Probiotics promoted head growth in extremely low birthweight infants in a double-blind placebo-controlled trial

Effects of extremely preterm birth on cytokine and chemokine responses induced by T-cell activation during infancy

Objectives

Extremely preterm (EPT; gestational week < 28 + 0, < 1000 g) neonates are vulnerable to infections and necrotising enterocolitis, important contributors to mortality and morbidity. However, knowledge regarding their immune maturation remains limited. We here investigated the longitudinal development of functional T-cell capacity in EPT infants.

Methods

Peripheral blood mononuclear cells were isolated at 14th and 28th day (D) and at gestational week 36 + 0 (Gw36) from EPT infants, participated in a randomised, double-blind, placebo-controlled study of Lactobacillus reuteri DSM 17938 probiotic supplementation. Blood collected from 25 full-term (FT) infants at D14 was used as control. The secretion of immune mediators was determined through comprehensive Luminex panels after stimulation with human T-cell activator CD3/CD28 beads.

Results

The levels of many mediators were low in EPT infants at D14, whereas the secretion of several chemokines was higher in EPT than in FT infants. Furthermore, Th2:Th1 cytokine ratios were higher in EPT than in FT infants. Progressively elevated secretion of, for example, IFN-γ, TNF and IL-17A in EPT infants was observed from D14 to D28 and then at Gw36. Elevated levels were observed for many proinflammatory mediators at D28. Probiotic supplementation or perinatal factors (e.g. clinical chorioamnionitis, preeclampsia and delivery mode) did not influence the cytokine and chemokine responses.

Conclusions

Immune mediators induced by T-cell activation in EPT infants were mainly reduced at D14 and Th2 skewed compared to those in FT infants, but mostly recovered at Gw36, indicating immune maturation. Increased proinflammatory responses at D28 may be related to the heightened risk of severe immune-associated complications seen in EPT infants.

Bifidobacterium infantis as a probiotic in preterm infants: a systematic review and meta-analysis

BACKGROUND

Bifidobacterium infantis has special abilities to utilise human milk oligosaccharides. Hence we hypothesised that probiotic supplements containing B. infantis may confer greater benefits to preterm infants than probiotic supplements without B. infantis.

METHODS

A systematic review with meta-analysis was conducted according to standard guidelines. We selected RCTs evaluating probiotics compared to placebo or no treatment in preterm and/or low birth weight infants. Probiotic effects on Necrotizing Enterocolitis (NEC), Late Onset Sepsis (LOS) and Mortality were analysed separately for RCTs in which the supplemented probiotic product contained B. infantis and those that did not contain B. infantis.

RESULTS

67 RCTs were included (n = 14,606), of which 16 used probiotics containing B. infantis (Subgroup A) and 51 RCTs did not (Subgroup B) Meta-analysis of all RCTs indicated that probiotics reduced the risk of NEC, LOS, and mortality. The subgroup meta-analysis demonstrated greater reduction in the incidence of NEC in subgroup A than subgroup B [(relative risk in subgroup A: 0.38; 95% CI, 0.27-0.55) versus (0.67; 95% CI, 0.55-0.81) in subgroup B; p value for subgroup difference: 0.01].

CONCLUSIONS

These results provide indirect evidence that probiotic supplements that include B. infantis may be more beneficial for preterm infants. Well-designed RCTs are necessary to confirm these findings.

IMPACT

Evidence is emerging that beneficial effects of probiotics are species and strain specific. This systematic review analyses if B. infantis supplementation provides an advantage to preterm infants. This is the first systematic review evaluating the effects of probiotics containing B. infantis in preterm infants. The results of this systematic review provides indirect evidence that probiotics that include B. infantis may be more beneficial for preterm infants. These results will help in guiding future research and clinical practice for using B. infantis as a probiotic in preterm infants.

Limosilactobacillus reuteri DSM 17938 as a probiotic in preterm infants: An updated systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Our previous strain-specific systematic review (SR) showed that Lactobacillus reuteri (LR) DSM 17938 reduces necrotizing enterocolitis (NEC), late-onset sepsis (LOS), and time to full feeds (TFF) in preterm infants. Considering progress in the field over the past 6 years, we aimed to update our SR.

METHODS

SR of randomized controlled trials (RCTs) and non-RCTs was conducted. MEDLINE, Embase, Emcare, Cochrane CENTRAL, and gray literature were searched in June 2023. Primary outcomes were TFF, NEC stage ≥II, LOS, and all-cause mortality. Meta-analysis was performed using random-effects model. Certainty of evidence (CoE) was summarized using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) guidelines. Trial sequential analysis (TSA) was applied for outcome of NEC in RCTs.

RESULTS

Twelve RCTs (n = 2284) and four non-RCTs (n = 1616) were included. Six RCTs and three non-RCTs were new. Meta-analysis of RCTs showed LR significantly reduced TFF (mean difference, -2.70 [95% CI, -4.90 to -1.31] days; P = 0.0001), NEC stage ≥II (risk ratio [RR], 0.57 [95% CI, 0.37-0.87]; P = 0.009; eight RCTs), and LOS (RR, 0.72 [95% CI, 0.54-0.97]; P = 0.03); but not mortality (RR, 0.76 [95% CI, 0.54-1.06]; P = 0.10). TSA showed diversity-adjusted required information size (DARIS) as 3624 for NEC. Overall CoE was "very low." Meta-analysis of non-RCTs showed LR reduced NEC (odds ratio, 0.34 [95% CI, 0.15-0.77]; P = 0.01) but not LOS. LR had no adverse effects.

