Probiotics for prevention of necrotizing enterocolitis in preterm infants

  • Review
  • Intervention

Authors


Abstract

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.

Résumé scientifique

Probiotiques pour la prévention de l'entérocolite nécrosante chez les nouveau-nés prématurés

Contexte

L'entérocolite nécrosante (ECN) et le sepsis nosocomial sont associés à une morbidité et une mortalité accrues chez les nouveau-nés prématurés. En prévenant la migration bactérienne au travers de la muqueuse, en favorisant l'exclusion compétitive des bactéries pathogènes et en améliorant la réponse immunitaire de l'hôte, les probiotiques (suppléments contenant des microbes vivants) prophylactiques entéraux pourraient jouer un rôle dans la réduction de l'ECN et de la morbidité qui en découle.

Objectifs

Comparer l'efficacité et l'innocuité des probiotiques prophylactiques entéraux par rapport à un placebo ou à l'absence de traitement dans la prévention de l'ECN sévère ou du sepsis, ou les deux, chez les nouveau-nés prématurés.

Stratégie de recherche documentaire

Pour cette mise à jour, des recherches ont été effectuées dans MEDLINE (de 1966 à octobre 2013), EMBASE (de 1980 à octobre 2013), le registre Cochrane des essais contrôlés (CENTRAL) dans la Bibliothèque Cochrane (2013, numéro 10), et les résumés des réunions annuelles de la Society for Pediatric Research (de 1995 à 2013).

Critères de sélection

Seuls les essais contrôlés randomisés ou quasi randomisés recrutant des nouveau-nés prématurés < 37 semaines d'âge gestationnel ou < 2 500 g de poids de naissance, ou les deux, ont été pris en compte. Les essais ont été inclus lorsqu'ils portaient sur l'administration entérale de tout supplément contenant des microbes vivants (probiotiques) et mesuraient au moins l'un des résultats cliniques prédéfinis.

Recueil et analyse des données

Les méthodes standard de la Collaboration Cochrane et de son groupe sur la néonatologie ont été utilisées pour l'évaluation de la qualité méthodologique des essais et pour le recueil et l'analyse des données.

Résultats principaux

Vingt-quatre essais éligibles ont été inclus. Les essais inclus différaient grandement en termes de critères d'inscription (poids de naissance et âge gestationnel), de risque d'ECN à l'inclusion dans les groupes témoins, de calendrier, de dose, de formulation des probiotiques et de régimes alimentaires. Dans une méta-analyse des données des essais, la supplémentation en probiotiques entéraux entraînait une réduction significative de l'incidence de l'ECN sévère (stade II ou plus) (risque relatif (RR) typique de 0,43, intervalle de confiance (IC) à 95 % de 0,33 à 0,56 ; 20 études, 5 529 nourrissons) et de la mortalité (RR typique de 0,65, IC à 95 % de 0,52 à 0,81 ; 17 études, 5 112 nourrissons). Il n'y avait aucune preuve de réduction significative du sepsis nosocomial (RR typique de 0,91, IC à 95 % de 0,80 à 1,03 ; 19 études, 5 338 nourrissons). Les essais inclus ne rapportaient aucune infection systémique associée aux organismes contenus dans les suppléments de probiotiques. Les préparations de probiotiques contenant soit des lactobacilles seuls ou associés aux bifidobactéries se sont avérées efficaces.

Conclusions des auteurs

La supplémentation entérale en probiotiques permet de réduire l'ECN sévère et la mortalité toutes causes confondues chez les nouveau-nés prématurés. Notre revue mise à jour des preuves disponibles est fortement favorable à un changement de pratique. Des études comparatives en face-à-face sont nécessaires pour évaluer les préparations les plus efficaces, le calendrier et la durée du traitement à utiliser.

アブストラクト

早産児における壊死性腸炎の予防に対するプロバイオティクス

背景

壊死性腸炎(NEC)および院内敗血症は、早産児における罹病率や死亡率の増加と関連がある。粘膜への細菌の広がりの予防、病原性細菌の競争的排除、および宿主の免疫反応の強化によって、予防的な腸内プロバイオティクス(生きた微生物の補充)がNECおよび関連する罹病率の減少に働く可能性がある。

目的

早産児における重度のNECまたは敗血症、もしくは両方の予防に対する、予防的プロバイオティクスの腸内投与の有効性と安全性を、プラセボまたは無治療と比較すること。

検索戦略

今回の更新では以下の検索を行った。MEDLINE(1966年~2013年10月)、EMBASE(1980年~2013年10月)、Cochrane Central Register of Controlled Trials (CENTRAL)inコクラン・ライブラリ(2013年10号)、およびthe Society for Pediatric Researchの年次総会の抄録(1995年~2013年)。

選択基準

37週未満、または出生時体重が2500 g未満、もしくは両方の早産児を登録した、ランダム化または準ランダム化比較試験のみについて対象とした。生きた微生物のサプリメント(プロバイオティクス)を腸内投与し、1つ以上の事前に定めた臨床アウトカムを評価した試験を選択した。

データ収集と分析

コクラン共同計画およびその新生児グループの標準的方法を用いて、試験、データ収集、および解析に関する方法論的な質を評価した。

主な結果

24件の適格な試験を選択した。選択した試験では、登録基準(出生時体重と在胎週数)、コントロール群におけるベースラインのNECのリスク、時期、用量、プロバイオティクス製剤、および補充方法が大きく異なっていた。試験データのメタアナリシスでは、腸内プロバイオティクスの補充により、重度のNEC(ステージII以上)の罹患率(標準的な相対リスク(RR)0.43, 95% 信頼区間(CI)0.33~0.56;20件の研究、乳児5529例)、および死亡率(標準的なRR 0.65, 95% CI 0.52~0.81;17件の研究、乳児5112例)が有意に減少した。院内敗血症の有意な減少を示すエビデンスはなかった(標準的なRR 0.91、95% CI 0.80~1.03;19件の研究、乳児5338例)。補充したプロバイオティクス生物による全身感染を報告した試験はなかった。乳酸菌単独またはビフィズス菌との混合を含有するプロバイオティクス製剤は、有効であることが明らかになった。

著者の結論

プロバイオティクスの腸内補充は、早産児における重度のNECや総死亡を防ぐ。レビューの更新で入手したエビデンスは、診療の変化を強く支持するものである。もっとも有効な製剤、時期、および治療期間を評価するには、直接比較する研究が必要である。

訳注

《実施組織》厚生労働省「「統合医療」に係る情報発信等推進事業」(eJIM:http://www.ejim.ncgg.go.jp/)[2015.12.31]
《注意》この日本語訳は、臨床医、疫学研究者などによる翻訳のチェックを受けて公開していますが、訳語の間違いなどお気づきの点がございましたら、eJIM事務局までご連絡ください。なお、2013年6月からコクラン・ライブラリーのNew review, Updated reviewとも日単位で更新されています。eJIMでは最新版の日本語訳を掲載するよう努めておりますが、タイム・ラグが生じている場合もあります。ご利用に際しては、最新版(英語版)の内容をご確認ください。

Resumo

Probióticos para a prevenção de enterocolite necrotizante em recém-nascidos prematuros.

Introdução

Enterocolite necrotizante (NEC) e sepse nosocomial estão associados com aumento da morbidade e mortalidade em recém-nascidos prematuros. Através da prevenção da migração bacteriana através da mucosa, da exclusão competitiva de bactérias patogênicas, e aumento da resposta imune do hospedeiro, probióticos profiláticos enterrais (suplementos microbianos vivos) podem desempenhar um papel na redução de NEC e na morbidade associada.

Objetivos

Comparar a eficácia e segurança da administração enteral profilática de probióticos versus placebo ou nenhum tratamento na prevenção de NEC severa ou sepse, ou ambos, em recém-nascidos prematuros.

Métodos de busca

Para essa atualização, foram feitas buscas no MEDLINE (1966 a Outubro de 2013), EMBASE (1980 a Outubro de 2013), Cochrane Central Register of Controlled Trials (CENTRAL) The Cochrane Library (2013, edição 10), e resumos de reuniões anuais da Society for Pediatric Research (1995 a 2013).

Critério de seleção

Apenas ensaios clínicos randomizados ou semi randomizados que envolveram recém-nascidos prematuros com menos de 37 semanas de idade gestacional ou peso de nascimento menor de 2500g, ou ambos, foram considerados. Ensaios clínicos foram incluídos se eles envolvessem administração enteral de qualquer suplemento microbiano vivo (probióticos) e medidos com pelo menos um resultado clínico pré-especificado.

Coleta dos dados e análises

Métodos standard da The Cochrane Collaboration e seu Neonatal Group foram usados para avaliar a qualidade metodológica dos ensaios clínicos e para coleta de dados e análise.

Principais resultados

Vinte e quatro estudos elegíveis foram incluídos. Os ensaios incluídos eram altamente variáveis no que diz respeito aos critérios de inscrição (que eram peso de nascimento e idade gestacional), risco de base da NEC em grupos controle, tempo, dose, formulação de probióticos, e regimes alimentares. Na metanálise dos dados de ensaios clínicos, a suplementação enteral de probióticos reduziu significantemente a incidência de NEC grave (estágio II ou mais) (risco relativo típico (RR) 0,43, intervalo de confiança de 95% (IC) 0,33 a 0,56; 20 estudos, 5529 crianças) e mortalidade (RR típico 0,65, IC 95% 0,52 a 0,81; 17 estudos, 5112 crianças). Não houve evidência de redução significativa de sepse nosocomial (TT típico 0,91, 95% CI 0,80 a 1,03; 19 estudos, 5338 crianças). Os ensaios inclusos não reportaram infecção sistêmica com a suplementação de probióticos. Preparações de probióticos contendo apenas lactobacilos ou em combinação com bifidobacterium foram descobertas como eficazes.

Conclusão dos autores

Suplementação enteral de probióticos previne NEC grave e todas as causas de mortalidade em prematuros. Nossa revisão atualizada de evidências disponíveis apóia fortemente uma mudança na prática. Confrontos de estudos comparativos são necessários para avaliar as preparações mais eficazes, tempo, e a duração da terapia a ser utilizada.

Notas de tradução

Notas de tradução CD005496.pub4. Maressa Maria de Medeirtos Moreira

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.

Résumé simplifié

Probiotiques pour la prévention de l'entérocolite nécrosante chez les nouveau-nés prématurés

L'entérocolite nécrosante (ECN) est une maladie grave qui affecte l'intestin des nouveau-nés prématurés au cours des premières semaines de vie. Bien que l'on ignore la cause exacte de l'ECN, l'alimentation au lait et la croissance bactérienne jouent un rôle dans son étiologie. Des probiotiques (compléments alimentaires contenant des levures ou des bactéries potentiellement bénéfiques) sont utilisés dans la prévention de l'ECN. Notre revue des études a observé que l'utilisation de probiotiques réduisait l'incidence de l'ECN et les décès chez les nouveau-nés prématurés d'un poids de naissance inférieur à 1 500 grammes. Les données sont insuffisantes concernant les bénéfices et les effets indésirables potentiels chez les nourrissons d'un poids de naissance inférieur à 1 000 grammes, pour lesquels le risque est le plus élevé.

Notes de traduction

Traduit par: French Cochrane Centre 22nd July, 2014
Traduction financée par: Financeurs pour le Canada : Instituts de Recherche en Santé du Canada, Ministère de la Santé et des Services Sociaux du Québec, Fonds de recherche du Québec-Santé et Institut National d'Excellence en Santé et en Services Sociaux; pour la France : Ministère en charge de la Santé

平易な要約

早産児における壊死性腸炎の予防に対するプロバイオティクス

壊死性腸炎(NEC)は、生後数週間の早産児の腸に影響を与える重篤な疾患である。NECの原因は完全には分かっていないが、ミルク育児や細菌の増殖が作用するとされる。プロバイオティクス(有益と考えられる細菌や酵母を含有する栄養補助食品)が、NECの予防に使われている。研究に関するレビューでは、プロバイオティクスを使うことで、1500g未満で生まれた早産児におけるNECの発症と死亡が減少することを見出した。もっともリスクが高い1000g未満で生まれた乳児について、効果と有害作用の可能性に関するデータは不十分である。

訳注

《実施組織》厚生労働省「「統合医療」に係る情報発信等推進事業」(eJIM:http://www.ejim.ncgg.go.jp/)[2015.12.31]
《注意》この日本語訳は、臨床医、疫学研究者などによる翻訳のチェックを受けて公開していますが、訳語の間違いなどお気づきの点がございましたら、eJIM事務局までご連絡ください。なお、2013年6月からコクラン・ライブラリーのNew review, Updated reviewとも日単位で更新されています。eJIMでは最新版の日本語訳を掲載するよう努めておりますが、タイム・ラグが生じている場合もあります。ご利用に際しては、最新版(英語版)の内容をご確認ください。

Ringkasan bahasa mudah

Probiotik untuk pencegahan necrotizing enterocolitis di kalangan bayi pramatang

Necrotizing enterocolitis (NEC ) adalah penyakit yang serius yang menjejaskan usus bayi pramatang dalam tempoh beberapa minggu pertama selepas lahir. Walaupun punca NEC tidak diketahui kesemuanya, penyusuan susu dan pertumbuhan bakteria memainkan peranan. Probiotik (makanan tambahan yang mengandungi bakteria atau yis yang berpotensi memberi manfaat) telah digunakan untuk mencegah NEC. Ulasan kami mendapati bahawa kegunaan probiotik mengurangkan kejadian NEC dan kematian di kalangan bayi pramatang dengan berat lahir kurang dari 1500 gram. Tiada data yang mencukupi mengenai kebaikan dan potensi kesan buruk bagi bayi paling berisiko, iaitu bertimbang kurang dari 1000 gram sewaktu kelahiran.

Catatan terjemahan

Diterjemahkan oleh Foo Sook Lee (Penang Medical College). Disunting oleh Tan May Loong (Penang Medical College). Untuk sebarang pertanyaan mengenai terjemahan ini sila hubungi fslee@pmc.edu.my.

Resumo para leigos

Probióticos para a prevenção de enterocolite necrotizante em recém-nascidos prematuros.

