Comparison between killed and living probiotic usage versus placebo for the prevention of necrotizing enterocolitis and sepsis in neonates

Probiotics to prevent necrotising enterocolitis in very preterm or very low birth weight infants

BACKGROUND

Intestinal dysbiosis may contribute to the pathogenesis of necrotising enterocolitis (NEC) in very preterm or very low birth weight (VLBW) infants. Dietary supplementation with probiotics to modulate the intestinal microbiome has been proposed as a strategy to reduce the risk of NEC and associated mortality and morbidity in very preterm or VLBW infants.

OBJECTIVES

To determine the effect of supplemental probiotics on the risk of NEC and associated mortality and morbidity in very preterm or very low birth weight infants.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, the Maternity and Infant Care database, and CINAHL from inception to July 2022. We searched clinical trials databases and conference proceedings, and examined the reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing probiotics with placebo or no probiotics in very preterm infants (born before 32 weeks' gestation) and VLBW infants (weighing less than 1500 g at birth).

DATA COLLECTION AND ANALYSIS

Two review authors independently evaluated risk of bias of the trials, extracted data, and synthesised effect estimates using risk ratios (RRs), risk differences (RDs), and mean differences (MDs), with associated 95% confidence intervals (CIs). The primary outcomes were NEC and all-cause mortality; secondary outcome measures were late-onset invasive infection (more than 48 hours after birth), duration of hospitalisation from birth, and neurodevelopmental impairment. We used the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 60 trials with 11,156 infants. Most trials were small (median sample size 145 infants). The main potential sources of bias were unclear reporting of methods for concealing allocation and masking caregivers or investigators in about half of the trials. The formulation of the probiotics varied across trials. The most common preparations contained Bifidobacterium spp., Lactobacillus spp., Saccharomyces spp., andStreptococcus spp., alone or in combination. Very preterm or very low birth weight infants Probiotics may reduce the risk of NEC (RR 0.54, 95% CI 0.46 to 0.65; I² = 17%; 57 trials, 10,918 infants; low certainty). The number needed to treat for an additional beneficial outcome (NNTB) was 33 (95% CI 25 to 50). Probiotics probably reduce mortality slightly (RR 0.77, 95% CI 0.66 to 0.90; I² = 0%; 54 trials, 10,484 infants; moderate certainty); the NNTB was 50 (95% CI 50 to 100). Probiotics probably have little or no effect on the risk of late-onset invasive infection (RR 0.89, 95% CI 0.82 to 0.97; I² = 22%; 49 trials, 9876 infants; moderate certainty). Probiotics may have little or no effect on neurodevelopmental impairment (RR 1.03, 95% CI 0.84 to 1.26; I² = 0%; 5 trials, 1518 infants; low certainty). Extremely preterm or extremely low birth weight infants Few data were available for extremely preterm or extremely low birth weight (ELBW) infants. In this population, probiotics may have little or no effect on NEC (RR 0.92, 95% CI 0.69 to 1.22, I² = 0%; 10 trials, 1836 infants; low certainty), all-cause mortality (RR 0.92, 95% CI 0.72 to 1.18; I² = 0%; 7 trials, 1723 infants; low certainty), or late-onset invasive infection (RR 0.93, 95% CI 0.78 to 1.09; I² = 0%; 7 trials, 1533 infants; low certainty). No trials provided data for measures of neurodevelopmental impairment in extremely preterm or ELBW infants.

AUTHORS' CONCLUSIONS

Given the low to moderate certainty of evidence for the effects of probiotic supplements on the risk of NEC and associated morbidity and mortality for very preterm or VLBW infants, and particularly for extremely preterm or ELBW infants, there is a need for further large, high-quality trials to provide evidence of sufficient validity and applicability to inform policy and practice.

The potential role of adherence factors in probiotic function in the gastrointestinal tract of adults and pediatrics: a narrative review of experimental and human studies

Numerous studies point to the important role of probiotic bacteria in gastrointestinal health. Probiotics act through mechanisms affecting enteric pathogens, epithelial barrier function, immune signaling, and conditioning of indigenous microbiota. Once administered, probiotics reach the gastrointestinal tract and interact with the host through bacterial surface molecules, here called adhesion factors, which are either strain- or specie-specific. Probiotic adhesion, through structural adhesion factors, is a mechanism that facilitates persistence within the gastrointestinal tract and triggers the initial host responses. Thus, an understanding of specific probiotic adhesion mechanisms could predict how specific probiotic strains elicit benefits and the potential of adherence factors as a proxy to predict probiotic function. This review summarizes the present understanding of probiotic adherence in the gastrointestinal tract. It highlights the bacterial adhesion structure types, their molecular communication with the host and the consequent impact on intestinal diseases in both adult and pediatric populations. Finally, we discuss knockout/isolation studies as direct evidence for adhesion factors conferring anti-inflammatory and pathogen inhibition properties to a probiotic.What is known: Probiotics can be used to treat clinical conditions.Probiotics improve dysbiosis and symptoms.Clinical trials may not confirm in vitro and animal studies.What is new: Adhesion structures may be important for probiotic function.Need to systematically determine physical characteristics of probiotics before selecting for clinical trials.Probiotics may be genetically engineered to add to clinical efficacy.

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

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

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.

Probiotics for Preventing Necrotizing Enterocolitis in Preterm Infants: A Network Meta-Analysis

BACKGROUND

Recent evidence supports a role of probiotics in preventing necrotizing enterocolitis (NEC) in preterm infants.

METHODS

A systematic review and network meta-analysis of randomized controlled trials (RCTs) on the role of probiotics in preventing NEC in preterm infants, focusing on the differential effect of type of feeding, was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A random-effects model was used; a subgroup analysis on exclusively human milk (HM)-fed infants vs. infants receiving formula (alone or with HM) was performed.

RESULTS

Fifty-one trials were included (10,664 infants, 29 probiotic interventions); 31 studies (19 different probiotic regimens) were suitable for subgroup analysis according to feeding. In the overall analysis, Lactobacillus acidophilus LB revealed the most promising effect for reducing NEC risk (odds ratio (OR), 0.03; 95% credible intervals (CrIs), 0.00-0.21). The subgroup analysis showed that Bifidobacterium lactis Bb-12/B94 was associated with a reduced risk of NEC stage ≥2 in both feeding type populations, with a discrepancy in the relative effect size in favour of exclusively HM-fed infants (OR 0.04; 95% CrIs <0.01-0.49 vs. OR 0.32; 95% CrIs 0.10-0.36).

CONCLUSIONS

B. lactis Bb-12/B94 could reduce NEC risk with a different size effect according to feeding type. Of note, most probiotic strains are evaluated in few trials and relatively small populations, and outcome data according to feeding type are not available for all RCTs. Further trials are needed to confirm the present findings.

