Probiotics for preterm infants?

Current Patterns of Probiotic Use in U.S. Neonatal Intensive Care Units: A Multi-Institution Survey

OBJECTIVE

Probiotic supplementation is associated with health benefits in preterm infants. The 2021 American Academy of Pediatrics (AAP) statement on probiotic use advised caution, citing heterogeneity and absence of federal regulation. We assessed the impact of the AAP statement and current institution-wide patterns of probiotic use across neonatal intensive care units (NICU) across the United States.

STUDY DESIGN

A cross-sectional web-based institutional survey using REDCap was emailed to 430 Children's Hospital Neonatal Consortium (CHNC) and Pediatrix Medical Group institutions. The survey captured data on probiotic formulations, supplementation, initiation and cessation criteria, reasons for discontinuation, interest in initiating, and AAP statement's impact.

RESULTS

Ninety-five (22.1%) hospitals, including 42/46 (91%) CHNC and 53/384 (14%) Pediatrix institutions, completed the survey. Thirty-seven (39%) currently use probiotics. Fourteen different probiotic formulations were reported. The common criteria for initiation were birth weight <1,500 g and gestational age <32 weeks. Parental consent or assent was obtained at only 30% of institutions. Five hospitals (11%) with prior probiotic use discontinued solely due to the AAP statement. Overall, 23 (24%) of hospitals indicated that the AAP statement significantly influenced their decision regarding probiotic use. Nineteen of 51 nonusers (37%) are considering initiation.

CONCLUSION

Probiotic use in preterm infants is likely increasing in NICUs across the United States, but significant variability exists. The 2021 AAP statement had variable impact on NICUs' decision regarding probiotic use. The growing interest in adopting probiotics and the significant interhospital variability highlight the need for better regulation and consensus guidelines to ensure standardized use.

KEY POINTS

· Probiotic use in preterm infants is likely increasing in U.S. NICUs, but clinical variability exists.. · The AAP statement on probiotic use in preterm infants had a modest impact on current practices.. · There's a need for better product regulation and consensus guidelines to ensure standardized use..

Probiotics to prevent necrotizing enterocolitis and reduce mortality in neonates: A meta-analysis

BACKGROUND

Probiotics are gradually being used as a supplementation to prevent necrotizing enterocolitis (NEC) and reduce mortality in neonates. We performed an updated meta-analysis to systematically evaluate the efficacy and safety of prophylactic probiotic supplementation for preventing NEC.

METHODS

The databases including PubMed, Embase, Scopus, Web of Science, and China National Knowledge Infrastructure were used to search the relevant articles. The latest retrieval date was up to December 2021. The meta-analysis was performed using Stata version 10.0. Finally, a total of 70 studies containing 8319 cases and 9283 controls were included. The strength of the association between the supplementation of probiotics and NEC was measured by risk ratios (RRs) with 95% confidence intervals (CIs). Pooled effect sizes across studies were performed by a random effect model.

RESULTS

The results showed that the probiotics could significantly reduce the incidence of NEC (stage II or more) (RR = 0.436, 95% CI = 0.357-0.531, P < .001), the overall mortality (RR = 0.651, 95% CI = 0.506-0.836, P < .001), and NEC-related mortality (RR = 0.639, 95% CI = 0.423-0.966, P = .034). Due to the lack of sufficient sample size, we did not perform the subgroup analysis by types of probiotic strain.

CONCLUSION

This meta-analysis indicates that the use of probiotics can effectively reduce the occurrence of NEC and mortality in neonates.

Human Breast Milk: The Key Role in the Maturation of Immune, Gastrointestinal and Central Nervous Systems: A Narrative Review

Premature birth is a major cause of mortality and morbidity in the pediatric population. Because their immune, gastrointestinal and nervous systems are not fully developed, preterm infants (<37 weeks of gestation) and especially very preterm infants (VPIs, <32 weeks of gestation) are more prone to infectious diseases, tissue damage and future neurodevelopmental impairment. The aim of this narrative review is to report the immaturity of VPI systems and examine the role of Human Breast Milk (HBM) in their development and protection against infectious diseases, inflammation and tissue damage. For this purpose, we searched and synthesized the data from the existing literature published in the English language. Studies revealed the significance of HBM and indicate HBM as the best dietary choice for VPIs.

Risk of infection in neonates born in accidental out-of-hospital deliveries

Accidental out-of-hospital deliveries (OHDs) are known to have a higher incidence of maternal and neonatal complications. However, neonatal infection related to OHDs has not been studied. The aim of this study was to determine the infection risk of OHDs. This retrospective cohort study enrolled neonates admitted at a children’s hospital in an urban setting from January 2004 to December 2017. Accidental OHDs were compared with in-hospital births, and neonatal infection was assessed. This study also investigated both maternal and neonatal risk factors associated with OHDs. A cohort of 158 OHD neonates was enrolled, of whom 29 (23.2%) were preterm. Prematurity and low birth weight were significantly associated with OHD. Eight neonates in the OHD cohort had a documented infection within the first 72 hours of life, which was 11-fold higher than infections documented for the in-hospital births. Multivariate analysis identified low birth weight as the only factor independently associated with increased risk of infection in OHD neonates. Several specific characteristics of mothers with OHDs were identified. Forty-nine (31%) OHD mothers lacked antenatal care, and 10 (6.3%) were unaware of their pregnancies. The OHD group comprised of more teenage mothers compared to the in-hospital deliveries category. Neonatal infection was more prevalent among OHDs than for in-hospital deliveries, and the infection rate was associated with low birth weight. Hospitalization for further care and observation is suggested for the OHD neonates. Social support should be provided for populations with an increased risk of OHD, such as teenage mothers.

Neonatal invasive candidiasis: updates on clinical management and prevention

Neonatal invasive candidiasis is an important cause of morbidity and mortality in preterm infants. The incidence of invasive candidiasis in this population has been declining in high-income settings, largely due to preventive measures, although there are still considerable variations in incidence between health-care centres. Surveillance data and large, multicentre studies in lower-income settings are not available, although preventive measures in these settings have been shown to decrease the incidence of neonatal invasive candidiasis. Understanding risk factors and pathogenesis are key to the prevention of invasive candidiasis. The difficulty of a definitive diagnosis of invasive candidiasis and the high risk for death or substantial neurodevelopmental impairment, even with appropriate treatment, further increase the need for effective preventive measures. In this Review, we examine the pathogenesis, clinical presentation, and diagnosis of invasive candidiasis. We highlight commonly used and emerging preventive and prophylactic measures, including standardised central line care, antibiotic stewardship, antifungal prophylaxis, and probiotics. Finally, we provide updates on empirical treatment, clinical management in confirmed cases of invasive candidiasis, and antifungal pharmacotherapy.

