Multi-modal approach to prophylaxis of necrotizing enterocolitis: clinical report and review of literature

Clinical NEC prevention practices drive different microbiome profiles and functional responses in the preterm intestine

Preterm infants with very low birthweight are at serious risk for necrotizing enterocolitis. To functionally analyse the principles of three successful preventive NEC regimens, we characterize fecal samples of 55 infants (<1500 g, n = 383, female = 22) longitudinally (two weeks) with respect to gut microbiome profiles (bacteria, archaea, fungi, viruses; targeted 16S rRNA gene sequencing and shotgun metagenomics), microbial function, virulence factors, antibiotic resistances and metabolic profiles, including human milk oligosaccharides (HMOs) and short-chain fatty acids (German Registry of Clinical Trials, No.: DRKS00009290). Regimens including probiotic Bifidobacterium longum subsp. infantis NCDO 2203 supplementation affect microbiome development globally, pointing toward the genomic potential to convert HMOs. Engraftment of NCDO 2203 is associated with a substantial reduction of microbiome-associated antibiotic resistance as compared to regimens using probiotic Lactobacillus rhamnosus LCR 35 or no supplementation. Crucially, the beneficial effects of Bifidobacterium longum subsp. infantis NCDO 2203 supplementation depends on simultaneous feeding with HMOs. We demonstrate that preventive regimens have the highest impact on development and maturation of the gastrointestinal microbiome, enabling the establishment of a resilient microbial ecosystem that reduces pathogenic threats in at-risk preterm infants.

Single Nucleotide Polymorphisms in Neonatal Necrotizing Enterocolitis

The etiopathogenesis of necrotizing enterocolitis (NEC) remains unclear, but increasing information suggests that the risk and severity of NEC may be influenced by single nucleotide polymorphisms in many genes. In this article, we have reviewed gene variations that have either been specifically identified in NEC or have been noted in other inflammatory bowel disorders with similar histopathological abnormalities. We present evidence from our own peer-reviewed laboratory studies and data from an extensive literature search in the databases PubMed, EMBASE, and Scopus. To avoid bias in the identification of existing studies, search keywords were short-listed both from our own studies and from PubMed's Medical Subject Heading (MeSH) thesaurus.

Long-term Follow-up of Preterm Infants Having Been Colonized With Extended Spectrum Beta-lactamase-producing Enterobacterales Over the First 6 Years of Life

We performed a retrospective case-control cohort study following 146 preterm infants (≤32 weeks of gestation) who had been colonized with extended spectrum beta-lactamase producing Enterobacterales and compared them with 1:1 matched controls regarding rates of hospitalizations and outpatient visits because of infectious and gastrointestinal diseases and developmental impairment up to school age. Preterm infants with extended spectrum beta-lactamase producing Enterobacterales colonization did have neither higher rates of gastrointestinal or infectious diseases nor higher rates of developmental impairments up to the age of 6 years.

Plasma Metabolomics to Evaluate Progression of Necrotising Enterocolitis in Preterm Pigs

Necrotising enterocolitis (NEC) is a microbiome-dependent gut disease in preterm infants in early life. Antibiotic treatment is a common intervention for NEC. How NEC lesions, with or without antibiotics, affect plasma metabolome was explored in this study. Formula-fed preterm pigs were used as a model for human NEC and treated with saline, parenteral or oral antibiotics (n = 15-17) for four days after delivery. Gut tissues were collected for evaluation of NEC-like lesions and plasma for metabolomic analysis by proton nuclear magnetic resonance spectroscopy (¹H-NMR). Metabolites were annotated, quantified and subjected to statistical modelling to delineate the effects of NEC and antibiotic treatment. Presence of severe NEC lesions, not antibiotic treatment, was the main drive for plasma metabolite changes. Relative to other pigs, pigs with severe NEC lesions had higher levels of alanine, histidine and myo-inositol, and lower levels of 3-hydroxybutyric acid and isobutyric acid. Across NEC lesion states (healthy, mild, severe), antibiotics directly affected only a few metabolites (tryptophan, 3-phenyllactic acid). Together and independently, NEC and antibiotic treatment affected circulating metabolites in preterm pigs. Amino acids and plasma metabolites, partly related to the gut microbiome, may be helpful to monitor progression of NEC lesions after proper validation.

