Double blind, randomised, placebo controlled study of oral vancomycin in prevention of necrotising enterocolitis in preterm, very low birthweight infants

Developmental Pharmacokinetics of Antibiotics Used in Neonatal ICU: Focus on Preterm Infants

Neonatal Infections are among the most common reasons for admission to the intensive care unit. Neonatal sepsis (NS) significantly contributes to mortality rates. Empiric antibiotic therapy of NS recommended by current international guidelines includes benzylpenicillin, ampicillin/amoxicillin, and aminoglycosides (gentamicin). The rise of antibacterial resistance precipitates the growth of the use of antibiotics of the Watch (second, third, and fourth generations of cephalosporines, carbapenems, macrolides, glycopeptides, rifamycins, fluoroquinolones) and Reserve groups (fifth generation of cephalosporines, oxazolidinones, lipoglycopeptides, fosfomycin), which are associated with a less clinical experience and higher risks of toxic reactions. A proper dosing regimen is essential for effective and safe antibiotic therapy, but its choice in neonates is complicated with high variability in the maturation of organ systems affecting drug absorption, distribution, metabolism, and excretion. Changes in antibiotic pharmacokinetic parameters result in altered efficacy and safety. Population pharmacokinetics can help to prognosis outcomes of antibiotic therapy, but it should be considered that the neonatal population is heterogeneous, and this heterogeneity is mainly determined by gestational and postnatal age. Preterm neonates are common in clinical practice, and due to the different physiology compared to the full terms, constitute a specific neonatal subpopulation. The objective of this review is to summarize the evidence about the developmental changes (specific for preterm and full-term infants, separately) of pharmacokinetic parameters of antibiotics used in neonatal intensive care units.

Early antibiotics and risk for necrotizing enterocolitis in premature infants: A narrative review

While prompt initiation of antibiotics at birth due to concerns for early onset sepsis is common, it often leads to many preterm infants being exposed to treatment despite negative blood cultures. Such exposure to early antibiotics can impact the developing gut microbiome putting infants at increased risk of several diseases. Necrotizing enterocolitis (NEC), a devastating inflammatory bowel disease that affects preterm infants, is among the most widely studied neonatal disease that has been linked to early antibiotics. While some studies have demonstrated an increased risk of NEC, other studies have demonstrated seemingly contrary findings of decreased NEC with early antibiotics. Studies using animal models have also yielded differing findings of benefit vs. harm of early antibiotic exposure on subsequent NEC susceptibility. We thus sought to conduct this narrative review to help clarify the relationship between early antibiotics exposure and future risk of NEC in preterm infants. Our objectives are to: (1) summarize findings from human and animal studies that investigated the relationship between early antibiotics and NEC, (2) highlight important limitations of these studies, (3) explore potential mechanisms that can explain why early antibiotics may increase or decrease NEC risk, and (4) identify future directions for research.

Neonatal antibiotics have long term sex-dependent effects on the enteric nervous system

Infants and young children receive the highest exposures to antibiotics globally. Although there is building evidence that early life exposure to antibiotics increases susceptibility to various diseases including gut disorders later in life, the lasting impact of early life antibiotics on the physiology of the gut and its enteric nervous system (ENS) remains unclear. We treated neonatal mice with the antibiotic vancomycin during their first 10 postnatal days, then examined potential lasting effects of the antibiotic treatment on their colons during young adulthood (6 weeks old). We found that neonatal vancomycin treatment disrupted the gut functions of young adult female and male mice differently. Antibiotic-exposed females had significantly longer whole gut transit while antibiotic-treated males had significantly lower faecal weights compared to controls. Both male and female antibiotic-treated mice had greater percentages of faecal water content. Neonatal vancomycin treatment also had sexually dimorphic impacts on the neurochemistry and Ca2+ activity of young adult myenteric and submucosal neurons. Myenteric neurons of male mice were more disrupted than those of females, while opposing changes in submucosal neurons were seen in each sex. Neonatal vancomycin also induced sustained changes in colonic microbiota and lasting depletion of mucosal serotonin (5-HT) levels. Antibiotic impacts on microbiota and mucosal 5-HT were not sex-dependent, but we propose that the responses of the host to these changes are sex-specific. This first demonstration of long-term impacts of neonatal antibiotics on the ENS, gut microbiota and mucosal 5-HT has important implications for gut function and other physiological systems of the host. KEY POINTS: Early life exposure to antibiotics can increase susceptibility to diseases including functional gastrointestinal (GI) disorders later in life. Yet, the lasting impact of this common therapy on the gut and its enteric nervous system (ENS) remains unclear. We investigated the long-term impact of neonatal antibiotic treatment by treating mice with the antibiotic vancomycin during their neonatal period, then examining their colons during young adulthood. Adolescent female mice given neonatal vancomycin treatment had significantly longer whole gut transit times, while adolescent male and female mice treated with neonatal antibiotics had significantly wetter stools. Effects of neonatal vancomycin treatment on the neurochemistry and Ca2+ activity of myenteric and submucosal neurons were sexually dimorphic. Neonatal vancomycin also had lasting effects on the colonic microbiome and mucosal serotonin biosynthesis that were not sex-dependent. Different male and female responses to antibiotic-induced disruptions of the ENS, microbiota and mucosal serotonin biosynthesis can lead to sex-specific impacts on gut function.

Enteral broad-spectrum antibiotics antagonize the effect of fecal microbiota transplantation in preterm pigs

Preterm infants are at risk of multiple morbidities including necrotizing enterocolitis (NEC). Suspected NEC patients receive intravenous antibiotics (AB) to prevent sepsis, although enteral AB is arguably more effective at reducing NEC but is rarely used due to the risk of AB resistance. Fecal microbiota transplantation (FMT) has shown protective effects against NEC in animal experiments, but the interaction between AB and FMT has not been investigated in neonates. We hypothesized that administration of enteral AB followed by rectal FMT would effectively prevent NEC with negligible changes in AB resistance and systemic immunity. Using preterm piglets, we examined host and gut microbiota responses to AB, FMT, or a sequential combination thereof, with emphasis on NEC development. In a saline-controlled experiment, preterm piglets (n = 67) received oro-gastric neomycin (50 mg/kg/d) and amoxicillin-clavulanate (50/12.5 mg/kg/d) (hereafter AB) for four days after cesarean delivery, and were subsequently given rectal FMT from healthy suckling piglet donors. Whereas AB protected the stomach and small intestine, and FMT primarily protected the colon, the sequential combination treatment surprisingly provided no NEC protection. Furthermore, minor changes in the gut microbiota composition were observed in response to either treatment, although AB treatment decreased species diversity and increased AB resistance among coliform bacteria and Enterococci, which were both partly reversed by FMT. Besides, enteral AB treatment suppressed cellular and functional systemic immune development, which was not prevented by subsequent FMT. We discovered an antagonistic relationship between enteral AB and FMT in terms of NEC development. The outcome may depend on choice of AB compounds, FMT composition, doses, treatment duration, and administration routes, but these results challenge the applicability of enteral AB and FMT in preterm infants.

