Probiotics for preterm neonates: what will it take to change clinical practice?

Role of the microbiome in pathophysiology of necrotising enterocolitis in preterm neonates

Although necrotising enterocolitis (NEC) is a serious, life-threatening disease, improved neonatal care is increasing the number of survivors with NEC among extremely preterm neonates. Therapy is nevertheless mostly symptomatic and the mortality rate remains high, especially among neonates requiring surgery. Therefore, it is important to focus on preventing the disease and modifiable risk factors. NEC's pathophysiology is multifaceted, with key factors being immaturity of the immune and barrier protective mechanisms of the premature gut and exaggerated proinflammatory reaction to insults like gut hypoxia, enteral nutrition or microbial dysbiosis. The role of the intestinal microbiome in the pathophysiology of NEC has been a subject of research for many years, but to date no specific pathogen or type of dysbiosis has been connected with NEC development. This review assesses current knowledge as to the role of the intestinal microbiota in the pathophysiology of NEC and the possibilities for positively influencing it.

Association of Hospital Adoption of Probiotics With Outcomes Among Neonates With Very Low Birth Weight

Importance

For neonates with very low birth weight (VLBW), randomized clinical trials (RCTs) indicate that probiotic treatment decreases the risk of necrotizing enterocolitis (NEC), with smaller decreases in the risk of sepsis and death. There is little evidence on the rate of probiotic adoption in US neonatal intensive care units (NICUs) and whether the benefits seen in trials have materialized in practice.

Objective

To estimate changes in probiotic use among neonates with VLBW and to test whether neonates with VLBW treated at NICUs adopting routine probiotic use experience better outcomes compared with neonates treated at nonadopting NICUs.

Design, Setting, and Participants

This cohort study used Vermont Oxford Network data on neonates with VLBW in US NICUs from January 1, 2012, to December 31, 2019. Data were analyzed from January 2022 through February 2023.

Exposure

Probiotics adoption vs nonadoption. Adopting NICUs were defined as those that currently or previously treated at least 20% of neonates with VLBW with probiotics.

Main Outcomes

The primary outcomes were rates of NEC, in-hospital mortality, and sepsis, defined as bacterial or fungal infection occurring after day 3 from birth. A difference-in-differences analysis compared changes in VLBW infant outcomes between adopting and nonadopting NICUs before and after hospital-level adoption of probiotics. Additional analyses used the proportion of neonates treated with probiotics in each neonate's birth NICU and year.

Results

The analysis included 307 905 neonates with VLBW (mean [SD] gestational age, 28.4 [2.9] weeks; 50.0% male) at 807 US hospitals. The rate of probiotic treatment of neonates with VLBW rose from 1572 of 38 296 neonates (4.1%) in 2012 to 4788 of 37 910 (12.6%) in 2019. Only 123 of 745 NICUs (16.5%) adopted probiotics by 2019, with 4591 of 6017 neonates with VLBW (76.3%) receiving probiotics in 2019 at adopting NICUs. Incidence of NEC declined by 18% at adopting NICUs (odds ratio [OR], 0.82; 95% CI, 0.70-0.95; P = .10) compared with nonadopting NICUs. Probiotic adoption was not associated with a significant reduction in sepsis (OR, 1.11; 95% CI, 0.98-1.25; P = .09) or mortality (OR, 0.93; 95% CI, 0.80-1.08; P = .33).

Conclusion and Relevance

In this cohort study, adoption of routine use of probiotics increased slowly in US NICUs and was associated with lower NEC risk but not with sepsis or mortality among neonates with VLBW. The findings for probiotic adoption and NEC, sepsis, and mortality were smaller than would have been predicted by the totality of RCT evidence but are consistent with a meta-analysis restricted to studies at low risk of bias.

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.

Supplementation with a probiotic mixture accelerates gut microbiome maturation and reduces intestinal inflammation in extremely preterm infants

Probiotics are increasingly administered to premature infants to prevent necrotizing enterocolitis and neonatal sepsis. However, their effects on gut microbiome assembly and immunity are poorly understood. Using a randomized intervention trial in extremely premature infants, we tested the effects of a probiotic product containing four strains of Bifidobacterium species autochthonous to the infant gut and one Lacticaseibacillus strain on the compositional and functional trajectory of microbiome. Daily administration of the mixture accelerated the transition into a mature, term-like microbiome with higher stability and species interconnectivity. Besides infant age, Bifidobacterium strains and stool metabolites were the best predictors of microbiome maturation, and structural equation modeling confirmed probiotics as a major determinant for the trajectory of microbiome assembly. Bifidobacterium-driven microbiome maturation was also linked to an anti-inflammatory intestinal immune milieu. This demonstrates that Bifidobacterium strains are ecosystem engineers that lead to an acceleration of microbiome maturation and immunological consequences in extremely premature infants.

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.

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.

Synbiotics use for preventing sepsis and necrotizing enterocolitis in very low birth weight neonates: a randomized controlled trial

BACKGROUND

Probiotics and prebiotics have strain-specific effects on the host. Synbiotics, a mixture of probiotics and prebiotics, are proposed to have more beneficial effects on the host than either agent has alone.

PURPOSE

We performed a randomized controlled trial to investigate the effect of Lactobacillus and Bifidobacterium together with oligosaccharides and lactoferrin on the development of necrotizing enterocolitis (NEC) or sepsis in very low birth weight neonates.

METHODS

Neonates with a gestational age ≤32 weeks and birth weight ≤1,500 g were enrolled. The study group received a combination of synbiotics and lactoferrin, whereas the control group received 1 mL of distilled water as placebo starting with the first feed until discharge. The outcome measures were the incidence of NEC stage ≥2 or late-onset cultureproven sepsis and NEC stage ≥2 or death.