Association between probiotics and bronchopulmonary dysplasia in preterm infants

Bronchopulmonary dysplasia is a chronic pulmonary disease with a high incidence in premature infants, and there is still no effective treatment. The purpose of our study was to analyze the association between the use of probiotics and BPD in premature infants. We retrospectively collected clinical data of infants with gestational age < 32 weeks admitted to the NICU of The First Hospital of Jilin University from January 1, 2019 to March 31, 2020. Demographic and clinicopathological data of the inclusion population were collected. The outcome was the incidence of BPD or death. The χ² tests was used to compare the categorical variables. The t test and non-parametric Wilcoxon rank-sum test were used to compare the continuous data. Univariate and multivariate logistic regression were used to analyze the association between probiotics and BPD. A total of 318 newborns met the inclusion criteria, of which 94 received probiotics and 224 received no probiotics. There were 16 deaths and 115 newborns with BPD in the included population. The results of univariate analysis showed differences in the maternal diabetes, the proportion of systemic antibiotics given to mother within 24 h before birth, the receiving rate of invasive mechanical ventilation, the prevalence of BPD/death, PDA, RDS and Ivh between newborns with and without probiotics (p < 0.05); The results of unadjusted univariate logistic regression model showed that probiotic (OR 0.034, 95% CI 0.012-0.096) was the factor affecting BPD in preterm infants (p < 0.05). Multivariate logistic regression result (OR 0.037, 95% CI 0.013-0.105) was consistent with univariate analysis (P < 0.001). Probiotics are associated with a reduced risk of BPD in preterm infants < 32 weeks of age. More prospective studies with large samples are still needed.

Involvement of Probiotics and Postbiotics in the Immune System Modulation

Intestinal microbiota interacts with other systems, especially the immune system, which is responsible for protecting the body by recognizing “stranger” (pathogen associated molecular patterns-PAMPs) and “danger” (damage-associated molecular patterns-DAMPs) molecular motifs. In this manner, it plays an important role in the pathogenesis of various diseases and health. Despite the use of probiotics that modulate the intestinal microbiota in providing health benefits and in the treatment of diseases, there are some possible concerns about the possibility of developing adverse effects, especially in people with suppressed immune systems. Since probiotics provide health benefits with bioactive compounds, studies are carried out on the use of products containing non-living probiotic microorganisms (paraprobiotics) and/or their metabolites (postbiotics) instead of probiotic products. It is even reported that these microbial compounds have more immunomodulatory activities than living microorganisms via some possible mechanism and eliminates some disadvantages of probiotics. Considering the increasing use of functional foods in health and disease, further studies are needed with respect to the benefits and advantages of parabiotic and/or postbiotic use in the food and pharmaceutical industry as well as immune system modulation. Although probiotics have been extensive studied for a long time, it seems that postbiotics are promising tools for future research and applications according to the recent literature. This review aimed to evaluate the interaction of probiotics and postbiotics with the immune systems and also their advantages and disadvantages in the area of food-pharmaceutical industry and immune system modulation.

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.

Probiotic Use and Safety in the Neonatal Intensive Care Unit: A Matched Cohort Study

OBJECTIVE

To determine the prevalence of probiotic administration in infants born preterm over time, as well as the association between probiotic administration and select adverse outcomes.

STUDY DESIGN

We performed a multicenter cohort study of infants 23-29 weeks of gestational age admitted to 289 neonatal intensive care units from 1997 to 2016. We evaluated the type of probiotics given and prevalence of exposure to probiotics over time and by site. We matched infants exposed to probiotics by several factors to unexposed infants receiving enteral feeds on the same postnatal day. We performed conditional logistic regression to evaluate the association between probiotics exposure and adverse outcomes, including necrotizing enterocolitis (NEC), bloodstream infections, meningitis, and death.

RESULTS

Of 78 076 infants, 3626 (4.6%) received probiotics. Probiotic use increased over the study period and varied among neonatal intensive care units. We matched 2178 infants exposed to probiotics to 33 807 without exposure. Probiotic administration was associated with a decrease in NEC (OR 0.62, 95% CI 0.48-0.80) and death (OR 0.52, 95% CI 0.39-0.70), an increase in Candida infection (OR 2.23, 95% CI 1.29-3.85), but no increase in bloodstream infection (OR 0.86, 95% CI 0.70-1.05) or meningitis (OR 1.18, 95% CI 0.40-3.46).

CONCLUSIONS

Probiotic use increased over time and was associated with decreased odds of NEC and death. Prospective, randomized-controlled studies of specific probiotic products are needed to further investigate the safety and efficacy of probiotics in preterm infants.

Functional Gastrointestinal Disorders in Outpatients Aged up to 12 Months: A French Non-Interventional Study

Background: The aim of this study was to estimate the frequency of functional gastrointestinal disorders (FGIDs) in infants aged up to 12 months according to the new ROME IV criteria defining these disorders, and to describe the management of FGIDs in France. Methods: This French non-interventional, cross-sectional, and multicenter study was conducted among private-outpatient physicians who each included four consecutive patients aged up to 12 months. The frequency of FGIDs was described using the ROME IV criteria versus clinicians’ diagnosis. The characteristics of infants with and without FGID were compared, and the management of the FGIDs was described. Results: In the 1722 infants analyzed, the following frequencies were observed according to the ROME IV criteria versus the physicians’ diagnosis: regurgitation 41% versus 45%; colic 18% versus 30%; constipation 9% versus 19%; diarrhea 3% versus 8%. Of note, FGID infants were less frequently exclusively breastfeeding at the maternity hospital (p < 0.001), were introduced to cow’s milk earlier after leaving the maternity hospital (p < 0.001), and more frequently had symptoms suggestive of cow’s milk protein allergy (p < 0.001). Physicians frequently recommended an adapted infant formula (in 77% to 82% of cases depending on the FGID diagnosed) and prescribed a specific treatment in 51% to 66% of infants (probiotics: 35% to 64%). Conclusions: This real-world study confirms the high frequency of FGIDs in infants in France, and provides new information regarding the characteristics of FGID infants.

