Prebiotic supplementation of formula in preterm neonates: a systematic review and meta-analysis of randomised controlled trials

An Updated Review on Prebiotics: Insights on Potentials of Food Seeds Waste as Source of Potential Prebiotics

Prebiotics are a group of biological nutrients that are capable of being degraded by microflora in the gastrointestinal tract (GIT), primarily Lactobacilli and Bifidobacteria. When prebiotics are ingested, either as a food additive or as a supplement, the colonic microflora degrade them, producing short-chain fatty acids (SCFA), which are simultaneously released in the colon and absorbed into the blood circulatory system. The two major groups of prebiotics that have been extensively studied in relation to human health are fructo-oligosaccharides (FOS) and galactooligosaccharides (GOS). The candidature of a compound to be regarded as a prebiotic is a function of how much of dietary fiber it contains. The seeds of fruits such as date palms have been reported to contain dietary fiber. An increasing awareness of the consumption of fruits and seeds as part of the daily diet, as well as poor storage systems for seeds, have generated an enormous amount of seed waste, which is traditionally discarded in landfills or incinerated. This cultural practice is hazardous to the environment because seed waste is rich in organic compounds that can produce hazardous gases. Therefore, this review discusses the potential use of seed wastes in prebiotic production, consequently reducing the environmental hazards posed by these wastes.

Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications

Prebiotics are a group of nutrients that are degraded by gut microbiota. Their relationship with human overall health has been an area of increasing interest in recent years. They can feed the intestinal microbiota, and their degradation products are short-chain fatty acids that are released into blood circulation, consequently, affecting not only the gastrointestinal tracts but also other distant organs. Fructo-oligosaccharides and galacto-oligosaccharides are the two important groups of prebiotics with beneficial effects on human health. Since low quantities of fructo-oligosaccharides and galacto-oligosaccharides naturally exist in foods, scientists are attempting to produce prebiotics on an industrial scale. Considering the health benefits of prebiotics and their safety, as well as their production and storage advantages compared to probiotics, they seem to be fascinating candidates for promoting human health condition as a replacement or in association with probiotics. This review discusses different aspects of prebiotics, including their crucial role in human well-being.

Comparative Effectiveness of Prophylactic Therapies for Necrotizing Enterocolitis in Preterm Infants: Protocol for a Network Meta-analysis of Randomized Trials

Necrotizing enterocolitis (NEC) is a common and devastating disease with high morbidity and mortality in premature infants. Current literature on the prevention of NEC has limitations including lack of direct and indirect comparisons of available therapies. We will search MEDLINE, EMBASE, Science Citation Index Expanded, Social Sciences Citation Index, CINAHL, Scopus, ProQuest Dissertations and Theses database, and grey literature sources to identify eligible trials evaluating NEC preventive therapies. Eligible studies will (1) enroll preterm (gestational age <37 weeks) and/or low birth weight (birth weight <2500 g) infants, (2) randomize infants to any preventive intervention or a placebo, or alternative active or nonactive intervention. Our outcomes of interest are severe NEC (stage II or more, based on Bell's criteria), all-cause mortality, NEC-related mortality, late-onset sepsis, duration of hospitalization, weight gain, time to establish full enteral feeds, and treatment-related adverse events. Two reviewers will independently screen trials for eligibility, assess risk of bias, and extract data. All discrepancies will be resolved by discussion. We will specify a priori explanations for heterogeneity between studies. For available comparisons between treatment and no treatment, and direct comparisons of treatments, we will conduct conventional meta-analysis using a random effects model. We will conduct a network meta-analysis using a random effects model within the Bayesian framework using Markov chain Monte Carlo methods to assess relative effects of eligible interventions. We will assess the certainty in direct, indirect, and network estimates using the Grading of Recommendations Assessment, Development and Evaluation approach.

Effect of early administration of probiotics on gut microflora and feeding in pre-term infants: a randomized controlled trial

BACKGROUND

This study aimed to evaluate the effect of early probiotic administration on gut microflora and influence on feeding in pre-term infants.

METHODS

A double-blind, randomized, controlled clinical study was conducted to assess the effect of probiotics [live, combined lactobacillus and bifidobacterium (LCB)] supplementation in pre-term infants. Sixty hospitalized pre-term babies were randomly assigned to two groups: a probiotics-supplemented group and the control group. The primary endpoint was measurement of lactobacillus and bifidobacterium in the gut. The secondary outcome was the rate of feeding intolerance.