CONCLUSIONS

Very low CoE suggests that LR DSM 17938 may reduce NEC and LOS and shorten TFF in preterm infants. Additional RCTs are required to confirm our findings.

Growth and neuro-developmental outcomes of probiotic supplemented preterm infants-a systematic review and meta-analysis

Gut dysbiosis is associated with sepsis and necrotizing enterocolitis in preterm infants, which can adversely affect long-term growth and neurodevelopment. We aimed to synthesise evidence for the effect of probiotic supplementation on growth and neurodevelopmental outcomes in preterm infants. MEDLINE, EMBASE, EMCARE, Cochrane CENTRAL, and grey literature were searched in February 2022. Only randomized controlled trials (RCTs) were included. Meta-analysis was performed using random effects model. Effect sizes were expressed as standardized mean difference (SMD), mean difference (MD) or risk ratio (RR) and their corresponding 95% confidence intervals (CI). Risk of Bias (ROB) was assessed using the ROB-2 tool. Certainty of Evidence (CoE) was summarized using GRADE guidelines. Thirty RCTs (n = 4817) were included. Meta-analysis showed that probiotic supplementation was associated with better short-term weight gain [SMD 0.24 (95%CI 0.04, 0.44); 22 RCTs (n = 3721); p = 0.02; I2 = 88%; CoE: low]. However, length [SMD 0.12 (95%CI -0.13, 0.36); 7 RCTs, (n = 899); p = 0.35; I2 = 69%; CoE: low] and head circumference [SMD 0.09 (95%CI -0.15, 0.34); 8 RCTs (n = 1132); p = 0.46; I2 = 76%; CoE: low] were similar between the probiotic and placebo groups. Probiotic supplementation had no effect on neurodevelopmental impairment [RR 0.91 (95%CI 0.76, 1.08); 5 RCTs (n = 1556); p = 0.27; I2 = 0%; CoE: low]. Probiotic supplementation was associated with better short-term weight gain, but did not affect length, head circumference, long-term growth, and neurodevelopmental outcomes of preterm infants. Adequately powered RCTs are needed in this area. Prospero Registration: CRD42020064992.

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.

Determinants of microbial colonization in the premature gut

Abnormal microbial colonization in the gut at an early stage of life affects growth, development, and health, resulting in short- and long-term adverse effects. Microbial colonization patterns of preterm infants differ from those of full-term infants in that preterm babies and their mothers have more complicated prenatal and postnatal medical conditions. Maternal complications, antibiotic exposure, delivery mode, feeding type, and the use of probiotics may significantly shape the gut microbiota of preterm infants at an early stage of life; however, these influences subside with age. Although some factors and processes are difficult to intervene in or avoid, understanding the potential factors and determinants will help in developing timely strategies for a healthy gut microbiota in preterm infants. This review discusses potential determinants of gut microbial colonization in preterm infants and their underlying mechanisms.

Probiotics for the Management of Pediatric Gastrointestinal Disorders: Position Paper of the ESPGHAN Special Interest Group on Gut Microbiota and Modifications

BACKGROUND

Probiotics, defined as live microorganisms that, when administered in adequate amounts, confer a health benefit on the host, are widely used despite uncertainty regarding their efficacy and discordant recommendations about their use. The European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) Special Interest Group on Gut Microbiota and Modifications provides updated recommendations for the use of probiotics for the management of selected pediatric gastrointestinal disorders.

METHODS

All systematic reviews and/or meta-analyses, as well as subsequently published randomized controlled trials (RCTs) (until December 2021), that compared the use of probiotics in all delivery vehicles and formulations, at any dose, with no probiotic (ie, placebo or no treatment), were eligible for inclusion. The recommendations were formulated only if at least 2 RCTs on a similar well-defined probiotic strain were available. The modified Delphi process was used to establish consensus on the recommendations.

RESULTS

Recommendations for the use of specific probiotic strains were made for the management of acute gastroenteritis, prevention of antibiotic-associated diarrhea, nosocomial diarrhea and necrotizing enterocolitis, management of Helicobacter pylori infection, and management of functional abdominal pain disorders and infant colic.

CONCLUSIONS

Despite evidence to support the use of specific probiotics in some clinical situations, further studies confirming the effect(s) and defining the type, dose, and timing of probiotics are still often required. The use of probiotics with no documented health benefits should be discouraged.

Role of gut-brain axis in neurodevelopmental impairment of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a common gastrointestinal disease of preterm infants with high morbidity and mortality. In survivors of NEC, one of the leading causes of long-term morbidity is the development of severe neurocognitive injury. The exact pathogenesis of neurodevelopmental delay in NEC remains unknown, but microbiota is considered to have dramatic effects on the development and function of the host brain via the gut-brain axis. In this review, we discuss the characteristics of microbiota of NEC, the impaired neurological outcomes, and the role of the complex interplay between the intestinal microbiota and brain to influence neurodevelopment in NEC. The increasing knowledge of microbial-host interactions has the potential to generate novel therapies for manipulating brain development in the future.