Enterolcolite necrotizante (NEC) é uma doença grave que afeta o intestino de recém-nascidos prematuros nas primeiras semanas de vida. Embora a causa de NEC não seja completamente conhecida, alimentação com leite e crescimento de bactérias desempenham papéis. Probióticos (suplementos dietéticos contendo bactérias potencialmente benéficas ou leveduras) têm sido usados para prevenir a NEC. Nossa revisão de estudos encontrou que o uso de probióticos reduz a ocorrência de NEC e óbitos de recém-nascidos prematuros pesando menos que 1500 gramas. Os dados são insuficientes no que diz respeito aos benefícios e potenciais efeitos adversos na maioria dos recém-nascidos de risco pesando menos de 1000 gramas ao nascimento.

Notas de tradução

Notas de tradução CD005496.pub4. Maressa Maria de Medeirtos Moreira

Background

Description of the condition

Necrotizing enterocolitis (NEC) is the most common serious acquired disease of the gastrointestinal tract in preterm infants (Lee 2003). It is characterized by bowel wall necrosis, of various length and depth. Bowel perforation occurs in one third of the affected infants (Kafetzis 2003). Although 5% to 25% of cases occur in term infants, it is primarily a disease of preterm infants with the majority of cases occurring in very low birth weight infants (infants with birth weight < 1500 g) (Kosloske 1994). The incidence of NEC varies across countries and neonatal centers. It has been reported to affect up to 10% of very low birth weight infants (VLBW) (Kosloske 1994). In a recent report of the Vermont Oxford Network for VLBW infants the incidence of NEC has risen slightly between 2000 to 2009 (Horbar 2012). NEC is categorized into three different stages, with clinical symptoms varying from feeding intolerance to severe cardiovascular compromise, coagulopathy, and peritonitis with or without pneumoperitoneum (Bell 1978).

The pathogenesis of NEC remains incompletely understood. NEC most likely represents a complex interaction of factors causing mucosal injury (Neu 1996). It is speculated that NEC occurs with the coincidence of two of the three pathologic events of intestinal ischemia, colonization of the intestine by pathologic bacteria, and excess protein substrate in the intestinal lumen (Kosloske 1984; La Gamma 1994). Bacterial colonization is necessary for the development of NEC (Kosloske 1990; Musemeche 1986). When compared to term infants, VLBW infants at risk of NEC have abnormal fecal colonization, demonstrate a paucity of normal enteric bacterial species, and have delayed onset of bacterial colonization (Gewolb 1999; Goldmann 1978). Nosocomial infection is also a frequent complication in VLBW infants. Data from the National Institute of Child Health and Human Development (NICHD) Network demonstrated that as many as 25% of these infants have at least one or more positive blood cultures, and 5% have positive cerebrospinal fluid cultures over the course of their hospitalization (Stoll 1996). Late onset sepsis is associated with an increased risk of death, neonatal morbidity, and prolonged hospitalization (Stoll 2002a; Stoll 2002b).

Description of the intervention

Probiotic bacteria are live microbial supplements that colonize the gastrointestinal tract and potentially provide benefit to the host (Millar 2003). The most frequently used probiotics are lactobacillus and bifidobacterium. There is increasing interest in the potential health benefits of proactive colonization of the gastrointestinal tract of preterm infants (Millar 2003).

How the intervention might work

Potential mechanisms by which probiotics may protect high risk infants from developing NEC or sepsis, or both, include an increased barrier to migration bacteria and their products across the mucosa (Mattar 2001; Orrhage 1999), competitive exclusion of potential pathogens (Reid 2001), modification of host response to microbial products (Duffy 2000), augmentation of immunoglobulin A (IGA) mucosal responses, enhancement of enteral nutrition that inhibits the growth of pathogens, and up-regulation of immune responses (Link-Amster 1994).

Why it is important to do this review

VLBW infants with NEC have a mortality rate of up to 20% (Caplan 2001; Holman 1997). Approximately 27% to 63% of affected infants require surgical intervention (Lee 2003). Strictures, primarily in the colon, occur in more than one third of affected infants (Ricketts 1994). An increased rate of total parenteral nutrition (TPN) related complications and extended hospitalization have been reported (Bisquera 2002). Recent data from the NICHD Network suggest an increase in neurodevelopmental impairment rates among infants with NEC and sepsis (Stoll 2004). There is a theoretical risk of bacteremia secondary to enterally administered probiotics strains, though few data support this concern. Bacillus species administered as probiotics were reported to be associated with invasive disease in target populations (Richard 1988).

Objectives

The primary objective was to compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe (stage II or more) NEC or sepsis, or both, in preterm infants.

The secondary objective was to conduct a subgroup analysis to investigate the effect of probiotics:

  • in very low birth weight ( (VLBW) (birth weight < 1500 g) and extremely low birth weight (ELBW) infants (birth weight < 1000 g);

  • according to species, time of initiation, and the duration of probiotics administrations.

Methods

Criteria for considering studies for this review

Types of studies

Only randomized and quasi-randomized controlled trials were included.

Types of participants

Preterm infants < 37 weeks and birth weight < 2500 g, or both.

Types of interventions

Enteral administration of any live microbial supplement (probiotics) at any dose for more than seven days compared to placebo or no treatment.

Types of outcome measures

Primary outcomes
  • Severe NEC (stage II or more) as per Bell's criteria (Bell 1978; Walsh 1986), diagnosed prior to discharge

  • Nosocomial sepsis, defined as positive blood or cerebrospinal fluid cultures taken beyond five days of age

  • All cause mortality

Secondary outcomes
  • Any NEC (according Bell's criteria)

  • The composite of nosocomial sepsis or NEC or death

  • Systemic infection with the supplemented organism

  • Duration of total parenteral nutrition (days)

  • Time to establish full enteral feeds (days)

  • Duration of hospitalization (days)

  • Weight gain (any measurement scale)

  • Neurodevelopmental impairment i.e. rates of cerebral palsy, cognitive delay, deafness, blindness, or their composite, reported at 18 months corrected age or later.

Search methods for identification of studies

Electronic searches

Our search was updated from October 2010 to October 2013. We used the standard search strategy for the Cochrane Neonatal Review Group. Randomized and quasi-randomized controlled trials that compared enteral probiotics to placebo or no treatment in premature infants were identified from Ovid MEDLINE, National Library of Medicine (1966 to October 2013) using the following subject headings (MeSH) and text word terms: "neonate(s), newborn(s), infant(s), probiotics, lactobacillus, bifidobacterium, saccharomyces and publication type 'controlled trial'. We restricted our search to English literature. Other databases were searched including: Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 10) and EMBASE (1980 to October 2013). Review authors performed the electronic database search independently.

Searching other resources

A manual search was performed of the abstract books published from the Society of Pediatric Research (SPR) and the European Society of Pediatric Research (ESPR) for the period from 1998 to 2013. Additional citations were sought using the references in articles retrieved from the searches. Subject experts were contacted to identify unpublished and ongoing studies. Authors of published trials were contacted to clarify or provide additional information. The review authors independently screened the candidate articles to check their eligibility for inclusion in the review.

We also searched clinical trials registries for ongoing or recently completed trials (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp).

Data collection and analysis

The standard methods of the Cochrane Neonatal Review Group were employed in creating this update.

Selection of studies

Retrieved articles were independently assessed for eligibility by two review authors. Discrepancies were resolved by discussion and consensus.

Data extraction and management

Data were abstracted independently by two review authors. Discrepancies were resolved by discussion and consensus. Where data were incomplete, the primary investigator was contacted for further information and clarification.

Assessment of risk of bias in included studies

Standard methods of The Cochrane Collaboration and the Neonatal Review Group were used to assess the methodological quality (to meet the validity criteria) of the trials. For each trial, information was sought regarding the method of randomization, and the blinding and reporting of all outcomes of all the infants enrolled in the trial. Each criterion was assessed as yes, no, can't tell. Two review authors separately assessed each study. Any disagreement was resolved by discussion. This information was added to the table Characteristics of included studies. In addition, for the updates in 2010 and 2013, the following issues were evaluated and entered into the risk of bias table.

1) Sequence generation (checking for possible selection bias). Was the allocation sequence adequately generated? 

For each included study, we categorized the method used to generate the allocation sequence as:  

  • adequate (any truly random process e.g. random number table; computer random number generator);

  • inadequate (any non random process e.g. odd or even date of birth; hospital or clinic record number);

  • unclear.

(2) Allocation concealment (checking for possible selection bias). Was allocation adequately concealed? 

For each included study, we categorized the method used to conceal the allocation sequence as:  

  • adequate (e.g. telephone or central randomization; consecutively numbered sealed opaque envelopes);

  • inadequate (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth);

  • unclear.

(3) Blinding (checking for possible performance bias). Was knowledge of the allocated intervention adequately prevented during the study? At study entry? At the time of outcome assessment? 

For each included study, we categorized the methods used to blind study participants and personnel from knowledge of which intervention a participant received. Blinding was assessed separately for different outcomes or classes of outcomes. We categorized the methods as:  

  • adequate, inadequate or unclear for participants;

  • adequate, inadequate or unclear for personnel;

  • adequate, inadequate or unclear for outcome assessors.

(4) Incomplete outcome data (checking for possible attrition bias through withdrawals, dropouts, protocol deviations). Were incomplete outcome data adequately addressed? 

For each included study and for each outcome, we described the completeness of data including attrition and exclusions from the analysis. We noted whether attrition and exclusions were reported, the numbers included in the analysis at each stage (compared with the total randomized participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information was reported or supplied by the trial authors, we re-included missing data in the analyses. We categorized the methods as:  

  • adequate (< 20% missing data);

  • inadequate (≥ 20% missing data);

  • unclear.

(5) Selective reporting bias. Are reports of the study free of suggestion of selective outcome reporting? 

For each included study, we described how we investigated the possibility of selective outcome reporting bias and what we found. We assessed the methods as: 

  • adequate (where it is clear that all of the study’s pre-specified outcomes and all expected outcomes of interest to the review have been reported); 

  • inadequate (where not all the study’s pre-specified outcomes have been reported; one or more reported primary outcomes were not pre-specified outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported); 

  • unclear.

(6) Other sources of bias. Was the study apparently free of other problems that could put it at a high risk of bias? 

For each included study, we described any important concerns we had about other possible sources of bias (for example, whether there was a potential source of bias related to the specific study design or whether the trial was stopped early due to some data-dependent process). We assessed whether each study was free of other problems that could put it at risk of bias as: 

  • yes;

  • no;

  • unclear.

If needed, we planned to explore the impact of the level of bias through undertaking sensitivity analyses.

Measures of treatment effect

For dichotomous outcomes, relative risk (RR), risk difference (RD), and the number needed to treat to benefit (NNTB) and the associated confidence intervals (CIs) were calculated. For continuous outcomes, treatment effect was expressed as mean difference (MD) and its calculated standard deviation (SD). When median, range, and sample size were reported, the mean and SD were estimated using established methods (Hozo 2005).

Assessment of heterogeneity

Heterogeneity was defined as a significant test of heterogeneity (P < 0.1) and differences in the treatment effects across studies. Tests for between-study heterogeneity (including the I2 statistic) were applied. If noticed, possible sources of heterogeneity were examined, including differences in the type or dose of probiotics used, the population under study (VLBW versus ELBW infants), and the quality of the study.

Data synthesis

Review Manager 5.2 software was used for statistical analysis. For estimates of typical RR and RD we used the Mantel-Haenszel method. For measured quantities we used the inverse variance method. All meta-analyses were done using the fixed-effect model.

Subgroup analysis and investigation of heterogeneity

The secondary objective was to conduct a subgroup analysis to investigate the effect of the probiotics in and for the following.

  • VLBW infants.

  • ELBW infants.

  • Different species of probiotics.

  • Different times of initiation of probiotics.

  • Different durations of probiotics administration.

Sensitivity analysis

A sensitivity analysis was carried out to assess the effect of trials methodological quality on the results of the meta-analysis. Studies were considered to be of high quality if allocation was concealed and adequately described.

Results

Description of studies

See the tables Characteristics of included studies; Characteristics of excluded studies.

Our updated search in October 2013 yielded eight additional studies meeting our inclusion criteria (Al-Hosni 2012; Braga 2011; Demirel 2013; Fernández-Carrocera 2013; Mihatsch 2010; ProPrems 2013; Rojas 2012; Romeo 2011a). Therefore, a total of 24 randomized trials were included in our updated review. Excluded studies and reasons for exclusion are outlined in Characteristics of excluded studies. The details of six identified ongoing studies are provided in Characteristics of ongoing studies.

Participants

Twenty-four included studies reported outcomes on 2761 infants treated with probiotics and 2768 control infants.

[ed note: please check the math. These numbers discussed here are only the infants enrolled in the studies that report on NEC. The total numbers must be greater]

While all studies enrolled infants < 37 weeks or with birth weight < 2500 g, or both, the entry criteria varied between studies. Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Fernández-Carrocera 2013; Kitajima 1997; Li 2004; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Reuman 1986; and Rojas 2012 enrolled infants based on birth weight criteria. On the other hand, Costalos 2003; Mihatsch 2010; Millar 1993; Mohan 2006; and Stratiki 2007 enrolled infants based on their gestational age. Dani 2002; Demirel 2013; Romeo 2011a; Rougé 2009; Samanta 2009; and Sari 2010 utilized both criteria to enroll infants. Only Al-Hosni 2012 limited enrolment to ELBW infants.

Intervention

The included studies randomized infants to different preparations, times of initiation and duration of therapy of probiotics.

While Dani 2002; Manzoni 2006; Manzoni 2009; Millar 1993; Reuman 1986; Rojas 2012; Romeo 2011a; and Sari 2010 administered Lactobacillus species to the intervention groups, Kitajima 1997; Li 2004; Mihatsch 2010; Mohan 2006; and Stratiki 2007 utilized the Bifidobacterium species; Costalos 2003 and Demirel 2013 utilized Saccharomyces boulardii, and Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Fernández-Carrocera 2013; Lin 2005; Lin 2008; ProPrems 2013; Rougé 2009; and Samanta 2009 used a mixture of species of probiotics.

The time of initiation was different among the included studies. Probiotics were administered either during the first 24 hours of life in Kitajima 1997; Li 2004; and Reuman 1986, on the second day in Braga 2011, at less than 48 hours of age in Rojas 2012, on the third day of life in Manzoni 2009, in the first 72 h in Romeo 2011a, at the time of the first feed in Al-Hosni 2012; Dani 2002; Fernández-Carrocera 2013; Lin 2005; Lin 2008; Mihatsch 2010; Millar 1993; Rougé 2009; Samanta 2009; and Sari 2010, when an infant was receiving at least 1 mL of milk four hourly in ProPrems 2013, or during the first week when enteral feeds were tolerated in Costalos 2003; Manzoni 2006; and Mohan 2006.