Vancomycin Use in Children and Neonates across Three Decades: A Bibliometric Analysis of the Top-Cited Articles

Vancomycin is frequently prescribed in pediatrics, especially in intensive care unit settings, to treat Gram-positive bacterial infections. This work aims to collect the top-cited articles of pediatric and infectious diseases areas to gather the current evidence and gaps of knowledge on the use of vancomycin in these populations. The most relevant journals reported in the "pediatrics" and "infectious diseases" categories of the 2019 edition of Journal Citation Reports were browsed. Articles with more than 30 citations and published over the last three decades were collected. A bibliometric analysis was performed and 115 articles were retrieved. They were published in 21 journals, with a median impact factor of 4.6 (IQR 2.9-5.4). Sixty-eight of them (59.1%) belonged to "infectious diseases" journals. The most relevant topic was "bloodstream/complicated/invasive infections", followed by "antibiotic resistance/MRSA treatment". As for population distribution, 27 articles were on children only and 27 on neonates, most of which were from intensive care unit (ICU) settings. The current literature mainly deals with vancomycin as a treatment for severe infections and antibiotic resistance, especially in neonatal ICU settings. Lately, attention to new dosing strategies in the neonatal and pediatric population has become a sensible topic.

Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory disease affecting premature infants. Intestinal microbial composition may play a key role in determining which infants are predisposed to NEC and when infants are at highest risk of developing NEC. It is unclear how to optimize antibiotic therapy in preterm infants to prevent NEC and how to optimize antibiotic regimens to treat neonates with NEC. This article discusses risk factors for NEC, how dysbiosis in preterm infants plays a role in the pathogenesis of NEC, and how probiotic and antibiotic therapy may be used to prevent and/or treat NEC and its sequelae.

Association of initial empirical antibiotic therapy with increased risk of necrotizing enterocolitis

Whether the prophylactic use of antibiotics increase the risk of necrotizing enterocolitis (NEC) remains controversial. This review aims to investigate initial empirical antibiotic therapy (IEAT) and is associated with the risk of NEC. PubMed, EMBASE, Cochrane Library, and Web of Science databases were searched through March 1, 2020. All studies on the impacts of antibiotic exposure on NEC development were included. Thirteen studies including 7901 participants were selected. Two reviewers independently examined the extracted data and assessed the quality of the included studies. Random-effects model was used to pool the effect estimates. We found that IEAT (≥ 5 days) was associated with an increased risk of NEC in adjusted (Odds risk [OR] 1.51, 95% confidence interval [CI] 1.22-1.87) and unadjusted (OR 2.35, 95% CI 1.54-3.57) analyses. Sensitivity analysis also supported these findings.Conclusion: The evidence suggests an association between IEAT (≥ 5 days) and the risk of NEC. Further studies are needed to address whether the association with IEAT is causal.What is Known:•Necrotizing enterocolitis (NEC) is acute inflammatory necrosis of the intestinal tractin the newborn infant.•Some observational studies have associated initial empirical antibiotics with an increased risk of subsequent NEC.What is New:•Initial empirical antibiotic therapy (IEAT) (≥ 5 days) appear to increase the risk of NEC.

Does oral vancomycin use necessitate therapeutic drug monitoring?

PURPOSE

Oral vancomycin use has generally increased as a consequence of the need to treat and/or prevent Clostridium (Clostridiodes) difficile-associated disease (CDAD). This review examines the cumulative scientific evidence that guides therapeutic monitoring of oral vancomycin therapy.

METHODS

The existing publications were reviewed from the time of the drug's inception to July 2019. This review utilized access as available in PubMed, EMBASE, CINAHL Plus, and the Cochrane Library.

RESULTS

Case reports and small patient series have documented anecdotal-associated elevations in serum levels. Correlation of absorbed vancomycin with subsequent toxicity is difficult to determine, but serum levels approaching those obtained after parenteral administration have raised concern. Prolonged usage and total dosing over 500 mg/day among adult age ranges have been associated with accumulation. In addition, risk factors for vancomycin accumulation systemically after oral dosing include renal compromise, combined oral and other enteral therapy, severe CDAD, other intercurrent bowel inflammation, polypharmacy, and increased patient complexity/morbidity.

CONCLUSION

Until systemic toxicity from oral vancomycin absorption is better understood, individual considerations should be made for therapeutic serum monitoring during oral vancomycin treatment. Therapeutic drug monitoring is suggested for several high-risk situations in which high blood levels may be anticipated.

Prevention of necrotizing enterocolitis in premature infants – an updated review

Necrotizing enterocolitis (NEC) is among the most common and devastating diseases encountered in premature infants, yet the true etiology continues to be poorly understood despite decades of research. Recently, gut bacterial dysbiosis has been proposed as a risk factor for the development of NEC. Based on this theory, several best clinical practices designed to reduce the risk of NEC have been proposed and/or implemented. This review summarizes the results of recent clinical trials and meta-analyses that support some of the existing clinical practices for reducing the risk of NEC in premature infants. It is evident that human milk feeding can reduce the incidence of NEC. While most of the studies demonstrated that probiotic supplementation can significantly reduce the incidence of NEC in premature infants, there are still some concerns regarding the quality, safety, optimal dosage, and treatment duration of probiotic preparations. Antibiotic prophylaxis does not reduce the incidence of NEC, and prolonged initial empirical use of antibiotics might in fact increase the risk of NEC for high-risk premature infants. Lastly, standardized feeding protocols are strongly recommended, both for prevention of postnatal growth restriction and NEC.

Probiotics and the prevention of necrotizing enterocolitis

BACKGROUND

Immaturity of the host immune system and alterations in the intestinal microbiome appear to be key factors in the pathogenesis of necrotizing enterocolitis (NEC). The aim of this paper is to weigh the evidence for the use of probiotics to prevent NEC in premature infants.

METHODS

Animal studies, randomized controlled trials, observational cohort studies and meta-analyses involving administration of probiotic products for the prevention of NEC were reviewed. This review of the evidence summarizes the available preclinical and clinical data.