Microbiome-targeting therapies in the neonatal intensive care unit: safety and efficacy

Microbiome-targeting therapies have received great attention as approaches to prevent disease in infants born preterm, but their safety and efficacy remain uncertain. Here we summarize the existing literature, focusing on recent meta-analyses and systematic reviews that evaluate the performance of probiotics, prebiotics, and/or synbiotics in clinical trials and studies, emphasizing interventions for which the primary or secondary outcomes were prevention of necrotizing enterocolitis, late-onset sepsis, feeding intolerance, and/or reduction in hospitalization length or all-cause mortality. Current evidence suggests that probiotics and prebiotics are largely safe but conclusions regarding their effectiveness in the neonatal intensive care unit have been mixed. To address this ambiguity, we evaluated publications that collectively support benefits of probiotics with moderate to high certainty evidence in a recent comprehensive network meta-analysis, highlighting limitations in these trials that make it difficult to support with confidence the routine, universal administration of probiotics to preterm infants.

Probiotics to prevent necrotizing enterocolitis in very low birth weight infants: A network meta-analysis

Objective

This study aims to review the evidence for the optimal regimen of probiotics for the prevention of necrotizing enterocolitis (NEC) in very low birth weight infants.

Design

Through searching PubMed, EMBASE, Cochrane Library, and Web of Science till September 30, 2022, only randomized controlled trials were included to evaluate the optimal regimen of probiotics for the prevention of NEC in very low birth weight infants. The methodological quality of the included studies was assessed by the Cochrane risk of bias assessment tool (RoB 2), and the collected data were analyzed accordingly using Stata software.

Results

Twenty-seven RCTs were included, and the total sample size used in the study was 529. The results of the network meta-analysis showed that Bovine lactoferrin + Lactobacillus rhamnosus GG (RR 0.03; 95% CI 0.00-0.35), Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (RR 0.06; 95% CI 0.00-0.70), Bifidobacterium lactis + inulin (RR 0.16; 95% CI 0.03-0.91) were superior to the control group (Bifidobacterium lactis + Bifidobacterium longum) in reducing the incidence of NEC. The reduction in the incidence of NEC were as follows: Bovine lactoferrin + Lactobacillus rhamnosus GG (SUCRA 95.7%) > Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (SUCRA 89.4%) > Bifidobacterium lactis + inulin (SUCRA 77.8%).

Conclusions

This network meta-analysis suggests that Lactobacillus rhamnosus GG combined with bovine lactoferrin maybe the most recommended regimen for the prevention of NEC in very low birth weight infants.

Using probiotics in paediatric populations

This statement defines probiotics and reviews the most recent literature on their use in paediatrics. Many studies have examined the potential benefit of probiotics, but significant variation in the strains and doses of probiotics used, the patient populations studied, and in study design, have led to heterogeneous results. Present evidence suggests that probiotics can decrease mortality and lower incidence of necrotizing enterocolitis in preterm and low birth weight neonates. Probiotics may also be beneficial in reducing feeding intolerance. In infants, probiotics may be considered to reduce symptoms of colic. In older children, probiotics can be considered to prevent antibiotic-associated diarrhea and Clostridium difficile -associated diarrhea. Probiotic supplements used in conjunction with standard therapy can help with Helicobacter pylori eradication and decrease the side effects of treatment. Lactobacillus species can be considered to treat irritable bowel syndrome. Probiotics can also be considered to help prevent atopic dermatitis and eczema. To optimize paediatric policy and practice, large, quality studies are needed to determine what types and combinations of probiotics are most efficacious.

L’utilisation des probiotiques dans la population pédiatrique

Le présent document de principes définit les probiotiques et fournit une analyse des publications scientifiques les plus récentes sur leur utilisation en pédiatrie. De nombreuses études ont évalué les avantages potentiels des probiotiques, mais en raison des variations importantes dans les souches et les doses utilisées, des populations de patients étudiées et des méthodologies privilégiées, les résultats sont hétérogènes. Selon les données probantes à jour, les probiotiques peuvent réduire le taux de mortalité et l’incidence d’entérocolite nécrosante chez les nouveau-nés prématurés et de petit poids à la naissance. Ils peuvent également être bénéfiques pour réduire l’intolérance alimentaire. Chez les nourrissons, on peut envisager de les utiliser pour limiter les symptômes de coliques, et chez les enfants plus âgés, pour prévenir la diarrhée associée aux antibiotiques ou au Clostridium difficile . Les suppléments de probiotiques utilisés conjointement avec un traitement standard peuvent contribuer à éradiquer l’Helicobacter pylori et à atténuer les effets secondaires du traitement. On peut envisager d’utiliser des espèces de Lactobacillus pour traiter le syndrome du côlon irritable ou de recourir à des probiotiques pour contribuer à prévenir la dermatite atopique et l’eczéma. Afin d’optimiser les politiques et les pratiques en pédiatrie, de vastes études de qualité devront être réalisées pour déterminer les types et les combinaisons de probiotiques les plus efficaces.