The duration of probiotics administration varied from two weeks in Reuman 1986, four to six weeks in Costalos 2003; Kitajima 1997; Lin 2008; and Manzoni 2009, until discharge in Al-Hosni 2012; Dani 2002; Fernández-Carrocera 2013; Li 2004; Lin 2005; Manzoni 2006; Mihatsch 2010; Rojas 2012; Rougé 2009; Samanta 2009; and Sari 2010, at discharge if it happened before the 30th day in Braga 2011, until discharge from hospital or 40 weeks postmenst rual age (term corrected age) in ProPrems 2013, or six weeks or until they were discharged from the neonatal intensive care unit (NICU) in Romeo 2011a.

Outcomes

The major outcomes reported in THE included studies were severe stage II-III NEC (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Costalos 2003; Dani 2002; Fernández-Carrocera 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; Mohan 2006; Rojas 2012; Rougé 2009; Samanta 2009; Sari 2010; Stratiki 2007), all cause mortality (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Dani 2002; Fernández-Carrocera 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; Reuman 1986; Rojas 2012; Rougé 2009; Samanta 2009), and any culture proven sepsis (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Costalos 2003; Dani 2002; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; Millar 1993; Rojas 2012; Rougé 2009; Samanta 2009; Sari 2010; Stratiki 2007). Weight gain was reported in five studies (Al-Hosni 2012; Costalos 2003; Millar 1993; Reuman 1986; Sari 2010) using different measurement scales. Only one study reported data on apnea and long term neurosensory outcomes (Kitajima 1997).

Risk of bias in included studies

Details of THE included studies are presented in the table Characteristics of included studies. The methodologic details of the studies were extracted from the published data and by contacting the primary authors.

  • Al-Hosni 2012: this was a multicenter study. All premature infants with birth weight 501 to 1000 g, appropriate for gestational age, and less than or equal to 14 days of age at the time of feeding were randomized to receive either probiotics consisting of Lactobacillus rhamnosus GG (LGG) (Culturelle, Amerifit Brand, Cromwell, CT, USA) at 500 million colony forming units (CFU) and Bifidobacterium infantis (Align, Procter and Gamble, Cincinnati, OH, USA) at 500 million CFU suspended in 0.5 mL of infant’s milk or to receive unsupplemented milk added to their daily feeding. Probiotic supplementation was added to the first enteral feeding and continued once daily with feedings thereafter until discharge or until 34 weeks postmenstrual age. The milk type was not known. Information regarding allocation concealment was not specified, the intervention and outcome assessment were blinded.

  • Bin-Nun 2005: this was a single centre study. Infants less than 1500 g were randomized to receive either probiotics mixture (Lactobacillus bifidus, streptococcus thermophillus, and bifidobactrium infantis) or placebo. Expressed mother’s milk, when available, or Similac Special Care formula was used. Information regarding allocation concealment was not specified, the intervention was masked, and blinding of outcome assessment was not specified. Of note, this trial was published in an abstract form on two previous occasions at the Society of Pediatrics Research (SPR 2003, 2005) with different inclusion criteria and clinical outcomes, which suggests a change in the a priori specified criteria and multiple looks at the trials results.

  • Braga 2011: this was a single center, prospective, double-blind, randomized controlled study. Infants with weights 750 to 1500 g were randomized to receive either 3 mL of pasteurized human milk once a day or Lactobacillus casei and Bifidobacterium breve (Yakult - LB) diluted with 3 mL of pasteurized human milk once a day on the second to the 30th day of life, or at discharge if it happened before the 30th day. All enrolled infants received human (expressed breast or donor) milk. Information regarding allocation concealment was adequate. Intervention and outcome assessment were masked. Of note, this study was terminated by the External Study Committee for a clear benefit in one of the probiotic groups after enrolment of 231 infants.

  • Costalos 2003: this was a single center study. Infants were randomized to receive either enteral probiotics (Saccharomyces boulardii) added to preterm formula or the same formula with maltodextrins. All enrolled infants received formula milk. Allocation concealment was apparently adequate. Intervention and outcome assessment were masked. All infants were accounted for in the final results. There was a discrepancy with regard to the infants enrolled in the groups (51 in the treatment group and 36 in the control). The author presented no explanation of whether this discrepancy was a result of imbalance in the randomization process or losses to follow-up.

  • Dani 2002: this was a multicenter study. Infants were randomized to receive either enteral probiotics (Lactobacillus GG) or placebo. Allocation was adequately concealed. The intervention was masked. Milk type was not known. All enrolled infants were accounted for and outcome measurement was blinded.

  • Demirel 2013: this was a single center study. Infants were randomized to receive either enteral probiotics, 250 mg (5 billion CFU) Saccharomyces boulardii (N = 135) added to breast milk or formula, or the control group (N = 136) that were fed as usual, without S. boulardii supplementation. Allocation concealment was apparently adequate. Intervention and outcome assessment were masked. All infants were accounted for in the final results.

  • Fernández-Carrocera 2013: this was a single center study. Infants (N = 150) were randomly assigned to the study group (N = 75) that received their regular feeds and a daily multispecies probiotic feeding supplement of 1 g/d diluted in 3 mL of expressed mother’s milk, when available, or a premature infant formula or to the control group (N = 75) that received their regular feeds from their mother’s own milk, when available, with nothing added or a premature infant formula. Allocation concealment was apparently adequate. Intervention and outcome assessment were masked.

  • Kitajima 1997: this was a single center study; 91 infants were randomized to receive enteral probiotics (Bifidobacterium breve) or to the control group. All enrolled infants received expressed breast milk and premature formula. It was unclear whether allocation was concealed, the intervention blinded, or the outcome assessment was blinded. Not all enrolled infants were accounted for in the final results (six infants were excluded for various reasons).

  • Li 2004: this was a single center study. Infants were randomized in to three groups to receive either enteral probiotics (Bifidobacterium breve) (group A, B) or control (group C). All enrolled infants received breast or artificial milk. Allocation concealment was not described. It was unclear whether the intervention or outcome assessment were blinded and whether all infants were included in the final results.

  • Lin 2005: this was a single centre study; infants less than 1500 g were randomized to either probiotics (Infloran® - L acidophilus and B infantis) or to a control group. All enrolled infants received maternal or banked breast milk. Allocation was adequately concealed. The intervention was masked (except for investigators and breast milk team). All enrolled infants were accounted for. Outcomes measurement was blinded.

  • Lin 2008: this was a multicenter trial. Infants less than 1500g were randomized to either probiotics (n = 217) given Bifidobacterium bifidum and Lactobacillus acidophilus, added to breast milk or mixed feeding (breast milk and formula), twice daily for six weeks or to control (n = 217) fed with breast milk or mixed feeding. Allocation was adequately concealed. The intervention was masked. All enrolled infants were accounted for. Outcomes measurement was blinded.

  • Manzoni 2006: this was a single centre study. Infants less than 1500 g were randomized to either probiotics (Dicoflor, Lactobacillus casei) or to a control group, all receiving human milk. All enrolled infants received only human (maternal or pooled donors’) milk. Although the authors utilized computer generated randomization, allocation concealment was not described. The intervention was masked for the human bank and microbiology workers, however it was unclear whether the care givers were masked or not. All enrolled infants were accounted for. Blinding of outcomes measurement was reported.

  • Manzoni 2009: this was a multicenter study. Infants less than 1500 g and younger than three days were randomized to either bovine lactoferrin (BLF) (100 mg/d) (LF100; Dicofarm SpA, Rome, Italy) alone or BLF plus LGG (6 x 109 CFU/d) (Dicoflor 60; Dicofarm SpA); the control group received placebo (2 mL of a 5% glucose solution). Treatment lasted six weeks (for birth weight 1000 g) or four weeks (birth weight 1001 to 1500 g) unless neonates were discharged earlier. Drug administration began on the third day of life with one daily dose; all doses including placebo were diluted in prepared milk so as to maintain blinding. Enrolled infants received any combination of expressed breast milk, donor breast milk, and preterm formula. Allocation was adequately concealed. The i ntervention was masked. All enrolled infants were accounted for. Outcomes measurement was blinded.

  • Mihatsch 2010: this was a single center study. VLBW infants less than 30 weeks were randomized to either receive B. lactis BB12 suspension or placebo given in addition to human milk, fortified human milk, or preterm formula. BB12 was provided as lyophilized powder mixed with a standard preterm infant human milk fortifier. Human milk fortifier powder only (Nestlé FM 85) was used as the placebo. In infants < 1500 g, 1 g of powder was dissolved in 10 ml of sterile water once a day. In infants ≥ 1500 g, 2 g of powder was dissolved in 20 mL of sterile water once a day. The control group received the identical volume of placebo suspension. All enrolled infants received maternal breast or formula milk. Allocation was adequately concealed. The intervention was masked. All enrolled infants were accounted for. Outcomes measurement was blinded.

  • Millar 1993: this was a single center study. Twenty infants were randomized to receive either enteral probiotics (Lactobacillus GG) or control. The infants received expressed breast milk or preterm formula, or both. The intervention was masked. All enrolled infants were accounted for. It was unclear whether the outcome assessment was blinded or not.

  • Mohan 2006: this was a single center study. Infants less than 37 weeks were randomized to the probiotic (n = 37) and placebo (n = 32) groups. The formula-based placebo (Nestlé FM 2000B) and verum (Nestlé FM 2000A) preparations were supplied by Nestlé, Konolfingen, Switzerland. The verum contained 2 x 109 cells of Bifidobacterium lactis Bb12 per g of powder. The administration of the study preparation started on the first day after birth and continued for 21 days. The study ended at the 35th day after birth or when the infant was discharged from the hospital, if earlier. Allocation concealment was not described. The intervention was double masked; however it was unclear whether the outcomes assessment was masked or not. All enrolled infants were accounted for. Of note, clinical data obtained through contact with the corresponding author were different from those recently published by Deshpande 2010.

  • ProPrems 2013: this was a multicenter study. The data in our systematic review were unpublished and extracted from the Society of Pediatric Research meeting 2013 proceedings and an oral presentation by the primary author. Infants were randomized to receive either a probiotic (n = 548) combination of B. infantis, Streptococcus thermophilus and B. lactis (ABC Dophilus Probiotic Powder for Infants®, Solgar, USA) with 1 x 109 total organisms per 1.5 g or maltodextrin powder as the placebo (n = 551). All enrolled infants received breast or formula milk. Randomization was adequate but allocation concealment was not clear. The intervention was double blinded. All enrolled infants were accounted for and outcome assessment was blinded.

  • Reuman 1986: this was a single center study. Three groups of infants were randomized to receive either enteral probiotics (Lactobacillus) or control. All enrolled infants received formula milk. Randomization and allocation concealment were clearly inadequate. The intervention was double masked. All infants enrolled were accounted for and outcome assessment was blinded.

  • Rojas 2012: this was a multicenter study. Infants were randomized to receive either probiotics, five drops of an oil-based suspension containing 108 CFU of L. reuteri DSM 17938 (BioGaia AB, Stockholm, Sweden) once a day, or placebo in an equal number of drops from an identical vial containing only the oil base. Enrolled infants received any combination of maternal breast milk and preterm formula. Randomization and allocation concealment were adequate. The intervention was double masked. All enrolled infants were accounted for and outcome assessment was blinded.

  • Romeo 2011a and Romeo 2011b (the same study): this was a single center study. Infants were randomized to either: Group I (n = 83; 12 with a birth weight < 1500 g, 71 ≥ 1500 g) that received supplementation with L. reuteri American Type Culture Collection (ATCC) 55730, 5 drops daily; Group II (n = 83; 28 < 1500 g, 55 ≥ 1500 g) that received supplementation with L. rhamnosus ATCC 53103 1 capsule daily; or Group III that included infants with no probiotics (control) (n = 83; 16 < 1500 g, 67 ≥ 1500 g). Patients received supplementation from the first 72 h after hospitalization for six weeks or until they were discharged from the NICU. All enrolled infants received breast or formula milk. Allocation concealment and blinding of intervention and outcome assessment were not documented. All enrolled infants were accounted for.

  • Rougé 2009: this trial was conducted in two centers. Infants less than 1500 g and gestational age < 32 weeks were randomized to either the probiotic group (n = 45; 108 lyophilized cells per unit of the probiotics L. rhamnosus GG (Valio, Ltd) and B. longum BB536 (Morinaga Milk Industry Co, Ltd, Tokyo, Japan) and maltodextrin beginning on the day when enteral feeding started until discharge) or the placebo group (n = 49; 4 daily capsules of a supplement containing maltodextrin alone). Infants were fed human (own mother’s expressed milk or bank milk) or preterm formula, or both. Allocation was adequately concealed. The intervention was masked. All enrolled infants were accounted for. Outcomes measurement was blinded.

  • Samanta 2009: this was a single center study. Infants < 32 weeks and < 1500 g started feed enterally and those that survived beyond 48 h of life were randomized to receive a probiotic mixture (Bifidobacteria infantis,Bifidobacteria bifidum,Bifidobacteria longum, andLactobacillus acidophilus, each 2.5 billion CFU) with expressed breast milk twice daily till discharge, the dosage being 125 g/kg, or breast milk only (control). The infants were fed only breast milk. Allocation concealment and blinding of intervention and outcome assessment were not adequately described. All enrolled infants were accounted for.

  • Sari 2010: this was a single center study. Infants < 33 weeks and < 1500 g who survived to start enteral feeding were randomized into two groups. Infants in the study group received L. sporogenes with a dose of 350 x 106 CFU added to breast milk or formula once a day, starting with the first feed, until discharge. All enrolled infants received breast milk or mixed feeding (breast milk and formula). Infants in the control group received no supplementation. Allocation concealment, blinding of the intervention and outcome assessment were adequately described. All enrolled infants were accounted for.

  • Stratiki 2007: this was a single center study. Infants (81 infants) with gestational ages between 27 and 37 weeks, stable state, and formula fed were randomized to group A given a BL supplemented preterm formula (Prenan Nestlé BLSPF) at a concentration of 2 x 107 CFU/g of milk powder or group B (control), which received exactly the same formula but without the addition of BL. All enrolled infants received only formula milk. Allocation concealment was not described. The intervention and outcome assessment were blinded and all infants were included in the final results.