RESULTS

Mean birth weight and gestational age of the study (n=104) and the control (n=104) groups were 1,197±235 g vs. 1,151±269 g and 29±1.9 vs. 28±2.2 weeks, respectively (P>0.05). Neither the incidence of NEC stage ≥2 or death, nor the incidence of NEC stage ≥2 or late-onset culture-proven sepsis differed between the study and control groups (5.8% vs. 5.9%, P=1; 26% vs. 21.2%, P=0.51). The only significant difference was the incidence of all stages of NEC (1.9% vs. 10.6%, P=0.019).

CONCLUSION

The combination of synbiotics and lactoferrin did not reduce NEC severity, sepsis, or mortality.

Probiotics and Preterm Infants: A Position Paper by the European Society for Paediatric Gastroenterology Hepatology and Nutrition Committee on Nutrition and the European Society for Paediatric Gastroenterology Hepatology and Nutrition Working Group for Probiotics and Prebiotics

More than 10,000 preterm infants have participated in randomised controlled trials on probiotics worldwide, suggesting that probiotics in general could reduce rates of necrotising enterocolitis (NEC), sepsis, and mortality. Answers to relevant clinical questions as to which strain to use, at what dosage, and how long to supplement are, however, not available. On the other hand, an increasing number of commercial products containing probiotics are available from sometimes suboptimal quality. Also, a large number of units around the world are routinely offering probiotic supplementation as the standard of care despite lacking solid evidence. Our recent network meta-analysis identified probiotic strains with greatest efficacy regarding relevant clinical outcomes for preterm neonates. Efficacy in reducing mortality and morbidity was found for only a minority of the studied strains or combinations. In the present position paper, we aim to provide advice, which specific strains might potentially be used and which strains should not be used. In addition, we aim to address safety issues of probiotic supplementation to preterm infants, who have reduced immunological capacities and occasional indwelling catheters. For example, quality reassurance of the probiotic product is essential, probiotic strains should be devoid of transferable antibiotic resistance genes, and local microbiologists should be able to routinely detect probiotic sepsis. Provided all safety issues are met, there is currently a conditional recommendation (with low certainty of evidence) to provide either Lactobacillus rhamnosus GG ATCC53103 or the combination of Bifidobacterium infantis Bb-02, Bifidobacterium lactis Bb-12, and Streptococcus thermophilus TH-4 in order to reduce NEC rates.

The Application of Metabolomics to Probiotic and Prebiotic Interventions in Human Clinical Studies

There is an ever-increasing appreciation for our gut microbiota that plays a crucial role in the maintenance of health, as well as the development of disease. Probiotics are live bacteria that are consumed to increase the population of beneficial bacteria and prebiotics are dietary substrates intended to promote the propagation of beneficial bacteria. In order to optimize the use of probiotics and prebiotics, a more complete biochemical understanding of the impact that these treatments have on the community and functioning of the gut microbiota is required. Nucleic acid sequencing methods can provide highly detailed information on the composition of the microbial communities but provide less information on the actual function. As bacteria impart much of their influence on the host through the production of metabolites, there is much to be learned by the application of metabolomics. The focus of this review is on the use of metabolomics in the study of probiotic and prebiotic treatments in the context of human clinical trials. Assessment of the current state of this research will help guide the design of future studies to further elucidate the biochemical mechanism by which probiotics and prebiotics function and pave the way toward more personalized applications.

Effect of Synthetic Vitamin A and Probiotics Supplementation for Prevention of Morbidity and Mortality during the Neonatal Period. A Systematic Review and Meta-Analysis of Studies from Low- and Middle-Income Countries

Background: Suboptimal nutritional status of a newborn is a risk factor for short- and long-term morbidity and mortality. The objectives of this review were to assess the efficacy and effectiveness of neonatal synthetic vitamin A supplementation, dextrose gel and probiotic supplementation for prevention of morbidity and mortality during infancy in low and middle-income countries. Methods: We included randomized trials. Primary outcome was all-cause mortality. We conducted electronic searches on multiple databases. Data were meta-analyzed to obtain relative risk (RR) and 95% confidence interval (CI). Studies for vitamin A and Probiotics were analyzed separately. No studies were found for dextrose gel supplementation during neonatal period. The overall rating of evidence was determined by Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Results: Sixteen studies assessed the effect of vitamin A supplementation during the neonatal period. Based on pooled data from community-based studies only, there was no significant effect of vitamin A on all-cause mortality at age 1 month (RR 0.99, 95% CI 0.90, 1.08), 6 months (RR 0.98; 95% CI 0.89-1.08) and 12 months (RR 1.04, 95% CI 0.94, 1.14) but increased risk of bulging fontanelle (RR 1.53, 95% CI 1.12, 2.09). The overall quality of evidence was high for the above outcomes. Thirty-three studies assessed the effect of probiotic supplementation during the neonatal period and were mostly conducted in the hospital setting. Probiotics reduced the risk of all-cause mortality (RR 0.80, 95% CI 0.66, 0.96), necrotizing enterocolitis (RR 0.46, 95% CI 0.35, 0.59) and neonatal sepsis (RR 0.78, 95% CI 0.70, 0.86). The grade ratings for the above three outcomes were high. Conclusions: Vitamin A supplementation during the neonatal period does not reduce all-cause neonatal or infant mortality in low and middle-income countries in the community setting. Probiotic supplementation during the neonatal period seems to reduce all-cause mortality, NEC, and sepsis in babies born low birth weight and/or preterm in the hospital setting.

Lactobacillus reuteri DSM 17938 Improves Feeding Intolerance in Preterm Infants

PURPOSE

Feeding tolerance is extremely important in preterm infants. This study aimed to evaluate whether preterm infants receiving Lactobacillus reuteri DSM 17938 would develop fewer symptoms of feeding intolerance. Secondary outcomes were duration of parenteral nutrition, time to reach full feeding, length of hospital stay, sepsis, necrotizing enterocolitis (NEC), diarrhea, and mortality.

METHODS

This double-blind randomized controlled trial of L. reuteri DSM 17938 versus placebo included 94 neonates with a gestational age of 28-34 weeks and birth weight of 1,000-1,800 g.