Early-life gut microbiome and cow's milk allergy- a prospective case - control 6-month follow-up study

Increasing evidence suggests that perturbations in the intestinal microbiota in early infancy are implicated in the pathogenesis of food allergy (FA); existing evidence on the structure and composition of the intestinal microbiota in human beings with FA is limited and conflicting. The main object of the study was to compare the faecal microbiota between healthy and cow’s milk allergy (CMA) infants at the baseline immediately after the diagnosis, and to evaluate the changes in the faecal microbiota after 6 months of treatment of CMA infants with hypoallergenic formula (HF), compared with healthy children fed on standard milk formulae. Sixty infants younger than 4 months of age with challenge-proven CMA and 60 healthy age-matched children were investigated in this prospective case - control follow-up study. Faecal samples were collected at baseline and at 6 months of follow-up, microbial diversity and composition were characterized by high-throughput 16S rRNA sequencing. The average age (±SD) of the infants at inclusion was 2.9 ± 1.0 months. Children with CMA have lower gut microbiota diversity and an elevated Enterobacteriaceae to Bacteroidaceae (E/B ratio) in early infancy compared with healthy children (115.8 vs. 0.8, P = 0.0002). After 6 months of treatment with HF, CMA infants had a higher Lactobacillaceae (6.3% vs. 0.5%, P = 0.04) and lower Bifidobacteriaceae (0.3% vs. 8.2%, P = 0.03) and Ruminococcaceae (1.5% vs. 10.5%, P = 0.03) abundance compared with control children. Conclusion: Low gut microbiota diversity and an elevated E/B ratio in early infancy may contribute to the development of FA, including CMA. A strict elimination diet may weaken FA by reducing E/B ratio and promoting a gut microbiota that would benefit the acquisition of oral tolerance.

Ghost probiotics with a combined regimen: a novel therapeutic approach against the Zika virus, an emerging world threat

The Zika virus (ZIKV) used to be an obscure flavivirus closely related to dengue virus (DENV). Transmission of this epidemic pathogen occurs mainly via mosquitoes, but it is also capable of placental and sexual transmission. Although the characteristics of these viruses are well defined, infections are unpredictable in terms of disease severity, unusual clinical manifestations, unexpected methods of transmission, long-term persistence, and the development of new strains. Recently, ZIKV has gained huge medical attention following the large-scale epidemics around the world, and reported cases of congenital abnormalities associated with Zika virus infections which have created a public health emergency of international concern. Despite continuous research on ZIKV, no specific treatment or vaccine has been developed, excepting a preventive strategy for congenital ZIKV infection. Probiotics, known as GRAS, are bacteria that confer various health beneficial effects, and have been shown to be effective at curing a number of viral diseases by modulating the immune system. Furthermore, probiotic preparations consisting of dead cells and cellular metabolites, so-called "Ghost probiotics", can also act as biological response modifiers. Here, we review available information on the epidemiology, transmission, and clinical features of ZIKV, and on treatment and prevention strategies. In addition, we emphasize the use of probiotics and plant-based natural remedies and describe their action mechanisms, and the green technologies for microbial conversion, which could contribute to the development of novel therapies that may reduce the pathogenicity of ZIKV. Accordingly, we draw attention to new findings, unanswered questions, unresolved issues, and controversies regarding ZIKV.

Probiotics for Preterm Infants: A Premature or Overdue Necrotizing Enterocolitis Prevention Strategy?

Common among preterm, very low birth weight (VLBW) and extremely low birth weight (ELBW) infants, necrotizing enterocolitis (NEC) is a gastrointestinal, infectious disease that remains a leading cause of morbidity and mortality among this high-risk population. To combat this devastating condition, research efforts have been redirected from treatment toward prevention strategies. Although there are several proposed risk-reduction strategies, one intervention gaining support is the administration of prophylactic enteral probiotics. Regardless of growing evidentiary support and a benign safety profile, neonatal providers have yet to embrace this therapy. This article provides an overview of the proposed benefits of probiotics, focusing on their role as a NEC prevention strategy. A review of several sentinel research studies targeting preterm, VLBW, and ELBW infants is provided. Considerations for ongoing research are reviewed. Finally, two evidence-based NEC prevention probiotics protocols are presented.

Protective Effect of Dual-Strain Probiotics in Preterm Infants: A Multi-Center Time Series Analysis

Objective

To determine the effect of dual-strain probiotics on the development of necrotizing enterocolitis (NEC), mortality and nosocomial bloodstream infections (BSI) in preterm infants in German neonatal intensive care units (NICUs).

Design

A multi-center interrupted time series analysis.

Setting

44 German NICUs with routine use of dual-strain probiotics on neonatal ward level.

Patients

Preterm infants documented by NEO-KISS, the German surveillance system for nosocomial infections in preterm infants with birth weights below 1,500 g, between 2004 and 2014.

Intervention

Routine use of dual-strain probiotics containing Lactobacillus acidophilus and Bifidobacterium spp. (Infloran) on the neonatal ward level.

Main outcome measures

Incidences of NEC, overall mortality, mortality following NEC and nosocomial BSI.

Results

Data from 10,890 preterm infants in 44 neonatal wards was included in this study. Incidences of NEC and BSI were 2.5% (n = 274) and 15.0%, (n = 1631), respectively. Mortality rate was 6.1% (n = 665). The use of dual-strain probiotics significantly reduced the risk of NEC (HR = 0.48; 95% CI = 0.38–0.62), overall mortality (HR = 0.60, 95% CI = 0.44–0.83), mortality after NEC (HR = 0.51, 95% CI = 0.26–0.999) and nosocomial BSI (HR = 0.89, 95% CI = 0.81–0.98). These effects were even more pronounced in the subgroup analysis of preterm infants with birth weights below 1,000 g.

Conclusion

In order to reduce NEC and mortality in preterm infants, it is advisable to add routine prophylaxis with dual-strain probiotics to clinical practice in neonatal wards.

Impact of oral probiotics on neurodevelopmental outcomes in preterm infants

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Trends and determinants of gastric bacterial colonization of preterm neonates in a NICU setting

BACKGROUND

Newborn gastrointestinal (GI) tract is considered sterile but rapidly acquires a diverse microbiota from its intimate environment. Early acquisition of a bacterial species in the upper GI tract may play a role in establishing the colonic microbiota. There is paucity of molecular data on the upper GI tract microbiota in preterm neonates.