Effects of interventions

Probiotics versus control (Comparison 1)

Primary outcomes

Severe necrotizing enterocolitis (stage II to III) (Outcome 1.1)

Twenty studies reported on severe stage II to III NEC (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Costalos 2003; Dani 2002; Demirel 2013; Fernández-Carrocera 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; Mohan 2006; ProPrems 2013; Rojas 2012; Rougé 2009; Samanta 2009; Sari 2010; and Stratiki 2007). The administration of prophylactic probiotics significantly reduced the incidence of severe stage II to III NEC (typical RR 0.43, 95% CI 0.33 to 0.56, NNTB 30).

Culture proven sepsis (Outcome 1.2)

Any sepsis (Outcome 1.2.1)

Ninteen studies reported on any culture proven sepsis (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Costalos 2003; Dani 2002; Demirel 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; Millar 1993; ProPrems 2013; Rojas 2012; Rougé 2009; Samanta 2009; Sari 2010; Stratiki 2007). Although there was a positive trend, probiotics didn't significantly alter the rate of culture proven sepsis in the pooled effect (typical RR 0.91, 95% CI 0.80 to 1.03).

Any bacterial sepsis (Outcome 1.2.2)

Only Al-Hosni 2012 reported on any bacterial sepsis; no significant difference was observed (typical RR 0.70, 95% CI 0.36 to 1.36).

Any fungal sepsis (Outcome 1.2.3)

Only Al-Hosni 2012 reported on any fungal sepsis with no significant difference among the groups (typical RR 5.10, 95% CI 0.25 to 103.6).

Mortality (Outcome 1.3)

Seventeen studies reported on mortality (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Dani 2002; Demirel 2013; Fernández-Carrocera 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; ProPrems 2013; Reuman 1986; Rojas 2012; Rougé 2009; Samanta 2009). Mortality was significantly lowered in the probiotics group (typical RR 0.65, 95% CI 0.52 to 0.81, NNTB 41). Seven studies (Bin-Nun 2005; Dani 2002; Kitajima 1997; Lin 2008; Mihatsch 2010; ProPrems 2013; Sari 2010) reported NEC related mortality. A similar positive effect was observed (typical RR 0.39, 95% 0.18 to 0.82).

Secondary outcomes

Parenteral nutrition duration (days) (Outcome 1.4)

Six studies reported this outcome (Dani 2002; Demirel 2013; Fernández-Carrocera 2013; Lin 2005; ProPrems 2013; Romeo 2011a; Romeo 2011b). Probiotics administration didn't decrease the total days of parenteral nutrition (typical weighted mean difference (WMD) -0.25, 95% CI -0.52 to 0.03).

Hospitalization duration (days) (Outcome 1.5)

Ten studies reported this outcome (Demirel 2013; Fernández-Carrocera 2013; Lin 2005; Lin 2008; ProPrems 2013; Reuman 1986; Rojas 2012; Romeo 2011a; Romeo 2011b; Rougé 2009; Samanta 2009). Probiotics administration significantly shortened hospitalization days compared to control (typical WMD -3.71, 95% CI -4.32 to -3.11).

Weight gain (Outcome 1.6)

Five studies (Al-Hosni 2012; Reuman 1986; Millar 1993; Costalos 2003; Sari 2010) reported weight gain results. No significant statistical difference in weight gain was observed among the study groups. Due to the use of different scales, that is g/week, g/day and g/kg/day, these results were not pooled.

Time to full enteral feeds (Outcome 1.7)

Eight studies (Braga 2011; Demirel 2013; Fernández-Carrocera 2013; Manzoni 2009; Mihatsch 2010; ProPrems 2013; Samanta 2009; Sari 2010) reported time to full enteral feeds. Pooled data of the studies showed a significant reduction in time to reach full enteral feeds (typical WMD -1.32, 95% CI -1.48 to -1.17).

The composite of death or severe NEC or sepsis (Outcome 1.8)

Only one study reported this outcome (Lin 2005). Probiotics significantly reduced the incidence of this composite endpoint (typical RR 0.54, 95% CI 0.37 to 0.79).

Long term outcomes (Outcome 1.9)

Kitajima 1997 reported mental retardation and cerebral palsy at six years. No significant statistical difference was observed among the study groups.

Systemic infection with the supplemented organism

None of the included studies reported any systemic infection caused by the supplemented probiotics organisms.

Subgroup comparisons

Very low birth weight infants (VLBW) (Comparison 2)

Seventeen trials reported on severe stage II to III NEC (Al-Hosni 2012; Bin-Nun 2005; Braga 2011; Dani 2002; Demirel 2013; Fernández-Carrocera 2013; Kitajima 1997; Lin 2005; Lin 2008; Manzoni 2006; Manzoni 2009; Mihatsch 2010; ProPrems 2013; Rojas 2012; Rougé 2009; Samanta 2009; Sari 2010) including VLBW infants only (< 1500 g at birth). The administration of prophylactic probiotics significantly reduced the incidence of severe stage II to III NEC in VLBW infants (typical RR 0.41, 95% CI 0.31 to 0.56) with no significant effect on culture proven sepsis (typical RR 0.92, 95% CI 0.81 to 1.04). Probiotics significantly reduced mortality (typical RR 0.63, 95% CI 0.50 to 0.81) and NEC related mortality (typical RR 0.38, 95% CI 0.18 to 0.82).

Extremely low birth weight infants (ELBW) (Comparison 3)

Al-Hosni 2012 and ProPrems 2013 were the only trials that limited their inclusion to ELBW infants. The administration of prophylactic probiotics did not reduce the incidence of severe stage II to III NEC (typical RR 0.76, 95% CI 0.37 to 1.58), sepsis (typical RR 0.82, 95% CI 0.63 to 1.06), or mortality (typical RR 0.94, 95% CI 0.58 to 1.53). However, the number of included ELBW infants was too small to detect a small meaningful clinical difference in this subgroup of infants.

Effect of different species of probiotics (Comparison 4)
Severe NEC - species of probiotics (Outcome 4.1)

Both the administration of Lactobacillus species (five trials) and a mixture of probiotics (nine trials) significantly reduced the incidence of severe stage II to III NEC (RR 0.45, 95% CI 0.27 to 0.75; RR 0.37, 95% CI 0.25 to 0.54 respectively). Four trials utilized bifidobactirium species alone, the pooled effect of included trials showed a lack of significant reduction of severe NEC stage II to III (RR 0.48, 95% CI 0.16 to 1.47). Two trials utilized Saccharomyces boulardii alone, the pooled effect of the included trials showed a lack of significant reduction of severe NEC stage II to III (RR 0.72, 95% CI 0.34 to 1.55).

Culture proven sepsis - species of probiotics (Outcome 4.2)

The administration of Lactobacillus species alone (five trials), bifidobactirium species alone (three trials), Saccharomyces boulardii alone (two trials), or a mixture of probiotics (nine trials) did not reduce the incidence of culture proven sepsis (RR 0.91, 95% CI 0.71 to 1.16; RR 0.88, 95% CI 0.58 to 1.34; RR 0.92, 95% CI 0.54 to 1.57; RR 0.91, 95% CI 0.78 to 1.06 respectively).

Mortality - species of probiotics (Outcome 4.3)

The administration of a mixture of probiotics (nine trials) significantly reduced the incidence of mortality (RR 0.62, 95% CI 0.47 to 0.81). The administration of Lactobacillus species alone (four trials), bifidobactirium species alone (two trials), or Saccharomyces boulardii alone (one trial) did not reduce mortality (RR 0.72, 95% CI 0.47 to 1.10; RR 0.71, 95% CI 0.14 to 3.6; RR 1.01, 95% CI 0.30 to 3.4 respectively).

Effect of different time of initiation of probiotics (Comparison 5)
Severe NEC - time of initiation (Outcome 5.1)

Probiotics were initiated at different times in the included studies. Nine studies started probiotics administration at the time of the first feed, with a typical RR of 0.44 (95% Cl 0.30 to 0.65). Most included studies initiated prophylaxis within the first week of life, therefore a significant overlap of time of initiation is observed among the included trials.

Culture proven sepsis - time of initiation (Outcome 5.2)

Nine studies started probiotics administration at the time of the first feed, with a typical RR of 0.96 (95% Cl 0.81 to 1.14).

Mortality - time of initiation (Outcome 5.3)

Nine studies started probiotics administration at the time of the first feed, with a typical RR of 0.41 (95% Cl 0.26 to 0.63).

Effect of different duration of probiotics administration (Comparison 6)

Severe NEC - the duration of probiotics administration (Outcome 6.1)

The included trials administered probiotics for either four to six weeks duration or till discharge. Both administration durations produced positive significant effects in reduction of severe stage II to III NEC.

Culture proven sepsis - the duration of probiotics administration (Outcome 6.2)

Included trials administered probiotics for either four to six weeks duration or till discharge. Both administration durations produced no significant effects in terms of reduction of culture proven sepsis.

Mortality - the duration of probiotics administration (Outcome 6.3)

Included trials administered probiotics for either four to six weeks duration or till discharge. Trials that administered probiotics for more than six weeks duration or till discharge showed significant effects in reducing mortality, with a typical RR of 0.65 (95% Cl 0.49 to 0.87).

High quality studies (Comparison 7)

Our results were not altered when a sensitivity analysis including only high quality studies was performed (typical RR for severe stage II or III NEC 0.41, 95% CI 0.29 to 0.58).

Discussion

Our updated review summarizes the evidence on probiotics efficacy in preterm infants. Twenty-four randomized trials and more than 5000 preterm infants are included. Since the publication of our first review, we note a tremendous increase in published studies, reviews, and editorials addressing the efficacy and safety of probiotics utilization in the preterm host. Probiotics are one of the most studied interventions in neonatal medicine.

Our update with more robust data shows that enteral administration of probiotics reduces the incidence of severe NEC, mortality, and NEC related mortality. In addition, the administration of probiotic organisms resulted in a shorter time to full feeds. Our data shows a trend toward a benefit in reduction of sepsis, however this didn't reach statistical significance. Although only two studies limited their inclusion criteria to ELBW infants, included studies had a large number of ELBW infants to assure sceptics of the value of this intervention in a high risk population. Based on the available evidence for probiotics efficacy and safety in preterm infants, the number of infants enrolled, the narrow confidence intervals, and the probiotics safety profile, a change in practice is warranted at this stage. More studies to address the optimal preparation, dosing, and duration of therapy are still needed in head to head comparative studies rather than placebo controlled trials.

Eleven of our included trials were classified as high quality trials based on adequacy of allocation concealment procedures and blinding of the intervention. Although all included trials evaluated probiotics use in preterm infants, the 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 probiotic used, and feeding regimens.

Case reports of systemic infections caused by probiotic organisms are found in the biomedical literature. None of our included studies reported this adverse effect. The use of probiotics was described as safe and well tolerated. Our update provides more robust safety data of probiotics utilization in the preterm host.

This review utilized a very thorough and comprehensive search strategy. All attempts were made to minimize potential publication bias. Only randomized or quasi-randomized controlled trials were included. To minimize the reviewer bias, all steps of this review were conducted independently by the review authors. The validity of our review's results is potentially compromised as the included trials utilized different preparations and dosing regimens of the intervention under study; and data on the highest risk population (ELBW infants) could not be retrieved.

The issue of whether it is time to change practice and adopt the use of probiotics as a standard of care in preterm infants has been widely discussed in the medical literature over the last few years. While some advocate a change in practice based on significant reduction in severe NEC and all cause mortality (Tarnow-Mordi 2010), others suggest to wait until precise data on efficacy and safety in ELBW infants are available, in addition to the determination of the most effective preparation and dosing to be utilized (Soll 2010). The evidence on probiotics efficacy and safety is substantial compared to other innovative interventions in neonatal medicine such as surfactant, hypothermia, and room air resuscitation (Janvier 2013). We believe that based on the available evidence and in comparison to other effective interventions in neonatal medicine, a change in practice is warranted. Recently, experts and scientific bodies have started to endorse probiotics utilization in the management of preterm infants (Downard 2012; Janvier 2013).

Probiotics are not licensed by regulatory authorities in many countries including the United States, and hence the wide availability of these products to the public, ethical questions and concerns could be raised in the adoption of this intervention or in the conduct of more placebo controlled trials. We believe that parents' choice to give or withhold probiotics in the management of preterm infants should be respected. Consent forms of planned or ongoing randomized trials should describe the positive effects of probiotics on severe NEC and mortality and the lack of significant side effects prior to enrolling infants in such trials. Enrolment into a randomized trial should not be a condition to receive probiotics in the institutions undertaking these trials (Janvier 2013).

Authors' conclusions

Implications for practice

Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our review strongly supports a change in practice and adoption of probiotics prophylaxis in the management of preterm infants.

Implications for research

More studies are needed to investigate the most effective formulation and dose to be utilized. Parents of preterm infants should be informed of current evidence if further placebo controlled randomized trials are to be conducted.

Acknowledgements

Editorial support of the Cochrane Neonatal Review Group has been funded with Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA, under Contract No. HHSN267200603418C.

We extend our sincere appreciation to the Deanship of Scientific Research at King Saud University for funding this project through Research Group project # RGB-VPP-248.

Data and analyses

Download statistical data

Comparison 1. Probiotics versus control (all infants)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe necrotising enterocolitis (stage II-III)205529Risk Ratio (M-H, Fixed, 95% CI)0.43 [0.33, 0.56]
2 Culture proven sepsis19 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Any sepsis195338Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.80, 1.03]
2.2 Any Bacterial sepsis1101Risk Ratio (M-H, Fixed, 95% CI)0.70 [0.36, 1.36]
2.3 Any Fungal sepsis1101Risk Ratio (M-H, Fixed, 95% CI)5.10 [0.25, 103.60]
3 Mortality18 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 All causes of neonatal mortality175112Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.52, 0.81]
3.2 NEC related mortality72755Risk Ratio (M-H, Fixed, 95% CI)0.39 [0.18, 0.82]
4 Parenteral nutrition duration (days)72804Mean Difference (IV, Fixed, 95% CI)-0.25 [-0.52, 0.03]
5 Hospitalization duration (days)113713Mean Difference (IV, Fixed, 95% CI)-3.71 [-4.32, -3.11]
6 Weight gain5 Mean Difference (IV, Fixed, 95% CI)Subtotals only
6.1 g/week187Mean Difference (IV, Fixed, 95% CI)7.20 [-0.06, 14.46]
6.2 g/day2131Mean Difference (IV, Fixed, 95% CI)2.14 [0.01, 4.27]
6.3 g/kg/day2241Mean Difference (IV, Fixed, 95% CI)0.28 [-0.93, 1.49]
7 Time to full enteral feeds82657Mean Difference (IV, Fixed, 95% CI)-1.32 [-1.48, -1.17]
8 Death or severe NEC or sepsis1367Risk Ratio (M-H, Fixed, 95% CI)0.54 [0.37, 0.79]
9 Long-term outcomes1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
9.1 Mental retardation and Cerebral palsy185Risk Ratio (M-H, Fixed, 95% CI)1.02 [0.15, 6.94]
Analysis 1.1.