Probiotics to prevent necrotising enterocolitis in very preterm or very low birth weight infants

BACKGROUND

Intestinal dysbiosis may contribute to the pathogenesis of necrotising enterocolitis (NEC) in very preterm or very low birth weight infants. Dietary supplementation with probiotics to modulate the intestinal microbiome has been proposed as a strategy to reduce the risk of NEC and associated mortality and morbidity.  OBJECTIVES: To determine the effect of supplemental probiotics on the risk of NEC and mortality and morbidity in very preterm or very low birth weight infants.

SEARCH METHODS

We searched Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 2) in the Cochrane Library; MEDLINE Ovid (1946 to 17 Feb 2020), Embase Ovid (1974 to 17 Feb 2020), Maternity & Infant Care Database Ovid (1971 to 17 Feb 2020), the Cumulative Index to Nursing and Allied Health Literature (1982 to 18 Feb 2020). We searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-RCTs.

SELECTION CRITERIA

We included RCTs and quasi-RCTs comparing probiotic supplementation with placebo or no probiotics in very preterm or very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. Two review authors separately evaluated trial quality, extracted data, and synthesised effect estimates using risk ratio (RR), risk difference (RD), and mean difference. We used the GRADE approach to assess the certainty of evidence for effects on NEC, all-cause mortality, late-onset infection, and severe neurodevelopmental impairment.

MAIN RESULTS

We included 56 trials in which 10,812 infants participated. Most trials were small (median sample size 149). Lack of clarity on methods to conceal allocation and mask caregivers or investigators were the main potential sources of bias in about half of the trials. Trials varied by the formulation of the probiotics. The most commonly used preparations contained Bifidobacterium spp., Lactobacillus spp., Saccharomyces spp., and Streptococcus spp. alone or in combinations. Meta-analysis showed that probiotics may reduce the risk of NEC: RR 0.54, 95% CI 0.45 to 0.65 (54 trials, 10,604 infants; I² = 17%); RD -0.03, 95% CI -0.04 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) 33, 95% CI 25 to 50. Evidence was assessed as low certainty because of the limitations in trials design, and the presence of funnel plot asymmetry consistent with publication bias. Sensitivity meta-analysis of trials at low risk of bias showed a reduced risk of NEC: RR 0.70, 95% CI 0.55 to 0.89 (16 trials, 4597 infants; I² = 25%); RD -0.02, 95% CI -0.03 to -0.01; NNTB 50, 95% CI 33 to 100. Meta-analyses showed that probiotics probably reduce mortality (RR 0.76, 95% CI 0.65 to 0.89; (51 trials, 10,170 infants; I² = 0%); RD -0.02, 95% CI -0.02 to -0.01; NNTB 50, 95% CI 50 to 100), and late-onset invasive infection (RR 0.89, 95% CI 0.82 to 0.97; (47 trials, 9762 infants; I² = 19%); RD -0.02, 95% CI -0.03 to -0.01; NNTB 50, 95% CI 33 to 100). Evidence was assessed as moderate certainty for both these outcomes because of the limitations in trials design. Sensitivity meta-analyses of 16 trials (4597 infants) at low risk of bias did not show an effect on mortality or infection. Meta-analysis showed that probiotics may have little or no effect on severe neurodevelopmental impairment (RR 1.03, 95% CI 0.84 to 1.26 (five trials, 1518 infants; I² = 0%). The certainty on this evidence is low because of limitations in trials design and serious imprecision of effect estimate. Few data (from seven of the trials) were available for extremely preterm or extremely low birth weight infants. Meta-analyses did not show effects on NEC, death, or infection (low-certainty evidence).

AUTHORS' CONCLUSIONS

Given the low to moderate level of certainty about the effects of probiotic supplements on the risk of NEC and associated morbidity and mortality for very preterm or very low birth weight infants, and particularly for extremely preterm or extremely low birth weight infants, further, large, high-quality trials are needed to provide evidence of sufficient quality and applicability to inform policy and practice.

Mixed probiotics decrease the incidence of stage II-III necrotizing enterocolitis and death: A systematic review and meta-analysis

BACKGROUND

Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in premature infants. In order to evaluate the efficacy of probiotics in the prevention of stage II-III NEC, we performed a meta-analysis of clinical studies.

METHODS

We searched in PubMed, Medline and Embase from 1 January 1990 to 16 January 2018. Heterogeneity was examined by Q-test. Publication bias was evaluated by funnel plot and Egger's regression test.

RESULTS

30 articles were identified meeting the inclusion criteria. Data showed that probiotics supplement could significantly reduce the risk of stage II-III NEC (RR = 0.51, 95% CI, 0.38 to 0.67, P < 0.001) and death rate (RR = 0.69, 95% CI, 0.55 to 0.87, P = 0.002). The mixed probiotics and lactobacillus could reduce the risk of stage II-III NEC (for mixed probiotics, RR = 0.39, 95% CI, 0.26 to 0.57; for lactobacillus, RR = 0.53, 95% CI, 0.36 to 0.78), while bifidobacterium or saccharomyces did not have such effect. The results also indicated that only the mixed probiotics could reduce the risk of deaths (RR = 0.52, 95%CI, 0.34 to 0.80). Subgroup analysis for mortality revealed that probiotics had significant effect in Asian region (RR = 0.54, 95% CI, 0.37 to 0.80, P = 0.002) but not in non-Asian region (RR = 0.84, 95% CI, 0.66 to 1.08, P = 0.179).

CONCLUSIONS

Probiotics could significantly decrease the risk of stage II-III NEC and death. Compared to using single probiotics species, the application of combining different probiotics has a better efficacy in the prevention of stage II-III NEC and death, especially in the Asian population.

Probiotics for Preterm Infants: A Strain-Specific Systematic Review and Network Meta-analysis

OBJECTIVES

Several randomized controlled trials (RCTs) on the use of probiotics to reduce morbidity and mortality in preterm infants have provided inconsistent results. Although meta-analyses that group all of the used strains together are suggesting efficacy, it is not possible to determine the most effective strain that is more relevant to the clinician. We therefore used a network meta-analysis (NMA) approach to identify strains with greatest efficacy.

METHODS

A PubMed search identified placebo-controlled or head-to-head RCTs investigating probiotics in preterm infants. From trials that recorded mortality, necrotizing enterocolitis, late-onset sepsis, or time until full enteral feeding as outcomes, data were extracted and Bayesian hierarchical random-effects models were run to construct a NMA.

RESULTS

Fifty-one RCTs involving 11,231 preterm infants were included. Most strains or combinations of strains were only studied in one or a few RCTs. Only 3 of 25 studied probiotic treatment combinations showed significant reduction in mortality rates. Seven treatments reduced necrotizing enterocolitis incidence, 2 reduced late-onset sepsis, and 3 reduced time until full enteral feeding. There was no clear overlap of strains, which were effective on multiple outcome domains.