METHODS

Gastric aspirates from 22 neonates with an average gestational age 27.7 weeks (±2.8), weighing 973.2 grams (±297.9) admitted to a neonatal intensive care unit were collected prospectively from weeks 1-4 of life. All samples were evaluated for microbiota using 16S rRNA-based Denaturing Gradient Gel Electrophoresis. Bacterial species colonization and its association with maternal and neonatal demographics, and neonatal clinical characteristics were analyzed.

RESULTS

Bacteroides spp. was the predominant species in all four weeks. Bifidobacterium spp. colonization was significantly higher in exclusively breast milk fed compared to partially breast milk (PBM) fed neonates in first (p = 0.03) and third (p = 0.03) week of life. Anaerobic bacteria colonization decreased from first through fourth week of life (p = 0.03). Aerobic bacteria colonization was highly dynamic throughout the four week period. Premature rupture of membrane (p = 0.05) and birth outside of study hospital (p = 0.006) influenced the acquisition of bacteria in the first week of life. Birth weight was positively correlated with total number of bacterial species (p = 0.002) and anaerobes (p = 0.004) in PBM-fed neonates during the fourth week of life. H. pylori and Ureaplasma were not detected in any of our samples.

CONCLUSION

Gastric bacterial colonization in preterm neonates is unstable during early weeks of life. Delayed oral feeding and use of antibiotics may be responsible for paucity of bacterial species. Monitoring of the gastric microbiota and concurrent examination of stool microbiota may yield important information on the utility of gastric signature patterns for predicting colon microbiota that may drive GI and immune dysfunctions.

The use of probiotics in pediatric gastroenterology: a review of the literature and recommendations by Latin-American experts

OBJECTIVE

The stability and composition of intestinal flora plays a vital role in human wellbeing throughout life from as early as birth. Over the past 50 years, several studies have been conducted to evaluate the effect of probiotic administration in pediatric gastroenterology. This document aims to provide a recommendation score on probiotic utilization in pediatric gastroenterology, together with a review of current knowledge concerning its benefits, tolerability, and safety.

STUDY DESIGN

Published literature was selected without study design restriction: clinical guidelines, meta-analyses, randomized controlled trials (RCTs), cohort studies, outcomes research and case-controlled studies were selected using the following MESH-validated terms: probiotics, diarrhea, acute diarrhea, antibiotic-associated diarrhea, traveler's diarrhea, bacterial diarrhea, nosocomial diarrhea, prophylactic diarrhea, Helicobacter pylori infection, colic, infantile colic, necrotizing enterocolitis (NEC), inflammatory bowel disease, constipation, and allergy. Once the validity and the quality of results were evaluated, a recommendation score and level of evidence were assigned for pediatric gastrointestinal-related conditions, according to the updated Evidence-Based Medicine guidelines: 1a for systematic review (SR) of RCTs, 1b for individual RCT, 1c for SR and individual RCT, 2a for SR of cohort studies, 2b for individual cohort studies, 2c for outcomes research, and 3a for SR of case-control studies.

RESULTS AND CONCLUSIONS

The Latin American Expert group consensus recommends the use of the following probiotics for pediatric gastrointestinal conditions: prevention of acute infectious diarrhea (AID): 1b for Bifidobacterium lactis, Lactobacillus rhamnosus GG (LGG), and L. reuteri; prevention of nosocomial diarrhea: 1 b for B. lactis Bb12, B. bifidum, LGG and Streptococcus thermophiles; treatment of AID: 1a for LGG and S. boulardii, 1b for L. reuteri; prevention of antibiotic-associated diarrhea: 1b for LGG and S. boulardii; prevention of traveler's diarrhea: 1b for S. boulardii; prevention of infantile colic: 1a for L. reuteri DSM 17938; treatment of infantile colic: 1b for L. reuteri DSM 17938; prevention of NEC: 1a for B. breve, mixtures of Bifidobacterium and Streptococcus, LGG, L. acidophilus and L. reuteri DSM 17938; induction and maintenance of remission in ulcerative colitis: 1b for VSL#3; improving symptoms of irritable bowel syndrome: 2c for LGG and VSL#3.

Probiotics Reduce Necrotizing Enterocolitis Severity in HIV-exposed Premature Infants

OBJECTIVE

To assess the effect of probiotics on the incidence of necrotizing enterocolitis (NEC) in premature infants born to human immunodeficiency virus (HIV)-positive and HIV-negative women.

PATIENTS AND METHODS

HIV-exposed and HIV-unexposed premature infants were randomized to either the probiotic or the placebo group. The probiotic consisted of 1 × 10(9) colony-forming units, Lactobacillus rhamnosus GG and Bifidobacterium infantis per day.

RESULTS

In total, 74 HIV-exposed and 110 HIV-unexposed infants were enrolled and randomized. The incidence of death [4 (5.4%) vs. 7 (6%); p = 0.79] and NEC [4 (5%) vs. 5 (5%); p = 0.76] did not differ significantly between the HIV-exposed and HIV-unexposed groups. A significant difference was found for total NEC incidence between the study and control groups [3 (3%) vs. 6 (6%); p = 0.029]. The incidence of NEC in the HIV-exposed group differed significantly [Bells I 2 (5%) vs. Bells III 2 (5%); p = 0.045).

CONCLUSION

Probiotic supplementation reduced the incidence of NEC in the premature very low birth weight infants; however, results failed to show a lower incidence of NEC in HIV-exposed premature infants. A reduction in the severity of disease was found in the HIV-exposed study group.

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 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.

Role of Enteric Supplementation of Probiotics on Late-onset Sepsis by Candida species in Preterm Low Birth Weight Neonates: A Randomized, Double Blind, Placebo-controlled Trial

Background:

The increase in invasive fungal infections (IFIs) in neonatal intensive care unit (NICU) is jeopardizing the survival of preterm neonates. Probiotics modulating the intestinal microflora of preterm neonates may minimize enteral fungal colonization.

Aims:

This study was to examine whether probiotic supplementation in neonates reduced fungal septicemia.

Materials and Methods:

This prospective, randomized, double blind trial investigating the supplementation of preterm infants with a probiotic was done from May 2012 to April 2013, with 112 subjects randomized into two groups. Primary outcome: Decreased fungal colonization in gastrointestinal tract. Others: Incidence of late onset septicemia; duration of the primary hospital admission; number of days until full enteral feeds established.