Human milk microbial species are associated with infant head-circumference during early and late lactation in Guatemalan mother-infant dyads

Human milk contains abundant commensal bacteria that colonize and establish the infant's gut microbiome but the association between the milk microbiome and head circumference during infancy has not been explored. For this cross-sectional study, head-circumference-for-age-z-scores (HCAZ) of vaginally delivered breastfed infants were collected from 62 unrelated Mam-Mayan mothers living in eight remote rural communities in the Western Highlands of Guatemala during two stages of lactation, 'early' (6-46 days postpartum, n = 29) or 'late' (109-184 days postpartum, n = 33). At each stage of lactation, infants were divided into HCAZ ≥ -1 SD (early: n = 18; late: n = 14) and HCAZ < -1 SD (early: n = 11; late: n = 19). Milk microbiome communities were assessed using 16S ribosomal RNA gene sequencing and DESeq2 was used to compare the differential abundance (DA) of human milk microbiota with infant HCAZ subgroups at both stages of lactations. A total of 503 ESVs annotated 256 putative species across the 64 human milk samples. Alpha-diversity using Chao index uncovered a difference in microbial community richness between HCAZ ≥ -1 SD and HCAZ < -1 SD groups at late lactation (p = 0.045) but not at early lactation. In contrast, Canonical Analysis of Principal Coordinates identified significant differences between HCAZ ≥ -1 SD and HCAZ < -1 SD at both stages of lactation (p = 0.003); moreover, 26 milk microbial taxa differed in relative abundance (FDR < 0.05) between HCAZ ≥ -1 SD and HCAZ < -1 SD, with 13 differentially abundant at each lactation stage. Most species in the HCAZ ≥ -1 SD group were Streptococcus species from the Firmicutes phylum which are considered human colonizers associated with human milk whereas the HCAZ < -1 SD group at late lactation had more differentially abundant taxa associated with environmentally and 'potentially opportunistic' species belonging to the Actinobacteria genus. These findings suggest possible associations between brain growth of breastfed infants and the milk microbiome during lactation. Importantly, these data provide the first evidence of cross talk between the human milk microbiome and the infant brain that requires further investigation.

Probiotic sepsis in preterm neonates-a systematic review

Sepsis due to the administered probiotic strain/s is a barrier against adoption of prophylactic probiotic supplementation in preterm infants to reduce the risk of necrotising enterocolitis (NEC ≥ Stage II), all-cause mortality, late-onset sepsis, and feeding intolerance. We aimed to conduct a systematic review for reports of probiotic sepsis in preterm infants (gestation < 37 weeks). Databases including PubMed, Embase, Emcare, Cochrane Central library, and Google Scholar were searched in August 2021 and updated in Jan 2022. Probiotic sepsis was defined as positive blood/CSF culture isolating administered probiotic strain with symptoms suggestive of infection. Data collection included birth weight, gestation, comorbidities (e.g. gut surgery, NEC), presence of central venous catheters, treatment, and outcome. Literature search revealed 1569 studies. A total of 16 reports [randomised control trial (RCT): none; non-RCT: 1; case series: 8; case report: 7] involving 32 preterm infants with probiotic sepsis were included after exclusions for various reasons. Majority of the cases were born < 32 weeks' gestation. Bifidobacterium (N = 19) was the most commonly isolated organism followed by Lactobacillus (N = 10), and Saccharomyces (N = 3). A total of 25/32 cases were confirmed to be due to the administered probiotic strain on full genomic analysis. Two studies reported one neonatal death each. Twelve neonates had comorbidities. Majority were treated with antibiotics (29/32) whereas others (3/32) required antifungal treatment.

CONCLUSION

Probiotics sepsis is relatively an uncommon event in preterm infants. Majority of the cases recovered after antibiotic or antifungal treatment. The importance of optimal surveillance and treatment of probiotic sepsis and research towards alternatives to probiotics (e.g. postbiotics) is emphasised.

WHAT IS KNOWN

• Probiotics have been shown to reduce necrotising enterocolitis, late-onset sepsis, all-cause mortality, and time to reach full enteral feeds in preterm infants. • Despite the evidence, use of probiotics is not universal due to concerns regarding probiotic-associated sepsis in preterm infants.

WHAT IS NEW

• This comprehensive systematic review showed that probiotic sepsis is a relatively rare phenomenon in preterm infants. • All except one case where the diagnosis was uncertain recovered after antimicrobial therapy.

Probiotic supplementation in neonates with congenital gastrointestinal surgical conditions: a pilot randomised controlled trial

OBJECTIVE

To evaluate whether probiotic supplementation attenuates gut-dysbiosis in neonates with congenital gastrointestinal surgical conditions (CGISC).

METHODS

Sixty-one neonates (≥35 weeks gestation) with CGISC were randomised to receive daily supplementation with a triple-strain bifidobacterial probiotic (n = 30) or placebo (n = 31) until discharge. Stool microbiota was analysed using 16S ribosomal RNA gene sequencing on samples collected before (T1), 1 week (T2), and 2 weeks (T3) after supplementation and before discharge (T4). The primary outcome was the sum of the relative abundance of potentially pathogenic families of Clostridiaceae, Enterobacteriaceae, Enterococcaceae, Pseudomonaceae, Staphylococcaeae, Streptococcaceae, and Yersiniaceae at T3.