CONCLUSIONS

This NMA showed efficacy in reducing mortality and morbidity only in a minority of the studied strains or combinations. This may be due to an inadequate number, or size, of RCTs, or due to a true lack of effect for certain species. Further large and adequately powered RCTs using strains with the greatest apparent efficacy will be needed to more precisely define optimal treatment strategies.

Whether viable and dead probiotic are equally efficacious?

Purpose

Consumer inclination towards probiotic foods has been stimulated due to well-documented evidence of health benefits of probiotic-containing products and consumer demand for natural products. It is assumed that the viability and metabolic activities of probiotics are essential for extending health benefits and for successful marketing of probiotics as a functional food. The purpose of this paper is to demonstrate that even dead or inactivated probiotic cells could extend health benefits, indicating that probiotic viability is not always necessary for exhibiting health benefits.

Design/methodology/approach

Attempt has been made to review the literature on the status of probiotic foods available in the world market, their impact on the gut flora and the various factors affecting their viability. Both review and research papers related to efficacy of inactivated, killed or dead probiotic cells towards health benefits have been considered. Keywords used for data search included efficacy of viable or killed, inactivated probiotic cells.

Findings

The reviewed literature indicated that inactivated, killed or dead probiotic cells also possess functional properties but live cells are more efficacious. All live probiotic cultures are not equally efficacious, and accordingly, dead or inactivated cells did not demonstrate functional properties to extend health benefits to all diseases.

Originality/value

Capability of non-viable microorganisms to confer health benefits may attract food manufacturers owing to certain advantages over live probiotics such as longer shelf-life, handling and transportation and reduced requirements for refrigerated storage and inclusion of non-bacterial, biologically active metabolites present in fermented milks’ fraction as dried powders to food matrixes may result in the development of new functional foods.

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

OBJECTIVE

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

DESIGN

Systematic review and meta-analysis of RCTs.

DATA SOURCES

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

ELIGIBILITY CRITERIA

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

RESULTS

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

CONCLUSION

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

Probiotics for the prevention of necrotising enterocolitis in very low-birth-weight infants: a meta-analysis and systematic review

We performed an updated meta-analysis incorporating the results of recent randomised controlled trials (RCTs) to measure the effectiveness of probiotic supplementation in preventing necrotising enterocolitis (NEC) and death in very low-birth-weight (VLBW) infants, and to investigate any differences in efficacy by probiotic agent. Using meta-regression analysis, we assessed the contribution of other measured variables on the overall effect size and between-study variability.

CONCLUSION

Overall, probiotics lead to significant reductions in NEC incidence and mortality in VLBW infants. Differences in probiotic agents and the influence of prenatal steroids and feeding regimens may explain the differences in outcomes between studies.

Is there a role for modified probiotics as beneficial microbes: a systematic review of the literature

Our objective was to conduct a systematic review and meta-analysis for the use of modified (heat-killed or sonicated) probiotics for the efficacy and safety to prevent and treat various diseases. Recent clinical research has focused on living strains of probiotics, but use in high-risk patients and potential adverse reactions including bacteremia has focused interest on alternatives to the use of live probiotics. We searched MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, CINAHL, Alt Health Watch, Web of Science, Scopus, PubMed, from inception to February 14, 2017 for randomised controlled trials involving modified probiotic strains. The primary outcome was efficacy to prevent or treat disease and the secondary outcome was incidence of adverse events. A total of 40 trials were included (n=3,913): 14 trials (15 arms with modified probiotics and 20 control arms) for the prevention of diseases and 26 trials (29 arms with modified probiotics and 32 control arms) for treatment of various diseases. Modified microbes were compared to either placebo (44%), or the same living probiotic strain (39%) or to only standard therapies (17%). Modified microbes were not significantly more or less effective than the living probiotic in 86% of the preventive trials and 69% of the treatment trials. Modified probiotic strains were significantly more effective in 15% of the treatment trials. Incidence rates of adverse events were similar for modified and living probiotics and other control groups, but many trials did not collect adequate safety data. Although several types of modified probiotics showed significant efficacy over living strains of probiotics, firm conclusions could not be reached due to the limited number of trials using the same type of modified microbe (strain, daily dose and duration) for a specific disease indication. Further research may illuminate other strains of modified probiotics that may have potential as clinical biotherapeutics.

Antimicrobial Activity of some <i>Lactobacillus</i> Species against Intestinal Pathogenic Bacteria

Probiotics have antibacterial effects against pathogenic bacteria in the gut while maintaining the balance of intestinal flora such as Lactobacillus. This study aimed to evaluate the antimicrobial activity of four Lactobacillus species against intestinal pathogenic. Four different species of Lactobacillus (Lactobacillus bulgaricus (PTCC 1332), Lactobacillus casei (PTCC 1608), Lactobacillus plantarum (PTCC 1058) and Lactobacillus Fermentum (PTCC 1638)) were experimented to investigate the inhibitory activity against 4 bacterial enteric pathogens (Escherichia coli, Staphylococcus aureus, Shigella dysenteriae and Salmonella paratyphi A) which were separately inoculated in MRS medium (de Man, Rogosa and Sharpe medium) for 48 hours at 37 °C and pH 7. Our results showed that enteropathogens growth was stopped in the presence of all Lactobacillus and inhibition zone was between 12 and 32 millimeter. It can be concluded that these four Lactobacillus strains had potential antimicrobial compounds against human enteric pathogens and should be further studied for their human health benefits.

Antimicrobial Activity of some <i>Lactobacillus</i> Species against Intestinal Pathogenic Bacteria

Probiotics have antibacterial effects against pathogenic bacteria in the gut while maintaining the balance of intestinal flora such as Lactobacillus. This study aimed to evaluate the antimicrobial activity of four Lactobacillus species against intestinal pathogenic. Four different species of Lactobacillus (Lactobacillus bulgaricus (PTCC 1332), Lactobacillus casei (PTCC 1608), Lactobacillus plantarum (PTCC 1058) and Lactobacillus Fermentum (PTCC 1638)) were experimented to investigate the inhibitory activity against 4 bacterial enteric pathogens (Escherichia coli, Staphylococcus aureus, Shigella dysenteriae and Salmonella paratyphi A) which were separately inoculated in MRS medium (de Man, Rogosa and Sharpe medium) for 48 hours at 37 °C and pH 7. Our results showed that enteropathogens growth was stopped in the presence of all Lactobacillus and inhibition zone was between 12 and 32 millimeter. It can be concluded that these four Lactobacillus strains had potential antimicrobial compounds against human enteric pathogens and should be further studied for their human health benefits.