Results:

Full feed establishment was earlier in probiotics group compared to placebo group (P = 0.016). The duration of hospitalization was less in the probiotic group (P = 0.002). Stool fungal colonization, an important outcome parameter was 3.03 ± 2.33 × 10⁵ colony formation units (CFU) in the probiotics group compared to 3 ± 1.5 × 10⁵ CFU in the placebo group (P = 0.03). Fungal infection is less in the study group (P = 0.001).

Conclusion:

The key features of our study were reduced enteral fungal colonization, reduce invasive fungal sepsis, earlier establishment of full enteral feeds, and reduced duration of hospital stay in the probiotics group.

Lactobacillus Reuteri for the prevention of necrotising enterocolitis in very low birthweight infants: a randomised controlled trial

OBJECTIVE

To evaluate the effect of oral Lactobacillus reuteri (L reuteri) first on the incidence and severity of Necrotising enterocolitis (NEC) and second on sepsis.

DESIGN

Prospective randomised controlled study.

SETTING

Tertiary neonatal intensive care unit.

PATIENTS AND INTERVENTIONS

Preterm infants with a gestational age of ≤32 weeks and a birth weight of ≤1500 g were included (n=400). Infants in the first group were given 100 million CFU/day (5 drops) of lyophilised L reuteri (DSM 17938) mixed in breast milk or formula, starting from first feeding until discharge. Participants in the control group were given a placebo.

MAIN OUTCOME MEASURES

To determine and compare the frequency of NEC and/or death after 7 days, frequency of proven sepsis, rates of feeding intolerance and duration of hospital stay.

RESULTS

There was no statistically significant difference between groups in terms of frequency of NEC stage ≥2 (4% vs 5%; p=0.63) or overall NEC or mortality rates (10% vs 13.5%; p=0.27). Frequency of proven sepsis was significantly lower in the probiotic group compared to the control group (6.5% vs 12.5%; p=0.041). A significant difference was also observed with regard to rates of feeding intolerance (28% vs 39.5%; p=0.015) and duration of hospital stay (38 (10-131) vs 46 (10-180) days; p=0.022).

CONCLUSIONS

Our results show that oral L reuteri does not seem to affect the overall rates of NEC and/or death in preterm infants followed up in the neonatal intensive care unit, and significant reductions were observed in the frequency of proven sepsis, rates of feeding intolerance and duration of hospital stay.

TRIAL REGISTRATION NUMBER

NCT01531179.

Saccharomyces boulardii for prevention of necrotizing enterocolitis in preterm infants: a randomized, controlled study

AIM

To evaluate the efficacy of orally administered Saccharomyces boulardii (S. boulardii) for reducing the incidence and severity of necrotizing enterocolitis (NEC) in very low-birth-weight (VLBW) infants.

METHODS

A prospective, randomised controlled trial was conducted in infants with gestational age ≤32 weeks and birth weight ≤1500 g. The study group received S. boulardii supplementation, and the control group did not. The primary outcomes were death or NEC (Bell's stage ≥2), and secondary outcomes were feeding intolerance and clinical or culture-proven sepsis.

RESULTS

A total of 271 infants were enrolled in the study, 135 in the study group and 136 in the control group. There was no significant difference in the incidence of death (3.7% vs. 3.6%, 95% CI of the difference, -5.20-5.25; p = 1.0) or NEC (4.4% vs. 5.1%, 95% CI, -0.65-5.12; p = 1.0) between the groups. However, feeding intolerance and clinical sepsis were significantly lower in the probiotic group compared with control.

CONCLUSION

Although Saccharomyces boulardii supplementation at a dose of 250 mg/day was not effective at reducing the incidence of death or NEC in VLBW infants, it improved feeding tolerance and reduced the risk of clinical sepsis.

Probiotics-supplemented feeding in extremely low-birth-weight infants

OBJECTIVE

The objective of this trial was to test whether probiotic-supplemented feeding to extremely low-birth-weight (ELBW) infants will improve growth as determined by decreasing the percentage of infants with weight below the 10th percentile at 34 weeks postmenstrual age (PMA). Other important outcome measures, such as improving feeding tolerance determined by tolerating larger volume of feeding per day and reducing antimicrobial treatment days during the first 28 days from the initiation of feeding supplementation were also evaluated.

STUDY DESIGN

We conducted a multicenter randomized controlled double-blinded clinical study. The probiotics-supplementation (PS) group received Lactobacillus rhamnosus GG and Bifidobacterium infantis added to the first enteral feeding and continued once daily with feedings thereafter until discharge or until 34 weeks (PMA). The control (C) group received unsupplemented feedings. Infant weight and feeding volumes were recorded daily during the first 28 days of study period. Weights were also recorded at 34 weeks PMA.

RESULT

A total of 101 infants were enrolled (PS 50 versus C 51). There was no difference between the two groups in the percentage of infants with weight below the 10th percentile at 34 weeks PMA (PS group 58% versus C group 60%, (P value 0.83)) or in the average volume of feeding during 28 days after study entry (PS group 59  ml  kg(-1) versus C group 71  ml  kg(-1), (P value 0.11)). Calculated growth velocity was higher in the PS group compared with the C group (14.9 versus 12.6  g per day, (P value 0.05)). Incidences of necrotizing enterocolitis (NEC), as well as mortality were similar between the two groups.

CONCLUSION

Although probiotic-supplemented feedings improve growth velocity in ELBW infants, there was no improvement in the percentage of infants with growth delay at 34 weeks PMA. There were no probiotic-related adverse events reported.

Physiological basis of food intolerance in VLBW

To provide an overview on the role of gut immunity, nervous system and motility patterns in the development of feeding intolerance in newborns. Maturation of the GI is important not only for digestion and absorption, but for endocrine and exocrine function as well. There is little data available about the development of the motility function and of the mucosal barrier of the human gut, and in particular about the motility patterns and mucosal changes in newborns during early days of life. It is known that functional maturation of the gastrointestinal tract is quite different over time with respect to its anatomical development. Besides, the gastrointestinal tract through innate and specific immunologic factors, acts as a defense against ingested antigens. In addition to the mucous membrane integrity and digestion, numerous specific immunologic cells and mediators orchestrate such defensive mechanisms. In case of food antigens, the outcome is usually in favor of tolerance. Defects in that barrier, however, can lead to the development of aberrant immunologic responses, including hypersensitivity reactions. It is obvious that an appropriate feeding regimen during early infancy is in favor of food tolerance. However, in addition to genetic predisposition, development of tolerance is facilitated by an adequate gut barrier (immune or nonimmune), well-coordinated GI motility and nervous network, and appropriate food regimen.