RESULTS

Feeding intolerance (vomiting and/or distension) was less common in the probiotic group than in the placebo group (8.5% vs. 25.5%; relative risk, 0.33; 95% confidence interval, 0.12-0.96; p=0.03). No significant intergroup differences were found in proven sepsis, time to reach full feeding, length of hospital stay, or diarrhea. The prevalence of NEC (stages 2 and 3) was 6.4% in the placebo group vs. 0% in the probiotic group (relative risk, 1.07; 95% confidence interval, 0.99-1.15; p=0.24). Mortality rates were 2.1% in the probiotic group and 8.5% in the placebo group, p=0.36).

CONCLUSION

The administration of L. reuteri DSM 17938 to preterm infants was safe and significantly reduced feeding intolerance. No significant differences were found in any other secondary outcomes.

Preventive strategies and factors associated with surgically treated necrotising enterocolitis in extremely preterm infants: an international unit survey linked with retrospective cohort data analysis

OBJECTIVES

To compare necrotising enterocolitis (NEC) prevention practices and NEC associated factors between units from eight countries of the International Network for Evaluation of Outcomes of Neonates, and to assess their association with surgical NEC rates.

DESIGN

Prospective unit-level survey combined with retrospective cohort study.

SETTING

Neonatal intensive care units in Australia/New Zealand, Canada, Finland, Israel, Spain, Sweden, Switzerland and Tuscany (Italy).

PATIENTS

Extremely preterm infants born between 24⁰ to 28⁶ weeks' gestation, with birth weights<1500 g, and admitted between 2014-2015.

EXPOSURES

NEC prevention practices (probiotics, feeding, donor milk) using responses of an on-line pre-piloted questionnaire containing 10 questions and factors associated with NEC in literature (antenatal steroids, c-section, indomethacin treated patent ductus arteriosus and sepsis) using cohort data.

OUTCOME MEASURES

Surgical NEC rates and death following NEC using cohort data.

RESULTS

The survey response rate was 91% (153 units). Both probiotic provision and donor milk availability varied between 0%-100% among networks whereas feeding initiation and advancement rates were similar in most networks. The 9792 infants included in the cohort study to link survey results and cohort outcomes, revealed similar baseline characteristics but considerable differences in factors associated with NEC between networks. 397 (4.1%) neonates underwent NEC surgery, ranging from 2.4%-8.4% between networks. Standardised ratios for surgical NEC were lower for Australia/New Zealand, higher for Spain, and comparable for the remaining six networks.

CONCLUSIONS

The variation in implementation of NEC prevention practices and in factors associated with NEC in literature could not be associated with the variation in surgical NEC incidence. This corroborates the current lack of consensus surrounding the use of preventive strategies for NEC and emphasises the need for research.

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.

Practice variations and rates of late onset sepsis and necrotizing enterocolitis in very preterm born infants, a review

The burden of late onset sepsis (LOS) and necrotizing enterocolitis (NEC) remains high for newborns in low- and high-income countries. Very preterm born infants born below 32 weeks gestation are at highest risk because their immune system is not yet adapted to ex-utero life, providing intensive care frequently compromises their skin or mucosa and they require a long duration of hospital stay. An epidemiological overview is difficult to provide because there is no mutually accepted definition available for either LOS or NEC. LOS incidence proportions are generally reported based on identified blood culture pathogens. However, discordance in minimum day of onset and whether coagulase negative staphylococci or fungi should be included into the reported proportions lead to variation in reported incidences. Complicating the comparison are the absence of biomarkers, ancillary lab tests or prediction models with sufficiently high positive and/or negative predictive values. The only high negative predictive values result from negative blood culture results with negative lab results allowing to discontinue antibiotic treatment. Similar difficulties exist in reporting and diagnosing NEC. Although most publications base their proportions on a modified version of Bell's stage 2 or 3, comparisons are made difficult by the multifactorial nature of the disease reflecting several pathways to intestinal necrosis, the absence of a reliable biomarker and the unclear differentiation from spontaneous intestinal perforations. Comparable reports in very low birthweight infants range between 5% and 30% for LOS and 1.6% to 7.1% for NEC. Evidence based guidelines to support treatment are missing. Treatment for LOS remains largely empirical and focused mainly on antibiotics. In the absence of a clear diagnosis, even unspecific early warning signals need to be met with antibiotic treatment. Cessation after negative blood culture is difficult unless the child was asymptomatic from the beginning. As a result, antibiotics are the most commonly prescribed medications, but unnecessary exposure may result in increased risk for mortality, NEC, further infections and childhood obesity or asthma. Finding ways to limit antibiotic use are thus important and have shown a large potential for improvement of care and limitation of cost. Over recent decades, none of the attempts to establish novel therapies have succeeded. LOS and NEC proportions remained mostly stable. During the past 10 years however, publications emerged reporting a reduction, sometimes by almost 50%. Most concern units participating in a surveillance system using quality improvement strategies to prevent LOS or NEC (e.g., hand hygiene, evidence based "bundles", feeding onset, providing own mother's milk). We conclude that these approaches display a potential for wider spread reduction of LOS and NEC and for a subsequently more successful development of novel therapies as these often address the same pathways as the prevention strategies.

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.

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 Role of Probiotics in the Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a frequent and severe life-threatening disease affecting the gastrointestinal tract of preterm infants. Given that NEC occurs in a well-defined population of patients, there might be a considerable benefit in identifying specific pharmacological and nutritional preventive strategies, that could reduce the incidence of NEC. Amongst nutritional strategies emphasis has been put on the use of probiotics. Therefore, the aim of this review is to summarize currently available evidence on the role of probiotics in general, as well as the role of specific probiotic strains or their combinations, in the prevention of NEC.