RESULTS

In the first weekend, the quantity of gut lactobacillus and bifidobacterium was significantly higher in the probiotics-supplemented group than in the control group [7.84 ± 0.35 versus 6.39 ± 0.53 (log copy number/g wet fecal weight), p = 0.013; 8.52 ± 0.23 versus 7.01 ± 0.48, p = 0.024, respectively]. In the second weekend, the amount of gut lactobacillus and bifidobacterium in the probiotics-supplemented group remained significantly higher (8.62 ± 0.28 versus 7.34 ± 0.59, p = 0.036 and 9.45 ± 0.64 versus 7.85 ± 0.43, p = 0.007, respectively). Fewer patients in the probiotics-supplemented group developed a feeding intolerance (13.3% versus 46.7%, p = 0.013).

CONCLUSIONS

Probiotic supplementation in the hospitalized pre-term infants in the first 2 weeks of life resulted in higher amounts of lactobacillus and bifidobacterium in the gut and a concomitant lower rate of feeding intolerance.

Intestinal microbiota and its relationship with necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in infants born prematurely. After birth, the neonatal gut must acquire a healthy complement of commensal bacteria. Disruption or delay of this critical process, leading to deficient or abnormal microbial colonization of the gut, has been implicated as key risk factor in the pathogenesis of NEC. Conversely, a beneficial complement of commensal intestinal microbiota may protect the immature gut from inflammation and injury. Interventions aimed at providing or restoring a healthy complement of commensal bacteria, such as probiotic therapy, are currently the most promising treatment to prevent NEC. Shifting the balance of intestinal microbiota from a pathogenic to protective complement of bacteria can protect the gut from inflammation and subsequent injury that leads to NEC. Herein, we review the relationship of intestinal microbiota and NEC in preterm infants.

Response on Pneumococcal Vaccine in Preterm Infants After Neutral and Acidic Oligosaccharides Supplementation

BACKGROUND

Supplementation of oligosaccharides in premature infants was shown to influence the immune system. We determined the effect of combined short-chain galacto-oligosaccharides (scGOS), long-chain fructo-oligosaccharides (lcFOS) and pectin-derived acidic oligosaccharides (pAOS) on antibody concentrations after pneumococcal conjugate vaccination in very preterm infants.

METHODS

Very preterm infants with gestational age <32 weeks and/or birth weight <1500 g were randomized to receive enteral supplementation with scGOS/lcFOS/pAOS or placebo between days 3 and 30 of life. Blood samples were collected at birth, 5 and 12 months of age and compared with term samples from a Dutch cross-sectional population-based serosurveillance study. IgG antibody levels to pneumococcal capsular polysaccharides were determined by multiplex immunoassay.

RESULTS

In total, 113 preterm infants were included with similar baseline and nutritional characteristics in both groups. After 3 primary pneumococcal vaccinations, the scGOS/lcFOS/pAOS-group had lower GMC antibody concentrations (µg/mL; serotype 4: 1.53, 6B:0.25, 9V: 1.19, 14: 2.39, 18C: 1.88, 19F: 7.42, 23F: 0.72) than the placebo group (serotype 4: 3.29, 6B: 0.79, 9V:2.64, 14: 4.52, 18C: 3.13, 19F: 14.64, 23F: 1.88; all P < 0.05), but comparable with those in the term control group (serotype 4: 0.97, 6B: 0.32, 9V: 1.67, 14: 3.24, 18C: 2.03, 19F: 5.06, 23F: 0.59; all P > 0.05). After the booster vaccination at 11 months, antibody levels were no longer different between the two preterm groups.

CONCLUSION

Enteral supplementation of scGOS/lcFOS/pAOS has a regulatory effect on the response to conjugated polysaccharide pneumococcal vaccine with normalization of the enhanced responses in preterm infants toward levels similar to healthy term infants.

Understanding the Biologic Therapies of Probiotics, Prebiotics, and Synbiotics: Exploring Current Evidence for Use in Premature Infants for the Prevention of Necrotizing Enterocolitis

Necrotizing enterocolitis remains a significant cause of morbidity and mortality in very low-birth-weight infants (<1500 g), with current preventive strategies unclear. Scientific evidence has recently emerged, suggesting that probiotics, prebiotics, and synbiotics may effectively and safely alter the premature intestinal microbiota, enhancing a deficient innate immune response and maturing the intestinal barrier to prevent necrotizing enterocolitis development. Currently, formal recommendations do not support routine use of these dietary supplementations for premature infants. Here, we examine how probiotic, prebiotic, and synbiotic preparations physiologically alter the underdeveloped intestinal microbial environment to potentially reduce necrotizing enterocolitis incidence and discuss current evidence that has examined safety and efficacy factors potentially supporting routine use among the premature infant population.