Introducing multi-modal enteral medication reduced morbidity and mortality associated with necrotising enterocolitis

AIM

Necrotising enterocolitis (NEC) is still a disease with high morbidity and mortality. The aim of the study was to analyse retrospectively whether the introduction of a multi-modal three-component enteral medication regimen resulted in a change in morbidity and mortality in neonates with NEC.

METHODS

When diagnosis of NEC was established, the following multi-modal three-component enteral medication regimen was administered enterally (via nasogastric tube): an antibiotic, an antifungal agent and a probiotic. The primary outcome parameters were intestinal perforation, surgical interventions and mortality during the observational periods.

RESULTS

In the study period, 2212 patients were admitted to the NICU, out of which 200 (9%) developed NEC. Significantly fewer infants died in the Intervention Group (13 of 104 infants, 13%) compared to the Control Group (38 of 96 infants, 40%) (P = .0001). No infant in the Intervention Group (0%) presented with an intestinal perforation, as compared to 15 infants (16%) within the Control Group (P = .0001). In the Control Group, 21 infants (22%) needed surgical intervention, whereas 0 (0%) infants needed this in the Intervention Group.

CONCLUSION

The introduction of an enteral multi-modal three-component medication regimen resulted in a significant reduction of mortality and of need for surgical intervention in infants suffering from NEC.

Extended-spectrum beta-lactamase (ESBL) producing Enterobacterales in stool surveillance cultures of preterm infants are no risk factor for necrotizing enterocolitis: a retrospective case-control study over 12 years

Purpose

Microbial dysbiosis has been found preceding necrotizing enterocolitis (NEC) in preterm infants; thus, we aimed to investigate whether there is evidence that neonates with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) positive stool cultures are at higher risk for NEC at the NICU.

Methods

We included very preterm inborn infants of ≤ 32 weeks of gestational age being fecal carriers of ESBL-E and compared them with 1:1 matched (gestational age, birth weight, gender and year) controls tested negative for ESBL-E in the stool between 2005 and 2016. An association with NEC was defined as the first detection of ESBL-E before or at the time of definite diagnosis of NEC.

Results

During the study period, we diagnosed 217 infants with a total of 270 ESBL-E. We identified ten different species with ESBL-producing Klebsiella oxytoca being the most common one (46%) followed by Klebsiella pneumoniae (19%), and Citrobacter freundii (17%). Ten out of 217 infants had any kind of NEC in the case group compared to two of the controls (p < 0.01), but only four cases with predefined criteria were associated with NEC ≥ stage IIa (1.8 vs. 0.5%, p = 0.089, OR 4.1, CI95% 0.45–36.6). NEC mortality rate was 2/8 (25%).

Conclusions

We observed a threefold increase of ESBL-E in stool surveillance cultures during study time and germs were dominated by ESBL-producing Klebsiella spp. There was no evidence that preterm infants colonized with ESBL-E in the stool were at higher risk for definite NEC.

Bronchopulmonary dysplasia in very preterm infants: Outcome up to preschool age, in a single center of Austria

BACKGROUND

Bronchopulmonary dysplasia (BPD) is the most frequent chronic lung disease in infancy and is associated with neonatal comorbidity and impairment in pulmonary and neurodevelopmental (ND) long-term outcome.

METHODS

This was a retrospective, single-center, cohort study to compare a cohort of very preterm infants (gestational age [GA], 24⁺⁰ -28⁺⁶ weeks) with BPD (n = 44), with a cohort of GA-matched preterm infants without BPD (n = 44) with regard to neonatal morbidity, incidence of lower respiratory tract infection (LRTI), ND outcome and growth to 2 years' corrected age (CA) and preschool age.

RESULTS

Bronchopulmonary dysplasia (incidence, 11.3%) was associated with a higher rate of neonatal pneumonia (26% vs 7%, P = 0.001), longer total duration of mechanical ventilation (mean days, 21 vs 13, P < 0.001), and a higher rate of pulmonary hypertension (20.5% vs 0%, P = 0.002) and of severe retinopathy of prematurity (13.6% vs 0%, P = 0.026). Incidence of LRTI was significantly higher in the BPD infants (50% vs 26%, P = 0.025). ND outcome did not differ between the two groups. Growth at neonatal intensive care unit discharge was similar. In the BPD cohort, rate of weight < 10th percentile was higher at 2 years' CA (52% vs 30%, P = 0.041) and rate of head circumference < 10th percentile was higher at preschool age (59% vs 27%, P = 0.028).