Comparison 1 Probiotics versus control (all infants), Outcome 1 Severe necrotising enterocolitis (stage II-III).

Analysis 1.2.

Comparison 1 Probiotics versus control (all infants), Outcome 2 Culture proven sepsis.

Analysis 1.3.

Comparison 1 Probiotics versus control (all infants), Outcome 3 Mortality.

Analysis 1.4.

Comparison 1 Probiotics versus control (all infants), Outcome 4 Parenteral nutrition duration (days).

Analysis 1.5.

Comparison 1 Probiotics versus control (all infants), Outcome 5 Hospitalization duration (days).

Analysis 1.6.

Comparison 1 Probiotics versus control (all infants), Outcome 6 Weight gain.

Analysis 1.7.

Comparison 1 Probiotics versus control (all infants), Outcome 7 Time to full enteral feeds.

Analysis 1.8.

Comparison 1 Probiotics versus control (all infants), Outcome 8 Death or severe NEC or sepsis.

Analysis 1.9.

Comparison 1 Probiotics versus control (all infants), Outcome 9 Long-term outcomes.

Comparison 2. Probiotics versus control (infants < 1500 g)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe necrotising enterocolitis (stage II-III)174914Risk Ratio (M-H, Fixed, 95% CI)0.41 [0.31, 0.56]
2 Culture proven sepsis16 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Any sepsis165154Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.81, 1.04]
2.2 Any Bacterial sepsis1101Risk Ratio (M-H, Fixed, 95% CI)0.70 [0.36, 1.36]
2.3 Any Fungal sepsis1101Risk Ratio (M-H, Fixed, 95% CI)5.10 [0.25, 103.60]
3 Mortality17 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 All causes of neonatal mortality175303Risk Ratio (M-H, Fixed, 95% CI)0.66 [0.53, 0.82]
3.2 NEC related mortality72755Risk Ratio (M-H, Fixed, 95% CI)0.39 [0.18, 0.82]
Analysis 2.1.

Comparison 2 Probiotics versus control (infants < 1500 g), Outcome 1 Severe necrotising enterocolitis (stage II-III).

Analysis 2.2.

Comparison 2 Probiotics versus control (infants < 1500 g), Outcome 2 Culture proven sepsis.

Analysis 2.3.

Comparison 2 Probiotics versus control (infants < 1500 g), Outcome 3 Mortality.

Comparison 3. Probiotics versus control (infants < 1000 g)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe necrotising enterocolitis (stage II-III)2575Risk Ratio (M-H, Fixed, 95% CI)0.76 [0.37, 1.58]
2 Culture proven sepsis21200Risk Ratio (M-H, Fixed, 95% CI)0.82 [0.63, 1.06]
3 Mortality21199Risk Ratio (M-H, Fixed, 95% CI)0.94 [0.58, 1.53]
Analysis 3.1.

Comparison 3 Probiotics versus control (infants < 1000 g), Outcome 1 Severe necrotising enterocolitis (stage II-III).

Analysis 3.2.

Comparison 3 Probiotics versus control (infants < 1000 g), Outcome 2 Culture proven sepsis.

Analysis 3.3.

Comparison 3 Probiotics versus control (infants < 1000 g), Outcome 3 Mortality.

Comparison 4. Probiotics versus control (species of probiotic)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe NEC- Species of probiotics20 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Lactobacillus51955Risk Ratio (M-H, Fixed, 95% CI)0.45 [0.27, 0.75]
1.2 Bifidobacterium4409Risk Ratio (M-H, Fixed, 95% CI)0.48 [0.16, 1.47]
1.3 Saccharomyces boulardii2357Risk Ratio (M-H, Fixed, 95% CI)0.72 [0.34, 1.55]
1.4 A mixture of two to three species of probiotics92807Risk Ratio (M-H, Fixed, 95% CI)0.37 [0.25, 0.54]
2 Culture proven sepsis19 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Lactobacillus51955Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.71, 1.16]
2.2 Bifidobacterium3348Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.58, 1.34]
2.3 Saccharomyces boulardii2358Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.54, 1.57]
2.4 A mixture of two to three species of probiotics92677Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.78, 1.06]
3 Mortality16 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 Lactobacillus41734Risk Ratio (M-H, Fixed, 95% CI)0.72 [0.47, 1.10]
3.2 Bifidobacterium2271Risk Ratio (M-H, Fixed, 95% CI)0.71 [0.14, 3.60]
3.3 Saccharomyces boulardii1271Risk Ratio (M-H, Fixed, 95% CI)1.01 [0.30, 3.40]
3.4 A mixture of two to three species of probiotics92806Risk Ratio (M-H, Fixed, 95% CI)0.62 [0.47, 0.81]
Analysis 4.1.

Comparison 4 Probiotics versus control (species of probiotic), Outcome 1 Severe NEC- Species of probiotics.

Analysis 4.2.

Comparison 4 Probiotics versus control (species of probiotic), Outcome 2 Culture proven sepsis.

Analysis 4.3.

Comparison 4 Probiotics versus control (species of probiotic), Outcome 3 Mortality.

Comparison 5. Probiotics versus control (time of initiation)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe NEC- Time of initiation16 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Less than 48 hours of age31072Risk Ratio (M-H, Fixed, 95% CI)0.49 [0.23, 1.05]
1.2 More than 48 hours of age1319Risk Ratio (M-H, Fixed, 95% CI)0.05 [0.00, 0.90]
1.3 At the time of the first feed92318Risk Ratio (M-H, Fixed, 95% CI)0.44 [0.30, 0.65]
1.4 During the first week when enteral feeds were tolerated3236Risk Ratio (M-H, Fixed, 95% CI)0.64 [0.26, 1.55]
2 Culture proven sepsis164017Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.79, 1.05]
2.1 Less than 48 hours of age31072Risk Ratio (M-H, Fixed, 95% CI)1.06 [0.79, 1.44]
2.2 More than 48 hours of age1319Risk Ratio (M-H, Fixed, 95% CI)0.27 [0.12, 0.60]
2.3 At the time of the first feed102459Risk Ratio (M-H, Fixed, 95% CI)0.96 [0.81, 1.14]
2.4 During the first week when enteral feeds were tolerated2167Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.58, 1.34]
3 Mortality143838Risk Ratio (M-H, Fixed, 95% CI)0.61 [0.47, 0.79]
3.1 Less than 48 hours of age31072Risk Ratio (M-H, Fixed, 95% CI)0.82 [0.58, 1.17]
3.2 More than 48 hours of age1319Risk Ratio (M-H, Fixed, 95% CI)0.56 [0.21, 1.45]
3.3 At the time of the first feed92367Risk Ratio (M-H, Fixed, 95% CI)0.41 [0.26, 0.63]
3.4 During the first week when enteral feeds were tolerated180Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.29, 2.64]
Analysis 5.1.

Comparison 5 Probiotics versus control (time of initiation), Outcome 1 Severe NEC- Time of initiation.

Analysis 5.2.

Comparison 5 Probiotics versus control (time of initiation), Outcome 2 Culture proven sepsis.

Analysis 5.3.

Comparison 5 Probiotics versus control (time of initiation), Outcome 3 Mortality.

Comparison 6. Probiotics versus control (duration of probiotics administration)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe NEC- The duration of probiotics administration16 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Four to six weeks51162Risk Ratio (M-H, Fixed, 95% CI)0.26 [0.13, 0.52]
1.2 More than six weeks or until discharged from NICU112985Risk Ratio (M-H, Fixed, 95% CI)0.53 [0.37, 0.75]
2 Culture proven sepsis143247Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.77, 1.02]
2.1 Four to six weeks51162Risk Ratio (M-H, Fixed, 95% CI)0.91 [0.71, 1.18]
2.2 More than six weeks or until discharged from NICU92085Risk Ratio (M-H, Fixed, 95% CI)0.87 [0.73, 1.04]
3 Mortality14 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 Four to six weeks41075Risk Ratio (M-H, Fixed, 95% CI)0.67 [0.45, 1.00]
3.2 More than six weeks or until discharged from NICU103591Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.49, 0.87]
Analysis 6.1.

Comparison 6 Probiotics versus control (duration of probiotics administration), Outcome 1 Severe NEC- The duration of probiotics administration.

Analysis 6.2.

Comparison 6 Probiotics versus control (duration of probiotics administration), Outcome 2 Culture proven sepsis.

Analysis 6.3.

Comparison 6 Probiotics versus control (duration of probiotics administration), Outcome 3 Mortality.

Comparison 7. Probiotics versus control (high quality studies)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Severe necrotising enterocolitis (stage II-III)114473Risk Ratio (M-H, Fixed, 95% CI)0.43 [0.31, 0.59]
2 Culture proven sepsis10 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Any sepsis104323Risk Ratio (M-H, Fixed, 95% CI)0.89 [0.77, 1.04]
3 Mortality10 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 All causes of neonatal mortality104386Risk Ratio (M-H, Fixed, 95% CI)0.71 [0.55, 0.91]
3.2 NEC related mortality42298Risk Ratio (M-H, Fixed, 95% CI)0.47 [0.20, 1.09]
Analysis 7.1.

Comparison 7 Probiotics versus control (high quality studies), Outcome 1 Severe necrotising enterocolitis (stage II-III).

Analysis 7.2.

Comparison 7 Probiotics versus control (high quality studies), Outcome 2 Culture proven sepsis.

Analysis 7.3.

Comparison 7 Probiotics versus control (high quality studies), Outcome 3 Mortality.

Feedback

Davies, 9 May 2008

Summary

I read with interest the review by AlFaleh and Bassler. It was a well conducted systematic review that revealed that the use of probiotics in preterm infants significantly reduces the incidence of NEC and death in preterm infants. I am not sure why the authors have concluded that probiotics should only be used for preterm infants with a birth weight greater than 1000 grams. If we assume that the data on birth weight from individual studies are normally distributed, we can surmise from the mean birth weight and standard deviations that approximately 25% of babies included in the studies that contribute to the two main meta-analyses (for the outcomes of severe NEC and mortality) had a birth weight of less than 1000 grams. Only about 3% or less had a birth weight of greater than 1500 grams. The authors conclusions imply that the use of probiotics is supported for infants who are preterm (born at < 37 weeks gestational age) and who had a birth weight of > 1500 grams (less than ˜3% of the study population), but is not supported for infants who had a birth weight of <1000 grams (˜25% of the study population). The results of the review and its meta-analysis are highly significant, both statistically and clinically. They should be applicable to the population of infants that contributed to the pooled data, i.e., preterm babies who were (almost all) <1500 grams at birth.

The authors should provide justification for their recommendation that extremely low birth weight infants should not be given this intervention that provides a 57% reduction in the risk of death. Also, if further large randomized controlled trial[s] are done they must include assessment of long-term
neurodevelopmental outcomes, not just important intermediate neonatal outcomes.

Reply

We first would like to thank you for your thoughtful comments on our recently published systematic review. Your question/comment was a one that we have thought of and discussed quite extensively prior to the publication of the review.

Although we agree that the efficacy of the probiotics in prevention of NEC or mortality holds true for the ELBW infant, we could not ensure the safety of this new intervention in a highly vulnerable group with the number of infants enrolled; especially with few cases of probiotics species sepsis reported in the literature.

Contributors

Khalid M Al-Faleh, July 2008

What's new

DateEventDescription
1 October 2013New search has been performedThis updates the review 'Probiotics for prevention of necrotizing enterocolitis in preterm infants' published in the Cochrane Database of Systematic Reviews (Al Faleh 2011).
1 October 2013New citation required but conclusions have not changedUpdated search identified eight new trials for inclusion in this review update.

History

Protocol first published: Issue 4, 2005
Review first published: Issue 1, 2008

DateEventDescription
3 November 2010New citation required and conclusions have changedWith the addition of seven new trials to this update, it brings the total to sixteen eligible trials randomizing 2842 infants. The previous review included nine eligible trials, randomizing 1425 infants.
3 November 2010New search has been performedThis updates the review "Probiotics for prevention of necrotizing enterocolitis in preterm infants" published in the Cochrane Database of Systematic Reviews (Al Faleh 2008).
New authorship: Khalid AlFaleh, Jasim Anabrees, Dirk Bassler, Turki Al-Kharfi.
Updated search identified seven new trials for inclusion in this review update.
12 November 2008Feedback has been incorporatedFeedback incorporated
22 July 2008AmendedConverted to new review format.

Contributions of authors

KA and JA updated the review.

Declarations of interest

None

Sources of support

Internal sources

  • McMaster University Medical Center, Canada.

External sources

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA.

    Editorial support of the Cochrane Neonatal Review Group has been funded with Federal funds from the Eunice Kennedy Shriver National Institute of Child Health and Human Development National Institutes of Health, Department of Health and Human Services, USA, under Contract No. HHSN275201100016C

Differences between protocol and review

None

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Al-Hosni 2012

MethodsMulticenter randomized controlled double blinded study
Participants

101 infants 501-1000 g, appropriate for gestational age, and ⋜14 days of age at the time of feeding initiation

Exclusion: Major congenital anomalies, and have known PS before study

Demographic data:
Probiotics Group N=50, Gestational age (weeks) 25.7 (1.4), birth weight 778 (138)
Placebo Group N=51, Gestational age (weeks) 25.7 (1.4), birth weight 779 (126)

Interventions

Probiotic group was given supplement consisting of Lactobacillus rhamnosus GG (LGG) (Culturelle, Amerifit Brand, Cromwell, CT, USA) 500 million colony forming units (CFU) and Bifidobacterium infantis (Align, Procter and Gamble, Cincinnati, OH, USA) 500 million CFU suspended in 0.5 mL of infant’s milk.
Probiotic supplementation was added to the first enteral feeding and continued once daily with feedings thereafter until discharge or until 34 weeks postmenstrual age. The control group received unsupplemented milk added to their daily feeding.