RESULTS

In animal models probiotic microbes alter the intestinal microbiome, decrease inflammation and intestinal permeability and decrease the incidence and severity of experimental NEC. In randomized, placebo-controlled trials and cohort studies of premature infants, probiotic microbes decrease the risk of NEC, death and sepsis.

CONCLUSION

Evidence is strong for the prevention of NEC with the use of combination probiotics in premature infants who receive breast milk. The potential risks and benefits of probiotic administration to premature infants should be carefully reviewed with parents.

TYPE OF STUDY

Therapeutic.

LEVEL OF EVIDENCE

I.

New Nutritional and Therapeutical Strategies of NEC

Necrotizing enterocolitis (NEC) is an acquired severe disease of the digestive system affecting mostly premature babies, possibly fatal and frequently associated to systemic complications. Because of the severity of this condition and the possible long-term consequences on the child's development, many studies have aimed at preventing the occurrence of the primary events at the level of the bowel wall (ischemia and necrosis followed by sepsis) by modifying or manipulating the diet (breast milk versus formula) and/or the feeding pattern (time for initiation after birth, continuous versus bolus feeding, modulation of intake according clinical events). Feeding have been investigated so far in order to prevent NEC. However, currently well-established and shared clinical nutritional practices are not available in preventing NEC. Nutritional and surgical treatments of NEC are instead well defined. In selected cases surgery is a therapeutic option of NEC, requiring sometimes partial intestinal resection responsible for short bowel syndrome. In this paper we will investigate the available options for treating NEC according to the Walsh and Kliegman classification, focusing on feeding practices in managing short bowel syndrome that can complicate NEC. We will also analyze the proposed ways of preventing NEC.

The initial prophylactic antibiotic usage and subsequent necrotizing enterocolitis in high-risk premature infants: a systematic review and meta-analysis

OBJECTIVE

To investigate the correlation between the initial prophylactic antibiotic use and the subsequent NEC in high-risk premature infants.

METHODS

We performed a literature search of PubMed, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), and the Web of Science, and nine studies with a total of 5207 infants were selected for inclusion in this study.

RESULTS

The pooled estimate for the seven studies combined indicating that prophylactic antibiotic usage was associated with a non-significant trend toward increased incidence of NEC [odds ratio (OR) 0.75; 95% confidence interval (CI) 0.26-2.17], and prolonged exposure to prophylactic antibiotics, compared with limited prophylactic antibiotic use, was associated with a significant trend toward the risk of increasing incidence of NEC (OR 1.31; 95% CI 1.08-1.59).

CONCLUSION

Current evidence does not support the use of prophylactic antibiotics to reduce the incidence of NEC for high-risk premature infants.

Antibiotic Treatment Preventing Necrotising Enterocolitis Alters Urinary and Plasma Metabolomes in Preterm Pigs

Necrotising enterocolitis (NEC) is a serious gut inflammatory condition in premature neonates, onset and development of which depend on the gut microbiome. Attenuation of the gut microbiome by antibiotics can reduce NEC incidence and severity. However, how the antibiotics-suppressed gut microbiome affects the whole-body metabolism in NEC-sensitive premature neonates is unknown. In formula-fed preterm pigs, used as a model for preterm infants, plasma and urinary metabolomes were investigated by LC-MS and ¹H NMR, with and without antibiotic treatment immediately after birth. While it reduced the gut microbiome density and NEC lesions as previously reported, the antibiotic treatment employed in the current study affected the abundance of 44 metabolites in different metabolic pathways. In antibiotics-treated pigs, tryptophan metabolism favored the kynurenine pathway, relative to the serotonin pathway, as shown by specific metabolites. Metabolites associated with the gut microbiome, including 3-phenyllactic acid, 4-hydroxyphenylacetic acid, and phenylacetylglycine, all from phenylalanine, and three bile acids showed lower levels in the antibiotics-treated pigs where the gut microbiome was extensively attenuated. Findings in the current study warrant further investigation of metabolic and developmental consequences of antibiotic treatment in preterm neonates.

Impact of Antibiotics on Necrotizing Enterocolitis and Antibiotic-Associated Diarrhea

Antibiotic treatment alters the composition and metabolic function of the intestinal microbiota. These alterations may contribute to the pathogenesis of necrotizing enterocolitis (NEC) and antibiotic-associated diarrhea (AAD). Recent studies are beginning to unravel the contribution of specific groups of microbes and their metabolic pathways to these diseases. Probiotics or other microbiota-targeted therapies may provide effect strategies to prevent and treat NEC and AAD.

Necrotizing: A historical perspective

Necrotizing enterocolitis is a devastating disease afflicting premature infants, though after 50 years of investigation, the pathophysiology remains elusive. This report describes the possible etiologic factors from a historical perspective, and outlines the importance of human milk, intestinal blood flow, and intestinal blood flow changes from a developmental perspective over the last 40-50 years.

Feeding issues in IUGR preterm infants

Intra-uterine growth restriction (IUGR) is a severe and quite common problem in obstetrics. A condition of placental dysfunction can lead to a cardiovascular adaptation in the fetus characterized by a redistribution of cardiac output to maintain oxygen supply to the heart, adrenal glands and brain - the so-called brain sparing effect - at the expense of visceral organs (such as the gastrointestinal system). This condition may predispose IUGR infants to impaired gut function after birth. A higher incidence of necrotizing enterocolitis (NEC) is documented in IUGR preterm infants. Therefore, a common practice in neonatal intensive care units is to delay feeds to reduce the risk of feeding intolerance. Recent trials, however, have shown that early enteral feeding in IUGR infants is safe and it would appear, on the basis of the few available data, that breast milk could offer protection against NEC. This mini-review offers an update on feeding in IUGR infants. Future perspectives on the usefulness of Doppler and regional splanchnic and cerebral saturation monitoring for deciding when to start feeding are also provided.

Early Versus Late Minimal Enteral Feeding in Weeks Preterm Growth-Restricted neonates with Abnormal Antenatal Doppler Studies

Abstract Background: Preterm and growth-restricted babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure. Objective: To evaluate the effects of an "early" enteral feeding regimen, starting on day 2 after birth compared to late enteral feeding, starting on day 6 after birth in preterm growth restricted babies with abnormal antenatal Doppler studies regarding the incidence of NEC and feeding intolerance. Patients and Methods: Babies with gestational age below 37 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen. Results: Hundred-thirty three infants enrolled in the study: 66 received early feeding and 67 received delayed feeding. The incidence of NEC and feeding intolerance was not significantly different between the two groups. Conclusion: Early minimal enteral feeding (MEF) of preterm infants with IUGR and abnormal antenatal Doppler results may not have a significant effect on the incidence of NEC or feeding intolerance.