CONCLUSION

Neonatal respiratory morbidity was significantly higher in the BPD cohort, but long-term ND outcome did not differ. Infants with BPD had poorer growth.

Changes of intestinal microbiota composition and diversity in very low birth weight infants related to strategies of NEC prophylaxis: protocol for an observational multicentre pilot study

Background

At the Division of Neonatology, Department of Paediatrics, Medical University Graz, a unique regimen of necrotizing enterocolitis (NEC) prophylaxis in preterm infants showing a < 1500 g birth weight (i.e. very low birth weight, VLBW) is used. The regimen includes oral antibiotic and antifungal therapy and probiotic preparations as well as a standardised feeding regimen. The incidence of NEC in preterm infants treated by this regimen has been shown to be lower, reflecting 0.7% when treatment was initiated on the first day of life, compared to international incidence rates (5.1%). However, the impact of the prophylaxis regimen on the intestinal microbiome is yet unknown.

Methods

We here report the protocol of an observational multicentre STROBE compliant pilot study in VLBW preterm infants. Research will compare three groups as defined by different NEC prophylaxis regimens. Each centre will provide 20 infants. Stool samples will be collected every 2 days throughout the first 2 weeks of life. Samples will be stored at − 80 °C until 16S-rRNA sequencing. 16S-rRNA genes will be amplified using suitable primers (specific for bacteria, fungi and archaea) and prepared for MiSeq Sequencing. Analyses will be performed using public analysis-pipelines, such as Mothur and Qiime, thus allowing an analysis of high-throughput community sequencing data. Abundance and composition changes in intestinal microbiota will be compared between the groups throughout the first 2 weeks of life.

Discussion

Different surroundings at the three participating study centres, including contacts to care takers and parents, as well as feeding or medication all might influence intestinal microbiota composition and abundance. In the planned sequel study, this should be kept in mind and a more standardised process ought to be established. However, the results obtained from the presented pilot study will display the burden of bias and help to establish a more strict protocol for the future.

Trial registration

Trial has been registered with the German Registry for Clinical Trials (registry ID DRKS00009290).

Electronic supplementary material

The online version of this article (10.1186/s40814-017-0195-y) contains supplementary material, which is available to authorized users.

Probiotics to prevent necrotising enterocolitis and nosocomial infection in very low birth weight preterm infants

The aim of the study was to determine whether routine probiotic supplementation (RPS) with Lactobacillus rhamnosus GG (LGG) or Lactobacillus acidophilus +Lactobacillus bifidum is associated with reduced risk of necrotising enterocolitis (NEC)≥Stage II in preterm neonates born at ≤32 weeks' gestation. We conducted a retrospective cohort study on the effect of probiotic supplementation in very low birth weight infants in our neonatal unit by comparing two periods: before and after supplementation. The incidence of NEC≥Stage II, late-onset sepsis and all-cause mortality was compared for an equal period 'before' (Period I) and 'after' (Period II) RPS with LGG or L. acidophillus+L. bifidum. Multivariate logistic regression analysis was conducted to adjust for relevant confounders. The study population was composed of 261 neonates (Period I v. II: 134 v. 127) with comparable gestation duration and birth weights. In <32 weeks, we observed a significant reduction in NEC≥Stage II (11·3 v. 4·8 %), late-onset sepsis (16 v. 10·5 %) and mortality (19·4 v. 2·3 %). The benefits in neonates aged ≤27 weeks did not reach statistical significance. RPS with LGG or L. acidophillus+L. bifidum is associated with a reduced risk of NEC≥Stage II, late-onset sepsis and mortality in preterm neonates born at ≤32 weeks' gestation.

"I Had One Job and That Was To Make Milk"

BACKGROUND

For very-low-birth-weight (VLBW) infants, breastfeeding may no longer be an immediate option. Mothers often turn to mechanically expressing their milk with a breast pump to provide their infants human milk. Research aim: This study aimed to describe mothers' experiences expressing milk for their VLBW infants in a level 3 neonatal intensive care unit.

METHODS

Qualitative, phenomenological methods were used to better understand the milk expression experiences of 17 mothers of VLBW infants. In-depth interviews were audio-recorded and transcribed verbatim. Transcripts were analyzed using Colaizzi's seven-step protocol, and themes were identified to illustrate the lived experience of the mothers.