Probiotics Prevent Late-Onset Sepsis in Human Milk-Fed, Very Low Birth Weight Preterm Infants: Systematic Review and Meta-Analysis

Growing evidence supports the role of probiotics in reducing the risk of necrotizing enterocolitis, time to achieve full enteral feeding, and late-onset sepsis (LOS) in preterm infants. As reported for several neonatal clinical outcomes, recent data have suggested that nutrition might affect probiotics' efficacy. Nevertheless, the currently available literature does not explore the relationship between LOS prevention and type of feeding in preterm infants receiving probiotics. Thus, the aim of this systematic review and meta-analysis was to evaluate the effect of probiotics for LOS prevention in preterm infants according to type of feeding (exclusive human milk (HM) vs. exclusive formula or mixed feeding). Randomized-controlled trials involving preterm infants receiving probiotics and reporting on LOS were included in the systematic review. Only trials reporting on outcome according to feeding type were included in the meta-analysis. Fixed-effects models were used and random-effects models were used when significant heterogeneity was found. The results were expressed as risk ratio (RR) with 95% confidence interval (CI). Twenty-five studies were included in the meta-analysis. Overall, probiotic supplementation resulted in a significantly lower incidence of LOS (RR 0.79 (95% CI 0.71-0.88), p < 0.0001). According to feeding type, the beneficial effect of probiotics was confirmed only in exclusively HM-fed preterm infants (RR 0.75 (95% CI 0.65-0.86), p < 0.0001). Among HM-fed infants, only probiotic mixtures, and not single-strain products, were effective in reducing LOS incidence (RR 0.68 (95% CI 0.57-0.80) p < 0.00001). The results of the present meta-analysis show that probiotics reduce LOS incidence in exclusively HM-fed preterm infants. Further efforts are required to clarify the relationship between probiotics supplementation, HM, and feeding practices in preterm infants.

Preventing necrotizing enterocolitis by food additives in neonates: A network meta-analysis revealing the efficacy and safety

BACKGROUND

Necrotizing enterocolitis (NEC) is a serious multifactorial gastrointestinal disease which is often discovered in premature infants. Various additives have been used to prevent NEC; yet, their relative efficacy and safety remain disputed. This study aims to compare the efficacy and safety of 5 food additives, namely, probiotics, probiotics + fructo-oligosaccharides, pentoxifylline, arginine, and lactoferrin in preventing NEC in neonates.

METHODS

Embase, PubMed, and Cochrane Library had been searched for all eligible randomized control trials. Odds ratios (ORs) were estimated for dichotomous data and mean differences with 95% credible intervals (CrIs) were estimated for continuous data. Surface under the cumulative ranking curve was used to rank efficacy and safety of the prevention methods on each endpoint.

RESULTS

A total of 27 eligible studies with 4649 preterm infants were included in this network meta-analysis (NMA), and the efficacy and safety of 5 food additives were evaluated. Probiotic and arginine exhibited better preventive efficacy compared with placebo (OR = 0.50, 95% CrIs: 0.32-0.73; OR = 0.30, 95% CrIs: 0.12-0.73, respectively). Only probiotic achieved a considerable decrease in the risk of mortality compared to placebo (OR = 0.68, 95% CrIs: 0.46-0.98). NEC patients with lactoferrin appeared to have lower incidence of sepsis than those of placebo (OR = 0.13, 95% CrIs: 0.03-0.61) or probiotic (OR = 0.18, 95% CrIs: 0.03-0.83).

CONCLUSION

Based on this NMA, probiotics had the potential to be the most preferable additive, since it exhibited a significant superiority for NEC and mortality as well as a relatively balanced performance in safety.

Probiotics for the prevention of surgical necrotising enterocolitis: systematic review and meta-analysis

AIM OF THE STUDY

Probiotic administration to preterm infants has the potential to prevent necrotising enterocolitis (NEC). Data from randomised controlled trials (RCT) are conflicting but meta-analyses seem to support this intervention. To date, these analyses have not focused on surgical NEC. We aimed to determine the effect of probiotic administration to preterm infants on prevention of surgical NEC.

METHODS

A systematic review of RCTs of probiotic administration to preterm infants was performed. Studies were included if RCT outcomes included any of (1) Bell's stage 3 NEC; (2) surgery for NEC; and (3) deaths attributable to NEC. Article selection and data extraction were performed independently by two authors; conflicts were adjudicated by a third author. Data were meta-analysed using Review Manager V.5.3. A random effects model was decided on a priori because of the heterogeneity of study design; data are risk ratio (RR) with 95% CI.

MAIN RESULTS

Thirty-five RCTs reported NEC as an outcome. Seventeen reported surgical NEC; all RCTs were included. A variety of probiotic products was administered across studies. Description of surgical NEC in most studies was poor. Only 6/16 specifically reported incidence of surgery for NEC, 12/17 Bell's stage 3 and 13/17 NEC-associated mortality. Although there was a trend towards probiotic administration reducing stage 3 NEC, this was not significant (RR 0.74 (0.52-1.05), p=0.09). There was no effect of probiotics on the RR of surgery for NEC (RR 0.84 (0.56-1.25), p=0.38). Probiotics did, however, reduce the risk of NEC-associated mortality (RR 0.56 (0.34-0.93), p=0.03).

CONCLUSION

Despite 35 RCTs on probiotic prevention of NEC, evidence for prevention of surgical NEC is not strong, partly due to poor reporting. In studies included in this meta-analysis, probiotic administration was associated with a reduction in NEC-related mortality.

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.

Etiology and medical management of NEC

Necrotising enterocolitis (NEC) is a serious infection of the bowel that predominantly affects preterm infants and is a leading cause for mortality and morbidity in preterm infants. It involves a spectrum of pathology including widespread inflammation of the intestinal mucosa, invasion of the immature gut by enteric gas forming bacteria, dissection of the gut wall and portal veins by this gas, often culminating in ischemic necrosis of the intestine. This article provides an overview of the incidence, etio-pathological risk factors, preventive strategies and medical management of NEC.

Probiotic Supplementation and Late-Onset Sepsis in Preterm Infants: A Meta-analysis

CONTEXT

Late-onset sepsis (LOS) is a major cause of mortality and morbidity in preterm infants. Despite various preventive measures, its incidence continues to remain high, hence the urgent need for additional approaches. One such potential strategy is supplementation with probiotics. The updated Cochrane Review (2014) did not find benefits of probiotics in reducing the risk of LOS in preterm infants (19 studies, N = 5338). Currently there are >30 randomized controlled trials (RCTs) of probiotics in preterm infants that have reported on LOS.

OBJECTIVES

To conduct a systematic review including all relevant RCTs.

DATA SOURCES

PubMed, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature, and E-abstracts from the Pediatric Academic Society meetings and other pediatric and neonatal conference proceedings were searched in June and August 2015.

STUDY SELECTION

RCTs comparing probiotics versus placebo/no probiotic were included.

DATA EXTRACTION

Relevant data were extracted independently by 3 reviewers.

RESULTS

Pooled results from 37 RCTs (N = 9416) using fixed effects model meta analysis showed that probiotics significantly decreased the risk of LOS (675/4852 [13.9%] vs 744/4564 [16.3%]; relative risk, 0.86; 95% confidence interval, 0.78-0.94; P = .0007; I(2) = 35%; number needed to treat, 44). The results were significant even after excluding studies with high risk of bias.