Strategies for the Preservation, Restoration and Modulation of the Human Milk Microbiota. Implications for Human Milk Banks and Neonatal Intensive Care Units

Studies carried in the last years have revealed that human milk contains a site-specific microbiota and constitutes a source of potentially beneficial bacteria to the infant gut. Once in the infant gut, these bacteria contribute to the assembly of a physiological gut microbiota and may play several functions, contributing to infant metabolism, protection against infections, immunomodulation or neuromodulation. Many preterm neonates are fed with pasteurized donor’s human milk (DHM) or formula and, therefore, are devoid of contact with human milk microbes. As a consequence, new strategies are required to allow the exposition of a higher number of preterm infants to the human milk microbiota early in life. The first strategy would be to promote and to increase the use of own mother’s milk (OMM) in Neonatal Intensive Care Units (NICUs). Even small quantities of OMM can be very valuable since they would be added to DHM in order to microbiologically “customize” it. When OMM is not available, a better screening of donor women, including routine cytomegalovirus (CMV) screening of milk, may help to avoid the pasteurization of the milk provided by, at least, a relevant proportion of donors. Finally, when pasteurized DHM or formula are the only feeding option, their supplementation with probiotic bacteria isolated from human milk, such as lactic acid bacteria or bifidobacteria, may be an alternative to try to restore a human milk-like microbiota before feeding the babies. In the future, the design of human milk bacterial consortia (minimal human milk microbiotas), including well characterized strains representative of a healthy human milk microbiota, may be an attractive strategy to provide a complex mix of strains specifically tailored to this target population.

Probiotic Lactococcus lactis decreases incidence and severity of necrotizing enterocolitis in a preterm animal model

BACKGROUND

Necrotizing enterocolitis (NEC) persists as the most common and serious gastrointestinal disorder among premature infants. Lactococcus lactis (LL), a lactic acid producing bacteria commonly found in buttermilk and cheese products, has several unique properties making it an ideal probiotic for neonates. We evaluated if the probiotic LL prevents development of NEC in a preterm rabbit model with Cronobacter sakazakii (CS).

METHODS

Two-day preterm New Zealand white rabbit pups were randomly assigned to three diets: control (no additives), CS, and CS+LL. Pups were gavage fed and given daily oral ranitidine and indomethacin. Anal blockage was performed using tissue adhesive. Subjects were sacrificed on day four, with tissue from distal ileum and proximal colon graded for NEC by a pediatric pathologist blinded to group assignments. Outcomes were compared using Fisher's exact test.

RESULTS

All pups in the control group survived to sacrifice and none developed NEC. Survival was 26% higher (p = 0.03) and incidence of NEC 51% less (P < 0.001) in CS+LL group compared to CS group. Of the pups that developed NEC, all pups in the CS+LL group had Grade 1 NEC, while one-third of pups in the CS group developed Grades 2-4 NEC.

CONCLUSIONS

In the presence of CS, LL is protective against development of NEC in a preterm rabbit model. Future studies are needed that evaluate utilization of prophylactic probiotics in the neonatal intensive care unit to determine if this intervention can successfully decrease rates of NEC in preterm infants.

Clinical Outcomes Related to the Gastrointestinal Trophic Effects of Erythropoietin in Preterm Neonates: A Systematic Review and Meta-Analysis

Erythropoietin (EPO) plays an important role in the development and maturation of the gastrointestinal tract. Recombinant EPO (rEPO) has been used to prevent anemia of prematurity. The gastrointestinal trophic effects of EPO may reduce feeding intolerance and necrotizing enterocolitis (NEC) in preterm neonates. The aim of this systematic review of randomized controlled trials (RCTs) was to evaluate the effects of rEPO on clinical outcomes such as feeding intolerance, stage II or higher NEC, any stage NEC, sepsis, retinopathy of prematurity, and bronchopulmonary dysplasia in preterm neonates. Twenty-five RCTs (intravenous: 13; subcutaneous: 10; enteral: 2; n = 4025) were eligible for inclusion. Meta-analysis of data from 17 RCTs (rEPO compared with placebo) with the use of a fixed-effects model showed no significant effect of rEPO on stage II or higher NEC (RR: 0.87; 95% CI: 0.64, 1.19; P = 0.39). Meta-analysis of data from 25 RCTs (rEPO compared with placebo) showed that rEPO significantly decreased the risk of any stage NEC [cases/total sample: 120/2058 (5.83%) compared with 146/1967 (7.42%); RR: 0.77; 95% CI: 0.61, 0.97; P = 0.03]. Only one RCT reported on time to full feedings. Meta-analysis of data from 15 RCTs showed a significant reduction in late-onset sepsis after rEPO administration (RR: 0.81; 95% CI: 0.71, 0.94; P = 0.004). Meta-analysis of 13 RCTs showed no significant effect of rEPO on mortality, retinopathy of prematurity, and bronchopulmonary dysplasia. Prophylactic rEPO had no effect on stage II or higher NEC, but it reduced any stage NEC, probably by reducing feeding intolerance, which is often labeled as stage I NEC. Adequately powered RCTs are required to confirm these findings.

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.

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.

Role of delayed cord clamping in prevention of necrotizing enterocolitis in preterm neonates: a systematic review

BACKGROUND

Necrotizing enterocolitis (NEC) is one of the leading causes of neonatal mortality and morbidity particularly in very-low-birth-weight (VLBW) neonates. The incidence of NEC varies across countries and neonatal centers in between 7% and 14%.

AIMS

The aim of this study is to evaluate the role of delayed cord clamping (DCC) for prevention of NEC in preterm neonates.

METHOD

The literature search was done for various randomized control trial (RCT) by searching the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, EMBASE, ongoing clinical trials, and abstract of conferences.

RESULTS

This review included six RCTs that fulfilled inclusion criteria. There was statistically significant reduction in the incidence of NEC in DCC group (12.2% versus 20.6%; risk ratio (RR) 0.59; 95% CI 0.37-0.94; p = .02; number needed to treat (NNT) 12). However, mortality due to any cause before hospital discharge was not statistically significant (RR 0.80; 95% CI 0.33-2.00; p = .64).