[Expert consensus on the nutritional aspects of initial and follow-on infant formulas]

INTRODUCTION

Infant feeding in the first months/years of life affects the health in the short and long term. Breastfeeding is the perfect food due to its many benefits. However, when breastfeeding is not possible, infant formulas are the best alternative. The aim of this study is to define the role of the supplemented formulas in infant nutrition using the opinion of a panel of experts in infant gastroenterology and nutrition.

MATERIAL AND METHODS

A survey, using 62 items, stratified into 5 blocks, was performed by 48 panelists using the Delphi method to achieve a professional criteria consensus on nutritional aspects of infant formulas.

RESULTS

A consensus was reached in 64.6% of the items, with a non-unified agreement being established as regards the nutritional aspects of infant formulas, and their influence in body and brain development and immune maturity.

CONCLUSIONS

According to the experts surveyed, there is consensus as regards the suitable composition of lipids, lactose, calcium, vitamin D, and prebiotics in infant formulas, for a correct cerebral, immune and somatic development. There was no consensus on the not yet well-defined subjects, such as nutritional quality of proteins, use of thickeners, taurine supplementation, probiotic, and symbiotic aspects. More studies are necessary to confirm these subjects.

Prebiotics in healthy infants and children for prevention of acute infectious diseases: a systematic review and meta-analysis

Prebiotics, defined as nondigestible dietary ingredients resistant to gastric acidity and fermented by the intestinal flora, are used to positively influence the composition of intestinal flora, thereby promoting health benefits. The objective of this systematic review was to assess the efficacy of prebiotics in the prevention of acute infectious diseases in children. A systematic literature search was conducted using the Ovid Medline, Scopus, Web of Science, and Cochrane Library's Central databases. Finally, five randomized controlled trials, all of them investigating infants and children 0-24 months of age, were included in the review. Pooled estimates from three studies revealed a statistically significant decrease in the number of infectious episodes requiring antibiotic therapy in the prebiotic group as compared with the placebo group (rate ratio 0.68; 95% confidence interval 0.61-0.77). Studies available indicate that prebiotics may also be effective in decreasing the rate of overall infections in infants and children 0-24 months of age. Further studies in the age group 3-18 years are required to determine whether prebiotics can be considered for the prevention of acute infectious diseases in the older pediatric population.

Probiotics and prebiotics in neonatal necrotizing enterocolitis: New opportunities for translational research

Neonatal necrotizing enterocolitis (NEC) in premature infants has been recognized as a defined disease entity for at least four decades. Although survival has increased due to the advent of more sophisticated intensive care, incidence and long term health impacts due to NEC remain unchanged and no preventive therapy is currently available. Different probiotic strains of bacteria have been examined in their ability to prevent NEC with varied but encouraging results. Undigestable prebiotic sugars known to promote the growth of probiotic bacteria in the colon have been used in neonates with no clear benefit. The literature on NEC and probiotics is now cluttered with more reviews and meta-analyses than number of clinical trials. On the other hand, significant new information is available on microbiota and their impact on gut immunity. This review attempts to reiterate the risk factors of NEC and the pathogenesis of NEC with special reference to gut permeability. The reader is then introduced to gut microbiota, uniqueness and differences among probiotic strains, and how multiple resident flora talk to each other in the community setting in the human gut. After presenting a concise review of available clinical research results, the reader is challenged to question as to why no precise answer is available at present. Some modalities to examine the complex microflora and changes in the neonatal gut are then proposed including non-invasive methods and mathematical modeling. The review concludes by attracting the reader's attention to known immunomodulators of inflammation and injury. Justice to this review will be done only if the readers, clinical, and basic science investigators from multiple fields gather courage for a paradigm shift and embark on understanding the pathophysiology of the disease and attempt to discern the difference from equally preterm, equally vulnerable neonates that do not develop NEC. Learning about the developing microbiota in neonatal gut and its immunological impacts on the host in the face of many variables will provide a leap in our pursuit to select better, if not the best candidate probiotics, and put them to work against this stubborn disease that continues to take a toll on our precious neonates and the society.

Treatment outcomes of infants with cyanotic congenital heart disease treated with synbiotics

OBJECTIVES

The goal was to investigate the effect of orally administered synbiotics on outcome of infants with cyanotic congenital heart disease (CCHD).

METHODS

A prospective, blinded, randomized controlled trial was conducted to evaluate the effect of synbiotics on outcome of infants with CCHD. The infants with CCHD were assigned randomly to 2 groups. Infants in the study group were given synbiotic (Bifidobacterium lactis plus inulin) added to breast milk or mixed feeding until discharge or death. Infants in the placebo group were fed with breast milk or mixed feeding. The outcome measurements were nosocomial sepsis, necrotizing enterocolitis (NEC; Bell stage ≥ 2), length of NICU stay, and death.