Antibiotic exposure in the newborn intensive care unit and the risk of necrotizing enterocolitis

OBJECTIVE

To determine whether duration of antibiotic exposure is an independent risk factor for necrotizing enterocolitis (NEC).

STUDY DESIGN

A retrospective, 2:1 control-case analysis was conducted comparing neonates with NEC to those without from 2000 through 2008. Control subjects were matched on gestational age, birth weight, and birth year. In each matched triad, demographic and risk factor data were collected from birth until the diagnosis of NEC in the case subject. Bivariate and multivariate analyses were used to assess associations between risk factors and NEC.

RESULTS

One hundred twenty-four cases of NEC were matched with 248 control subjects. Cases were less likely to have respiratory distress syndrome (P = .018) and more likely to reach full enteral feeding (P = .028) than control subjects. Cases were more likely to have culture-proven sepsis (P < .0001). Given the association between sepsis and antibiotic use, we tested for and found a significant interaction between the two variables (P = .001). When neonates with sepsis were removed from the cohort, the risk of NEC increased significantly with duration of antibiotic exposure. Exposure for >10 days resulted in a nearly threefold increase in the risk of developing NEC.

CONCLUSIONS

Duration of antibiotic exposure is associated with an increased risk of NEC among neonates without prior sepsis.

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 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 and/or sepsis in preterm infants.

SEARCH STRATEGY

For this update, searches were made of MEDLINE (1966 to October 2010), EMBASE (1980 to October 2010), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2010), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2010).

SELECTION CRITERIA

Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age and/or < 2500 g birth weight 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, data collection and analysis.

MAIN RESULTS

Sixteen eligible trials randomizing 2842 infants were included. Included trials were highly variable with regard to enrollment criteria (i.e. birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. Data regarding extremely low birth weight infants (ELBW) could not be extrapolated. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical RR 0.35, 95% CI 0.24 to 0.52) and mortality (typical RR 0.40, 95% CI 0.27 to 0.60). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.90, 95% CI 0.76 to 1.07). The included trials reported no systemic infection with the probiotics supplemental organism. The statistical test of heterogeneity for NEC, mortality and sepsis was insignificant.

AUTHORS' CONCLUSIONS

Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence supports a change in practice. More studies are needed to assess efficacy in ELBW infants and assess the most effective formulation and dose to be utilized.

Efficacy of Bifidobacterium breve and Lactobacillus casei oral supplementation on necrotizing enterocolitis in very-low-birth-weight preterm infants: a double-blind, randomized, controlled trial

BACKGROUND

Probiotics are used for the prevention of necrotizing enterocolitis (NEC) because of their positive effects on intestinal motor function, modulation of inflammatory response, and mucosal barrier function.

OBJECTIVE

The objective was to assess whether the combined use of Lactobacillus casei and Bifidobacterium breve may prevent the occurrence of NEC stage ≥ 2 by the criteria of Bell in very-low-birth-weight preterm infants.

DESIGN

A double-blind, randomized, controlled clinical trial was conducted in 231 preterm infants weighing from 750 to 1499 g at birth. The intervention group was composed of 119 infants who received human milk with probiotic supplementation (B. breve and L. casei) and a control group of 112 infants who received human milk containing no probiotics. The primary outcome was the occurrence of NEC stage ≥ 2 as defined by Bell's modified criteria.

RESULTS

Four confirmed cases of NEC stage ≥ 2 by Bell's criteria occurred only in the control group.

CONCLUSIONS

Oral supplementation of B. breve and L. casei reduced the occurrence of NEC (Bell's stage ≥ 2). It was considered that an improvement in intestinal motility might have contributed to this result. This trial was registered at www.isrctin.org as number 67165178 (International Standard Randomized Controlled Trial).

Nutritional modulation of the gut microbiota and immune system in preterm neonates susceptible to necrotizing enterocolitis

The gastrointestinal inflammatory disorder, necrotizing enterocolitis (NEC), is among the most serious diseases for preterm neonates. Nutritional, microbiological and immunological dysfunctions all play a role in disease progression but the relationship among these determinants is not understood. The preterm gut is very sensitive to enteral feeding which may either promote gut adaptation and health, or induce gut dysfunction, bacterial overgrowth and inflammation. Uncontrolled inflammatory reactions may be initiated by maldigestion and impaired mucosal protection, leading to bacterial overgrowth and excessive nutrient fermentation. Tumor necrosis factor alpha, toll-like receptors and heat-shock proteins are identified among the immunological components of the early mucosal dysfunction. It remains difficult, however, to distinguish the early initiators of NEC from the later consequences of the disease pathology. To elucidate the mechanisms and identify clinical interventions, animal models showing spontaneous NEC development after preterm birth coupled with different forms of feeding may help. In this review, we summarize the literature and some recent results from studies on preterm pigs on the nutritional, microbial and immunological interactions during the early feeding-induced mucosal dysfunction and later NEC development. We show that introduction of suboptimal enteral formula diets, coupled with parenteral nutrition, predispose to disease, while advancing amounts of mother's milk from birth (particularly colostrum) protects against disease. Hence, the transition from parenteral to enteral nutrition shortly after birth plays a pivotal role to secure gut growth, digestive maturation and an appropriate response to bacterial colonization in the sensitive gut of preterm neonates.

Using a mathematical model to analyze the role of probiotics and inflammation in necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is a severe disease of the gastrointestinal tract of pre-term babies and is thought to be related to the physiological immaturity of the intestine and altered levels of normal flora in the gut. Understanding the factors that contribute to the pathology of NEC may lead to the development of treatment strategies aimed at re-establishing the integrity of the epithelial wall and preventing the propagation of inflammation in NEC. Several studies have shown a reduced incidence and severity of NEC in neonates treated with probiotics (beneficial bacteria species).