CONCLUSION

The role of DCC in the prevention of NEC is supported by the current evidences. However, given the small sample sizes and other limitations of these studies, current evidences are not sufficient. We need large high-quality trials, with sufficient power to reliably assess clinically relevant differences in important outcomes.

Standardized feeding regimen for reducing necrotizing enterocolitis in preterm infants: an updated systematic review

OBJECTIVE

A systematic review (2005) of observational studies has reported 87% reduction in the incidence of necrotizing enterocolitis (NEC) after introducing standardized feeding regimen (SFR) in preterm infants. Considering the many new studies in this field since 2005 and the continued health burden of NEC, we aimed to systematically review the incidence of NEC in preterm infants 'before' vs 'after' implementing a SFR.

STUDY DESIGN

PubMed, EMBASE, CINAHL and E-abstracts from the Pediatric Academic Society meetings and other pediatric and neonatal conference proceedings were searched in May 2016. Observational studies reporting incidence of NEC before and after implementing a SFR were included. Relevant data were extracted independently by two reviewers. Meta-analysis was conducted using random effects model (REM) and results rechecked with fixed effects model.

RESULTS

Pooled results from 15 observational studies (N=18 160) using REM showed that SFR significantly reduced the incidence of NEC (risk ratio 0.22; 95% confidence interval 0.13 to 0.36; P<0.00001; I2=74%). The results remained significant after comparing studies in two epochs (1978 to 2003 vs 2004 to 2016).

CONCLUSION

SFR continues to be an important tool in prevention of NEC in preterm 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.

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

Necrotizing enterocolitis (NEC) is a devastating intestinal disease in preterm infants characterized by barrier disruption, intestinal microbial dysbiosis, and persistent inflammation of the colon, which results in high mortality rates. Current strategies used to manage this disease are not sufficient, although the use of human breast milk reduces the risk of NEC. Mother's milk is regarded as a fundamental nutritional source for neonates, but pasteurization of donor breast milk affects the composition of bioactive compounds. Current research is evaluating the benefits and potential pitfalls of adding probiotics and prebiotics to pasteurized milk so as to improve the functionality of the milk and thereby reduce the burden of illness caused by NEC. Probiotics (live micro-organisms that confer health to the host) and prebiotics (nondigestible oligosaccharides that stimulate the growth of healthy bacteria) are functional foods known to mediate immune responses and modulate microbial populations in the gut. Clinical research shows strain- and compound-specific responses when probiotics or prebiotics are administered in conjunction with donor breast milk for the prevention of NEC. Despite ongoing controversy surrounding optimal treatment strategies, randomized controlled studies are now investigating the use of synbiotics to reduce the incidence and severity of NEC. Synbiotics, a combination of probiotics and prebiotics, have been proposed to enhance beneficial health effects in the intestinal tract more than either agent administered alone. This review considers the implications of using probiotic-, prebiotic-, and synbiotic-supplemented breast milk as a strategy to prevent NEC and issues that could be encountered with the preparations.

Necrotising enterocolitis and mortality in preterm infants after introduction of probiotics: a quasi-experimental study

Evidence on the clinical effectiveness of probiotics in the prevention of necrotising enterocolitis (NEC) in preterm infants is conflicting and cohort studies lacked adjustment for time trend and feeding type. This study investigated the association between the introduction of routine probiotics (Lactobacillus acidophilus and Bifidobacterium bifidum; Infloran(®)) on the primary outcome 'NEC or death'. Preterm infants (gestational age <32 weeks or birth weight <1500 gram) admitted before (Jan 2008-Sep 2012; n = 1288) and after (Oct 2012-Dec 2014; n = 673) introduction of probiotics were compared. Interrupted time series logistic regression models were adjusted for confounders, effect modification by feeding type, seasonality and underlying temporal trends. Unadjusted and adjusted analyses showed no difference in 'NEC or death' between the two periods. The overall incidence of NEC declined from 7.8% to 5.1% (OR 0.63, 95% CI 0.42-0.93, p = 0.02), which was not statistically significant in the adjusted models. Introduction of probiotics was associated with a reduced adjusted odds for 'NEC or sepsis or death' in exclusively breastmilk-fed infants (OR 0.43, 95% CI 0.21-0.93, p = 0.03) only. We conclude that introduction of probiotics was not associated with a reduction in 'NEC or death' and that type of feeding seems to modify the effects of probiotics.

Barriers to Knowledge Translation Regarding the Use of Probiotics as a Risk-Reduction Strategy for Necrotizing Enterocolitis

BACKGROUND

Increasingly, evidence supports enteral probiotics are an important risk-reduction strategy for necrotizing enterocolitis (NEC) among very low birth-weight and extremely low birth-weight preterm infants. Yet, the majority of providers remain reluctant to implement practice changes.

PURPOSE

The aim of this study was to better understand the discrepancy between the available evidence and clinical practice regarding the use of probiotics and other NEC prevention strategies in New Jersey.

METHODS

Using an exploratory descriptive design, a multimodal interprofessional survey was developed and executed to elicit intensive care nursery provider knowledge, views, and current practice.

RESULTS

Although the sample size was small (N = 29), approximately one-half of respondents familiar with the literature rated the quality of the evidence regarding probiotics as "above average" to "excellent." These respondents were "very likely" to "extremely likely" to recommend probiotics as an NEC prevention strategy; however, none actually prescribed this intervention. The most important reason respondents did not prescribe probiotics was the focus on providing exclusive maternal and donor breast milk feedings. Other confounding factors included provision of oral colostrum care, standardized feeding protocols, and withholding feedings during blood transfusion.

IMPLICATIONS FOR PRACTICE

Study results suggested that some providers (primarily nurses) were not familiar with probiotic literature, which may contribute to deficits in knowledge translation to practice.

IMPLICATIONS FOR RESEARCH

Areas for future study include identifying improved mechanisms for knowledge dissemination, recognizing and addressing barriers and facilitators to knowledge translation, and understanding how probiotics fit and/or contrast with other NEC risk-reduction strategies in the research and clinical settings.