RESULTS

A total of 100 infants were enrolled in the trial: 50 in each arm. There were 9 cases of culture-proven sepsis (18%) in the placebo group and 2 cases (4%) in the synbiotic group (P = .03). Length of NICU stay did not differ between the groups (26 [14-36] vs 32 days [20-44], P = .07]. There were 5 cases of NEC (10%) in the placebo group and none in the synbiotic group (P = .03). The incidence of death was lower in synbiotic group (5 [10%] of 50 vs 14 [28.0%] of 50, respectively; P = .04).

CONCLUSIONS

Synbiotics administered enterally to infants with CCHD might reduce the incidence of nosocomial sepsis, NEC, and death.

Neutral and acidic oligosaccharides supplementation does not increase the vaccine antibody response in preterm infants in a randomized clinical trial

BACKGROUND

In preterm infants, a decreased immunological response and lower serological effectiveness are observed after immunizations due to ineffectiveness of both humoral and cellular immune mechanisms.

OBJECTIVE

To determine the effect of 80% neutral oligosaccharides [small-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides (scGOS/lcFOS)] in combination with 20% pectin-derived acidic oligosaccharides (pAOS) on antibody concentrations after DTaP-IPV-Hib immunization in preterm infants.

DESIGN

In this randomized clinical trial, preterm infants with gestational age <32 weeks and/or birth weight <1500 g received enteral supplementation with scGOS/lcFOS/pAOS or placebo (maltodextrin) between days 3 and 30 of life. Blood samples were collected at 5 and 12 months of age.

RESULTS

In total, 113 infants were included. Baseline and nutritional characteristics were not different in both groups. Geometric mean titers were not different after prebiotic supplementation at 5 months, Ptx (37/44 EU/ml), FHA (78/96 EU/ml), Prn (78/80 EU/ml), Diphtheria (0.40/0.57 IU/ml), Tetanus (0.74/0.99 IU/ml) and Hib (0.35/0.63 µg/ml), and at 12 months Ptx (55/66 EU/ml), FHA (122/119 EU/ml), Prn (116/106 Eu/ml), Diphtheria (0.88/1.11 IU/ml), Tetanus (1.64/1.79 IU/ml) and Hib (2.91/2.55 µg/ml).

CONCLUSIONS

Enteral supplementation of neutral (scGOS/lcFOS) and acidic oligosaccharides (pAOS) does not improve the immunization response in preterm infants.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN16211826 ISRCTN16211826.

Prebiotics in infants for prevention of allergy

BACKGROUND

Prebiotics (commonly oligosaccharides) added to infant feeds have the potential to prevent sensitisation of infants to dietary allergens.

OBJECTIVES

To determine the effect of prebiotic given to infants for the prevention of allergy.

SEARCH METHODS

We performed an updated search in August 2012 of the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 8), MEDLINE, EMBASE, conference proceedings, citations, expert informants and clinical trials registries.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials that compared the use of a prebiotic to no prebiotic, or a specific prebiotic compared to a different prebiotic in infants for prevention of allergy.

DATA COLLECTION AND ANALYSIS

Assessment of trial quality, data extraction and synthesis of data were performed using the standard methods of The Cochrane Collaboration.

MAIN RESULTS

The 2012 update identified 13 studies classified as ongoing or awaiting classification (yet to report allergy outcomes). Forty-three studies were excluded, primarily as no allergy data were reported, although none of these enrolled infants were at high risk of allergy. Four studies enrolling 1428 infants were eligible for inclusion. All studies were at high risk of attrition bias. Allergy outcomes were reported from four months to two years of age.Meta-analysis of two studies (226 infants) found no significant difference in infant asthma although significant heterogeneity was found between studies. Meta-analysis of four studies found a significant reduction in eczema (1218 infants, typical risk ratio 0.68, 95% CI 0.48 to 0.97; typical risk difference -0.04, 95% CI -0.07 to -0.00; number needed to treat to benefit (NNTB) 25, 95% CI 14 to > 100; P = 0.03). No statistically significant heterogeneity was found between studies. One study reported no significant difference in urticaria.No statistically significant subgroup differences were found according to infant risk of allergy or type of infant feed. However, individual studies reported a significant reduction in asthma and eczema from supplementation with a mixture of galacto- and fructo-oligosaccharide (GOS/FOS 9:1 ratio) (8 g/L) in infants at high risk of allergy; and in eczema from supplementation with GOS/FOS (9:1) (6.8 g/L) and acidic oligosacccharide (1.2 g/L) in infants not selected for allergy risk.