CONCLUSIONS

Probiotic supplementation reduces the risk of LOS in preterm infants.

Prevention of Necrotizing Enterocolitis Through Manipulation of the Intestinal Microbiota of the Premature Infant

PURPOSE

In spite of four decades of research, necrotizing enterocolitis (NEC) remains the most common gastrointestinal complication in premature infants with high mortality and long-term morbidity. The composition of the intestinal microbiota of the premature infant differs dramatically from that of the healthy term infant and appears to be an important risk factor for NEC.

METHODS

We review the evidence of an association between intestinal dysbiosis and NEC and summarize published English language clinical trials and cohort studies involving attempts to manipulate the intestinal microbiota in premature infants.

FINDINGS

Promising NEC prevention strategies that alter the intestinal microbiota include probiotics, prebiotics, synbiotics, lacteroferrin, and human milk feeding.

IMPLICATIONS

Shaping the intestinal microbiota of the premature infant through human milk feeding and dietary supplements decreases the risk of NEC. Further studies to identify the ideal microbial composition and the most effective combination of supplements are indicated.

Probiotics and Innate and Adaptive Immune Responses in Premature Infants

Premature infants are at increased risk for morbidity and mortality due to necrotizing enterocolitis (NEC) and sepsis. Probiotics decrease the risk of NEC and death in premature infants; however, mechanisms of action are unclear. A wide variety of probiotic species have been evaluated for potential beneficial properties in vitro, in animal models, and in clinical trials of premature infants. Although there is variation by species and even strain, common mechanisms of protection include attenuation of intestinal inflammation, apoptosis, dysmotility, permeability, supplanting other gut microbes through production of bacteriocins, and more effective use of available nutrients. Here, we review the most promising probiotics and what is known about their impact on the innate and adaptive immune response.

Probiotics for prevention of necrotizing enterocolitis in preterm infants: systematic review and meta-analysis

Necrotizing enterocolitis (NEC) affects predominantly preterm infants, who have specific risk factors leading to intestinal dysbiosis. Manipulations of gut microbiota through probiotics have the potential to prevent NEC.

The aim of this systematic review and meta-analysis was to evaluate the effect of probiotics for NEC prevention in preterm infants, with a focus on specific strains, microbiological strength of currently available studies, and high-risk populations.

PubMed and the Cochrane Library were searched for trials published within 4th February 2015. Randomized-controlled trials reporting on NEC and involving preterm infants who were given probiotics in the first month of life were included in the systematic review.

Twenty-six studies were suitable for inclusion in the meta-analysis.

Data about study design, population, intervention and outcome were extracted and summarized independently by two observers. Study quality and quality of evidence were also evaluated.

Fixed-effects models were used and random-effects models where significant heterogeneity was present. Subgroup analyses were performed to explore sources of heterogeneity among studies. Results were expresses as risk ratio (RR) with 95 % confidence interval (CI).

The main outcome was incidence of NEC stage ≥2 according to Bell’s criteria.

Probiotics prevented NEC in preterm infants (RR 0.47 [95 % CI 0.36–0.60], p < 0.00001). Strain-specific sub-meta-analyses showed a significant effect for Bifidobacteria (RR 0.24 [95 % CI 0.10–0.54], p = 0.0006) and for probiotic mixtures (RR 0.39 [95 % CI 0.27–0.56], p < 0.00001). Probiotics prevented NEC in very-low-birth-weight infants (RR 0.48 [95 % CI 0.37–0.62], p < 0.00001); there were insufficient data for extremely-low-birth-weight infants. The majority of studies presented severe or moderate microbiological flaws.

Probiotics had an overall preventive effect on NEC in preterm infants. However, there are still insufficient data on the specific probiotic strain to be used and on the effect of probiotics in high-risk populations such as extremely-low-birth-weight infants, before a widespread use of these products can be recommended.

Factors influencing gastrointestinal tract and microbiota immune interaction in preterm infants

The role of microbial colonization is indispensable for keeping a balanced immune response in life. However, the events that regulate the establishment of the microbiota, their timing, and the way in which they interact with the host are not yet fully understood. Factors such as gestational age, mode of delivery, environment, hygienic measures, and diet influence the establishment of microbiota in the perinatal period. Environmental microbes constitute the most important group of exogenous stimuli in this critical time frame. However, the settlement of a stable gut microbiota in preterm infants is delayed compared to term infants. Preterm infants have an immature gastrointestinal tract and immune system which predisposes to infectious morbidity. Neonatal microbial dynamics and alterations in early gut microbiota may precede and/or predispose to diseases such as necrotizing enterocolitis (NEC), late-onset sepsis or others. During this critical period, nutrition is the principal contributor for immunological and metabolic development, and microbiological programming. Breast milk is a known source of molecules that act synergistically to protect the gut barrier and enhance the maturation of the gut-related immune response. Host-microbe interactions in preterm infants and the protective role of diet focused on breast milk impact are beginning to be unveiled.

Probiotics for prevention of necrotizing enterocolitis in preterm infants

BACKGROUND

Necrotizing enterocolitis (NEC) and nosocomial sepsis are associated with increased morbidity and mortality in preterm infants. Through prevention of bacterial migration across the mucosa, competitive exclusion of pathogenic bacteria, and enhancing the immune responses of the host, prophylactic enteral probiotics (live microbial supplements) may play a role in reducing NEC and the associated morbidity.

OBJECTIVES

To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC or sepsis, or both, in preterm infants.

SEARCH METHODS

For this update, searches were made of MEDLINE (1966 to October 2013), EMBASE (1980 to October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 10), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2013).

SELECTION CRITERIA

Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age or < 2500 g birth weight, or both, were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome.

DATA COLLECTION AND ANALYSIS

Standard methods of The Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials and for data collection and analysis.

MAIN RESULTS

Twenty-four eligible trials were included. Included trials were highly variable with regard to enrolment criteria (that is birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical relative risk (RR) 0.43, 95% confidence interval (CI) 0.33 to 0.56; 20 studies, 5529 infants) and mortality (typical RR 0.65, 95% CI 0.52 to 0.81; 17 studies, 5112 infants). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.91, 95% CI 0.80 to 1.03; 19 studies, 5338 infants). The included trials reported no systemic infection with the supplemental probiotics organism. Probiotics preparations containing either lactobacillus alone or in combination with bifidobacterium were found to be effective.

AUTHORS' CONCLUSIONS

Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence strongly supports a change in practice. Head to head comparative studies are required to assess the most effective preparations, timing, and length of therapy to be utilized.