Necrotizing enterocolitis in very low birth weight infants: a systemic review

Necrotizing enterocolitis (NEC) is the most common serious gastrointestinal disorder affecting very preterm or very low birth weight infants. The risk is inversely proportional to gestational age and weight at birth. Fetal growth restriction and compromise may be additional specific risk factors. Despite extensive research and animal studies etiopathogenesis, preventive strategies and management options remain controversial. The present paper reviews the literature for recent advances and newer insights for changing epidemiological trends, pathogenesis, role of inflammatory cytokines, and various preventive and management strategies.

Risk factors for necrotizing enterocolitis totalis: a case-control study

OBJECTIVE

The objective of this study was to compare demographic and clinical events in three groups of preterm neonates: those with necrotizing enterocolitis totalis (NEC-T), those with NEC non-totalis (NEC non-T) and in preterm patients without NEC.

STUDY DESIGN

This retrospective case-control study was conducted at Yale New Haven Children's Hospital using patient data from January 1991 to December 2007. Study patients were less than 36 weeks of gestational age (GA) at birth, without gastrointestinal (GI) malformations. Cases (NEC-T) were diagnosed at operation or at autopsy with observation of >80% necrosis of the GI tract. Two control groups were assigned: Group 1 or NEC non-T and Group II or Non-NEC. Two to four controls per case were matched to cases by GA at birth±2 weeks. Demographic and clinical data for the day of diagnosis and retrospectively up to 7 days preceding diagnosis were recorded for those with NEC-T and NEC. Group II controls were matched for date of birth and day of life, in addition to GA at birth.

RESULT

A total of 14 075 patients were admitted to the Newborn Special Care Unit during the study interval. Overall 328 patients (2.3%) developed NEC≥Bell's Stage II; 39 patients met inclusion criteria for NEC-T case status; 148 NEC non-T and 110 non-NEC controls were assigned. In the comparison of NEC T and NEC non-T neonates, use of breast milk was associated with decreased risk of NEC-T, adjusted odds ratio (OR)=0.26, 95% confidence interval (CI) of OR=0.08-0.085, P=0.03. When NEC T and non-NEC patients were compared, having reached full-enteral feeds before the date of diagnosis of the matched case (adjusted OR=28.5, 95% CI of OR=2.7-299, P=0.005) and use of breast milk (adjusted OR=0.09, 95% CI of OR=0.02-0.56, P=0.01) were significantly different between the two groups.

CONCLUSION

Breast milk usage was significantly associated with decreased occurrence of NEC-T in our comparison of NEC-T, NEC non-T and non-NEC patients. Although there were some differences, the majority of demographic and clinical variables assessed were not shown to be significantly different between cases and controls. This highlights the need for more biological data in assessing risk of developing NEC-T.

ADEPT - Abnormal Doppler Enteral Prescription Trial

BACKGROUND

Pregnancies complicated by abnormal umbilical artery Doppler blood flow patterns often result in the baby being born both preterm and growth-restricted. These babies are at high risk of milk intolerance and necrotising enterocolitis, as well as post-natal growth failure, and there is no clinical consensus about how best to feed them. Policies of both early milk feeding and late milk feeding are widely used. This randomised controlled trial aims to determine whether a policy of early initiation of milk feeds is beneficial compared with late initiation. Optimising neonatal feeding for this group of babies may have long-term health implications and if either of these policies is shown to be beneficial it can be immediately adopted into clinical practice.

METHODS AND DESIGN

Babies with gestational age below 35 weeks, and with birth weight below 10th centile for gestational age, will be randomly allocated to an "early" or "late" enteral feeding regimen, commencing milk feeds on day 2 and day 6 after birth, respectively. Feeds will be gradually increased over 9-13 days (depending on gestational age) using a schedule derived from those used in hospitals in the Eastern and South Western Regions of England, based on surveys of feeding practice. Primary outcome measures are time to establish full enteral feeding and necrotising enterocolitis; secondary outcomes include sepsis and growth. The target sample size is 400 babies. This sample size is large enough to detect a clinically meaningful difference of 3 days in time to establish full enteral feeds between the two feeding policies, with 90% power and a 5% 2-sided significance level. Initial recruitment period was 24 months, subsequently extended to 38 months.

DISCUSSION

There is limited evidence from randomised controlled trials on which to base decisions regarding feeding policy in high risk preterm infants. This multicentre trial will help to guide clinical practice and may also provide pointers for future research.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN: 87351483.

Enteral glutamine and/or arginine supplementation have favorable effects on oxidative stress parameters in neonatal rat intestine

OBJECTIVE

To investigate and compare the effects of enteral glutamine and arginine supply on lipid peroxidation and antioxidant enzyme levels in the small intestine of healthy breast-fed rats.

MATERIALS AND METHODS

The study comprised 40 newborn Sprague-Dawley rats born to 5 mother rats. Newborn rats were randomly divided into 4 groups. Starting from day 1 until day 21, group I received only breast milk; group II received breast milk and 200 mg/kg/day oral glutamine; group III received breast milk and 200 mg/kg/day oral arginine; and group IV received breast milk, 200 mg/kg/day glutamine, and 200 mg/kg/day arginine. Malondialdehyde levels and glutathione peroxidase (GPx) and superoxide dismutase activities were measured.

RESULTS

The lowest malondialdehyde levels were found in group II (P = 0.0001). Superoxide dismutase activity was found to be significantly higher in group II than group I (P < 0.001). Of the 4 groups, GPx activity was highest in group IV. GPx activity in group II was significantly higher than in group I (P = 0.001) or group III (P = 0.001). GPx activity was higher in group IV than in group I (P = 0.001) or group III (P = 0.001).

CONCLUSIONS

Enteral glutamine alone or in the presence of arginine has favorable effects on oxidative stress not only in experimental models of hypoxia-reoxygenation, but also in healthy newborn rats. This suggests that in premature neonates with insufficient oxidative resistance, glutamine and arginine supplementation may help prevent necrotizing enterocolitis.