RESULTS

The median gestational age [38 weeks (IQR: 37.1-38.9)] was similar in both groups. The probiotic group had lower rates of caesarean deliveries (40% versus 70%, p = 0.02). The relative abundance of potentially pathogenic families was lower in the probiotic group compared to placebo at T3 [(median: 50.4 (IQR: 26.6-67.6) versus 67.1 (IQR: 50.9-96.2); p = 0.04). Relative abundance of Bifidobacteriaceae was higher in the probiotic group at T3 [(median: 39.8 (IQR: 24.9-52.1) versus 0.03 (IQR 0.02-2.1); p < 0.001). Stratified analysis continued to show a higher abundance of Bifidobacteriaceae in the probiotic group, irrespective of the mode of delivery.

CONCLUSIONS

Probiotic supplementation attenuated gut dysbiosis in neonates with CGISC.

TRIAL REGISTRATION

http://www.anzctr.org.au (ACTRN12617001401347).

IMPACT

Probiotic supplementation attenuates gut dysbiosis and improves stool short-chain fatty acid levels in neonates with congenital gastrointestinal surgical conditions. This is the second pilot RCT of probiotic supplementation in neonates with congenital gastrointestinal conditions. These findings will pave the way for conducting multicentre RCTs in this area.

Probiotic Supplementation for Promotion of Growth in Children: A Systematic Review and Meta-Analysis

Probiotics are commonly prescribed to promote a healthy gut microbiome in children. Our objective was to investigate the effects of probiotic supplementation on growth outcomes in children 0-59 months of age. We conducted a systematic review and meta-analysis which included randomized controlled trials (RCTs) that administered probiotics to children aged 0-59 months, with growth outcomes as a result. We completed a random-effects meta-analysis and calculated a pooled standardized mean difference (SMD) or relative risk (RR) and reported with a 95% confidence interval (CI). We included 79 RCTs, 54 from high-income countries (HIC), and 25 from low- and middle-income countries (LMIC). LMIC data showed that probiotics may have a small effect on weight (SMD: 0.26, 95% CI: 0.11-0.42, grade-certainty = low) and height (SMD 0.16, 95% CI: 0.06-0.25, grade-certainty = moderate). HIC data did not show any clinically meaningful effect on weight (SMD: 0.01, 95% CI: -0.04-0.05, grade-certainty = moderate), or height (SMD: -0.01, 95% CI: -0.06-0.04, grade-certainty = moderate). There was no evidence that probiotics affected the risk of adverse events. We conclude that in otherwise healthy children aged 0-59 months, probiotics may have a small but heterogenous effect on weight and height in LMIC but not in children from HIC.

Eligibility Criteria and Representativeness of Randomized Clinical Trials That Include Infants Born Extremely Premature: A Systematic Review

OBJECTIVE

To assess the eligibility criteria and trial characteristics among contemporary (2010-2019) randomized clinical trials (RCTs) that included infants born extremely preterm (<28 weeks of gestation) and to evaluate whether eligibility criteria result in underrepresentation of high-risk subgroups (eg, infants born at <24 weeks of gestation).

STUDY DESIGN

PubMed and Scopus were searched January 1, 2010, to December 31, 2019, with no language restrictions. RCTs with mean or median gestational ages at birth of <28 weeks of gestation were included. The study followed the PRISMA guidelines; outcomes were registered prospectively. Data extraction was performed independently by multiple observers. Study quality was evaluated using a modified Jadad scale.

RESULTS

Among RCTs (n = 201), 32 552 infants were included. Study participant characteristics, interventions, and outcomes were highly variable. A total of 1603 eligibility criteria were identified; rationales were provided for 18.8% (n = 301) of criteria. Fifty-five RCTs (27.4%) included infants <24 weeks of gestation; 454 (1.4%) infants were identified as <24 weeks of gestation.

CONCLUSIONS

The present study identifies sources of variability across RCTs that included infants born extremely preterm and reinforces the critical need for consistent and transparent policies governing eligibility criteria.

Extreme prematurity and sepsis strongly influence frequencies and functional characteristics of circulating γδ T and natural killer cells

Objectives

Extremely low gestational age neonates with extremely low birthweight (ELGAN/ELBW) are highly susceptible to infection. This is linked to their relatively immature immune system which is not yet fully compatible with an extra‐uterine environment. Here, we performed a longitudinal characterisation of unconventional T and natural killer (NK) cells in ELGAN/ELBW during their first months of life.

Methods

Peripheral blood mononuclear cells were collected from 97 ELGAN/ELBW at 14 and 28 days of life and at a time point corresponding to postmenstrual week 36 + 0. γδ T‐cell, NKT‐cell, mucosa‐associated invariant T‐cell and NK cell frequencies and characteristics were analysed by flow cytometry. As control, cells from 14‐day‐old full‐term (FT) infants were included.

Results

Extreme prematurity had significant bearing on γδ T‐cell and NK cell frequencies and characteristics. ELGAN/ELBW had significantly higher proportions of γδ T cells that were skewed towards effector and effector memory phenotypes, characteristics that were maintained throughout the study period. Expression of the gut homing receptor CCR9 was also more common in γδ T cells from ELGAN/ELBW. Conversely, NK cell frequencies were markedly lower and skewed towards a cytotoxic phenotype in the ELGAN/ELBW group at 14 days of age. Culture‐proven sepsis with an onset during the first 14 days after birth further manifested these differences in the γδ T‐ and NK cell populations at 14 days of age.