PLAIN LANGUAGE SUMMARY

Probiotics for prevention of necrotizing enterocolitis in preterm infants Necrotizing enterocolitis (NEC) is a serious disease that affects the bowel of premature infants in the first few weeks of life. Although the cause of NEC is not entirely known, milk feeding and bacterial growth play a role. Probiotics (dietary supplements containing potentially beneficial bacteria or yeast) have been used to prevent NEC. Our review of studies found that the use of probiotics reduces the occurrence of NEC and death in premature infants born weighing less than 1500 grams. There is insufficient data with regard to the benefits and potential adverse effects in the most at risk infants weighing less than 1000 grams at birth.

Probiotics and pregnancy

Complications of pregnancy are associated with adverse outcomes for mother and baby in the short and long term. The gut microbiome has been identified as a key factor for maintaining health outside of pregnancy and could contribute to pregnancy complications. In addition, the vaginal and the recently revealed placental microbiome are altered in pregnancy and may play a role in pregnancy complications. Probiotic supplementation could help to regulate the unbalanced microflora composition observed in obesity and diabetes. Here, the impact of probiotic supplementation during pregnancy and infancy is reviewed. There are indications for a protective role in preeclampsia, gestational diabetes mellitus, vaginal infections, maternal and infant weight gain and allergic diseases. Large, well-designed randomised controlled clinical trials along with metagenomic analysis are needed to establish the role of probiotics in adverse pregnancy and infancy outcomes.

[Correlation of the microbiota and intestinal mucosa in the pathophysiology and treatment of irritable bowel, irritable eye, and irritable mind syndrome]

Accumulating clinical evidence supports co-morbidity of irritable bowel, irritable eye and irritable mind symptoms. Furthermore, perturbation of the microbiota-host symbiosis (dysbiosis) is considered a common pathogenic mechanism connecting gastrointestinal, ocular and neuropsychiatric symptoms. Consequently, maintaining or restoring microbiota-host symbiosis represents a new approach to treat these symptoms or to prevent their relapses. Current treatment approach assigned a primary role to live probiotics alone or in combination with prebiotics to enhance colonization of beneficial bacteria and to strengthen the symbiosis. However, several papers showed major benefits of heat-killed probiotics as compared to their live counterparts on both intestinal and systemic symptoms. Recently, in addition to killing probiotics, in a proof of concept study lysates (fragments) of probiotics in combination with vitamins A, B, D and omega 3 fatty acids were successfully tested. These findings suggested a conceptual change in the approach addressed to both the microbiota and host as targets for intervention.

Probiotics for prevention of necrotizing enterocolitis in preterm infants

BACKGROUND

Necrotizing enterocolitis (NEC) and nosocomial sepsis are associated with increased morbidity and mortality in preterm infants. Through prevention of bacterial migration across the mucosa, competitive exclusion of pathogenic bacteria, and enhancing the immune responses of the host, prophylactic enteral probiotics (live microbial supplements) may play a role in reducing NEC and the associated morbidity.

OBJECTIVES

To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC or sepsis, or both, in preterm infants.

SEARCH METHODS

For this update, searches were made of MEDLINE (1966 to October 2013), EMBASE (1980 to October 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 10), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2013).

SELECTION CRITERIA

Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age or < 2500 g birth weight, or both, were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome.

DATA COLLECTION AND ANALYSIS

Standard methods of The Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials and for data collection and analysis.

MAIN RESULTS

Twenty-four eligible trials were included. Included trials were highly variable with regard to enrolment criteria (that is birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical relative risk (RR) 0.43, 95% confidence interval (CI) 0.33 to 0.56; 20 studies, 5529 infants) and mortality (typical RR 0.65, 95% CI 0.52 to 0.81; 17 studies, 5112 infants). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.91, 95% CI 0.80 to 1.03; 19 studies, 5338 infants). The included trials reported no systemic infection with the supplemental probiotics organism. Probiotics preparations containing either lactobacillus alone or in combination with bifidobacterium were found to be effective.

AUTHORS' CONCLUSIONS

Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence strongly supports a change in practice. Head to head comparative studies are required to assess the most effective preparations, timing, and length of therapy to be utilized.

Probiotic guideline for necrotizing enterocolitis prevention in very low-birth-weight neonates

Necrotizing enterocolitis (NEC) is a gastrointestinal emergency that leads to inflammation and intestinal necrosis. Although probiotics can decrease the incidence of NEC, consistent recommendations for probiotic administration to very low-birth-weight (VLBW) neonates are lacking. Here, the best available evidence is reviewed and a practice guideline for probiotic administrations to VLBW neonates is described. A systematic review was conducted using MEDLINE and EMBASE, and the strength of evidence was classified using the Centre for Evidence-Based Medicine classification schema. Probiotics for VLBW neonates may decrease the incidence of NEC. Providers may choose to give probiotics to VLBW neonates at risk of acquiring NEC in facilities with a high NEC incidence. Clinicians must monitor infants for possible adverse effects. Contraindications for probiotic use include extremely low birth weight, clinical instability, abnormal abdominal examination, the presence of congenital abnormalities, post-NEC, stage III asphyxia, and umbilical catheters.

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.

Irritable eye syndrome: neuroimmune mechanisms and benefits of selected nutrients

Previous studies showed comorbidity of some ocular, enteral, and affective symptoms comprising irritable eye syndrome. Aims of the present study were to learn more about the pathogenic mechanisms of this syndrome and to evaluate benefits of food supplements on these disorders. In in vitro assay, Lactobacillus acidophilus lysate inhibited interleukin (IL)-1β and tumor necrosis factor (TNF)-α generation of lipopolysaccharide (LPS)-stimulated macrophages in dose- and size-dependent manner. For a prospective, open-label phase I/II controlled clinical trial, 40 subjects affected by ocular dysesthesia and hyperesthesia and comorbid enteral and anxiety-depression symptoms were randomly assigned either into the treated group, which received a composition containing probiotic lysate, vitamins A, B, and D and omega 3 fatty acids, or into the control group, which received vitamins and omega 3 fatty acids. For reference, 20 age- and sex-matched healthy subjects were also selected. White blood count (WBC) and lymphocyte and monocyte counts, as well as IL-6 and TNF-α levels, were significantly above the reference levels in both treated and control groups. After 8 weeks, WBC and lymphocyte and monocyte counts, and cytokine levels significantly decreased, and ocular, enteral, and anxiety-depression symptoms significantly improved in the treated group as compared to the control group. This proof-of-concept study suggested that subclinical inflammation may be a common mechanism connecting ocular, enteral, and anxiety/depression symptoms, and supplements affecting dysbiosis may be a new approach to treating this syndrome.

Efficacy of different probiotic combinations on death and necrotizing enterocolitis in a premature rat model

OBJECTIVE

The aim of the present study was to investigate the most effective probiotic combinations to prevent death and necrotizing enterocolitis (NEC) in a premature rat model.