Probiotic and prebiotic supplementation for the prevention of neonatal necrotizing enterocolitis

The pathophysiology of necrotizing enterocolitis (NEC) has not been clearly elucidated, but recent studies support the role of unbalanced pro-inflammatory signaling, leading to intestinal necrosis in premature infants. Although breast milk feeding is thought to reduce the risk of this condition, there are no preventive or therapeutic approaches that have consistently shown to be effective for this common and devastating disease. Recent studies show that probiotic colonization is abnormal in preterm neonates, and enteral supplementation with a variety of probiotic organisms can reduce the risk of disease. This chapter summarizes the current state-of-the-art regarding probiotics and NEC, but suggests caution until appropriately regulated products are available for use in this high-risk population.

Outcomes of the "clip and drop" technique for multifocal necrotizing enterocolitis

BACKGROUND

The "clip and drop" (CD) has been proposed as a useful strategy in the management of severe multifocal necrotizing enterocolitis (NEC). There is little published data on clinical outcomes after this intervention. We report a 2-center experience with this technique.

METHODS

A retrospective review of infants who underwent CD between 1998 and 2006 at 2 tertiary pediatric surgery centers. Data recorded included intestinal resections, interval between laparotomies, anastomoses at subsequent surgery, time to full feeds, and complications including mortality. Data are reported as median with ranges.

RESULTS

Thirteen infants (7 male, 6 female) with a birth weight of 811 (514-2110) g underwent CD of up to 5 bowel segments. In 8 of 9 early survivors, all CD segments were viable. Six patients (46%) were alive at 29 (9-96) months. Survivors underwent 4 (3-4) laparotomies and 4 (2-6) bowel anastomoses and had intestinal continuity restored at 67 (51-162) days.

CONCLUSIONS

With multiple interventions, half the infants in this high-risk group survived and achieved full enteral feeds. The CD is a valuable technique in a selected group of infants with fulminant NEC.

Necrotizing enterocolitis in newborns: pathogenesis, prevention and management

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

Necrotising enterocolitis in very low birth weight infants in Italy: incidence and non-nutritional risk factors

Incidence and non-nutritional risk factors were estimated for necrotising enterocolitis in 2035 very low birth weight infants, admitted to 14 tertiary-level neonatal intensive care units in Lombardy, northern Italy. There were 62 necrotising enterocolitis cases, with an overall incidence of 3.1%. After adjustment for gestational age and centre, the risk factors were mechanical ventilation, patent ductus arteriosus, and late-onset sepsis, whereas surfactant treatment was associated with decreased risk. Significant variations in necrotising enterocolitis incidence among hospitals were found.

Uso de fatores de crescimento epidérmico e estimulador de colônias de granulócitos na prevenção e tratamento da enterocolite necrosante no recém-nascido

OBJETIVO: Revisar os conhecimentos existentes em relação ao uso de fatores de crescimento epidérmico e estimulador de colônias de granulócitos na prevenção e/ou no tratamento da enterocolite necrosante (ECN) durante o período neonatal. FONTES DE DADOS: Revisão da literatura, nas bases de dados Medline, Lilacs, SciELO e PubMed, utilizando os unitermos "recém-nascidos", "enterocolite" e "fatores de crescimento", no período de 2003 a 2007. Nesta busca, 49 artigos foram encontrados, sendo 17 pertinentes ao tema. Também foram utilizados outros artigos, independente do ano de publicação, relacionados a aspectos definidores da ECN no recém-nascido. SÍNTESE DOS DADOS: A ECN continua sendo responsável por uma elevada morbimortalidade neonatal. Os mecanismos fisiopatológicos vêm sendo elucidados e, a partir deles, são discutidas novas terapias, como o uso de fatores de crescimento, destacando-se o fator de crescimento epidérmico e o fator estimulador de colônias de granulócitos. CONCLUSÕES: O uso de fatores de crescimento no tratamento e prevenção da ECN neonatal parece promissor. É necessário maior número de ensaios clínicos para comprovar sua eficácia e segurança. Enquanto isso, a melhor prática médica continua sendo a prevenção da doença.

Necrotizing enterocolitis: recent scientific advances in pathophysiology and prevention

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality among infants in the neonatal intensive care unit. Here we review the epidemiology and pathophysiology of NEC, with an emphasis on the latest research findings and potential areas for future research. NEC continues to be one of the most devastating and unpredictable diseases affecting premature infants. Despite decades of research, the pathogenesis of this disease remains unclear, and prevention and treatment strategies are limited. Hopefully, future studies aimed at understanding premature intestinal defenses, commensal or probiotic bacterial influences, and possible genetic predisposition will lead to the improvement of prevention and treatment strategies.

Necrotizing enterocolitis

In necrotizing enterocolitis (NEC) the small (most often distal) and/or large bowel becomes injured, develops intramural air, and may progress to frank necrosis with perforation. Even with early, aggressive treatment, the progression of necrosis, which is highly characteristic of NEC, can lead to sepsis and death. This article reviews the current scientific knowledge related to the etiology and pathogenesis of NEC and discusses some possible preventive measures.

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.

High-dose oral erythromycin decreased the incidence of parenteral nutrition-associated cholestasis in preterm infants

BACKGROUND & AIMS

Feeding intolerance because of functional gastrointestinal dysmotility and parenteral nutrition-associated cholestasis (PNAC) are common problems in preterm, very-low-birth-weight (VLBW) infants. This double-blind, randomized, placebo-controlled study aimed to assess the effectiveness of "high-dose" oral erythromycin as a prokinetic agent in decreasing the incidence of PNAC. Two secondary end points, including the time to achieve full enteral feeding and the duration of parenteral nutrition, were also evaluated.

METHODS

Infants consecutively admitted to the neonatal unit were randomized to receive erythromycin (12.5 mg/kg/dose every 6 hours for 14 days) or an equivalent volume of normal saline (placebo) if they attained less than half the total daily fluid intake (<75 mL/kg/day) as milk feeds on day 14 of life.

RESULTS

Of 182 VLBW infants enrolled, 91 received erythromycin. The incidence of PNAC was significantly lower in erythromycin-treated infants (18/91) compared with placebo infants (37/91; P = .003). Treated infants achieved full enteral nutrition significantly earlier (mean, 10.1; SE, 1.7 days; P < .001), and the duration of parenteral nutrition was also significantly decreased by 10 days (P < .001). Importantly, fewer infants receiving erythromycin had 2 or more episodes of septicemia (n = 4) compared with placebo patients (n = 13, P = .03). No serious adverse effect was associated with erythromycin treatment.

CONCLUSIONS

High-dose oral erythromycin can be considered as a rescue measure for VLBW infants who fail to establish adequate enteral nutrition and in whom anatomically obstructive pathologies of the gastrointestinal tract have been excluded.

