJECTIVE

Although there is an overall reduction in underfive mortality rate, the progress in reducing neonatal mortality rate has been very slow. Over the last 20 years, preterm births have steadily increased in low-income and medium-income countries (LMICs) particularly in sub-Saharan Africa and South Asia. Preterm birth is associated with increased mortality and morbidity, particularly in LMICs. Based on systematic reviews of randomised controlled trials (RCTs), many neonatal units in high-income countries have adopted probiotics as standard of care for preterm neonates. We aimed to systematically review the safety and efficacy of probiotics in reducing mortality and morbidity in preterm neonates in LMICs.

DESIGN

Systematic review and meta-analysis of RCTs.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature and E-abstracts from Pediatric Academic Society meetings and other paediatric and neonatal conference proceedings were searched in January 2017.

ELIGIBILITY CRITERIA

RCTs comparing probiotics versus placebo/no probiotic in preterm neonates (gestation<37 weeks) conducted in LMICs.

RESULTS

Total 23 (n=4783) RCTs from 4 continents and 10 LMICs were eligible for inclusion in the meta-analysis using fixed effect model. The risk of necrotising enterocolitis (NEC greater than or equal to stage II) (risk ratio (RR) 0.46 (95% CI 0.34 to 0.61), P<0.00001, numbers needed to treat (NNT) 25 (95% CI 20 to 50)), late-onset sepsis (LOS) (RR 0.80 (95% CI 0.71 to 0.91), P=0.0009, NNT 25 (95% CI 17 to 100)) and all-cause mortality (RR 0.73 (95% CI 0.59 to 0.90), P=0.003, NNT 50 (95% CI 25 to 100)) were significantly lower in probiotic supplemented neonates. The results were significant on random effects model analysis and after excluding studies with high risk of bias. No significant adverse effects were reported.

CONCLUSION

Probiotics have significant potential to reduce mortality and morbidity (eg, NEC, LOS) in preterm neonates in LMICs.

Probiotic supplementation in preterm infants does not affect the risk of retinopathy of prematurity: a meta-analysis of randomized controlled trials

Retinopathy of prematurity (ROP) is a vascular disorder of the developing retina in preterm infants and is a leading cause of childhood blindness. Perinatal infection plays a pathogenic role in ROP. Probiotic supplementation reduces the risk of late onset sepsis (LOS) in preterm infants but it remains to be determined whether this reduction translates into a reduction of other complications. We conducted a systematic review and meta-analysis to evaluate the possible role of probiotics in altering the risk of ROP. Eleven randomized controlled trials (4250 infants; probiotics: 2121) were included in the meta-analysis that showed a significantly decreased rate of LOS with a risk ratio (RR) of 0.807 and a 95% confidence interval (CI) of 0.705 to 0.924 (P = 0.010; fixed effects model) but could not demonstrate a significant effect of probiotics on any stage ROP (RR 1.053, 95% CI 0.903 to 1.228, P = 0.508, 4 studies), or severe ROP (RR 0.841, 95% CI 0.666 to 1.063, P = 0.148, 9 studies). Meta-regression did not show any significant association between the RR for LOS and the RR for severe ROP. In conclusion, our results suggest that infection prevention by probiotics does not affect the risk of developing ROP in preterm infants.

Reducing Incidence of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a multifactorial disease that occurs when multiple risk factors and/or stressors overlap, leading to profound inflammation and intestinal injury. Due to its multifactorial nature, there has been much uncertainty in identifying clear strategies for prevention of NEC. Despite these obstacles, the incidence of NEC has gradually been decreasing over the past 10 years, in part due to quality improvement (QI) initiatives to prevent NEC. Current QI strategies primarily target the various predisposing conditions. This article reviews the evidence on which QI interventions to prevent NEC have been based and provides examples of successful QI interventions.