METHODS

One hundred fifty-eight premature Sprague-Dawley premature rats were enrolled. Probiotic strains Bifidobacterium bifidum, B longum, Lactobacillus acidophilus, L plantarum, and B breve were fed as a single strain or mixture with 2 or 3 strains for a total of 9 study groups; control groups received no exogenous probiotic supplement. Fecal samples were collected for 72 hours to detect probiotic strains and pathologic strains by real-time polymerase chain reaction. Colony counts of probiotic strains Escherichia coli and Klebsiella were compared between groups before and after 36 hours of the study period. The incidence of death and NEC were compared via Fisher exact test between groups.

RESULTS

The results demonstrated that L plantarum alone (P = 0.0026) and B bifidum with B longum together (P = 0.0017) were more effective in reducing NEC as compared with the control group. All of the study groups except B breve and B bifidum with B breve definitely prevented death compared with controls. B bifidum and B longum together had significantly lower mortality than the control group (P < 0.0001). Colony counts of E coli and Klebsiella in stool samples were significantly decreased in the B bifidum, B longum, and L plantarum group compared with the other study and control groups after 36 hours.

CONCLUSIONS

Administration of a mixture of probiotic strains with B bifidum and B longum was most effective in preventing death and NEC in this animal model, and these observations provide an evidence-based strategy for designing further neonatal clinical trials.

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.

Effectiveness of probiotics in the prophylaxis of necrotizing enterocolitis in preterm neonates: a systematic review and meta-analysis

OBJECTIVE

To elucidate the benefits of using probiotics in the prevention of necrotizing enterocolitis (NEC) and its complications in preterm newborns.

METHOD

This was a systematic review of randomized controlled trials, which included studies retrieved from three databases (MEDLINE, Embase, and LILACS), using a combination of the terms (necrotizing enterocolitis) AND (probiotics).

RESULTS

11 randomized trials were included, totaling 2,887 patients, 1,431 in the probiotic group and 1,456 in the control group. There was a reduction in the incidence of NEC (NNT=25), overall death (NNT=34), and neonatal sepsis (NNT=34) in the probiotic group compared to the control group. Patients that received probiotic supplementation had lower food reintroduction time (p<0.001) and hospitalization time (p<0.001) when compared to those not receiving probiotics. There was no difference in mortality caused by NEC.

CONCLUSION

In premature newborns, the use of probiotics is effective as a prophylaxis for NEC and its complications.

Probiotics and necrotizing enterocolitis: finding the missing pieces of the probiotic puzzle

Necrotizing enterocolitis (NEC) is one of the leading causes of death in the neonatal intensive care unit. Morbidity and mortality rates significantly increase with decreases in gestational age and birth weight. Strong evidence suggests probiotic prophylaxis may significantly decrease the incidence of NEC and should therefore be incorporated into the standard of care for preterm infants. However, debate still remains because of limitations of completed studies. The purpose of this review was to provide an overview of the controversies regarding probiotic use in preterm infants and to shed light on the practical considerations for implementation of probiotic supplementation.

Effect of routine probiotic, Lactobacillus reuteri DSM 17938, use on rates of necrotizing enterocolitis in neonates with birthweight < 1000 grams: a sequential analysis

Background

Necrotizing enterocolitis (NEC) is a disease in neonates, often resulting in death or serious medical or neurodevelopmental complications. The rate of NEC is highest in the smallest babies and many efforts have been tried to reduce the rate of NEC. In neonates born below 1500 grams, the rate of NEC has been significantly reduced with the use of various probiotics. This study examines the impact of routine use of a probiotic, Lactobacillus reuteri DSM 17938 (BioGaia®), on the rate of NEC in neonates at highest risk for developing NEC, those with birth weight ≤1000 grams.

Methods

This is a retrospective cohort study comparing the rates of NEC in neonates with birth weight ≤ 1000 grams. The groups are separated into those neonates born from January 2004 to June 30, 2009, before introduction of L. reuteri , and neonates born July 2009 through April 2011 who received routine L. reuteri prophylaxis. The chart review study was approved by our institutional review board and exempted from informed consent.

Neonates were excluded if they died or were transferred within the first week of life. The remainder were categorized as having no NEC, medical NEC, surgical NEC, or NEC associated death. Since no major changes occurred in our NICU practice in recent years, and the introduction of L. reuteri as routine prophylaxis was abrupt, we attributed the post-probiotic changes to the introduction of this new therapy. Rates of NEC were compared using Chi square analysis with Fisher exact t-test.

Results

Medical records for 311 neonates were reviewed, 232 before- and 79 after-introduction of L. reuteri prophylaxis. The incidence of NEC was significantly lower in the neonates who received L. reuteri (2 of 79 neonates [2.5%] versus 35 of 232 untreated neonates [15.1%]). Rates of late-onset gram-negative or fungal infections (22.8 versus 31%) were not statistically different between treated and untreated groups. No adverse events related to use of L reuteri were noted.

Conclusions

Prophylactic initiation of L. reuteri as a probiotic for prevention of necrotizing enterocolitis resulted in a statistically significant benefit, with avoidance of 1 NEC case for every 8 patients given prophylaxis.

Probiotics in neonatology

Probiotics are micro-organisms that confer health benefits on the host. Postulated mechanisms include: increasing resistance of the mucosal barrier to migration of bacteria and their toxins by strengthening intestinal cell junctions, modification of host response to microbial products, augmentation of immunoglobulin A mucosal responses, enhancement of enteral nutrition to inhibit the growth of pathogens; production of antimicrobial proteins; and competitive exclusion of potential pathogens. Published meta-analyses and systematic reviews report the effects of probiotics on important clinical outcomes in neonates. This paper will review the evidence for probiotic supplementation in neonatology, with a focus on preterm infants.

A.S.P.E.N. clinical guidelines: nutrition support of neonatal patients at risk for necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is one of the most devastating diseases in the neonatal population, with extremely low birth weight and extremely preterm infants at greatest risk.

METHOD

A systematic review of the best available evidence to answer a series of questions regarding nutrition support of neonates at risk of NEC was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development and Evaluation working group. A consensus process was used to develop the clinical guideline recommendations prior to external and internal review and approval by the A.S.P.E.N. Board of Directors. RESULTS/ CONCLUSIONS: (1) When and how should feeds be started in infants at high risk for NEC? We suggest that minimal enteral nutrition be initiated within the first 2 days of life and advanced by 30 mL/kg/d in infants ≥ 1, 000 g. (Weak) (2) Does the provision of mother's milk reduce the risk of developing NEC? We suggest the exclusive use of mother's milk rather than bovine-based products or formula in infants at risk for NEC. (Weak) (3) Do probiotics reduce the risk of developing NEC? There are insufficient data to recommend the use of probiotics in infants at risk for NEC. (Further research needed.) (4) Do nutrients either prevent or predispose to the development of NEC? We do not recommend glutamine supplementation for infants at risk for NEC (Strong). There is insufficient evidence to recommend arginine and/or long chain polyunsaturated fatty acid supplementation for infants at risk for NEC. (Further research needed.) (5) When should feeds be reintroduced to infants with NEC? There are insufficient data to make a recommendation regarding time to reintroduce feedings to infants after NEC. (Further research needed.).