IP-10 is an early diagnostic marker for identification of late-onset bacterial infection in preterm infants

Very low birth weight (VLBW) infants with suspected late-onset infection requiring sepsis screening were enrolled in a prospective study to evaluate the diagnostic utilities of a comprehensive panel of key chemokines and cytokines, both individually and in combination, to identify diagnostic markers for early recognition of bacterial sepsis and necrotizing enterocolitis (NEC). Plasma chemokines interleukin (IL)-8, interferon-gamma-inducible protein 10 (IP-10), monokine induced by interferon-gamma (MIG), monocyte chemoattractant protein 1 (MCP-1), growth-related oncogene-alpha (GRO-alpha), and regulated upon activation of normal T cell expressed and secreted (RANTES) and cytokines IL-1beta, IL-6, IL-10, IL-12p70, and tumor necrosis factor alpha (TNF-alpha) were measured at the onset of sepsis (0 h) and 24 h later. Of 155 suspected infection episodes, 44 were classified as infected. Concentrations of all studied inflammatory mediators (except IL-1beta and RANTES) were significantly higher in the infected than in the noninfected group at 0 h, but the levels decreased precipitously by 24 h. IP-10 with a plasma cutoff concentration > or = 1250 pg/mL could identify all septicemic and NEC cases and had the highest overall sensitivity (93%) and specificity (89%) at 0 h. We conclude that preterm infants have the ability to induce a robust chemokine and cytokine response during sepsis, and IP-10 is a sensitive early marker of infection.

Necrotising enterocolitis

Necrotising enterocolitis is one of the most common gastrointestinal emergencies in newborn infants. Here we review the epidemiology, clinical presentation, and pathophysiology of the disease, as well as strategies for diagnosis, management, and prevention. Necrotising enterocolitis is one of the most devastating and unpredictable diseases affecting premature infants. Despite decades of research, its pathogenesis remains unclear; diagnosis can be difficult; and treatment is challenging. We will need to improve our understanding of intestinal defences in premature infants, dietary and bacterial factors, and genetic effects that could predispose infants to necrotising enterocolitis before we can develop new strategies for prevention and treatment.

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

For the first time a multimodal approach to NEC prophylaxis is reported, consisting of early trophic feeding with human breast milk, and enteral administration of an antibiotic, an antifungal agent, and probiotics. A retrospective analysis of local protocol of NEC prophylaxis is presented. Included were all VLBWI admitted to the NICU, including transfers within the first 28 days of life. These infants were divided into two groups, an "inborn group" (infants admitted within the first 24 h of life) and an "outborn group" (infants admitted after the onset of their second day of life). Prophylaxis of NEC according to protocol was started at the day of admission, and was continued until discharge. Between 1998 and 2004, 405 VLBWI were admitted, including all transfers within the first 28 days of life. A total of 334 (82%) infants were admitted within the first 24 h of life (inborn group), and 71 (18%) were admitted after 24 h of life (outborn group). Five infants developed clinical features of necrotizing enterocolitis. The inborn group showed a NEC incidence of 0.7% (two infants), whereas the outborn group showed a NEC incidence of 4.5% (three infants), respectively. This difference was significant (P=0.049, Fisher's exact test). A surgical treatment with bowel resection was performed in two infants (both from the outborn group). The present study used a combination of different strategies, all having shown to have some beneficial effect, but not having brought a clinical breakthrough in single administration studies. Combinated were the beneficial effects of human breast milk feeding, oral antiobiotics, oral antifungal agents, and the administration of probiotics. In a homogenous group of preterm infants, using this protocol of multimodal NEC prophylaxis, there was a very low incidence of NEC, when started within the first 24 h of life.

Control of imported and acquired methicillin-resistant Staphylococcus aureus (MRSA) in mechanically ventilated patients: a dose-response study of enteral vancomycin to reduce absolute carriage and infection

This study aimed to quantify the animate source provided by the patients using the concept of "absolute carriage" by multiplying the carrier rate by the level of carriage; and to compare the impact of a low and high dose of an oropharyngeal vancomycin gel on the absolute MRSA carriage and infection. In all, 265 patients were included, 126 were MRSA positive. Fifty-five patients received 2% vancomycin gel during the first year whilst 4% vancomycin gel was given to 50 patients during the second year. Surveillance swabs of throat and rectum were obtained from all eligible patients on admission and then twice weekly. The vancomycin protocol was started as soon as the surveillance cultures were positive for MRSA. Those patients received one gram of enteral vancomycin daily, divided into four doses. During the first year 2% vancomycin gel 4 ml (80 mg) was applied in the oropharynx in four doses in addition to the enteral solution (Group A). During the second year 4% vancomycin gel 4 ml (160 mg) was used (Group B). The absolute carriage was high during both periods: 3.6 for Group A, and 3.2 for Group B. The 4% vancomycin protocol significantly reduced the absolute carriage, compared to the 2% vancomycin protocol: 2.6 versus 1.5 (P < 0.01). Significant reduction in secondary endogenous infections was found in the second year: seven versus 15 patients (P < 0.05). A total of 3,588 microbiological samples were processed. Neither Staphylococcus aureus with intermediate sensitivity to vancomycin (VISA) nor vancomycin-resistant enterococci (VRE) were detected.

Carbon monoxide protects against the development of experimental necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a disease of neonates that is increasing in incidence and often results in significant morbidity and mortality. Carbon monoxide (CO), a byproduct of the catabolism of heme, is known to have anti-inflammatory and antiapoptotic properties. In this study, we aimed to demonstrate that inhaled CO protects against the development of intestinal inflammation in a model of experimental NEC as well as decreases enterocyte cell death in vitro. Additionally, we also aimed to demonstrate that CO decreases enterocyte production of inducible nitric oxide synthase (iNOS) and nitric oxide (NO). Neonatal rats were exposed to intermittent hypoxia exposure and formula feeding to induce experimental NEC. Animals randomized to CO treatment were put in an environment containing 0.025% CO for 1 h/day on days 1-3 of life. All animals were killed on day 4 of life. In vitro experiments were performed with IEC-6 cells, a rat enterocyte cell line. Cells were examined for viability, iNOS production, and elaboration of NO. We found that CO diminished levels of serum inflammatory cytokines and nitrites, protected against intestinal inflammation, and decreased ileal iNOS production and protein nitration in a model of experimental NEC. In vitro, CO decreased cytokine- or hypoxia/endotoxin-induced iNOS and NO production. CO also abrogated TNF-alpha- and actinomycin D-induced apoptosis or hypoxia/endotoxin-induced cell death. In conclusion, 1 h of daily low-dose inhaled CO protected against the development of intestinal inflammation in a model of experimental NEC. iNOS and NO production were decreased by CO both in vivo and in vitro. CO may prove to be a useful clinical adjunct in the treatment of NEC.