Milk type was not known

OutcomesPrimary outcome: Weight <10th percentile at 34 weeks
Secondary outcomes: Average volume of feeding, Growth velocity, Average daily weight gain, Antimicrobial days, Antibacterial days, Antifungal days, NEC, IVH, ROP, and CLD
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot mentioned
Allocation concealment (selection bias)Unclear riskNot mentioned
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Bin-Nun 2005

MethodsSingle centre randomized study
Method of generating randomization sequence: not described
Blinding of randomization: not described
Blinding of intervention: yes
Blinding of outcome measurement: yes
Completeness of follow-up: not specified
Participants145 infants less than 1500 g at birth
Demographic data:
Probiotics Group N=72, Gestational age (weeks) 29.2 (2.6), birth weight 1152 (262)
Placebo Group
N=73, Gestational age (weeks) 29.3 (4.3), birth weight 1111 (278)
InterventionsProbiotics group (N=72) received mixture of Lactobacillus bifidus, streptococcus thermophillus, andbifidobactrium infantis added to 3 ml of expressed breast milk or premature formula enteral feeds
Control group (N=73) received 3 ml of expressed milk or premature formula with no supplements added
OutcomesStage 2 or 3 NEC
Mortality
NEC or mortality
Sepsis
Days to full feeds
Days till TPN stopped
NotesIsrael
Period of study: Sept 2001-Sept 2004
Published: Journal of Pediatrics 2005
Source of Funding: ABC Dophilus
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskMethod of generating randomization sequence: not described
Allocation concealment (selection bias)Unclear riskBlinding of randomization: not described
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: yes
Blinding of outcome measurement: yes
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskCompleteness of follow-up: not specified
Selective reporting (reporting bias)Low riskAll clinically important outcomes are described

Braga 2011

MethodsA prospective, double blind, randomized controlled trial
Participants

231 Infants with weight 750-1500 g

Demographic data:
Probiotics Group N=119, Gestational age (weeks) 29.5 (2.5), birth weight 1194.7 (206.3)
Placebo Group N=112, Gestational age (weeks) 29.2 (2.6), birth weight 1151.4 (224.9)

Interventions

The participants randomised into two groups of 231 infants:
Control group: 3 mL of pasteurized human milk once a day
Intervention group: Lactobacillus casei andBifidobacterium breve (Yakult - LB) diluted with 3 mL of pasteurized human milk once a day on the second day to the 30th day of life, or at discharge if it happens before the 30th day

All enrolled infants received human (expressed breast milk or donor) milk

OutcomesPrimary: Necrotising enterocolitis classified as higher or equal to 2 according to Bell's criteria
Secondary: The pathogenic bacteria in the faeces, duration of birth weight recovery, Time to full enteral feeds, and hospital stay
Notes

Brazil
ISRCTN67165178

Supported by Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (grant number 473704/2006-4) and research grants (to PIC de Lira and M de Carvalho Lima)

External Study Committee observed a major benefit in one of the groups and recommended that the study be interrupted; at this time there were a total of 231 participants

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk 
Allocation concealment (selection bias)Low risk 
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Costalos 2003

MethodsSingle center randomized double blind study
Method of generating randomization sequence: Cards in sealed envelopes
Allocation concealment: Possibly adequate
Blinding of intervention: Yes
Blinding of outcome measurement: Not described
Complete follow-up: Yes
Participants87 infants, gestational age 28-32 weeks
Exclusion criteria:
Major anomalies, receiving antibiotics or anti-fungals, receiving breast milk
Demographic data:
Probiotics Group N=51, Gestational age (weeks) 31.1 (2.5), birth weight 1651 (470)
Placebo Group N=36, Gestational age (weeks) 31.8 (2.7), birth weight 1644 (348)
Interventions

Probiotics group (N=51) received preterm formula containing approximately 15 nmol/dL polyamines with added Saccharomyces boulardii 50mg/kg every 12 hours during the first week of life when enteral feed are tolerated for 30 days
Placebo group (N=36) received same formula with maltodextrins

All enrolled infants received formula milk

OutcomesNEC
Weight gain
Abdominal distension
Vomiting
Gastric retention
Stool characteristics
Sepsis
NotesGreece
Period of study: not specified
Published: 2003
Source of Funding: Unclear
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: Cards in sealed envelopes
Allocation concealment (selection bias)Low riskAllocation concealment: Possibly adequate
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Yes
Blinding of outcome measurement: Not described
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes

Dani 2002

MethodsMulticenter randomized double blind study (12 centers)
Method of generating randomization sequence: not described
Allocation concealment: Clearly adequate
Blinding of intervention: Yes
Blinding of outcome measurement: Yes
Complete follow-up: Yes
Participants

585 infants, < 33 weeks gestation or <1500 g birth weight enrolled
Exclusion criteria:
Congenital malformation and death within two weeks of birth
Demographic data:
Probiotics Group N=295, gestational age (weeks) 30.8 (2.4), birth weight 1325 (361)
Placebo Group N=290, gestational age (weeks) 30.7 (2.3), birth weight 1345 (384)

Milk type was not known

InterventionsProbiotics group (N=295) received standard milk with Lactobacillus GG (Dicoflor®, Dicofarm, Rome, Italy) with an added dose of 6×109 colony forming units (cfu) once a day until discharge, starting with first feed
Placebo group (N=290) received standard milk with placebo which was an indistinguishable dried powder of maltodextrins
OutcomesSevere NEC
Incidence of PDA
Duration of parenteral nutrition
Urinary tract infection
Bacterial sepsis (culture proven)
Stage 2 and 3 NEC
Single course of antibiotics treatment
NEC related mortality
NotesItaly
Period of study: not specified in paper
Published: 2002
Source of Funding: not specified in paper
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot described
Allocation concealment (selection bias)Low riskClearly adequate
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of Intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete Follow-up: Yes
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Demirel 2013

MethodsDouble blind placebo controlled randomized trial
Participants

271 infants

Inclusion criteria: Infants with gestational age ≤32 weeks and birth weight ≤1500 g who survived to start enteral feeding were enrolled in the study

Exclusion criteria: major congenital anomalies and lack of parental consent

Demographic data:

Probiotics group N=135, gestational age (weeks) 29.4 (2.3), birth weight 1164 (261)
Placebo group N=136, gestational age (weeks) 29.2 (2.5), birth weight 1131 (284)

All enrolled infants received breast milk or formula

InterventionsThe infants in the study group were given 250 mg (5 billion CFU) S. boulardii added to breast milk or formula once a day, starting with the first feed, until they were discharged. The infants in the control group were fed as usual, without supplementation. The supplementation did not change the physical appearance of the milk or formula
Feeding commenced within 48 h of birth when the infant had stable vital signs, active bowel sounds without abdominal distension, and no bile or blood from the nasogastric tube
OutcomesPrimary Outcome: NEC stage ≥2 and death
Secondary Outcomes: clinical or culture-proven sepsis, feeding difficulties, and days required to reach full enteral feeding
NotesNCT01315821
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation was simple and unadjusted and was performed using sequential numbers generated at the computer centre of the NICU
Allocation concealment (selection bias)Low riskThe allocations were sealed in opaque, sequentially numbered envelopes
Blinding (performance bias and detection bias)
All outcomes
Low riskThe supplements were prepared by personnel on the breast milk team following the instructions in the sealed envelope. These individuals were the only personnel who were aware of the group assignments, and they were not involved in the care of the infants
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Fernández-Carrocera 2013

MethodsA randomized, double blind clinical trial
Participants

150 infants <1500 g birth weight enrolled
Demographic data:
Probiotics Group N=75, gestational age (weeks) 31.2 (26–35.4), birth weight 1090 (580–1495)
Placebo Group N=75, gestational age (weeks) 31 (27–36), birth weight 1170 (540–1492)

Exclusion criteria: Preterm newborns with a low Apgar score (<6 at 5 min), gastrointestinal malformations, genetic syndromes, asphyxia and IA–IB NEC stages were excluded

Interventions

Infants were randomly assigned to:
The study group received their regular feeds and a daily multi species probiotic feeding supplement of 1 g/d diluted in 3 ml of expressed mother’s milk when available or a premature infant formula

The control group received their regular feeds from their mother’s own milk when available with nothing added, or a premature infant formula

Outcomes

Primary outcome: the occurrence of NEC

Secondary outcomes: sepsis, apnea, anaemia, patent ductus arteriosus, and death

Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk 
Allocation concealment (selection bias)Low risk 
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Kitajima 1997

MethodsSingle center randomized study
Method of generating randomization sequence: Not described
Allocation concealment: Not described
Blinding of intervention: Not described
Blinding of outcome measurement: Not described
Complete follow-up: No (6 patients dropped)
Participants91 infants, birth weight <1500 g enrolled
Exclusion criteria:
Major anomalies, severe asphyxia, severe IUGR
Demographic data:
Probiotics Group N=45, gestational age (weeks) 28.3 (2.3), birth weight 1026 (24)
Placebo Group N=46, gestational age (weeks) 28.2 (2.1), birth weight 1026 (205)
Interventions

Probiotics group (N=45) received 1 ml supplement of Bifidobacterium breve with distilled water 0.5×109 of live B. breve within the 1st 24 hrs of life once per day for 28 days
Control group (N=46) received distilled water

All enrolled infants received expressed breast milk and premature formula

OutcomesColonization rate
Mean aspired air volume
Vomiting times/week
Apnoea times/week
Weight gain
Mental retardation and cerebral palsy outcome at 6 years
NotesJapan
Period of study: May 1990-April 1991
Published: 1997
Source of funding: Unclear
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot described
Allocation concealment (selection bias)Unclear riskNot described
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of Intervention: Not described
Blinding of outcome measurement: Not described
Incomplete outcome data (attrition bias)
All outcomes
High riskComplete Follow-up: No (6 patients dropped)
Selective reporting (reporting bias)High riskImportant patient oriented outcomes are not included

Li 2004

MethodsSingle center randomized study
Participants30 infants, of low birth weight.
Exclusion criteria:
Major anomalies, chromosomal anomalies, intrauterine infection
Demographic data:
Probiotics Group A N=10, gestational age (weeks) 33.8 (2.9), birth weight 1523 (490)
Probiotics Group B N=10, gestational age (weeks) 33.8 (3.2), birth weight 1354 (280)
Control (C) Group N=10, gestational age (weeks) 32.4 (3.1), birth weight 1480 (237)
Interventions

Probiotics group (N=10) received through gastric tube Bifidobacterium breve twice a day with feeds till discharge. Group A within several hours of birth, while group B after the 1st 24 hrs
Control group (N=10) received no supplement

Breast and artificial milk was utilized for feeding

OutcomesColonization rate
Sepsis
NotesJapan
Period of study: Jan 2000- Aug 2002
Published: 2004
Source of funding: Morinaja Milk industry and Meiji Dairies
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskUnclear
Allocation concealment (selection bias)Unclear riskNot described
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Not described
Blinding of outcome measurement: Not described
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskComplete follow-up: Unclear
Selective reporting (reporting bias)High riskImportant patient oriented outcomes are not included

Lin 2005

MethodsSingle centre randomized study
Method of generating randomization sequence: Random-number table sequence.
Allocation concealment: Clearly adequate
Blinding of intervention: Yes, only investigators and breast milk team were unblinded.
Blinding of outcome measurement: Yes
Completeness of follow up: Yes
Participants367 infants less than 1500 g at birth, survived beyond 7 days of life, and started on enteral feed were enrolled
Demographic data:
Probiotics Group N=180, gestational age (weeks) 28.5(2.5), birth weight 1104 (242)
Placebo Group N=187, gestational age (weeks) 28.2 (2.5), birth weight 1071 (243)
InterventionsProbiotics group (N=180) received Infloran® (L. acidophilus and B. infantis) obtained from the American Type Culture Collection in 1973, 125 mg/kg/dose twice daily with breast milk until discharge. All enrolled infants received maternal or banked breast milk
Control group (N=187) received breast milk without any addition (no placebo)
OutcomesDeath
Stage 2 or 3 NEC
Sepsis (culture proven)
Composite outcomes of death + NEC, sepsis + NEC, death + NEC + sepsis
Duration of parenteral nutrition
Hospitalization days
NotesTaiwan
Period of study: July 1999- December 2003
Published: 2005
Source of funding: supported by research department of China medical university hospital
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: Random number table sequence
Allocation concealment (selection bias)Low riskAllocation concealment: Clearly adequate
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes, only investigators and breast milk team were unblinded
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskCompleteness of follow up: Yes
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Lin 2008

MethodsMulticenter trial
Method of generating randomization sequence: Sequential numbers generated at the computer center
Allocation concealment: Adequate
Blinding of intervention: Yes
Blinding of outcome measurement: Yes
Completeness of follow up: Yes
ParticipantsVery low birth weight infants (birth weight ≤1500 g)
Demographic data:
The study group N=217, birth weight 1028.9 (246)
The control Group N=217, birth weight 1077 (214.4)
InterventionsInfants in the study group were given Bifidobacterium bifidum andLactobacillus acidophilus, added to breast milk or mixed feeding (breast milk and formula), twice daily for 6 weeks
Infants in the control group were fed with breast milk or mixed feeding
OutcomesDeath or severe NEC
NEC, ≥ stage 2
Death not attributable to NEC
Death attributable to NEC
Sepsis
CLD
PVL
IVH, ≥ grade 3
Notes7 NICUs in Taiwan
Period of study: January 2005 - May 2007
Published: 2008
Sources of support: National Science Council of Taiwan
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: Sequential numbers generated at the computer center
Allocation concealment (selection bias)Low riskAllocation concealment: Adequate
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskCompleteness of follow-up: Yes
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Manzoni 2006