Safety assessment of the Clostridium butyricum MIYAIRI 588® probiotic strain including evaluation of antimicrobial sensitivity and presence of Clostridium toxin genes in vitro and teratogenicity in vivo

Probiotics are live microorganisms ingested for the purpose of conferring a health benefit on the host. Development of new probiotics includes the need for safety evaluations that should consider factors such as pathogenicity, infectivity, virulence factors, toxicity, and metabolic activity. Clostridium butyricum MIYAIRI 588® (CBM 588®), an anaerobic spore-forming bacterium, has been developed as a probiotic for use by humans and food animals. Safety studies of this probiotic strain have been conducted and include assessment of antimicrobial sensitivity, documentation of the lack of Clostridium toxin genes, and evaluation of CBM 588® on reproductive and developmental toxicity in a rodent model. With the exception of aminoglycosides, to which anaerobes are intrinsically resistant, CBM 588® showed sensitivity to all antibiotic classes important in human and animal therapeutics. In addition, analysis of the CBM 588® genome established the absence of genes for encoding for α, β, or ε toxins and botulin neurotoxins types A, B, E, or F. There were no deleterious reproductive and developmental effects observed in mice associated with the administration of CBM 588®. These data provide further support for the safety of CBM 588® for use as a probiotic in animals and humans.

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.

Impact of oral probiotics on neurodevelopmental outcomes in preterm infants

OBJECTIVE

The aim of the study was to evaluate the neurodevelopment outcomes of very low birth weight (VLBW) preterm infants supplemented with oral probiotics for the prevention of necrotizing enterocolitis (NEC).

METHODS

A prospective follow-up study was performed in a cohort of VLBW preterm infants enrolled in a single center randomized controlled clinical trial to evaluate the efficacy of oral probiotics for the prevention of NEC. Cognitive and neuromotor developments were assessed by using the Bayley scales of infant development II. Sensory and neurological performance was evaluated by standard techniques. The primary outcome was neurodevelopmental impairment at 18-24 months' corrected age.

RESULTS

A total of 400 infants completed the trial protocol. Of the 370 infants eligible for follow-up, 249 infants (124 in the probiotics group and 125 in the control group) were evaluated. There was no significant difference in any of the neurodevelopmental and sensory outcomes between the two groups.

CONCLUSION

Oral probiotic given to VLBW infants to reduce the incidense and severity of NEC started with the first feed did not affect neuromotor, neurosensory and cognitive outcomes at 18-24 months' corrected age.

Benefits of Bifidobacterium breve M-16V Supplementation in Preterm Neonates - A Retrospective Cohort Study

Background

Systematic reviews of randomised controlled trials report that probiotics reduce the risk of necrotising enterocolitis (NEC) in preterm neonates.

Aim

To determine whether routine probiotic supplementation (RPS) to preterm neonates would reduce the incidence of NEC.

Methods

The incidence of NEC ≥ Stage II and all-cause mortality was compared for an equal period of 24 months ‘before’ (Epoch 1) and ‘after’ (Epoch 2) RPS with Bifidobacterium breve M-16V in neonates <34 weeks. Multivariate logistic regression analysis was conducted to adjust for relevant confounders.

Results

A total of 1755 neonates (Epoch I vs. II: 835 vs. 920) with comparable gestation and birth weights were admitted. There was a significant reduction in NEC ≥ Stage II: 3% vs. 1%, adjusted odds ratio (aOR) = 0.43 (95%CI: 0.21–0.87); ‘NEC ≥ Stage II or all-cause mortality’: 9% vs. 5%, aOR = 0.53 (95%CI: 0.32–0.88); but not all-cause mortality alone: 7% vs. 4%, aOR = 0.58 (95% CI: 0.31–1.06) in Epoch II. The benefits in neonates <28 weeks did not reach statistical significance: NEC ≥ Stage II: 6% vs. 3%, aOR 0.51 (95%CI: 0.20–1.27), ‘NEC ≥ Stage II or all-cause mortality’, 21% vs. 14%, aOR = 0.59 (95%CI: 0.29–1.18); all-cause mortality: 17% vs. 11%, aOR = 0.63 (95%CI: 0.28–1.41). There was no probiotic sepsis.

Conclusion

RPS with Bifidobacterium breve M-16V was associated with decreased NEC≥ Stage II and ‘NEC≥ Stage II or all-cause mortality’ in neonates <34 weeks. Large sample size is required to assess the potential benefits of RPS in neonates <28 weeks.

Bifidobacterium longum subsp. infantis BB-02 attenuates acute murine experimental model of inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions, characterised by remissions and relapses episodes, whose main manifestations are ulcerative colitis and Crohn's disease. Ulcerative colitis (UC), one of the main forms of IBD, has as standard treatment the use of corticosteroids and anti-inflammatory drugs. The use of antibiotics has been also reported, but the possible adverse effects, such as disturbance of the indigenous microbiota or resistance induction, should be taken into consideration, and thus the use of probiotics emerges as a possible alternative option of treatment. In this study, the oral administration of Bifidobacterium longum subsp. infantis BB-02 was evaluated as a preventive strategy for acute experimental UC induced in female BALB/c mice by ingestion of 3.5% dextran sulphate sodium in drinking water during 7 days. During this time, the daily disease activity index was evaluated, and on the seventh day the animals were euthanised to collect intestines and liver for analysis. Treatment with the probiotic resulted in clinical improvement of the animals. The histological and morphometric analyses showed a reduction of lesions and oedema in the gut, but there was no increase in the production of mucin. The dosage of secretory immunoglobulin A was significantly higher in the colitis group and reduced in the group treated with the probiotic. There was also a reduction in the inflammation of the colon, as demonstrated by a decrease in neutrophils infiltration, and KC/CXCL-1 levels. The intestinal permeability, which is typically increased during the onset of IBD, was also reduced by treatment with probiotic. Based on these data, it can be concluded that the bacterium B. infantis BB-02 has a probiotic potential for the attenuation of UC, but further studies should be conducted to verify the mechanism of protective action of the bacterium.