Too much short chain fatty acids cause neonatal necrotizing enterocolitis

Nenatal necrotizing enterocolitis (NEC) is a disease mainly affects premature infants. It is well known that prematurity, enteral formula feeding, and bacterial colonization are three major risk factors for NEC. Acetic acid, propionic acid and butyric acid are short chain fatty acids (SCFAs), which are produced mainly in the colon by bacterial fermentation of undigested carbohydrates. Although luminal production of modest quantities of SCFAs is essential for normal colonic mucosal function, excessive production/accumulation of SCFAs may arise in premature infants due to increased luminal carbohydrates malabsorption and poor gastrointestinal motility, and may have deleterious effects on mucosal integrity. Therefore, it is proposed that too much luminal short chain fatty acids cause neonatal NEC.

Necrotizing enterocolitis: preventative strategies

Necrotizing enterocolitis (NEC) remains a major cause of morbidity and mortality in premature infants. Although the pathogenesis of NEC is unclear, prevention strategies have been developed based on clinical observations and epidemiologic and experimental data. Most current strategies have centered on feeding practices (eg, institution of feeds, advancement of feeds, composition of feeds, and standardization of feeding practices). Emerging strategies include amino acid supplementation, the use of platelet-activating factor(PAF) antagonists or PAF-acetylhydrolase administration, polyunsaturated fatty acid administration, epidermal growth factor administration, and the use of pre- and probiotics.

Effectiveness and safety of enteral vancomycin to control endemicity of methicillin-resistant Staphylococcus aureus in a medical/surgical intensive care unit

A prospective trial was undertaken to assess the effectiveness and safety of enteral vancomycin in controlling methicillin-resistant Staphylococcus aureus (MRSA) in an endemic setting. Over the 49 month period patients aged >14 years were enrolled, following admission to a medical/surgical intensive care unit (ICU) and expected to require ventilation for three days or more. A total of 799 patients were included in the trial. Period one, 1 July 1996-30 April 1997, (N=140), was observational. During period two, 1 May 1997-30 September 1998, (N=258), surveillance samples were obtained. MRSA carriers were isolated and received enteral vancomycin. During period three, 1 October 1998-31 July 2000, (N=400), all ventilated patients were given selective digestive decontamination (SDD) with polymyxin E, tobramycin, amphotericin B and vancomycin and four days of intravenous cefotaxime. The primary endpoints were: (1) incidence of patients with diagnostic samples positive for MRSA acquired on the ICU; (2) incidence of patients with vancomycin-resistant enterococci (VRE) in surveillance or diagnostic samples; (3) incidence of patients with samples positive for S. aureus with intermediate sensitivity to glycopeptides (GISA). The incidence of patients with MRSA in diagnostic samples were 31%, 14%, and 2% in periods one, two and three, respectively (P<0.001). There was a VRE outbreak involving 13 patients during period three. VRE disappeared with no change in policy. GISA was not detected. These findings support the effectiveness and safety of enteral vancomycin in the control of MRSA.

Neonatal necrotizing enterocolitis: an overview

PURPOSE OF REVIEW

Necrotizing enterocolitis represents a disease entity that remains quite challenging for neonatologists all around the world, in that its aetiology has yet to be revealed, but it is the cause of death for many premature infants each year, affecting up to 28% of very low birthweight infants. This is an attempt to improve the management of affected babies and stimulate more research concerning new diagnostic tools.

RECENT FINDINGS

Current trends in the field of (early) diagnosis, such as: (1) imaging techniques, e.g. contrast radiography, portal vein ultrasonography, magnetic resonance, radionuclide scanning; (2) gastrointestinal tonometry; (3) the detection of biochemical markers, cytokines, growth factors; and (4) the determination of the mean peak hydrogen: carbon dioxide ratio excreted in breath, are only some of those mentioned. Various novel preventive techniques are also presented, among which platelet-activating factor acetyl hydrolase activity enhancement, platelet-activating factor receptor antagonists and probiotics, such as Bifidobacterium infantis and Lactobacillus acidophilus, seem quite promising. Regarding treatment, the use of oxygenated perfluorocarbon has added to the limited alternatives available. These data along with other recent discoveries concerning the risk factors and pathogenesis of this disease create a full picture of the current opinion on this topic.

SUMMARY

Keeping in mind that the key to confronting such a devastating disorder as necrotizing enterocolitis is early diagnosis and prevention, both clinically applicable and experimental advances are presented with the hope of improving the survival rates of patients affected.

Enteral vancomycin to control methicillin-resistant Staphylococcus aureus outbreak in mechanically ventilated patients

BACKGROUND

Screening for and treating gut carriage of methicillin-resistant Staphylococcus aureus (MRSA) may control transmission and subsequent endemicity of MRSA.

OBJECTIVE

Enteral vancomycin was evaluated as a measure to control an outbreak of MRSA infection in the intensive care unit (ICU).

METHODS

During the 8-month study of sequential design, 176 patients were admitted, 65 (37%) of whom required a minimum of 3 days of ventilation. Forty-four patients were studied in the first 5 months, during which traditional measures were reinforced (control group). During the following 3 months, 13 of 21 patients developed MRSA carriage and received 2 g/day of enteral vancomycin, with high standards of hygiene maintained (treatment group).

RESULTS

Thirty-three MRSA infections occurred in 22 patients (50%) in the control group, whereas 2 patients (9.5%) had 2 MRSA infections in the treatment group (P <.05 for carriage, infection rates, and episodes). Of the 33 MRSA infections in the control group, 27 were due to MRSA acquired in the ICU, whereas the 2 infections in the treatment group were primary endogenous (ie, caused by MRSA present in the patient's admission flora). The probability of developing an MRSA infection was reduced in patients receiving enteral vancomycin compared with patients in the control group (odds ratio, 0.37; 95% CI, 0.24-0.58). Enteral vancomycin significantly reduced the level of MRSA carriage; the mean carriage index was 1.01 in the control group versus 0.58 in the test group (P <.05). Neither vancomycin-resistant enterococci nor vancomycin-intermediate Staphylococcus aureus were isolated from either surveillance or diagnostic samples.

CONCLUSIONS

The eradication of MRSA gut carriage by enteral vancomycin in a small subset of ICU patients was effective in the control of an MRSA outbreak.