MethodsSingle center randomized study
Method of generating randomization sequence: Computer generated randomization
Allocation concealment: Unclear
Blinding of intervention: Can't tell
Blinding of outcome measurement: Can't tell
Completeness of follow up: Yes
Participants80 infants less than 1500 g at birth, survived beyond 3 days of life, and started on human or donor milk enteral feed were enrolled
Demographic data:
Probiotics Group N=39, gestational age (weeks) 29.6 (5), birth weight 1212 (290)
Placebo Group N=41, gestational age (weeks) 41 (4), birth weight 1174 (340)
InterventionsProbiotics group (N=39) received LGG (Diclofor 60; Dicofarm spa); single dose (1/2 packet of Diclofor 60) daily mixed with human or donor milk till end of the sixth week or discharge
Control group (N=41) received human or donor milk without any addition (no placebo)
OutcomesFungal colonization rates
Stage 2 or 4 NEC
Death
Sepsis (culture proven)
Time to full feeds
NotesItaly
Period of study: 12 months
Published: 2006
Sources of support: non reported
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: computer generated randomization
Allocation concealment (selection bias)Unclear riskAllocation concealment: Unclear
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Can't tell
Blinding of outcome measurement: Can't tell
Incomplete outcome data (attrition bias)
All outcomes
Low riskCompleteness of follow up: Yes
Selective reporting (reporting bias)Low risk 

Manzoni 2009

MethodsMulticenter trial
Method of generating randomization sequence: using ralloc.ado version 3.2.5 in Stata 9.2 (Stata-Corp, College Station, Texas)
Allocation concealment: Yes
Blinding of intervention: Yes
Blinding of outcome measurement: Yes
Completeness of follow up: Yes
ParticipantsVLBW neonates younger than 3 days
Demographic data:
Probiotics Group N=151, gestational age (weeks) 29.8 (23-35), birth weight 1138 (550-1500)
Control Group N=153, gestational age (weeks) 29.5 (23-39), birth weight 1109 (437-1500)
Interventions

Infants received either BLF (Bovine Lactoferrin) (100mg/d) (LF100; Dicofarm SpA, Rome, Italy) alone or BLF plus LGG (6x109 colony-forming units/d) (Dicoflor60; Dicofarm SpA); the control group received placebo (2 mL of a 5% glucose solution).
Treatment lasted 6 (birth weight 1000 g) or 4 (birth weight 1001-1500 g) weeks, unless neonates were discharged earlier.
Drug administration began on the third day of life with 1 daily dose; all doses including placebo were diluted in prepared milk so as to maintain blinding.

Enrolled infants received any combination of expressed breast milk, donor breast milk, and preterm formula.

OutcomesFirst episode of late-onset sepsis
Incidence of gram-positive/gram-negative bacterial and fungal sepsis
Mortality prior to discharge
Incidence of urinary tract infections, fungal colonization, progression from fungal colonization to invasive fungal infection
Severe NEC
Threshold ROP
Severe (grade 3-4) IVH
BPD
Alteration of liver function
Adverse effects or intolerance
Notes11 Italian tertiary NICU
Period of study: October 1, 2007, and July 31, 2008
Published: 2009
Source of Funding: Dicofarm SpA
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence:using ralloc.ado version 3.2.5 in Stata 9.2 (Stata-Corp, College Station, Texas)
Allocation concealment (selection bias)Low riskAllocation concealment: Yes
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskCompleteness of follow-up: Yes
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Mihatsch 2010

MethodsA randomized controlled trial
Participants

183 VLBW infants <30 weeks of gestation

Demographic data:
Probiotics Group N=91, gestational age (weeks) 26.6 (1.8), birth weight 856 (251)
Control Group N=89, gestational age (weeks) 26.7 (1.7), birth weight 871 (287)

Exclusion criteria were major congenital malformations and anomalies which might interfere with nourishing

Interventions

B. lactis BB12 suspension or placebo was given in addition to human milk, fortified human milk or preterm formula. BB12 was provided as lyophilized powder mixed with a standard preterm infant human milk fortifier. Human milk fortifier powder only (FM85; Nestlé) was used as placebo. In infants <1,500 g, 1 g of powder was dissolved once a day in 10 ml of sterile water. In infants ≥1,500 g, 2 g of powder were dissolved once a day in 20 ml of sterile water.

The control group received the identical volume of placebo suspension

All enrolled infants received maternal breast or formula milk

Outcomes

Primary outcome was the ‘incidence density’ of nosocomial infections from day 7 after initiation of milk feeding until the 42nd day of life

Secondary outcomes was the incidence of necrotizing enterocolitis (NEC; ≥ stage 2)

Notes

Division of Neonatology (Children’s Hospital, University of Ulm, Germany)

The study was supported by Nestlé AG, Frankfurt, Germany.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risksealed envelopes, computer-generated, blocked randomization lists, block size of four
Allocation concealment (selection bias)Low riskThe two indistinguishable powders were provided as blinded coded 10 gram sachets
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Millar 1993

MethodsSingle center randomized blinded study
Method of generating randomization sequence: Not described
Allocation concealment: Not described
Blinding of Intervention: Yes
Blinding of outcome measurement: Unclear
Complete follow-up: Yes
Participants20 infants, < 33 weeks gestation enrolled
Demographic data:
Probiotics Group N=10, gestational age (weeks) 30.5(26-33), birth weight 1445 (800-2560)
Placebo Group N=10, gestational age (weeks) 30.0 (24-33), birth weight 1500 (830-2150)
InterventionsProbiotics group received milk feeds with Lactobacillus GG 108 (cfu) twice a day for 14 days, starting with first feed
Placebo group received unsupplemented milk. Enrolled infants received any combination of expressed breast milk, formula, and preterm formula
OutcomesWeight gain
Sepsis clinical or lab proven
Antibiotics treatment
Oxygen and ventilatory requirements
Hospital stay
Perineal candidal infection
Duration of hospital stay
NotesUK
Period of study: Sept 1991-Jan 1992
Published: 1993
Source of Funding: Wessex Medical Trust
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot described
Allocation concealment (selection bias)Unclear riskNot described
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Yes
Blinding of outcome measurement: Unclear
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)High riskImportant patient oriented outcomes are not included

Mohan 2006

MethodsA double blind, placebo controlled, randomized trial
Method of generating randomization sequence: Randoma software version 4.3
Allocation concealment: Not described
Blinding of intervention: Yes
Blinding of outcome measurement: Unclear
Complete follow-up: Yes
ParticipantsGestational age of less than 37 weeks
No demographic data were provided
Interventions

69 preterm infants
The probiotic and placebo groups contained 37 and 32 preterm infants, respectively
The verum contained 2 x109 cells of Bifidobacterium lactis Bb12 per gram of powder. The concentration of Bb12 in 1 ml solution of verum in water was 4 x108. The verum group received 1.6 x109 cells on day 1 to 3 and 4.8 x109 cells from day 4 onward. Started on the first day after birth and continued for 21 days. The study ended at the 35th day after birth or when the infant was discharged from the hospital, if earlier.

The formula-based placebo (Nestlé FM 2000B) and verum (Nestlé FM 2000A) preparations were supplied by Nestlé, Konolfingen, Switzerland

OutcomesNo clinical outcomes were presented in the published data
NEC and sepsis data were collected by contacting the corresponding author
NotesThe Ernst von Bergmann hospital, Potsdam, Germany
Period of study: August 2003 - June 2005
Published: 2006
Source of funding: Not reported
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: Randoma software version 4.3
Allocation concealment (selection bias)Unclear riskAllocation concealment: Not described
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Yes
Blinding of outcome measurement: Unclear
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)High riskImportant patient oriented outcomes are not included

ProPrems 2013

MethodsA prospective multicenter, double blinded, placebo controlled, randomized trial
Participants

Infants, born <32 completed weeks’ gestation and weighing <1500g, were eligible for enrolment within 72 hours of birth

Infants were excluded if they had major congenital or chromosomal anomalies, if death was considered likely within 72 hours of birth, or if the mother was taking non-dietary probiotic supplements

Interventions

The intervention was the probiotic combination B. infantis, Streptococcus thermophilus and B. lactis (ABC Dophilus Probiotic Powder for Infants®, Solgar, USA) with 1 x 109 total organisms per 1.5 g, in a maltodextrin base powder.

The placebo was maltodextrin powder. The intervention was only administered when an infant was receiving at least 1mL of milk 4 hourly. The daily dose was two 1mL spoons, equivalent to 1.5g of study powder, reconstituted with 3mL breast milk or formula. When an infant received <3mL milk per feed, one 1mL spoon of powder was mixed with 1·5mL milk and given twice daily. The dose was the same irrespective of the infant’s current weight or postnatal age and was administered daily by gastric tube or mouth, until discharge from hospital or term corrected age.

All enrolled infants received breast or formula milk

Outcomes

The primary outcome was the incidence of at least one episode of definite late-onset sepsis before 40 weeks’ postmenstrual age or discharge home, whichever occurred first

Secondary outcomes were the incidence of definite or clinical sepsis, the composite outcome of definite or clinical late-onset sepsis, the number of courses and duration of antibiotic treatment, the incidence of definite sepsis with a probiotic species, mortality, the incidence of NEC, duration of primary hospitalization and intravenous nutrition, time to enteral feeds of 120 mL/kg/day for ≥3 days, breast milk feeding rates, days to regain birth weight, weight at 28 days of age and at discharge, PDA treated, IVH grade 3 or 4 or cystic PVL, ROP ≥ grade 3, oxygen treatment and/ or respiratory support

Notes

ProPrems trial was conducted in Australia (n = 8) and New Zealand (n = 2)

ACTRN12607000144415

Included data in this review are unpublished

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low risk 
Allocation concealment (selection bias)Low riskThe schedule was provided to the pharmacist at RWH who made up individual bottles for each randomized infant, coded by sequential study number
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Reuman 1986

MethodsRandomized double blind study
Method of generating randomization sequence: random number charts and the last digit of patient's chart number, the next matched infants is assigned to the opposite group
Allocation concealment: clearly inadequate
Blinding of intervention: Yes
Blinding of outcome measurement: Yes
Complete follow-up: Yes
Participants45 infants, <2000 gm at birth weight who survived beyond first 24 hrs and are younger than 72 hrs
Demographic data:
Probiotics Group N=15, gestational age (weeks) 30.6 (2.7), birth weight 1366 (302)
Placebo Group N=15, gestational age (weeks) 30.5 (2.8), birth weight 1377 (344)
Untreated group N=15, gestational age(weeks) 30.7 (2.9), birth weight 1329 (337)
Interventions

Probiotics group received at least 1 mL of formula containing lactobacillus. 5x1010 organisms/mL preparation diluted 100 times in infants formula
Placebo group received 1 mL of formula with no added lactobacillus
Both groups started within 72 hrs of birth
The untreated group received nothing per mouth for 2 weeks

All enrolled infants received formula milk

OutcomesDeath
Colonization rates
Hospitalization duration
Daily weight gain
Hospital acquired infection
NotesUS
Period of study: not specified in paper
Published: 1986
Source of
Funding: not specified in paper
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)High riskMethod of generating randomization sequence: random number charts and the last digit of patient's chart number, the next matched infants is assigned to the opposite group
Allocation concealment (selection bias)High riskAllocation concealment: Clearly inadequate
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)High risk 

Rojas 2012

MethodsMulticenter, double blinded, randomized, placebo controlled trial
Participants

Inclusion criteria: admission to the NICU, birth weight ≤2000 g, hemodynamically stable, and ≤48 hours of age

Infants with evidence or suspicion of congenital intestinal obstruction or perforation, gastroschisis, large omphalocele, congenital diaphragmatic hernia, major congenital heart defects, or anticipated transfer to a NICU not participating in the study were excluded

Interventions

Infants in the probiotic group received 5 drops of an oil-based suspension containing 108 colony-forming units of L. reuteri DSM 17938 (BioGaia AB, Stockholm, Sweden) once a day
For infants in the placebo group, an equal number of drops from an identical vial containing only the oil base were administered

Enrolled infants received any combination of maternal breast milk and/or preterm formula

OutcomesThe primary outcome was death or NI
Secondary outcomes included nosocomial pneumonia, NEC, feeding intolerance, and duration of hospitalization
NotesColombia
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskComputer generated balanced block randomization scheme
Allocation concealment (selection bias)Low riskSealed, sequentially numbered, opaque envelopes, color-coded for strata, available in each NICU pharmacy
Blinding (performance bias and detection bias)
All outcomes
Low risk 
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Romeo 2011a

MethodsProspective randomized trial (Romeo11a and Romeo 2011b are the same trial)
Participants

249 preterms with a birth weight <2500 g and a gestational age <37 weeks

All the infants were outborn. Inclusion criteria were admission to the NICU, a stable oral feeding within 72 h of birth and an informed parental consent; exclusion criteria were the presence of major congenital malformation or antenatal and perinatal risk factors for sepsis

Interventions

The newborns were randomized into three groups:

Group I (n=83; 12 with a birth weight <1500 g, 71 ≥1500 g) received supplementation with L. reuteri American Type Culture Collection (ATCC) 55730 5 drops daily

Group II (n=83; 28 <1500 g, 55 ≥1500 g) received supplementation with L. rhamnosus ATCC 53103 1 capsule daily

Group III included newborns with no probiotics (control; n=83; 16 <1500 g, 67 ≥1500 g). Patients received supplementation from the first 72 h after hospitalization for 6 weeks or until they were discharged from the NICU

All enrolled infants received breast or formula milk

Outcomes

The primary outcome was to evaluate the incidence of enteric fungal colonization

The secondary outcomes were days of parenteral nutrition, days of antibiotic treatment, days of hospitalization, etc

NotesNICU of the Policlinico University of Catania, Italy
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom number table
Allocation concealment (selection bias)Unclear riskNot mentioned
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Romeo 2011b

MethodsProspective randomized trial (Romeo11a and Romeo 2011b are the same trial)
Participants

249 preterms with a birth weight <2500 g and a gestational age <37 weeks

All the infants were outborn. Inclusion criteria were admission to the NICU, a stable oral feeding within 72 h of birth and an informed parental consent; exclusion criteria were the presence of major congenital malformation or antenatal and perinatal risk factors for sepsis

Interventions

The newborns were randomized into three groups:

Group I (n=83; 12 with a birth weight <1500 g, 71 ≥1500 g) received supplementation with L. reuteri American Type Culture Collection (ATCC) 55730 5 drops daily

Group II (n=83; 28 <1500 g, 55≥1500 g) received supplementation with L. rhamnosus ATCC 53103 1 capsule daily