Critical systematic review of the level of evidence for routine use of probiotics for reduction of mortality and prevention of necrotizing enterocolitis and sepsis in preterm infants

BACKGROUND & AIMS

Probiotics have been suggested to prevent severe necrotizing enterocolitis (NEC) and decrease mortality in preterm infants. The aim of this paper was to systematically analyze the level of evidence (LoE) of published controlled randomized trials (RCTs) on probiotics in preterm infants.

METHODS

Literature searches were made up to November 2010. LoE of recommendations based on single trials or meta-analyses were scored following the Oxford Center for Evidence based Medicine approach (1a - meta-analyses of 1b LoE studies; 1b - well designed RCT; 2a - meta-analyses which include 2b LoE studies; 2b - lesser quality RCT).

RESULTS

Fifteen trials were included (Two 1b LoE trials and thirteen 2b LoE trials). Methodological assessment revealed considerable heterogeneity. Some probiotics may be beneficial in relation to reduction of severe NEC (2b LoE) and reduction of mortality (2b LoE). Probiotics do not accelerate feeding advancement (1b and 2b LoE). There was no convincing benefit with regard to prevention of sepsis (1b and 2b LoE).

CONCLUSION

There is insufficient evidence to recommend routine probiotics. However, there is encouraging data (2b LoE) which justifies the further investigation regarding the efficacy and safety of specific probiotics in circumstances of high local incidence of severe NEC.

Myth: necrotizing enterocolitis: probiotics will end the disease, and surgical intervention improves the outcome

Necrotizing enterocolitis remains an important contributor to neonatal morbidity and mortality. Recent studies suggest that probiotic supplementation may reduce the risk of the disease in premature infants, and some authors recommend that this approach is ready to be utilized as standard-of-care. Once necrotizing enterocolitis is diagnosed and progresses toward peritonitis or perforation, surgical intervention is thought to improve the outcome, and investigators have suggested that peritoneal drainage is as effective as an exploratory laparotomy. In this chapter, we review the current state of knowledge, and suggest that additional studies are necessary to confirm that probiotics will end this disease, and that surgical intervention may not significantly improve the outcome after diagnosis in these compromised patients.

The ProPrems trial: investigating the effects of probiotics on late onset sepsis in very preterm infants

Background

Late onset sepsis is a frequent complication of prematurity associated with increased mortality and morbidity. The commensal bacteria of the gastrointestinal tract play a key role in the development of healthy immune responses. Healthy term infants acquire these commensal organisms rapidly after birth. However, colonisation in preterm infants is adversely affected by delivery mode, antibiotic treatment and the intensive care environment. Altered microbiota composition may lead to increased colonisation with pathogenic bacteria, poor immune development and susceptibility to sepsis in the preterm infant.

Probiotics are live microorganisms, which when administered in adequate amounts confer health benefits on the host. Amongst numerous bacteriocidal and nutritional roles, they may also favourably modulate host immune responses in local and remote tissues. Meta-analyses of probiotic supplementation in preterm infants report a reduction in mortality and necrotising enterocolitis. Studies with sepsis as an outcome have reported mixed results to date.

Allergic diseases are increasing in incidence in "westernised" countries. There is evidence that probiotics may reduce the incidence of these diseases by altering the intestinal microbiota to influence immune function.

Methods/Design

This is a multi-centre, randomised, double blinded, placebo controlled trial investigating supplementing preterm infants born at < 32 weeks' gestation weighing < 1500 g, with a probiotic combination (Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis). A total of 1,100 subjects are being recruited in Australia and New Zealand. Infants commence the allocated intervention from soon after the start of feeds until discharge home or term corrected age. The primary outcome is the incidence of at least one episode of definite (blood culture positive) late onset sepsis before 40 weeks corrected age or discharge home. Secondary outcomes include: Necrotising enterocolitis, mortality, antibiotic usage, time to establish full enteral feeds, duration of hospital stay, growth measurements at 6 and 12 months' corrected age and evidence of atopic conditions at 12 months' corrected age.

Discussion

Results from previous studies on the use of probiotics to prevent diseases in preterm infants are promising. However, a large clinical trial is required to address outstanding issues regarding safety and efficacy in this vulnerable population. This study will address these important issues.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN012607000144415

The product "ABC Dophilus Probiotic Powder for Infants^®", Solgar, USA has its 3 probiotics strains registered with the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ - German Collection of Microorganisms and Cell Cultures) as BB-12 15954, B-02 96579, Th-4 15957.

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.

What is the power of evidence recommending routine probiotics for necrotizing enterocolitis prevention in preterm infants?

PURPOSE OF REVIEW

There is a lively discussion in literature whether routine use of probiotics should be recommended to reduce the incidence of severe necrotizing enterocolitis (NEC) and mortality in preterm infants. The aim of the present review is to analyze the level of evidence of published randomized controlled trials (RCTs) that different probiotic products reduce the incidence of severe NEC and mortality in preterm infants following Oxford Center for Evidence-based Medicine approach.

RECENT FINDINGS

Application of probiotics is not a homogeneous intervention and meta-analyses across the available trials may be misleading with the risk that generalized conclusions are erroneously extrapolated to other probiotics. Each individual probiotic intervention should be analyzed separately. Currently, there are 16 RCTs studying 12 different probiotic preparations in preterm infants which report data on clinically important outcomes such as NEC, mortality, sepsis, or feeding advancement. Certain probiotics may be beneficial in relation to severe NEC (level of evidence, LoE 2b).

SUMMARY

In circumstances of high local incidence of severe NEC, there is encouraging data (LoE 2b) for the use of probiotics. However, currently there is no level 1a evidence to recommend that all preterm infants should be fed probiotics routinely. Further, well designed RCTs on specific probiotics are required.

Progress in the field of probiotics: year 2011

PURPOSE OF REVIEW

The interest and scope for research in the field of probiotics has significantly widened in recent years. This brief review covers the significant advances in the field of probiotics.

RECENT FINDINGS

These include conclusive evidence for the benefits of probiotics in preventing all cause mortality and necrotizing enterocolitis (NEC) in preterm very low birth weight (VLBW) neonates, understanding the role of probiotics as vaccine adjuvants, and in modulating inflammatory bowel diseases, bowel cancer, type 1 diabetes mellitus, obesity, high cholesterol levels, and bacterial resistance. Other areas of progress include understanding the role of probiotics in oral health and ageing.

SUMMARY

Current evidence will lead to routine probiotic supplementation to prevent all cause mortality and NEC in preterm VLBW neonates. Probiotics may also become novel agents as vaccine adjuvants, and in dealing with major public health issues such as obesity, type I diabetes mellitus, and poor oral health. Research in applications of probiotics in food products will rationalize product development, and health claims. As new frontiers continue to be explored the challenges to the basis of the hygiene hypothesis will influence further developments in the field of probiotics.