METHODOLOGY/PRINCIPAL FINDINGS

The objective of this study is to use a mathematical model to predict the conditions under which probiotics may be successful in promoting the health of infants suffering from NEC. An ordinary differential equation model is developed that tracks the populations of pathogenic and probiotic bacteria in the intestinal lumen and in the blood/tissue region. The permeability of the intestinal epithelial layer is treated as a variable, and the role of the inflammatory response is included. The model predicts that in the presence of probiotics health is restored in many cases that would have been otherwise pathogenic. The timing of probiotic administration is also shown to determine whether or not health is restored. Finally, the model predicts that probiotics may be harmful to the NEC patient under very specific conditions, perhaps explaining the detrimental effects of probiotics observed in some clinical studies.

CONCLUSIONS/SIGNIFICANCE

The reduced, experimentally motivated mathematical model that we have developed suggests how a certain general set of characteristics of probiotics can lead to beneficial or detrimental outcomes for infants suffering from NEC, depending on the influences of probiotics on defined features of the inflammatory response.

Changes in faecal microbiota of infants with cow's milk protein allergy--a Spanish prospective case-control 6-month follow-up study

Major differences have been found in gut microbiota between healthy and allergic children, and a possible association between allergy and altered microbiota patterns have been postulated. The main object of the study was to compare the faecal microbiota between healthy and cow's milk protein allergy (CMPA) infants at the baseline immediately after the diagnosis, and to evaluate the changes in the faecal microbiota after 6 months of treatment of CMPA infants fed on extensively cow's milk protein hydrolyzed formulae without pre- or probiotics, compared with healthy children fed on standard milk formulae. The population comprised 92 infants aged 2-12 months who were non-allergic (n=46) or diagnosed with IgE-mediated CMPA (n=46). At baseline and at 6 months, faecal samples were collected into sterile plastic tubes, immediately placed into anaerobic jars and processed within 2 h of their collection. Weighed faeces samples were diluted from 10(-1) to 10(-7) and cultured in selective media for total count of aerobes, anaerobes, enterobacteria, bifidobacteria, lactobacilli, clostridia and yeasts. Samples from non-allergic and allergic infants were compared at baseline and at 6 months using appropriate statistical tests, considering p<0.05 to be significant. In comparison with healthy infants, CMPA infants had higher total bacteria and anaerobic counts and a lower yeast count at baseline, finding no difference in the proportions of each bacterial group between groups. After 6 months, CMPA infants showed higher anaerobic and lactobacilli counts, a higher proportion of lactobacilli, a lower count and proportion of bifidobacteria, and lower proportions of enterobacteria and yeasts. Comparison of faecal samples from CMPA infants between baseline and at 6 months showed an increase in count and proportion of lactobacilli and a decrease in counts and proportions of enterobacteria and bifidobacteria. Differences in the composition of gut microbiota between CMPA and healthy infants may influence in the development of or protection from this allergy.

A randomized placebo-controlled comparison of 2 prebiotic/probiotic combinations in preterm infants: impact on weight gain, intestinal microbiota, and fecal short-chain fatty acids

OBJECTIVE

To compare the effect of 2 prebiotic/probiotic products on weight gain, stool microbiota, and stool short-chain fatty acid (SCFA) content of premature infants.

PATIENTS AND METHODS

This randomized, blinded, placebo-controlled trial included 90 premature infants treated with either a dietary supplement containing 2 lactobacillus species plus fructooligosaccharides (CUL, Culturelle, ConAgra, Omaha, NE), a supplement containing several species of lactobacilli and bifidobacteria plus fructooligosaccharides (PBP, ProBioPlus DDS, UAS Laboratories, Eden Prairie, MN), or placebo (a dilute preparation of Pregestamil formula) twice daily for 28 days or until discharge if earlier. The primary outcome was weight gain. Secondary outcomes were stool bacterial analysis by culture and 16S rDNA quantitative polymerase chain reaction and stool SCFA content measured by high performance liquid chromatography.

RESULTS

Both prebiotic/probiotic combinations contained more bacterial species than noted on the label. No significant effect on infant growth of either prebiotic/probiotic supplement was observed. By cultures, 64% of infants receiving PBP became colonized with bifidobacteria, compared with 18% of infants receiving CUL and 27% of infants receiving placebo (chi-square, P = 0.064). No differences were noted between groups in colonization rates for lactobacilli, Gram-negative enteric bacteria, or staphylococci. By 16S rDNA polymerase chain reaction analysis, the bifidobacteria content in the stools of the infants receiving PBP was higher than in the infants receiving CUL or placebo (Kruskal-Wallis, P = 0.011). No significant differences in stool SCFA content were detected between groups. No adverse reactions were noted.

CONCLUSIONS

Infants receiving PBP were more likely to become colonized with bifidobacteria. No significant differences in weight gain or stool SCFA content were detected.

Necrotizing enterocolitis in newborns: pathogenesis, prevention and management

Necrotizing enterocolitis (NEC) is primarily a disease process of the gastrointestinal (GI) tract of premature neonates that results in inflammation and bacterial invasion of the bowel wall. Despite advances in the care of premature infants, NEC remains one of the leading causes of morbidity and mortality in this population. It occurs in 1-5% of all neonatal intensive care admissions and 5-10% of all very low birthweight (<1500 g) infants. Although research has presented an interesting array of potential contributing factors, the precise aetiology of this multifactorial disease process remains elusive. Historically, it was believed that NEC arose predominantly from ischaemic injury to the immature GI tract, yet alternate plausible hypotheses indicate that many factors are likely to be involved. These may include issues related to the introduction and advancement of enteric feeding, alterations in the normal bacterial colonization of the GI tract, bacterial translocation and activation of the cytokine cascade, decreased epidermal growth factor, increased platelet activating factor, and mucosal damage from free radical production. Clinical manifestations of NEC may be vague, including increased episodes of apnoea, desaturations, bradycardia, lethargy and temperature instability. There may also be GI-specific symptoms such as feeding intolerance, emesis, bloody stools, abdominal distention and tenderness, and abdominal wall discolouration. Laboratory values may be indicative of infection, coagulation abnormalities and fluid retention. Radiographic signs may include ileus, dilated or fixed intestinal loops, air in the intestinal wall or free air in the abdomen. Medical treatment typically consists of bowel rest and decompression, antibacterial therapy, and management of other haematological or electrolyte imbalances. Increased respiratory and cardiovascular support is sometimes needed. In neonates who do not respond adequately to medical management, or if pneumoperitoneum is present, surgical intervention may occur with either use of a peritoneal drain or laparotomy. Advances in antenatal and neonatal care have resulted in increased survival of extremely preterm neonates. As this at-risk population continues to increase, an effective preventative strategy for NEC is needed. One preventative strategy is the use of antenatal corticosteroids to enhance maturation of the fetus if preterm delivery is likely. Recommendation of use of breast milk, early initiation of trophic feeds and judicoius advancement of enteric feeds are current postnatal strategies. Other preventative strategies that have been investigated include the use of oral antibacterials, antioxidants, supplementation of arginine and epidermal growth factor, none of which have changed clinical practice. Recent promising data indicate that prophylactic use of probiotics may play a role in preventing the onset of NEC. However, more large-scale, definitive studies are needed.