Group III included newborns with no probiotics (control; n=83; 16 <1500 g, 67 ≥1500 g). Patients received supplementation from the first 72 h after hospitalization for 6 weeks or until they were discharged from the NICU

All enrolled infants received breast or formula milk

Outcomes

The primary outcome was to evaluate the incidence of enteric fungal colonization

The secondary outcomes were days of parenteral nutrition, days of antibiotic treatment, days of hospitalization, etc

NotesNICU of the Policlinico University of Catania, Italy
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandom number table
Allocation concealment (selection bias)Unclear riskNot mentioned
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned
Incomplete outcome data (attrition bias)
All outcomes
Low risk 
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Rougé 2009

MethodsTwo centers
ParticipantsGestational age, <32 wk, a birth weight, <1500 g
Demographic data:
Probiotics Group N=45, gestational age (weeks) 28.1 (1.9), birth weight 1115 (251)
Placebo Group N=49, gestational age (weeks) 28.1 (1.8), birth weight 1057 (260)
Interventions

Placebo group (N 49) receive 4 daily capsules of a supplement containing maltodextrin alone
Probiotic group (N 45) 108 lyophilized cells per unit of the probiotics L. rhamnosus GG (Valio, Ltd) and B. longum BB536 (Morinaga Milk Industry Co, Ltd, Tokyo, Japan) and maltodextrin beginning on the day when enteral feeding started until discharge

Infants were fed human (own mother’s expressed milk or bank milk) and/or preterm formula

OutcomesThe percentage of infants receiving more than 50% of their nutritional needs via enteral feeding on the 14th day of life
Nutrition on day 14 (more than 50% of calories received enterally and total calories delivered enterally)
Nosocomial infections
Sepsis with positive blood culture
Duration of antibiotic use
Necrotizing enterocolitis
Duration of ventilatory support
Duration of CPAP
Duration of oxygen therapy
Systemic postnatal corticoid treatment
Duration of hospital stay
Death
NotesFrance
Period of study: Aprill 2005 - January 2007
Published: 2009
Source of Funding:from the Programme Hospitalier de Recherche Clinique of the French Ministry of Health and the Délégation à la Recherche Clinique, CHU de Nantes
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: In-house software (Nantes University Hospital, Nantes, France)
Allocation concealment (selection bias)Unclear riskNot mentioned
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)Low risk 
Other biasLow risk 

Samanta 2009

MethodsProspective randomized double blind controlled trial
ParticipantsGestational age <32 weeks and VLBW infants (<1500 g) started feed enterally and survived beyond 48 h of life
Demographic data:
Probiotics Group N=91, gestational age 30.12 (weeks) (1.63), birth weight 1172 (143)
Control Group N=95, gestational age 30.14 (weeks) (1.59), birth weight 1210 (143)
Interventions

The probiotic group received a probiotic mixture (Bifidobacteria infantis, Bifidobacteria bifidum, Bifidobacteria longum andLactobacillus acidophilus, each 2.5 billion CFU) with expressed breast milk twice daily, the dosage being 125 g kg -1 till discharge. The control group was fed with breast milk only.

Infants were fed breast milk only

OutcomesFeed tolerance in terms of days required to reach full enteral feeding
Length of hospital stay
NEC
Sepsis
Death due to NEC or sepsis
NotesNeonatal Care Unit of Medical College and Hospital, Kolkata, India
Period of study: October 2007 - March 2008
Published: 2009
Source of Funding: not specified in paper
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskCan't tell
Allocation concealment (selection bias)Unclear riskCan't tell
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Can't tell
Blinding of outcome measurement: Can't tell
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes

Sari 2010

MethodsSingle center
ParticipantsGestational age <33 weeks or birth weight <1500 g
Demographic data:
Probiotics Group N=110, gestational age 29.5 (weeks) (2.4), birth weight 1231 (262)
Control Group N=111, gestational age 29.7 (weeks) (2.4), birth weight 1278 (282)
Interventions

VLBW infants who survived to start enteral feeding were randomized
The study group were given L. sporogenes with a dose of 350.000.000 colony forming units added to breast milk or formula once a day starting with first feed until discharge.
The control group were fed without L. sporogenes supplementation.

All enrolled infants received breast milk or mix feeding (breast milk and formula)

OutcomesDeath or severe NEC
NEC (stage 2, 3, ≥ 2)
Death (attributable to NEC, not attributable to NEC)
Total parental nutrition
Intraventricular hemorrhage, grade 3-4,
Sepsis (culture proven, gram negative, gram positive, fungus)
NICU stay
Feeding (amount, full feeding, intolerance)
Weight gain
NotesTurkey
Period of study: October 2008 and June 2009
Published: Unpublished
Source of Funding: not specified in paper
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskMethod of generating randomization sequence: Sequential numbers generated at the computer center of the NICU
Allocation concealment (selection bias)Unclear riskAllocation concealment: Can't tell
Blinding (performance bias and detection bias)
All outcomes
Unclear riskBlinding of intervention: Can't tell
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)Low risk 

Stratiki 2007

MethodsSingle center
ParticipantsGestational age between 27 and 37 weeks, stable state, formula fed
Demographic data:
Probiotics Group N=41, gestational age 31 weeks (27–37), birth weight 1500 (900–1780)
Control Group N=34, gestational age 30.5 weeks (26–37), birth weight 1500 (700–1900)
Interventions

81 infants
Group A (study group) was given a BL supplemented preterm formula – Prenan Nestlé – (BLSPF) at a concentration of 2×107 CFU/g of milk powder
Group B (control) received exactly the same formula but without the addition of BL

All enrolled infants received only formula milk

OutcomesIntestinal permeability
Somatic growth
Tolerance
Sepsis
Necrotizing enterocolitis
NotesGreece
Period of study: January 2004 - December 2005
Published: 2007
Source of Funding: not specified in paper (Nestlé Company, Vevey provide the B. lactis supplemented milk formula)
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskMethod of generating randomization sequence: Can't tell
Allocation concealment (selection bias)Unclear riskAllocation concealment: Can't tell
Blinding (performance bias and detection bias)
All outcomes
Low riskBlinding of intervention: Yes
Blinding of outcome measurement: Yes
Incomplete outcome data (attrition bias)
All outcomes
Low riskComplete follow-up: Yes
Selective reporting (reporting bias)High riskImportant patient oriented clinical outcomes are not included

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Agarwal 2003No clinical outcomes were presented (Agarwal 2003)
Awad 2010Data included full term infants (Awad 2010)
Di 2010Article in Chinese, reference retrieved by manual search of included studies references in Wang 2012
Havranek 2013A substudy of multicenter trial by Al-Hosni 2012
Huang 2009Article in Chinese, reference retrieved by manual search of included studies references in Wang 2012
Ke 2008Article in Chinese, reference retrieved by manual search of included studies references in Wang 2012
Ren 2010Article in Chinese, reference retrieved by manual search of included studies references in Wang 2012
Stansbridge 1993No clinical outcomes were presented (Stansbridge 1993)
Uhlemann 1999Data included full term infants (Uhlemann 1999)

Characteristics of ongoing studies [ordered by study ID]

Cooper

Trial name or titleNecrotizing Enterocolitis and B. Lactis in Premature Babies
MethodsMulti-centre double-blind placebo-controlled randomized trial
Participants

Inclusion Criteria: Weight between 800-1500 g, Tolerating enteral feeding within 48 hours, Having obtained his/her parents or legal representative informed consent

Exclusion Criteria: Chromosomal abnormality, Hydrops featalis, Congenital malformation of the gastrointestinal tract, Congenital heart defects or other major congenital abnormalities likely to affect feeding and/or feeding tolerance, or Currently participating in another clinical trial

InterventionsOne capsule containing probiotics per day added to milk
OutcomesPrimary Outcome: NEC onset
Secondary Outcome: Antibiotic administration and stool microbiology
Starting dateNovember 2009
Contact information

Peter A. Cooper

peter.cooper@wits.ac.za

Notes

Sponsor by Nestlé

South Africa

NCT00977912

Ongoing

Costeloe

Trial name or titleThe administration of probiotic to premature babies to prevent infection, severe intestinal complication (i.e. necrotising enterocolitis) and death
MethodsMulticenter double-blind placebo-controlled randomized trial
Participants1. Both males and females, born before 31 completed weeks of gestation, i.e. up to and including 30 weeks + 6 days by the best estimate of Expected Date of Delivery
2. Less than 48 hours old
3. With written informed parental consent
4. Babies already on antibiotics for suspected or proven infection are eligible for recruitment to the study
Interventions Bifidobacterium breve strain BBG (B breve BBG)
The placebo is corn starch alone
Both products are manufactured in identical foil sachets each containing 1 gram of product
The intervention will be given once daily starting as soon as possible after randomization and continuing until 36 completed weeks of post-menstrual age (36 weeks + 0 days) or death or discharge from hospital if sooner
1,300 babies will be recruited over 30 months
OutcomesPrimary:
1. Any baby with an episode of blood stream infection, with any organism other than a skin commensal
2. Necrotising enterocolitis, Bell stage II or III
3. Death before discharge
Secondary:
1. Number of babies with the composite outcome of any or a combination of the 3 primary outcomes
Outcomes 2 to 7 are for samples taken more than 72 hours after birth and before death or discharge home:
2. Number of babies with any positive blood culture with an organism recognized as a skin commensal e.g. CoNS or Corynebacteria
3. Number of babies with blood cultures taken
4. Number of blood cultures taken per baby
5. Number of babies with episodes of blood stream infection with organisms other than skin commensals by organism
6. Number of babies with isolates of organisms other than skin commensals from a normally sterile site other than blood
7. Number of babies with a positive culture of B breve BBG from any normally sterile site
8. Total duration of days of antibiotics and/or anti-fungals administered per baby after 72 hours and until death or discharge
9. The number of babies colonized with the administered probiotic strain
10. Stool flora
11. Age at achieving full enteral nutrition (defined as 150 ml/kg/day for 1 day)
12. Change of weight Z score from birth to 36 weeks post-menstrual age or discharge from hospital if sooner
13. Broncho-pulmonary dysplasia
14. Hydrocephalus and/or intraparenchymal cysts confirmed by cerebral ultrasound scan performed during the baby's in-patient stay
15. Worst stage of retinopathy of prematurity in either eye at discharge or death
16. Length of stay in intensive, high dependency and special care (British Association of Perinatal Medicine (BAPM) 2001: definitions)
Starting date01/12/2009
Contact informationProf  Kate  Costeloe
Barts and the London School of Medicine and Dentistry
Neonatal Unit
Homerton University Hospital
Homerton Row
Notes

UK
ISRCTN05511098

Completed

Kusuda

Trial name or titleEffect of Bifidobacterium Bifidum Supplementation on Morbidity of Very Low Birth Weight Infants
MethodsDouble-blind placebo-controlled randomized trial
Participants

Inclusion Criteria: Infants with birth weight less than 1500g

Exclusion Criteria: Sever bacteremia, Congenital anomaly, Not suitable for the trial defined by an attending neonatologist

Interventions B. bifidum (OLB6378) supplementation with approximately 2.5*10 to 9th bacteria per day
OutcomesPrimary Outcome:Postnatal day when enteral feeding exceeded at 100ml/kg/day
Secondary Outcome:standard deviation scores of bodyweight and head circumference
Necrotizing enterocolitis or sepsis
Intestinal flora
Starting dateJanuary 2010
Contact information

Satoshi Kusuda

Tokyo Women's Medical University

Notes

NCT01375309

Completed

Moral

Trial name or titleEffects of Lactobacillus Reuteri in Premature Infants
MethodsMulticenter double-blind placebo-controlled randomized trial
Participants

Inclusion criteria:

  • Preterm newborns admitted to the neonatal intensive care units with a birth weight 700-1500 g and who survive more than 3 days

Exclusion criteria:

  • Chromosomal anomalies.

  • Major congenital anomalies (complex cardiac anomalies, congenital hydrocephalus, renal dysplasia)

  • Congenital (e.g. jejunal atresia) and acquired (e.g. GI perforation) gastrointestinal pathology precluding oral feed and/or requiring major surgical or medical intervention

  • Parental refusal

  • Prior enrolment into a conflicting clinical trial

Interventions L. reuteri DSM will be given at a dose of 1x108 colony forming units (CFU)/day
OutcomesPrimary Outcome: Time to reach full feeds
Secondary Outcome: Intestinal colonization and Intestinal immunological response
Starting dateJuly 2010
Contact information

Teresa del Moral

University of Miami

Notes

NCT01181791

Chile

Oncel

Trial name or title Lactobacillus Reuteri for Prevention of Necrotizing Enterocolitis in Very Low-birth Weight Infants
MethodsRandomised placebo controlled trial
Participants

Inclusion Criteria: Very low birth weight infants < 1500 g, Gestational age < 32 weeks

Exclusion Criteria: Genetic anomalies, Short bowel syndrome, Not willing to participate, Allergy to L. reuteri components

Interventions L. reuteri 100 million CFU/day for 3 months
OutcomesPrimary Outcome: NEC in VLBW infants
Secondary Outcomes:Culture proved sepsis, Weight gain, and Length of hospital stay
Starting dateFebruary 2012
Contact information

Mehmet Yekta Oncel 

Zekai Tahir Burak Maternity Teaching Hospital, Neonatology Unit

Notes

NCT01531179

Completed

Punnahitananda

Trial name or titleEffect of Oral Probiotic Supplementation on The Rate of Hospital Acquired Infection and Necrotizing Enterocolitis in PretermVery Low Birth Weight Infants
MethodsRandomised placebo controlled trial
Participants

VLBW preterm infants (Gestational age < 35 weeks , BW < 1500 g ) admitted to the NICU who survived the first 3 days of life

Exclusion Criteria: Infants with chromosome abnormality or severe congenital defects, especially gastrointestinal anomalies and infants with unstable hemodynamic status

Interventions

Daily enteral probiotic supplementation (live Lactobacillus acidophilus andBifidobacterium infantis) at a dose of 2.5 x 108 CFU of each strain once a day for at least 28 days or until discharge

The control group received daily placebo

OutcomesPrimary Outcome:incidence of nosocomial infections
Secondary Outcome:incidence of NEC, feeding tolerance, time to full enteral feeding
Starting dateJanuary 2005
Contact information

Santi Punnahitananda, Faculty of Medicine Chulalongkorn University

Thailand

Notes

Study First Received: April 19, 2011

ISRCTN 39142169

Completed

Ancillary