RESULTS

Five global themes emerged from interviews with mothers. However, this article focuses on one global theme, "I had one job and that was to make milk," and the supporting subthemes: (1) "I was heartbroken," (2) "Pumping is a full-time thing," and (3) "I literally sacrificed nights."

CONCLUSION

This study provides insight into the complex experience that mothers in the southeastern United States undergo when expressing milk for their VLBW infants.

Prophylactic Probiotics for Preterm Infants: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Necrotizing enterocolitis (NEC) is a major morbidity and cause of mortality in preterm neonates. Probiotics seem to have a beneficial role in preventing NEC, which is confirmed in meta-analyses of randomized controlled trials (RCTs). We therefore aimed to review and confirm the efficacy of probiotics in preterm neonates obtained in observational studies.

OBJECTIVE

To assess the effects of prophylactic probiotics in preterm infants.

METHODS

A meta-analysis was performed searching PubMed, EMBASE, CENTRAL (the Cochrane Library) and www.clinicaltrials.gov. Reference lists of reviews of RCTs were also searched. Included studies were observational studies that enrolled preterm infants <37 weeks of gestational age. Trials were included if they administered any probiotics and measured at least one clinical outcome (e.g. NEC, all-cause mortality, sepsis or long-term development scores). Two authors extracted characteristics and outcomes from included studies. The Newcastle-Ottawa Scale was used for quality assessment. A random-effects meta-analysis model was used, and heterogeneity was assessed by the I2 test.

RESULTS

We included 12 studies with 10,800 premature neonates (5,144 receiving prophylactic probiotics and 5,656 controls). The meta-analysis showed a significantly decreased incidence of NEC (risk ratio, RR = 0.55, 95% confidence interval, 95% CI, 0.39-0.78; p = 0.0006) and mortality (RR = 0.72, 95% CI, 0.61-0.85; p < 0.0001). Sepsis did not differ significantly between the two groups (RR = 0.86, 95% CI, 0.74-1.00; p = 0.05).

CONCLUSIONS

Probiotic supplementation reduces the risk of NEC and mortality in preterm infants. The effect sizes are similar to findings in meta-analyses of RCTs. However, the optimal strain, dose and timing need further investigation.

Necrotizing enterocolitis: controversies and challenges

Necrotizing enterocolitis is a devastating intestinal disease that affects ~5% of preterm neonates. Despite advancements in neonatal care, mortality remains high (30–50%) and controversy still persists with regards to the most appropriate management of neonates with necrotizing enterocolitis. Herein, we review some controversial aspects regarding the epidemiology, imaging, medical and surgical management of necrotizing enterocolitis and we describe new emerging strategies for prevention and treatment.

Necrotizing enterocolitis: have we made any progress in reducing the risk?

Necrotizing enterocolitis (NEC) is a disease affecting premature infants with potentially devastating complications in the neonatal intensive care unit (NICU). Inadequate knowledge regarding the underlying pathophysiology of this disease has contributed to the minimal progress made in decreasing the incidence and severity of NEC. Because of an improved survival rate of the most immature infants, the number of diagnosed cases of NEC is anticipated to increase. Unfortunately, decades of research have failed to reduce the risk or improve the prognosis of NEC, magnifying the need for risk-reduction strategies for decreasing significant NEC-related morbidity and mortality. Advancements in our understanding of this disease process have facilitated the development of several strategies that have been investigated in the risk reduction of NEC. This article discusses the pathophysiology and causes of NEC and presents strategies investigated regarding risk reduction of this devastating disease.

Necrotizing enterocolitis risk: state of the science

Necrotizing enterocolitis (NEC) is the most common cause of gastrointestinal-related morbidity and mortality in the neonatal intensive care unit (NICU). Its onset is sudden and the smallest, most premature infants are the most vulnerable. Necrotizing enterocolitis is a costly disease, accounting for nearly 20% of NICU costs annually. Necrotizing enterocolitis survivors requiring surgery often stay in the NICU more than 90 days and are among those most likely to stay more than 6 months. Significant variations exist in the incidence across regions and units. Although the only consistent independent predictors for NEC remain prematurity and formula feeding, others exist that could increase risk when combined. Awareness of NEC risk factors and adopting practices to reduce NEC risk, including human milk feeding, the use of feeding guidelines, and probiotics, have been shown to reduce the incidence of NEC. The purpose of this review is to examine the state of the science on NEC risk factors and make recommendations for practice and research.