Probiotics and prebiotics: A brief overview

Probiotics and prebiotics are 2 food ingredients that confer physiologic effects through the gastrointestinal tract. Probiotics have been defined as viable microorganisms that (when ingested) have a beneficial effect in the prevention and treatment of specific pathologic conditions. These microorganisms are believed to exert biological effects through a phenomenon known as colonization resistance, whereby the indigenous anaerobic flora limits the concentration of potentially pathogenic (mostly aerobic) flora in the digestive tract. Other modes of action, such as supplying enzymes or influencing enzyme activity in the gastrointestinal tract, may also account for some of the other physiologic effects that have been attributed to probiotics. Conversely, prebiotics are nondigestible food ingredients that beneficially affect host health by selectively stimulating the growth and/or activity of 1 or a limited number of bacteria in the colon. The prebiotic, fructooligosaccharide (FOS), is found naturally in many foods, such as wheat, onions, bananas, honey, garlic, or leeks. They can also be isolated from chicory root or synthesized enzymatically from sucrose. Fermentation of FOS in the colon results in a large number of physiologic effects including increasing the numbers of bifidobacteria in the colon, increasing calcium absorption, increasing fecal weight, shortening of gastrointestinal transit time, and possibly lowering blood lipid levels. Other effects that have been observed in animal models include an increase in cecal weight and an increase in fecal nitrogen excretion. The increase in bifidobacteria has been assumed to benefit human health by producing compounds to inhibit potential pathogens, by reducing blood ammonia levels, and by producing vitamins and digestive enzymes.

Age-dependent changes in the regulation of cyclooxygenases in the gastrointestinal tract after gram-negative endotoxemia

BACKGROUND

Cyclooxygenases (COXs) modulate prostaglandin synthesis in the gastrointestinal tract. Prostaglandins have been shown to have a cytoprotective effect on bowel mucosa in adults, but no similar data are available in neonates. Thus, the purpose of the current study was to evaluate age-dependent changes in gastrointestinal tract COX regulation after Escherichia coli lipopolysaccharide exposure in rats.

METHODS

Stomach, small bowel, and large bowel COX-1 and COX-2 mRNA levels (reverse transcription polymerase chain reaction technique) and protein content (Western blot) were obtained from neonates (younger than 3 days old) and adult rats 18 hours after exposure to E. coli O111:B4 lipopolysaccharide toxin. Untreated animals served as controls.

RESULTS

Stomach, small bowel, and large bowel tissue COX-1 mRNA levels in the newborn were significantly lower (P < 0.01) than in the adult. No age-dependent differences were found for COX-2 mRNA levels. After lipopolysaccharide exposure, no significant changes in COX-1 levels were seen at either age, whereas COX-2 mRNA levels were increased only in the stomach for both ages. Western blot analysis of small bowel tissue for COX-1 and COX-2 showed no lipopolysaccharide-induced changes in protein content, but the COX-1 content was significantly lower in the newborn (P < 0.01).

CONCLUSIONS

In the rat, COX expression in the gastrointestinal tract is regulated in an age-dependent fashion. Lower COX-1 expression and a lack of observable increase in COX-2 mRNA levels in the newborn small bowel after endotoxemia may render the bowel more susceptible to bowel injury early in life.

Enteral human IgG for prevention of necrotising enterocolitis: a placebo-controlled, randomised trial

BACKGROUND

Neonatal necrotising enterocolitis is a serious, commonly fatal disease in premature neonates. Although feeding with expressed breast milk and other good nursery practices are partly protective, preventive measures are needed. Treating neonates enterally with a mixture of human IgA and IgG, prepared from donated blood, has been claimed to protect against necrotising enterocolitis. However, no IgA preparation is available in Australia. Our aim, therefore, was to identify whether or not enteral IgG could prevent the disorder.

METHODS

We did a multicentre, double-blind, placebo- controlled trial. We randomly assigned 768 infants to receive human IgG 1200 mg/kg daily, and 761 to receive placebo, for up to 28 days. Treatment began at the same time as enteral feeding. The primary outcome measure was the proportion of infants who developed definite necrotising enterocolitis during the trial, and any deaths that resulted from the disorder in the treatment and placebo groups. Analysis was on an intention-to-treat basis.

FINDINGS

43 infants developed definite necrotising enterocolitis in the IgG group, ten of whom died. In the placebo group, 41 infants contracted the disorder and six died (p=0.47). 25 infants on IgG and 36 on placebo had suspect necrotising enterocolitis (p=0.14).

INTERPRETATION

Supplementation of enteral feeds with human IgG does not reduce necrotising enterocolitis.

Randomised controlled study of oral erythromycin for treatment of gastrointestinal dysmotility in preterm infants

AIM

To evaluate the effectiveness of oral erythromycin as a prokinetic agent for the treatment of moderately severe gastrointestinal dysmotility in preterm very low birthweight infants.

METHODS

A prospective, double blind, randomised, placebo controlled study in a tertiary referral centre of a university teaching hospital was conducted on 56 preterm infants (< 1500 g) consecutively admitted to the neonatal unit. The infants were randomly allocated by minimisation to receive oral erythromycin (12.5 mg/kg, every six hours for 14 days) or an equivalent volume of placebo solution (normal saline) if they received less than half the total daily fluid intake or less than 75 ml/kg/day of milk feeds by the enteral route on day 14 of life. The times taken to establish half, three quarters, and full enteral feeding after the drug treatment were compared between the two groups. Potential adverse effects of oral erythromycin and complications associated with parenteral nutrition were assessed as secondary outcomes.

RESULTS

Twenty seven and 29 infants received oral erythromycin and placebo solution respectively. The times taken to establish half, three quarters, and full enteral feeding after the drug treatment were significantly shorter in the group receiving oral erythromycin than in those receiving the placebo (p < 0.05, p < 0.05 and p < 0.0001 respectively). There was also a trend suggesting that more infants with prolonged feed intolerance developed cholestatic jaundice in the placebo than in the oral erythromycin group (10 v 5 infants). None of the infants receiving oral erythromycin developed cardiac dysrhythmia, pyloric stenosis, or septicaemia caused by multiresistant organisms.

CONCLUSIONS

Oral erythromycin is effective in facilitating enteral feeding in preterm very low birthweight infants with moderately severe gastrointestinal dysmotility. Treated infants can achieve full enteral feeding 10 days earlier, and this may result in a substantial saving on hyperalimentation. However, until the safety of erythromycin has been confirmed in preterm infants, this treatment modality should remain experimental. Prophylactic or routine use of this medication for treatment of mild cases of gastrointestinal dysmotility is probably not warranted at this stage.