Validating bifidobacterial species and subspecies identity in commercial probiotic products

BACKGROUND

The ingestion of probiotics to attempt to improve health is increasingly common; however, quality control of some commercial products can be limited. Clinical practice is shifting toward the routine use of probiotics to aid in prevention of necrotizing enterocolitis in premature infants, and probiotic administration to term infants is increasingly common to treat colic and/or prevent atopic disease. Since bifidobacteria dominate the feces of healthy breast-fed infants, they are often included in infant-targeted probiotics.

METHODS

We evaluated 16 probiotic products to determine how well their label claims describe the species of detectable bifidobacteria in the product. Recently developed DNA-based methods were used as a primary means of identification, and were confirmed using culture-based techniques.

RESULTS

We found that the contents of many bifidobacterial probiotic products differ from the ingredient list, sometimes at a subspecies level. Only 1 of the 16 probiotics perfectly matched its bifidobacterial label claims in all samples tested, and both pill-to-pill and lot-to-lot variation were observed.

CONCLUSION

Given the known differences between various bifidobacterial species and subspecies in metabolic capacity and colonization abilities, the prevalence of misidentified bifidobacteria in these products is cause for concern for those involved in clinical trials and consumers of probiotic products.

Prophylactic Probiotics for Preterm Infants: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Necrotizing enterocolitis (NEC) is a major morbidity and cause of mortality in preterm neonates. Probiotics seem to have a beneficial role in preventing NEC, which is confirmed in meta-analyses of randomized controlled trials (RCTs). We therefore aimed to review and confirm the efficacy of probiotics in preterm neonates obtained in observational studies.

OBJECTIVE

To assess the effects of prophylactic probiotics in preterm infants.

METHODS

A meta-analysis was performed searching PubMed, EMBASE, CENTRAL (the Cochrane Library) and www.clinicaltrials.gov. Reference lists of reviews of RCTs were also searched. Included studies were observational studies that enrolled preterm infants <37 weeks of gestational age. Trials were included if they administered any probiotics and measured at least one clinical outcome (e.g. NEC, all-cause mortality, sepsis or long-term development scores). Two authors extracted characteristics and outcomes from included studies. The Newcastle-Ottawa Scale was used for quality assessment. A random-effects meta-analysis model was used, and heterogeneity was assessed by the I2 test.

RESULTS

We included 12 studies with 10,800 premature neonates (5,144 receiving prophylactic probiotics and 5,656 controls). The meta-analysis showed a significantly decreased incidence of NEC (risk ratio, RR = 0.55, 95% confidence interval, 95% CI, 0.39-0.78; p = 0.0006) and mortality (RR = 0.72, 95% CI, 0.61-0.85; p < 0.0001). Sepsis did not differ significantly between the two groups (RR = 0.86, 95% CI, 0.74-1.00; p = 0.05).

CONCLUSIONS

Probiotic supplementation reduces the risk of NEC and mortality in preterm infants. The effect sizes are similar to findings in meta-analyses of RCTs. However, the optimal strain, dose and timing need further investigation.

Routine Use of Probiotics in Preterm Infants: Longitudinal Impact on the Microbiome and Metabolome

BACKGROUND

Probiotics are live microbial supplements that colonize the gut and potentially exert health benefit to the host.

OBJECTIVES

We aimed to determine the impact of a probiotic (Infloran®: Lactobacillus acidophilus-NCIMB701748 and Bifidobacterium bifidum-ATCC15696) on the bacterial and metabolic function of the preterm gut while in the neonatal intensive care unit (NICU) and following discharge.

METHODS

Stool samples (n = 88) were collected before, during, and after probiotic intake from 7 patients, along with time-matched controls from 3 patients. Samples were also collected following discharge home from the NICU. Samples underwent bacterial profiling analysis by 16S rRNA gene sequencing and quantitative PCR (qPCR), as well as metabolomic profiling using liquid chromatography mass spectrometry.

RESULTS

Bacterial profiling showed greater Bifidobacterium (15.1%) and Lactobacillus (4.2%) during supplementation compared to the control group (4.0% and 0%, respectively). While Lactobacillus became reduced after the probiotic had been stopped, Bifidobacterium remained high following discharge, suggestive of successful colonisation. qPCR analysis showed a significant increase (p ≤ 0.01) in B. bifidum in infants who received probiotic treatment compared to controls, but no significant increase was observed for L. acidophilus (p = 0.153). Metabolite profiling showed clustering based on receiving probiotic or matched controls, with distinct metabolites associated with probiotic administration.

CONCLUSIONS

Probiotic species successfully colonise the preterm gut, reducing the relative abundance of potentially pathogenic bacteria, and effecting gut functioning. Bifidobacterium (but not Lactobacillus) colonised the gut in the long term, suggesting the possibility that therapeutically administered probiotics may continue to exert important functional effects on gut microbial communities in early infancy.

Bifidobacterium breve alters immune function and ameliorates DSS-induced inflammation in weanling rats

BACKGROUND

Bifidobacterium breve M-16V (M16V) is a probiotic bacterial strain with a long tradition of use in neonatal intensive care units in some countries. Previous study showed that the effects of M16V administration on gene expression were greater during the weaning period than in the neonatal period and were greater in the colon than in the small intestine and spleen, suggesting that M16V has anti-inflammatory effects. In this study, we evaluated the effects of inflammation during the weaning period and the effects of M16V on normal and inflammatory conditions.

METHODS

From postnatal day (PD) 21 to 34, weanling rats were administered of 2.5 × 10(9) of M16V daily, and colitis was induced by administration of 2% dextran sulfate sodium from PD28 to 35. Colitis severity, immune function, and microbiota were investigated.

RESULTS

Colitis caused a reduction in body weight gain, colon shortening, poor nutritional status, anemia, changes in blood and spleen lymphocyte populations, spleen T-cell malfunctions, and alterations in colon microbiota. M16V administration improved some but not all of the changes induced by colitis.