Evidence-based guidelines for use of probiotics in preterm neonates

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Orally administered colistin leads to colistin-resistant intestinal flora and fails to prevent faecal colonisation with extended-spectrum β-lactamase-producing enterobacteria in hospitalised newborns

Colonisation and infection with extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) is an emerging problem. The aim of this study was to investigate whether colistin, which is reported to be effective against multiresistant enterobacteria, prevents ESBL-E colonisation in neonates. For prophylaxis of necrotising enterocolitis, oral gentamicin (15 mg/kg/day) is routinely used in all neonates hospitalised at the Neonatal Intensive Care Unit of University Hospital Graz (Austria). During the study period from May 2005 to September 2007, three ESBL-E outbreaks (total duration 18 months) occurred. During these outbreaks, gentamicin was immediately replaced by oral colistin (8 mg/kg/day) in all hospitalised neonates. All neonates colonised with ESBL-E during the study period were retrospectively analysed with regard to the influence of colistin on ESBL-E colonisation. Genetic relatedness of isolates was assessed by repetitive sequence-based polymerase chain reaction (rep-PCR). During the study period, 30 (4.5%) of 667 neonates were colonised with ESBL-E. Twelve of twenty-one patients colonised with Klebsiella pneumoniae (ESBL-Kp) and one of nine patients colonised with Klebsiella oxytoca (ESBL-Ko) had received oral colistin at time of colonisation with ESBL-E. Amongst ESBL-Kp, the rate of colistin resistance was significantly higher in the colistin group (P=0.0075). Four different clones of ESBL-Kp and three different clones of ESBL-Ko were isolated, indicating the occurrence of patient-to-patient transmission. Colistin-resistant as well as colistin-susceptible isolates were detected within the same clones, indicating induction of resistance. At the dosage used, oral colistin did not prevent colonisation with ESBL-E and appeared to select colistin-resistant strains or to induce colistin resistance.

Can we cut the incidence of necrotizing enterocolitis in half--today?

Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency of neonates. Population studies estimate the incidence of NEC at between 0.3 and 2.4 per 1000 live births in the United States, with a predominance of cases among preterm neonates born at the earliest gestational ages. The disease burden of NEC includes an overall disease-specific mortality rate of 15-20%, with yet higher rates in those of earliest gestations. The NEC burden also includes an increase in hospital costs approximating $100,000/case, as well as severe late sequellae including parenteral nutrition-associated liver disease and short bowel syndrome. Differentiating NEC from other forms of acquired neonatal intestinal disease is critical to assessing the success of NEC prevention strategies. Promising new prevention strategies are now being tested; one such is prophylactic heparin-binding epidermal growth factor-like growth factor (HB-EGF) administration. However, two prevention strategies have already been shown in meta-analyses to reduce the incidence of NEC, but we speculate that these are not being fully utilized. They are; 1) implementing a written set of feeding guidelines (also called standardized feeding regimens) for newborn intensive care unit (NICU) patients, and 2) implementing programs to increase the availability of human milk for patients at risk of developing NEC.

The human microbiome and probiotics: implications for pediatrics

The “human super-organism” refers to the human body and the massive numbers of microbes which dwell within us and on the skin surface. Despite the large numbers of microbes co-existing within the human body, humans including infants and children achieve a physiologic state of equilibrium known as health in the context of this microbial world. These key concepts suggest that many individual members of the human microbiome, including bacterial and fungal species, confer different benefits on the human host. Probiotics, or beneficial microbes, may modulate immune responses, provide key nutrients, or suppress the proliferation and virulence of infectious agents. The human microbiome is in fact dynamic and often in flux, which may be indicative of the continuous interplay among commensal microbes, pathogens, and the human host. In this article we review the state-of-the-art regarding probiotics applications to prevent or treat diseases of the pediatric gastrointestinal and genitourinary systems. Additionally, probiotics may regulate local and systemic immunity, thereby reducing allergic disease severity and susceptibilities of infants and children to allergies and atopic diseases. In summary, beneficial microbes offer promising alternatives for new strategies in therapeutic microbiology with implications for different subspecialties within pediatrics. Instead of simply trying to counteract microbes with vaccines and antibiotics, a new field of medical microbiology is emerging that strives to translate human microbiome research into new probiotics strategies for promotion of health and prevention of disease in children.