Women and Their Microbes: The Unexpected Friendship

Communities of microbiota have been associated with numerous health outcomes, and while much emphasis has been placed on the gastrointestinal niche, there is growing interest in the microbiome specific for female reproductive health and the health of their offspring. The vaginal microbiome plays an essential role not only in health and dysbiosis, but also potentially in successful fertilization and healthy pregnancies. In addition, microbial communities have been isolated from formerly forbidden sterile niches such as the placenta, breast, uterus, and Fallopian tubes, strongly suggesting an additional microbial role in women's health. A combination of maternally linked prenatal, birth, and postnatal factors, together with environmental and medical interventions, influence early and later life through the microbiome. Here, we review the role of microbes in female health focusing on the vaginal tract and discuss how male and female reproductive microbiomes are intertwined with conception and how mother-child microbial transfer is a key determinant in infant health, and thus the next generation.

The Microbiota of the Extremely Preterm Infant

Colonization of the extremely preterm infant's gastrointestinal tract and skin begins in utero and is influenced by a variety of factors, the most important including gestational age and environmental exposures. The composition of the intestinal and skin microbiota influences the developing innate and adaptive immune responses with short-term and long-term consequences including altered risks for developing necrotizing enterocolitis, sepsis, and a wide variety of microbe-related diseases of children and adults. Alteration of the composition of the microbiota to decrease disease risk is particularly appealing for this ultra-high-risk cohort that is brand new from an evolutionary standpoint.

Selective method for identification and quantification of Bifidobacterium animalis subspecies lactis BB-12 (BB-12) from the gastrointestinal tract of healthy volunteers ingesting a combination probiotic of BB-12 and Lactobacillus rhamnosus GG

AIM

To develop a novel validated method for the isolation of Bifidobacterium animalis ssp. lactis BB-12 (BB-12) from faecal specimens and apply it to studies of BB-12 and Lactobacillus rhamnosus GG (LGG) recovered from the healthy human gastrointestinal (GI) tract.

METHODS AND RESULTS

A novel method for isolating and enumerating BB-12 was developed based on its morphologic features of growth on tetracycline-containing agar. The method identified BB-12 correctly from spiked stool close to 100% of the time as validated by PCR confirmation of identity, and resulted in 97-104% recovery of BB-12. The method was then applied in a study of the recovery of BB-12 and LGG from the GI tract of healthy humans consuming ProNutrients^® Probiotic powder sachet containing BB-12 and LGG. Viable BB-12 and LGG were recovered from stool after 21 days of probiotic ingestion compared to baseline. In contrast, no organisms were recovered 21 days after baseline in the nonsupplemented control group.

CONCLUSIONS

We demonstrated recovery of viable BB-12, using a validated novel method specific for the isolation of BB-12, and LGG from the GI tract of healthy humans who consumed the probiotic supplement.

SIGNIFICANCE AND IMPACT OF THE STUDY

This method will enable more detailed and specific studies of BB-12 in probiotic supplements, including when in combination with LGG.

Impact of probiotics on necrotizing enterocolitis

A large number of randomized placebo-controlled clinical trials and cohort studies have demonstrated a decrease in the incidence of necrotizing enterocolitis with administration of probiotic microbes. These studies have prompted many neonatologists to adopt routine prophylactic administration of probiotics while others await more definitive studies and/or probiotic products with demonstrated purity and stable numbers of live organisms. Cross-contamination and inadequate sample size limit the value of further traditional placebo-controlled randomized controlled trials. Key areas for future research include mechanisms of protection, optimum probiotic species or strains (or combinations thereof) and duration of treatment, interactions between diet and the administered probiotic, and the influence of genetic polymorphisms in the mother and infant on probiotic response. Next generation probiotics selected based on bacterial genetics rather than ease of production and large cluster-randomized clinical trials hold great promise for NEC prevention.