Conclusion

Prematurity strongly influences the levels of γδ T and NK cells, in particular in cases where sepsis debuts during the first 2 weeks of life.

[Efficacy of probiotics in preventing late-onset sepsis in very low birth weight infants: a Meta analysis]

OBJECTIVE

To study the efficacy of probiotics in preventing late-onset sepsis (LOS) in very low birth weight (VLBW) infants.

METHODS

Databases including PubMed, Web of Science, Cochrane Library, Wanfang Data, China National Knowledge Infrastructure, and Chinese Biomedical Literature Database were searched for randomized controlled trials (RCTs) of probiotics in preventing LOS in VLBW infants. LOS was classified as clinical LOS and confirmed LOS. RevMan 5.4 was used to perform the Meta analysis.

RESULTS

A total of 31 RCTs were included, with 3 490 VLBW infants in the probiotics group and 3 376 VLBW infants in the control group. The Meta analysis showed that compared with the control group, the probiotics group had significantly lower risks of clinical LOS (RR=0.79, 95%CI:0.66-0.94, P=0.009) and clinical/confirmed LOS (RR=0.79, 95% CI:0.67-0.94, P=0.007). In the probiotics group, the infants receiving exclusive breastfeeding had a significantly lower risk of confirmed LOS (RR=0.77, 95%CI:0.62-0.96, P=0.02).

CONCLUSIONS

Current evidence indicates that probiotics may reduce the risk of clinical LOS and clinical/confirmed LOS in VLBW infants, and the risk of confirmed LOS in VLBW infants who are exclusively breastfed.

Lactobacillus reuteri Colonisation of Extremely Preterm Infants in a Randomised Placebo-Controlled Trial

Lactobacillus reuteri DSM 17938 supplementation reduces morbidities in very low birth weight infants (<1500 g), while the effect on extremely low birth weight infants (ELBW, <1000 g) is still questioned. In a randomised placebo-controlled trial (ClinicalTrials.gov ID NCT01603368), head growth, but not feeding tolerance or morbidities, improved in L. reuteri-supplemented preterm ELBW infants. Here, we investigate colonisation with the probiotic strain in preterm ELBW infants who received L. reuteri DSM 17938 or a placebo from birth to postmenstrual week (PMW) 36. Quantitative PCR was used on 582 faecal DNA samples collected from 132 ELBW infants at one, two, three, and four weeks, at PMW 36, and at two years of age. Human milk oligosaccharides were measured in 31 milk samples at two weeks postpartum. At least 86% of the ELBW infants in the L. reuteri group were colonised with the probiotic strain during the neonatal period, despite low gestational age, high antibiotic pressure, and independent of infant feeding mode. Higher concentrations of lacto-N-tetraose, sialyl-lacto-N-neotetraose c, and 6′-sialyllactose in mother’s milk weakly correlated with lower L. reuteri abundance. Within the L. reuteri group, higher L. reuteri abundance weakly correlated with a shorter time to reach full enteral feeding. Female sex and L. reuteri colonisation improved head growth from birth to four weeks of age. In conclusion, L. reuteri DSM 17938 supplementation leads to successful colonisation in ELBW infants.

Populating preterm infants with probiotics

A randomized placebo-controlled trial by Martí et al.1 shows that probiotic supplementation of premature infants can modulate the infant gut microbiota soon after birth.

Effects of Lactobacillus reuteri supplementation on the gut microbiota in extremely preterm infants in a randomized placebo-controlled trial

Extremely low birth weight (ELBW) infants often develop an altered gut microbiota composition, which is related to clinical complications, such as necrotizing enterocolitis and sepsis. Probiotic supplementation may reduce these complications, and modulation of the gut microbiome is a potential mechanism underlying the probiotic effectiveness. In a randomized, double-blind, placebo-controlled trial, we assessed the effect of Lactobacillus reuteri supplementation, from birth to post-menstrual week (PMW)36, on infant gut microbiota. We performed 16S amplicon sequencing in 558 stool samples from 132 ELBW preterm infants at 1 week, 2 weeks, 3 weeks, 4 weeks, PMW36, and 2 years. Probiotic supplementation results in increased bacterial diversity and increased L. reuteri abundance during the 1^st month. At 1 week, probiotic supplementation also results in a lower abundance of Enterobacteriaceae and Staphylococcaceae. No effects were found at 2 years. In conclusion, probiotics may exert benefits by modulating the gut microbiota composition during the 1^st month in ELBW infants.

L. reuteri DSM 17938 dominates the microbiota in supplemented ELBW infants

Supplemented ELBW infants have higher gut microbiota richness and diversity

Supplemented infants have lower abundance of Enterobacteriaceae and Staphylococcaceae

No effects of probiotic supplementation on the gut microbiota at PMW36 and 2 years

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.

Effects of Probiotics in Preterm Infants: A Network Meta-analysis

CONTEXT

Probiotics have proven to be effective in promoting premature infants' health, but the optimal usage is unknown.

OBJECTIVE

To compare probiotic supplements for premature infants.