AUTHORS' CONCLUSIONS

Further research is needed before routine use of prebiotics can be recommended for prevention of allergy in formula fed infants. There is some evidence that a prebiotic supplement added to infant feeds may prevent eczema. It is unclear whether the use of prebiotic should be restricted to infants at high risk of allergy or may have an effect in low risk populations; or whether it may have an effect on other allergic diseases including asthma.

Therapeutic use of prebiotics, probiotics, and postbiotics to prevent necrotizing enterocolitis: what is the current evidence?

Necrotizing enterocolitis (NEC) is a leading cause of neonatal morbidity and mortality, and preventive therapies that are both effective and safe are urgently needed. Current evidence from therapeutic trials suggests that probiotics are effective in decreasing NEC in preterm infants, and probiotics are currently the most promising therapy for this devastating disease. However, concerns regarding safety and optimal dosing have limited the widespread adoption of routine clinical use of probiotics in preterm infants. This article summarizes the current evidence regarding the use of probiotics, prebiotics, and postbiotics in the preterm infant, including their therapeutic role in preventing NEC.

Probiotics and prebiotics: role in prevention of nosocomial sepsis in preterm infants

Nosocomial sepsis is associated with increased mortality and morbidity including neurodevelopmental impairment and prolonged hospital stay. Prevention of sepsis especially in the preterm infants in the neonatal intensive care unit remains a major challenge. The gastrointestinal tract is an important source of potential pathogens causing nosocomial sepsis as the immature intestinal epithelium can permit translocation of bacteria and yeast. The intestinal tract and its microflora play an important role in the immunity. Altering the gut microflora has been extensively studied for immunomodulation in preterm infants. Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Probiotics have been used for prevention and treatment of various medical conditions in children and adults. Studies on probiotics in premature infants have focused on normalizing intestinal flora, improvement in feeding intolerance, prevention of necrotizing enterocolitis and sepsis. In this paper, we discuss the intestinal bacterial colonization pattern; the rational for probiotics and prebiotic therapy with special focus on the prevention of nosocomial sepsis in preterm infants.

Facultative to strict anaerobes ratio in the preterm infant microbiota: a target for intervention?

During recent years there has been an increasing interest on the development of strategies for modulating the process of microbiota establishment in preterm infants. For successfully developing of such strategies, a detailed knowledge of the microbiota establishment process in these infants is needed. In a previous study we evidenced clear alterations in the process of microbiota establishment in preterm newborns when compared with a control group of full-term breast-fed infants. Here we have analyzed these data more in depth, corroborating a reduced proportion of strict anaerobes with respect to facultatives in the fecal microbiota of preterm infants. The potential benefits, as well as the side effects, of strategies aimed at counterbalancing this alteration in the facultative to strict anaerobes ratio are discussed in this addendum.

Short bowel syndrome in children: current and potential therapies

Short bowel syndrome (SBS) reflects a state of malabsorption that occurs due to loss of a significant portion of the small bowel. The pathophysiology of SBS is determined largely by the process of adaptation, which is the innate attempt by the remnant portions of the intestine to increase fluid and nutrient reabsorption. In recent years, emphasis has been placed on intestinal rehabilitation with multidisciplinary teams as a comprehensive approach to the management of patients with SBS. In our institution, the multidisciplinary team members include pediatric gastroenterologists, pediatric surgeons, pediatric dieticians, physical therapists, occupational therapists, neonatologists (especially for patients still under their care), transplant surgeons, transplant coordinators and social workers. Parenteral nutrition plays a significant role in the management of SBS, but its use is associated with many potential complications, including cholestatic liver disease. Fish oil-based lipid emulsions have shown promise in their ability to reverse and also prevent the development of cholestasis in these patients. Clinical trials have shown that growth factors and other trophic hormones facilitate the process of adaptation. The most significant impact has been shown with the use of glucagon-like peptide-2 and its analog (teduglutide). Surgical interventions remain an important part of the management of SBS to facilitate adaptation and treat complications. Intestinal transplantation is a last resort option when the process of adaptation is unsuccessful. This review article is intended to provide an overview of the conventional and emerging therapies for pediatric SBS.

The effect of neutral and acidic oligosaccharides on stool viscosity, stool frequency and stool pH in preterm infants

AIM

To determine the effect of neutral oligosaccharides [small-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides (scGOS/lcFOS)] in combination with acidic oligosaccharides (pAOS) on stool viscosity, stool frequency and stool pH in preterm infants.