Nutritional factors influencing infections in preterm infants

In contrast with clinical studies in term infants or older children, it is very difficult to investigate possible immunoregulatory effects of a novel infant formula composition in preterm infants. This is mainly because of the multicausal origin of infections in this high-risk population that is usually admitted to the neonatal intensive care unit. Possible effects of nutrition composition on onset and incidence of nosocomial infections in these very small infants have to be compared with infections that may have originated in utero. The development of the gastrointestinal tract may be inhibited after severe intrauterine growth retardation, leading to functional impairment of the gut shortly after birth. This may be related to the onset of necrotizing enterocolitis of the newborn. However, this disease in very small preterm infants is possibly also related to the initiation of oral feeding and/or the amount of feeding. Specific infection risks of neonatal intensive care as a result of invasive techniques such as artificial ventilation or total parenteral nutrition using indwelling umbilical and/or Silastic lines and so-called "all-in-one" mixtures may influence the incidence of infections. Widespread use of intravenous antibiotics in the neonatal intensive care unit may create an even larger infection risk. Investigation of possible immunomodulatory effects of factors such as prebiotics and probiotics added to the nutrition of preterm infants should always be considered along with other nutritional factors known to influence the immature immune system.

Comparison of intestinal microflora in healthy infants and infants with allergic colitis

Twenty-eight exclusively breast-fed healthy infants and 16 infants also exclusively breast-fed with allergic colitis (aged 85 +/- 60 and 98 +/- 58 d, respectively) were screened for differences in fecal flora. Bifidobacteria were detected in 23 healthy infants and only in 4 fecal samples of infants with allergic colitis. All bifidobacteria-free infants possessed Gram-positive regular rods as a major group of their fecal flora. These bacteria were identified as clostridia using genus-specific FISH probe. Infants with allergy colitis possessed significantly lower counts of bifidobacteria and total anaerobes and significantly higher counts of clostridia in their feces. In healthy infants, Bifidobacterium longum was the most frequently found species (54.5% of the samples), followed by B. adolescentis (20.0), B. breve (18.2), B. bifidum (16.4), B. dentium (10.9) and B. pseudocatenulatum (1.80). Bifidobacterial isolates from two babies with allergic colitis were identified as B. longum, one child from patients group contained species B. dentium and one baby B. adolescentis. Our results suggest that there are significantly lower counts of bifidobacteria in infants with allergic colitis than in healthy infants.

The effects of probiotics on feeding tolerance, bowel habits, and gastrointestinal motility in preterm newborns

OBJECTIVE

To investigate the effect of dietary supplementation with a probiotic on feeding tolerance and gastrointestinal motility in healthy formula-fed preterm infants.

STUDY DESIGN

Thirty preterm newborns were enrolled; 10 were exclusively breast-fed, and the remaining 20 were randomly assigned in a double-blind manner to receive either Lactobacillus reuteri ATCC 55730 (at dose of 1 x 10(8) colony forming units a day) or placebo for 30 days. Clinical symptoms of gastrointestinal function (regurgitation, vomiting, inconsolable crying, and evacuation) and physiological variables (gastric electrical activity and emptying) were recorded before and after the dietary intervention.

RESULTS

Body weight gains per day were similar for the 3 groups, and no adverse events were recorded. Newborns receiving probiotics showed a significant decrease in regurgitation and mean daily crying time and a larger number of stools compared with those given placebo. Gastric emptying rate was significantly increased, and fasting antral area was significantly reduced in both the newborns receiving L. reuteri and breast-fed newborns compared with placebo.

CONCLUSIONS

Our results suggest a useful role for L. reuteri supplementation in improving feeding tolerance and gut function in formula-fed preterm newborns.

Necrotizing enterocolitis: A multifactorial disease with no cure

Necrotizing enterocolitis is an inflammatory bowel disease of neonates with significant morbidity and mortality in preterm infants. Due to the multifactorial nature of the disease and limitations in disease models, early diagnosis remains challenging and the pathogenesis elusive. Although preterm birth, hypoxic-ischemic events, formula feeding, and abnormal bacteria colonization are established risk factors, the role of genetics and vasoactive/inflammatory mediators is unclear. Consequently, treatments do not target the specific underlying disease processes and are symptomatic and surgically invasive. Breast-feeding is the most effective preventative measure. Recent advances in the prevention of necrotizing enterocolitis have focused on bioactive nutrients and trophic factors in human milk. Development of new disease models including the aspect of prematurity that consistently predisposes neonates to the disease with multiple risk factors will improve our understanding of the pathogenesis and lead to discovery of innovative therapeutics.

Probiotics: role in pathophysiology and prevention in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease largely affecting low birth weight, premature infants. Once acquired, NEC is accompanied by significant mortality and morbid sequelae. Our understanding of the pathophysiology of NEC continues to evolve, and the development of NEC is likely multifactorial with resultant bowel injury mediated through a final, common inflammatory pathway. The predisposition for NEC appears to involve the interplay between intestinal integrity and function, enteral feeding and bacterial colonization, and regulation of the gastrointestinal and systemic inflammatory response. Commensal organisms or probiotics have been shown to be crucial in the development and modulation of each of these factors within the intestinal epithelium. As a result, probiotic supplementation has been proposed as a promising new intervention for the prevention of NEC. To understand the potential utility of probiotics in NEC, we will discuss: the components of gut defense; the role of the intestinal ecosystem in modulating immunity and inflammation; bacterial colonization patterns in the preterm infant compared with patterns seen in the healthy, full-term infant; the evidence for probiotic use in other populations and diseases; and finally, the evidence of probiotic use specific to the preterm infant and NEC.