DATA SOURCES

We searched PubMed, Embase, Cochrane, and ProQuest from inception of these databases to June 1, 2020.

STUDY SELECTION

Randomized trials of probiotic supplement intervention for preterm infants were screened by 2 reviewers independently. The primary outcomes were mortality and the morbidity of necrotizing enterocolitis (NEC). Secondary outcomes were morbidity of sepsis, time to achieve full enteral feeding, and length of hospital stay.

DATA EXTRACTION

The data of primary and secondary outcomes were extracted by 2 reviewers and pooled with a random-effects model.

RESULTS

The meta-analysis included 45 trials with 12 320 participants. Bifidobacterium plus Lactobacillus was associated with lower rates of mortality (risk ratio 0.56; 95% credible interval 0.34-0.84) and NEC morbidity (0.47; 0.27-0.79) in comparison to the placebo; Lactobacillus plus prebiotic was associated with lower rates of NEC morbidity (0.06; 0.01-0.41) in comparison to the placebo; Bifidobacterium plus prebiotic had the highest probability of having the lowest rate of mortality (surface under the cumulative ranking curve 83.94%); and Lactobacillus plus prebiotic had the highest probability of having the lowest rate of NEC (surface under the cumulative ranking curve 95.62%).

LIMITATIONS

In few studies did authors report the data of infants with a lower birth weight or gestational age.

CONCLUSIONS

The efficacy of single probiotic supplements is limited, compared to combined use of probiotics. To achieve optimal effect on premature infant health, combined use of prebiotic and probiotic, especially Lactobacillus or Bifidobacterium, is recommended.

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.

Meconium microbiome and its relation to neonatal growth and head circumference catch-up in preterm infants

The purpose was identify an association between meconium microbiome, extra-uterine growth restriction, and head circumference catch-up.

MATERIALS AND METHODS

Prospective study with preterm infants born <33 weeks gestational age (GA), admitted at Neonatal Unit and attending the Follow-Up Preterm Program of a tertiary hospital. Excluded out born infants; presence of congenital malformations or genetic syndromes; congenital infections; HIV-positive mothers; and newborns whose parents or legal guardians did not authorize participation. Approved by the institution's ethics committee. Conducted 16S rRNA sequencing using PGM Ion Torrent meconium samples for microbiota analysis.

RESULTS

Included 63 newborns, GA 30±2.3 weeks, mean weight 1375.80±462.6 grams, 68.3% adequate weight for GA at birth. Polynucleobacter (p = 0.0163), Gp1 (p = 0.018), and Prevotella (p = 0.038) appeared in greater abundance in meconium of preterm infants with adequate birth weight for GA. Thirty (47.6%) children reached head circumference catch-up before 6 months CA and 33 (52.4%) after 6 months CA. Salmonella (p<0.001), Flavobacterium (p = 0.026), and Burkholderia (p = 0.026) were found to be more abundant in meconium in the group of newborns who achieved catch-up prior to 6th month CA.

CONCLUSION

Meconium microbiome abundance was related to adequacy of weight for GA. Meconium microbiome differs between children who achieve head circumference catch-up by the 6th month of corrected age or after this period.

Probiotics Reduce Mortality and Morbidity in Preterm, Low-Birth-Weight Infants: A Systematic Review and Network Meta-analysis of Randomized Trials

BACKGROUND & AIMS

We aimed to compare the effectiveness of single- vs multiple-strain probiotics in a network meta-analysis of randomized trials.

METHODS

We searched MEDLINE, Embase, Science Citation Index Expanded, CINAHL, Scopus, Cochrane CENTRAL, BIOSIS Previews, and Google Scholar through January 1, 2019, for studies of single-strain and multistrain probiotic formulations on the outcomes of preterm, low-birth-weight neonates. We used a frequentist approach for network meta-analysis and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of evidence. Primary outcomes included all-cause mortality, severe necrotizing enterocolitis (NEC) (Bell stage II or more), and culture-proven sepsis.

RESULTS

We analyzed data from 63 trials involving 15,712 preterm infants. Compared with placebo, a combination of 1 or more Lactobacillus species (spp) and 1 or more Bifidobacterium spp was the only intervention with moderate- or high-quality evidence of reduced all-cause mortality (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.39-0.80). Among interventions with moderate- or high-quality evidence for efficacy compared with placebo, combinations of 1 or more Lactobacillus spp and 1 or more Bifidobacterium spp, Bifidobacterium animalis subspecies lactis, Lactobacillus reuteri, or Lactobacillus rhamnosus significantly reduced severe NEC (OR, 0.35 [95% CI, 0.20-0.59]; OR, 0.31 [95% CI, 0.13-0.74]; OR, 0.55 [95% CI, 0.34-0.91]; and OR, 0.44 [95% CI, 0.21-0.90], respectively). There was moderate- or high-quality evidence that combinations of 1 or more Lactobacillus spp and 1 or more Bifidobacterium spp and Saccharomyces boulardii reduced the number of days to reach full feeding (mean reduction of 3.30 days [95% CI, reduction of 5.91-0.69 days]). There was moderate- or high-quality evidence that, compared with placebo, the single-species product B animalis subsp lactis or L reuteri significantly reduced duration of hospitalization (mean reduction of 13.00 days [95% CI, reduction of 22.71-3.29 days] and mean reduction of 7.89 days [95% CI, reduction of 11.60-4.17 days], respectively).