METHODS

In this explorative RCT, preterm infants with gestational age <32 weeks and/or birth weight <1500 g received enteral supplementation with scGOS/lcFOS/pAOS or placebo (maltodextrin) between days 3 and 30 of life. Stool samples were collected at day 30 after birth.

RESULTS

In total, 113 infants were included. Baseline and nutritional characteristics were not different between both groups. Stool viscosity at day 30 was lower in the prebiotics group (16.8N) (3.9-67.8) compared with the placebo group (26.3N) (1.3-148.0) (p = 0.03; 95% CI -0.80 to 0.03). There was a trend towards higher stool frequency in the prebiotics group (3.1 ± 0.8) compared with the placebo group (2.8 ± 0.7) (p = 0.15; 95% CI -0.08 to 0.52). Stool pH at day 30 was lower in the in the prebiotics group (5.9 ± 0.6) compared with the placebo group (6.2 ± 0.3) (p = 0.009; 95% CI 0.08 to 0.53).

CONCLUSIONS

Enteral supplementation of a prebiotic mixture consisting of neutral (scGOS/lcFOS) and acidic oligosaccharides (pAOS) decreases stool viscosity and stool pH with a trend towards increased stool frequency in preterm infants. The inclusion of pAOS in a formula containing a mixture of scGOS/lcFOS does not add specific advantages to the formula in terms of stool viscosity, frequency, pH as well as feeding tolerance.

Colonization of the Gastrointestinal Tract in Neonates

Bacterial colonization of the neonatal gastrointestinal tract has emerged as an issue involving nutrition, immunity, and overall mortality. Bacterial organisms colonizing the gastrointestinal tract play a vital role in maintaining intestinal homeostasis, including digestion, nutrient absorption, and immunological mechanisms. In neonates, these bacteria are essential in postnatal development of intestinal mucosa and gut-associated lymphoid tissue critical for immunological protection. Colonization of bacteria is thought to occur over the first 1 to 2 weeks of life. Delivery mode, feeding method, and environment affect the succession and establishment of the beneficial bacteria in the neonate. Neonates delivered vaginally are colonized by the bacteria from the mother, whereas neonates delivered via caesarean section initially colonize with bacteria from the environment. Feeding method is another factor; Bifidobacterium species are believed to dominate the microflora of breastfed infants by day of life 2 to 3 and are thought to be critical in postnatal immunology. Formula-fed infants often have a more diverse microflora and a less obvious presence of the Bifidobacterium. Compared with healthy, term neonates, preterm infants have a significant delay in bacterial colonization. The effects of an immature gastrointestinal track, lack of enteral feeding, and the frequent use of antibiotic therapy are believed to contribute to the delay and imbalance in the microflora of preterm infants. Prolonged exposure to hospital bacteria increases the risk of colonization with strains specific to hospital flora.

Evidence-based guidelines for use of probiotics in preterm neonates

BACKGROUND

Current evidence indicates that probiotic supplementation significantly reduces all-cause mortality and definite necrotising enterocolitis without significant adverse effects in preterm neonates. As the debate about the pros and cons of routine probiotic supplementation continues, many institutions are satisfied with the current evidence and wish to use probiotics routinely. Because of the lack of detail on many practical aspects of probiotic supplementation, clinician-friendly guidelines are urgently needed to optimise use of probiotics in preterm neonates.

AIM

To develop evidence-based guidelines for probiotic supplementation in preterm neonates.

METHODS

To develop core guidelines on use of probiotics, including strain selection, dose and duration of supplementation, we primarily used the data from our recent updated systematic review of randomised controlled trials. For equally important issues including strain identification, monitoring for adverse effects, product format, storage and transport, and regulatory hurdles, a comprehensive literature search, covering the period 1966-2010 without restriction on the study design, was conducted, using the databases PubMed and EMBASE, and the proceedings of scientific conferences; these data were used in our updated systematic review.

RESULTS

In this review, we present guidelines, including level of evidence, for the practical aspects (for example, strain selection, dose, duration, clinical and laboratory surveillance) of probiotic supplementation, and for dealing with non-clinical but important issues (for example, regulatory requirements, product format). Evidence was inadequate in some areas, and these should be a target for further research.

CONCLUSION

We hope that these evidence-based guidelines will help to optimise the use of probiotics in preterm neonates. Continued research is essential to provide answers to the current gaps in knowledge about probiotics.