Probiotics in early life: a preventative and treatment approach

Microbial colonization of the infant gut plays a key role in immunological and metabolic pathways impacting human health. Since the maturation of the gut microbiota coincides with early life development, failure to develop a health compatible microbiota composition may result in pathology and disease in later life. Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. Maternal transfer of microorganisms is possible during pregnancy and lactation, and the mother's diet and microbiota can influence that of her offspring. Furthermore, pre-term birth, Caesarean section birth, formula feeding, antibiotic use, and malnutrition have been linked to dysbiosis, which in turn is associated with several pathologies such as necrotizing enterocolitis, inflammatory bowel diseases, antibiotic associated diarrhea, colic, and allergies. Thus, early life should represent a preferred stage of life for probiotic interventions. In this context, they could be regarded as a means to 'program' the individual for health maintenance, in order to prevent pathologies associated with dysbiosis. In order to elucidate the mechanisms underlying the benefits of probiotic administration, pre-clinical studies have been conducted and found an array of positive results such as improved microbial composition, intestinal maturation, decreased pathogenic load and infections, and improved immune response. Moreover, specific probiotic strains administered during the perinatal period have shown promise in attenuating severity of necrotizing enterocolitis. The mechanisms elucidated suggest that probiotic interventions in early life can be envisaged for disease prevention in both healthy offspring and offspring at risk of chronic disease.

The "Golden Age" of Probiotics: A Systematic Review and Meta-Analysis of Randomized and Observational Studies in Preterm Infants

BACKGROUND

Over the last few years, probiotics have been one of the most studied interventions in neonatal medicine.

OBJECTIVES

The aim of this work was to analyse all studies (randomized controlled trials, RCTs, and observational studies) assessing the use of probiotics in very low birth weight (VLBW) preterm infants.

SEARCH METHODS

A systematic literature search was conducted using PubMed, Embase, Cochrane Library, and Web of Science. The data from RCTs and observational studies were pooled and analysed separately.

SELECTION CRITERIA

RCTs and observational studies that enrolled VLBW infants with enteral administration of probiotics were considered. Extracted study data included probiotic characteristics and at least 1 clinical outcome (necrotizing enterocolitis [NEC], late-onset sepsis or all-cause mortality).

DATA COLLECTION AND ANALYSIS

Forty-four studies were eligible for our review: 30 RCTs and 14 observational studies. Severe NEC rates (stage II or more) and all-cause mortality were reduced among the probiotic groups in both the RCTs (RR 0.57, 95% CI 0.47-0.70, and RR 0.77, 95% CI 0.65-0.92, respectively) and the observational studies (RR 0.51, 95% CI 0.37-0.70, and RR 0.71, 95% CI 0.62-0.81, respectively). Furthermore, there was a 12% reduction in the risk of sepsis in RCTs and a 19% reduction in observational studies. The meta-analysis of observational studies showed a reduction in the risk of NEC in extremely low birth weight infants. However, this was not statistically significant.

CONCLUSIONS

This meta-analysis of RCT and observational studies found that the use of probiotics was beneficial for the prevention of severe NEC, late-onset sepsis, and all-cause mortality in VLBW infants.

Perinatal Microbiomes' Influence on Preterm Birth and Preterms' Health: Influencing Factors and Modulation Strategies

Microbial communities inhabiting the human host play important roles in maintaining health status, including reproduction and early life programming, which is particularly important in the context of preterm neonates' health. Preterm birth (PTB) is often the result of a microbial dysbiosis or infection. In addition, preterm neonates experience different levels of organ immaturity and an abnormal gut microbiota establishment, as compared to full-term neonates. This exacerbates their developmental problems and can have negative consequences at systemic level. In addition, preterm babies are commonly exposed to delayed enteral feeding and hospital environments, which increases the risk of short- and long-term health problems. Some of these clinical conditions, such as necrotizing enterocolitis or sepsis, may be life threatening, whereas others may translate into life-long conditions, including cognitive problems. Increasing scientific interest has focused on understanding developmental problems in preterm neonates related to abnormalities in the settlement of their microbial communities, with the final goal of selecting appropriate microbiome-targeted strategies (eg, probiotics), to reduce preterm health risks and improve overall quality of life.This review aims to summarize current knowledge on microbiological factors influencing PTB initiation and gastrointestinal development, and on the health consequences to the preterm neonate. Scientific evidences on dietary strategies reducing PTB incidence and minimizing sequelae in this particularly sensitive human group subpopulation are also discussed.