CONCLUSIONS

In a systematic review and network meta-analysis of studies to determine the effects of single-strain and multistrain probiotic formulations on outcomes of preterm, low-birth-weight neonates, we found moderate to high evidence for the superiority of combinations of 1 or more Lactobacillus spp and 1 or more Bifidobacterium spp vs single- and other multiple-strain probiotic treatments. The combinations of Bacillus spp and Enterococcus spp, and 1 or more Bifidobacterium spp and Streptococcus salivarius subsp thermophilus, might produce the largest reduction in NEC development. Further trials are needed.

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

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

Characterization of the γδ T-cell compartment during infancy reveals clear differences between the early neonatal period and 2 years of age

γδ T cells are unconventional T cells that function on the border of innate and adaptive immunity. They are suggested to play important roles in neonatal and infant immunity, although their phenotype and function are not fully characterized in early childhood. We aimed to investigate γδ T cells in relation to age, prematurity and cytomegalovirus (CMV) infection. Therefore, we used flow cytometry to characterize the γδ T-cell compartment in cord blood and peripheral blood cells from 14-day-, 2-year- and 5-year-old children, as well as in peripheral blood samples collected at several time points during the first months of life from extremely premature neonates. γδ T cells were phenotypically similar at 2 and 5 years of age, whereas cord blood was divergent and showed close proximity to γδ T cells from 14-day-old neonates. Interestingly, 2-year-old children and adults showed comparable Vδ2+ γδ T-cell functionality toward both microbial and polyclonal stimulations. Importantly, extreme preterm birth compromised the frequencies of Vδ1+ cells and affected the functionality of Vδ2+ γδ T cells shortly after birth. In addition, CMV infection was associated with terminal differentiation of the Vδ1+ compartment at 2 years of age. Our results show an adult-like functionality of the γδ T-cell compartment already at 2 years of age. In addition, we demonstrate an altered γδ T-cell phenotype early after birth in extremely premature neonates, something which could possible contribute to the enhanced risk for infections in this vulnerable group of children.

Extremely Preterm Infants Have Significant Alterations in Their Conventional T Cell Compartment during the First Weeks of Life

Extremely preterm neonates are particularly susceptible to infections, likely because of severely impaired immune function. However, little is known on the composition of the T cell compartment in early life in this vulnerable population. We conducted a comprehensive phenotypic flow cytometry-based longitudinal analysis of the peripheral conventional T cell compartment of human extremely low gestational age neonates (ELGAN) with extremely low birth weight (ELBW; <1000 g) participating in a randomized placebo-controlled study of probiotic supplementation. PBMCs from ELGAN/ELBW neonates were collected at day 14, day 28, and postmenstrual week 36. Comparisons were made with full-term 14-d-old neonates. Total CD4⁺ and CD8⁺ T cell frequencies were markedly lower in the preterm neonates. The reduction was more pronounced among the CD8⁺ population, resulting in an increased CD4/CD8 ratio. The preterm infants were also more Th2 skewed than the full-term infants. Although the frequency of regulatory T cells seemed normal in the ELGAN/ELBW preterm neonates, their expression of the homing receptors α4β7, CCR4, and CCR9 was altered. Notably, ELGAN/ELBW infants developing necrotizing enterocolitis before day 14 had higher expression of CCR9 in CD4⁺T cells at day 14. Chorioamnionitis clearly associated with reduced T regulatory cell frequencies and functional characteristics within the preterm group. Finally, probiotic supplementation with Lactobacillus reuteri did not impose any phenotypic changes of the conventional T cell compartment. In conclusion, notable immaturities of the T cell compartment in ELGAN/ELBW neonates may at least partially explain their increased susceptibility to severe immune-mediated morbidities.

Lactobacillus reuteri DSM 17938 Improves Feeding Intolerance in Preterm Infants

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Low Diversity of Human Milk Oligosaccharides is Associated with Necrotising Enterocolitis in Extremely Low Birth Weight Infants

Difference in human milk oligosaccharides (HMO) composition in breast milk may be one explanation why some preterm infants develop necrotizing enterocolitis (NEC) despite being fed exclusively with breast milk. The aim of this study was to measure the concentration of 15 dominant HMOs in breast milk during the neonatal period and investigate how their levels correlated to NEC, sepsis, and growth in extremely low birth weight (ELBW; <1000 g) infants who were exclusively fed with breast milk. Milk was collected from 91 mothers to 106 infants at 14 and 28 days and at postmenstrual week 36. The HMOs were analysed with high-performance anion-exchange chromatography with pulsed amperometric detection. The HMOs diversity and the levels of Lacto-N-difucohexaose I were lower in samples from mothers to NEC cases, as compared to non-NEC cases at all sampling time points. Lacto-N-difucohexaose I is only produced by secretor and Lewis positive mothers. There were also significant but inconsistent associations between 3′-sialyllactose and 6′-sialyllactose and culture-proven sepsis and significant, but weak correlations between several HMOs and growth rate. Our results suggest that the variation in HMO composition in breast milk may be an important factor explaining why exclusively breast milk fed ELBW infants develop NEC.