A fermented formula in pre-term infants: clinical tolerance, gut microbiota, down-regulation of faecal calprotectin and up-regulation of faecal secretory IgA

Intestinal bacterial colonisation in pre-term infants is delayed compared with full-term infants, leading to an increased risk of gastrointestinal disease. Modulation of colonisation through dietary supplementation with probiotics or prebiotics could decrease such a risk. The present study evaluated clinical tolerance, the effects on gut microbiota, and inflammatory and immunological mucosal responses to an infant formula adapted for pre-term infants that included in its manufacturing process a fermentation step with two probiotic strains, Bifidobacterium breve C50 and Streptococcus thermophilus 065, inactivated by heat at the end of the process. A total of fifty-eight infants (gestational age: 30–35 weeks), fed either the fermented pre-term formula or a standard pre-term formula, were followed up during their hospital stay. Clinical tolerance, faecal microbiota using a culture and a culture-independent method (temporal temperature gel electrophoresis), faecal calprotectin and secretory IgA were analysed weekly. No difference was observed regarding anthropometric data and digestive tolerance, except for abdominal distension, the incidence of which was lower in infants fed the fermented formula for 2 weeks. Bacterial colonisation was not modified by the type of feeding, particularly for bifidobacteria. Faecal calprotectin was significantly lower in infants fed the fermented formula for 2 weeks, and secretory IgA increased with both mother's milk and the fermented formula. The fermented formula was well tolerated and did not significantly modulate the bacterial colonisation but had benefits on inflammatory and immune markers, which might be related to some features of gastrointestinal tolerance.

Necrotizing enterocolitis is associated with neonatal intestinal injury

PURPOSE

We hypothesized that a subset of premature newborns has subclinical, intestinal mucosal compromise that predisposes to the development of necrotizing enterocolitis (NEC) days or weeks later.

METHODS

Fifty-five newborns of 23 to 36 weeks' gestational age were identified, and urine was collected over the first 90 hours of life. The urinary concentration of intestinal fatty acid binding protein (iFABP(u)), a sensitive marker for intestinal injury, was determined. The diagnosis of NEC was based upon clinical condition, pathology, and/or imaging findings.

RESULTS

Neonatal iFABP(u) exceeded 800 pg/mL in 27 subjects, including 9 of 9 who subsequently developed stage 2 or 3 NEC. This degree of iFABP(u) elevation, but not asphyxia, was significantly associated with the development of NEC (P < .01).

CONCLUSION

In this population of premature newborns, there was a substantial incidence of intestinal mucosal compromise. All infants who subsequently developed stage 2 or 3 NEC had an elevated iFABP(u). This finding suggests a model for the pathogenesis of some cases of NEC, whereby perinatal mucosal injury predisposes to further damage when feedings are initiated. In addition, neonatal iFABP(u) assessment may represent a tool to identify infants at the highest risk for NEC and allow for the institution of focused, preventive measures.

The effect of enteral supplementation of a prebiotic mixture of non-human milk galacto-, fructo- and acidic oligosaccharides on intestinal permeability in preterm infants

Preterm infants have an impaired gut barrier function. We aimed to determine the effects of enteral supplementation of a prebiotic mixture consisting of neutral oligosaccharides (short-chain galacto-oligosaccharides (SCGOS)/long-chain fructo-oligosaccharides (LCFOS)) and acidic oligosaccharides (AOS) on intestinal permeability of preterm infants as measured by the sugar absorption test in the first week of life. Furthermore, we determined host- and treatment-related factors associated with intestinal permeability. In a randomised controlled trial, preterm infants with a gestational age < 32 weeks and/or birth weight (BW) < 1500 g received enteral supplementation of SCGOS/LCFOS/AOS or placebo (maltodextrin) between days 3 and 30 of life. Intestinal permeability, reflected by the urinary lactulose/mannitol (L/M) ratio after oral ingestion of lactulose and mannitol, was assessed at three time points: before the start of the study (t = 0), at day 4 (t = 1) and at day 7 (t = 2) of life. Data were analysed by generalised estimating equations. In total, 113 infants were included. Baseline patient and nutritional characteristics were not different between the SCGOS/LCFOS/AOS (n 55) and the placebo groups (n 58). SCGOS/LCFOS/AOS had no effect on the L/M ratio between t = 0 and t = 2. In both the groups, the L/M ratio decreased from t = 0 to t = 2 (P < 0·001). Low BW increased the L/M ratio (P = 0·002). Exclusive breast milk feeding and mixed breast milk/formula feeding during the first week of life decreased the L/M ratio (P < 0·001 and P < 0·05, respectively). In conclusion, enteral supplementation of a prebiotic mixture does not enhance the postnatal decrease in intestinal permeability in preterm infants in the first week of life.

Probiotics and prebiotics in preterm infants: where are we? Where are we going?

BACKGROUND

Uncertainty exists regarding the efficacy and safety of using probiotics and prebiotics in preterm infants.