Risk factors for necrotizing enterocolitis in preterm infants: how race, gender, and health status contribute

PURPOSE

To examine 5 infant characteristics and health factors that might be risk factors for necrotizing enterocolitis (NEC) in preterm infants.

SUBJECTS

One hundred thirty-four preterm infants at high risk for NEC because of either having a birth weight of <1500 g or requiring mechanical ventilation at birth.

DESIGN

Descriptive secondary analysis using data from a larger longitudinal study.

METHODS

Weekly review of infants' medical record until discharge; demographic questionnaire completed by mothers at the time of enrollment; and data analysis done with logistic regression, Fischer's exact tests, and correlations.

OUTCOME MEASURES

Total number of days the infant required mechanical ventilation, birth weight in grams, number of infections prior to NEC diagnosis, maternal race (black, white, or Asian), and infant gender were used to predict the development of NEC.

RESULTS

Maximum likelihood estimates indicated that mechanical ventilation had a positive relationship with developing NEC, such that as the number of days of mechanical ventilation increased so did the risk of developing NEC. There was also a very strong positive relationship between the number of nosocomial infections and NEC, indicating that as the number of infections increased, the likelihood of developing NEC increased. Although the relationship between race and NEC was not significant in the logistic regression, the Fisher exact test showed that black preterm infants had increased incidence of NEC as compared with other races. This relationship was not due to correlations between race and mechanical ventilation or infections. No relationship between gender and NEC was noted. Birth weight was not significantly associated with NEC in the logistic regression but was correlated with NEC, probably because of its correlation with mechanical ventilation and number of infections.

CONCLUSIONS

In this sample, number of infections and length of mechanical ventilation were the primary predictors of NEC in preterm infants. In addition, the frequency that black infants are diagnosed with NEC is significantly higher than that of other races. Knowledge of risk factors for NEC can allow healthcare providers to evaluate and adjust care practices for preterm infants who present with higher risk for NEC on the basis of empirical data.

Probiotics and other preventative strategies for necrotising enterocolitis

Necrotising enterocolitis (NEC) remains one of the commonest causes of death and significant morbidity in preterm infants after the first few postnatal days. NEC affects approximately 5-10% of infants born at <or=28 weeks; about a third will die. Although there do not appear to be any 'simple fixes', it is clear that there are many clinical strategies that affect NEC. There is controlled trial evidence for breast milk, fluid regimes, enteral antibiotics, immunonutrients and probiotic supplements. This paper will review the evidence relevant to current populations of preterm infants and determine which, if any, can be safely and effectively introduced into current clinical practice.

Evidence vs experience in neonatal practices in necrotizing enterocolitis

INTRODUCTION

Necrotizing enterocolitis (NEC) has been recognized for over 40 years as a cause of inflammation and necrosis of the small and large intestine of infants born at less than 36 weeks of gestation. NEC remains a significant health problem for infants born prematurely and may become the leading cause of morbidity and mortality among these infants worldwide. The sequence of events leading to NEC is complex and multifactorial, although damage to the intestinal epithelium and invasion by bacteria are known to play central roles in disease pathogenesis.

STUDY DESIGN

Bacteria initiate a cascade of inflammation that may progress to intestinal necrosis and perforation with sepsis and death.

RESULT

Treatment of infants at risk for NEC with probiotic bacteria may be an area of great potential, as probiotic bacteria may promote maturation of the epithelial barrier and function to exclude bacterial pathogens from critical niches in the intestine, thereby disrupting a primary pathway in disease pathogenesis.

CONCLUSION

Understanding how probiotic bacteria, or other novel therapies, prevent or limit disease propagation in NEC will be paramount in limiting the impact of disease in a growing population of premature newborns.

Bacteria and early human development

Our understanding of the relationship between microbes and their animal hosts have changed dramatically in the last decade. The development of powerful new molecular methods as well as different animal models, particularly germ free rodents, has enabled precise characterisation of the ways in which commensal bacteria in the gastrointestinal tract and other areas interact with their hosts. It is now clear that animal development, far from being genetically determined is intimately bound up with the microbial flora of that particular animal. In germ free mice, the addition of Bacteroides thetaiotaomicron mediates the maturation and function of the gastrointestinal tract in several different ways. Similarly Bacteroides fragilis directs the development of the immune system both in and outside the gastrointestinal tract. The relevance of these findings and others to our understanding of human development and disease is discussed.