CONCLUSION

M16V could suppress inflammation and, therefore, can be considered a safe strain to use not only during the neonatal period but also the weaning period.

[Colonization-outbreak of two clonally different strains of Serratia marcescens in a neonatal intensive care unit]

We describe an outbreak of two clonally different strains of Serratia marcescens in a neonatal intensive care unit. Three colonization cases in the first outbreak phase were related to contact transmission from an index patient during emergency respiratory treatment while eight colonizations in the second phase were caused by contaminated bathing lotion. All transmissions resulted in colonization only and no infections were recorded. Based on our experience and the literature review sufficient staffing levels, basic hygiene and a goal-directed investigation of the environment are the cornerstones of a rapid outbreak termination. The epidemiological search for parallels in cases should be assisted by sophisticated electronic records.

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.

Gut microbiota biomodulators, when the stork comes by the scalpel

The microbial communities that reside in the human gut (microbiota) and their impact on human health and disease are nowadays one of the most exciting new areas of research. A well-balanced microbial intestinal colonization in early postnatal life is necessary for the development of appropriate innate and adaptive immune responses and to establish immune homeostasis later in life. Although the composition and functional characteristics of a 'healthy' gut microbiota remain to be elucidated, perturbations in the microbial colonization of an infant's gastrointestinal tract have been associated with an increased risk of short- and long-term immunologically mediated diseases. Emerging evidence suggests that gut microbiota biomodulators, such as probiotics, prebiotics, synbiotics, and postbiotics may support disease prevention in infants who tend to have a delayed and/or aberrant initial colonization with reduced microbiota diversity (delivery by caesarean section, premature delivery, and excessive use of perinatal antibiotics). Under these dysbiosis conditions probiotics could act as 'surrogate' colonizers to prevent immune-mediated diseases. This review focuses on the influence of delivery mode on the colonization of the infant gastro-intestinal tract. In particular, it examines the manipulation of the gut microbiota composition through the use of gut microbiota biomodulators, in the management of aberrant initial gut colonization and subsequent consequences for the health of the offspring.

Probiotics (Lactobacillus acidophilus and Bifidobacterium infantis) prevent NEC in VLBW infants fed breast milk but not formula [corrected]

BACKGROUND

Specific probiotics prevent necrotizing enterocolitis (NEC). A mixture of lactobacilli and bifidobacteria (Infloran) was highly effective in Asian very-low-birth-weight (VLBW) infants. We analyzed the effect of Infloran on NEC, NEC severity, and the influence of enteral feedings (breast milk vs. formula) on NEC prevention in a cohort of European VLBW infants.

METHODS

Infloran was implemented for routine use at our department. VLBW infants receiving probiotics were prospectively followed (2010-2012) and compared with historic controls (2008-2009). Data on NEC, neonatal morbidity, feeding tolerance, and descriptive parameters on NEC cases were analyzed.

RESULTS

Infloran had no statistically significant impact on NEC (controls: 24/233 (10.3%); probiotics: 16/230 (7%); P = 0.2). However, NEC was significantly reduced in infants of the probiotics group who were fed any breast milk (20/179 (11.2%) vs. 10/183 (5.5%); P = 0.027), whereas it was ineffective in infants exclusively fed formula (4/54 (7.4%) vs. 6/44 (13.6%); P = 0.345). Occurrence of severe NEC (IIIb), time until full feeds, and gastric residuals were similar.

CONCLUSION

Infloran was of lower efficacy in a European VLBW cohort and showed a reduction of NEC only in infants fed breast milk. Future studies should investigate the influence of feeding formula or breast milk on the effect of probiotics.

Bifidobacterium longum subspecies infantis: champion colonizer of the infant gut

Oligosaccharides are abundant in human milk. Production of these highly diverse structures requires significant energy expenditure by the mother and yet these human milk oligosaccharides offer no direct nutritive value to her infant. A primary function of human milk oligosaccharides is to shape the infant's intestinal microbiota with life-long consequences. Bifidobacterium longum subspecies infantis (B. infantis) is unique among gut bacteria in its prodigious capacity to digest and consume any human milk oligosaccharide structure, the result of a large repertoire of bacterial genes encoding an array of glycosidases and oligosaccharide transporters not found in other bacterial species. In vitro, B. infantis grows better than other bacterial strains in the presence of human milk oligosaccharides, displays anti-inflammatory activity in premature intestinal cells, and decreases intestinal permeability. In premature infants, B. infantis given in combination with human milk increases B. infantis and decreases Enterobacteriaceae in the feces. Probiotics containing B. infantis decrease the risk of necrotizing enterocolitis in premature infants. Colonization with B. infantis is also associated with increased vaccine responses. Probiotic organisms have historically been selected based on ease of production and stability. The advantages of B. infantis, selected through coevolution with human milk glycans, present an opportunity for focused manipulation of the infant intestinal microbiota.

The human neonatal gut microbiome: a brief review

The field of genomics has expanded into subspecialties such as metagenomics over the course of the last decade and a half. The development of massively parallel sequencing capabilities has allowed for increasingly detailed study of the genome of the human microbiome, the microbial super organ that resides symbiotically within the mucosal tissues and integumentary system of the human host. The gut microbiome, and particularly the study of its origins in neonates, has become subtopics of great interest within the field of genomics. This brief review seeks to summarize recent literature regarding the origins and establishment of the neonatal gut microbiome, beginning in utero, and how it is affected by neonatal nutritional status (breastfed versus formula fed) and gestational age (term versus preterm). We also explore the role of dysbiosis, a perturbation within the fragile ecosystem of the microbiome, and its role in the origin of select pathologic states, specifically, obesity and necrotizing enterocolitis (NEC) in preterm infants. We discuss the evidence supporting enteral pre- and pro-biotic supplementation of commensal organisms such as Bifidobacterium and Lactobacillus in the neonatal period, and their role in the prevention and amelioration of NEC in premature infants. Finally, we review directions to consider for further research to promote human health within this field.

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.