AIM

To review the evidence on the effects of administering probiotics and/or prebiotics to preterm infants.

METHODS

MEDLINE and the Cochrane Library were searched in August 2008. A supplemental search was conducted in July 2009. Only systematic reviews/meta-analyses and randomized controlled trials (RCTs) that evaluated the effects of probiotics and/or prebiotics on relevant short- and long-term primarily clinically important health outcomes published in the English language were included.

RESULTS

One systematic review and 2 well-performed meta-analyses suggest that probiotics reduce the risk of necrotizing enterocolitis (NEC) (stage > or =2). One subsequently published RCT reported similar results. The 2 meta-analyses also demonstrated that probiotics reduce the risk of death due to all causes, but do not have an effect on the risk of sepsis or death due to NEC. Regarding prebiotics, one meta-analysis of 4 RCTs demonstrated that prebiotic-supplemented formula increases stool colony counts of bifidobacteria and lactobacilli in preterm neonates without adversely affecting weight gain. Because of the limited data regarding synbiotics, the relationship between their use and clinical outcomes in preterm infants remains unclear.

CONCLUSIONS

The findings from the 2 meta-analyses of the effects of probiotic administration on the prevention of NEC show potential for such dietary supplementation. However, they must be interpreted with caution because the beneficial effects of probiotics seem to be strain specific, thus, pooling data from different strains may result in misleading conclusions. Before the routine use of probiotics and/or prebiotics in preterm infants, data regarding which products should be administered, at what dose, and for how long are needed.

Adjunctive immunologic interventions in neonatal sepsis

Because of inadequate sample sizes of randomized controlled trials, few immunologic interventions to treat or prevent neonatal sepsis have been reliably evaluated. International collaboration is essential in achieving timely, adequate samples to assess effects on mortality or disability-free survival reliably. Promising or possible therapeutic interventions in severe or gram-negative sepsis include exchange transfusions, pentoxifylline, and IgM-enriched intravenous immunoglobulin. Promising or possible prophylactic interventions include lactoferrin, with or without a probiotic; selenium; early curtailment of antibiotics after sterile cultures; breast milk; and earlier initiation of colostrum in high risk preterm infants. Prophylactic oral probiotics are safe and effective (P<.00001) in reducing all-cause mortality and necrotizing enterocolitis in preterm infants by over half, but do not reduce sepsis.

Maternal milk, but not formula, regulates the immune response to beta-lactoglobulin in allergy-prone rat pups

Controversy exists regarding the timing of the introduction of allergic foods into the diet. We investigated the immune response of rat pups exposed to beta-lactoglobulin (BLG), one of the main allergenic proteins in cow milk. Brown Norway allergy-prone rats were allocated into groups: dam-reared and unchallenged (DR), DR challenged with BLG via gavage (11 mg/d), or rats fed via gastric cannula a formula containing BLG (11 mg/d). BLG was given from d 4 of life. Rats were killed at d 10, 14, or 21. Sera were assayed for total IgE, BLG-specific IgG1, and rat mucosal mast cell protease II (RMCPII; indicator of mucosal mast cell degranulation). Ileum was assessed for cytokine mRNA. Mesenteric lymph nodes (MLN) were assessed for forkhead boxP3 (Foxp3) and chemokine (C-C motif) receptor 7 (CCR7) expression by real-time PCR and immunostained for Foxp3(+) CD4(+) regulatory cells. Formula feeding compared with dam-rearing with or without oral BLG challenge resulted in significantly greater serum IgE, BLG-specific IgG1, RMCPII, and intestinal mast cells but reduced MLN Foxp3(+) cells, Foxp3, and CCR7 expression and ileal cytokines, interleukin (IL)-4, IL-10, and interferon-gamma (P < 0.05). Importantly, giving BLG in the presence of maternal milk resulted in an immune response profile similar to that of unchallenged DR rats but with greater Foxp3 and CCR7 mRNA expression and CD4(+) Foxp3(+) cells (P < 0.05). We conclude that introducing an allergenic food with breast milk reduces immunological indicators of an allergic response, whereas introduction during formula feeding generates an allergic response.

Probiotics and prevention of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating disease affecting primarily premature infants. Despite advances in neonatal care, the mortality rate following NEC has not changed significantly in the past 30 years. New preventative measures are needed. In this review, we will provide information to assess the possible role of probiotics, prebiotics and related agents in the prevention of this devastating disease. We will also discuss short and long term safety issues as well as potential alternatives. Although it is tempting to rebuild the intestinal microbiota using the agents such as pro and prebiotics during infancy, routine use is not yet warranted a cautious approach on the basis of sounds scientific data is needed.