Probiotics and neonatal intestinal infection

Benefits of probiotics in preterm neonates in low-income and medium-income countries: a systematic review of randomised controlled trials

OBJECTIVE

Although there is an overall reduction in underfive mortality rate, the progress in reducing neonatal mortality rate has been very slow. Over the last 20 years, preterm births have steadily increased in low-income and medium-income countries (LMICs) particularly in sub-Saharan Africa and South Asia. Preterm birth is associated with increased mortality and morbidity, particularly in LMICs. Based on systematic reviews of randomised controlled trials (RCTs), many neonatal units in high-income countries have adopted probiotics as standard of care for preterm neonates. We aimed to systematically review the safety and efficacy of probiotics in reducing mortality and morbidity in preterm neonates in LMICs.

DESIGN

Systematic review and meta-analysis of RCTs.

DATA SOURCES

Medline, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature and E-abstracts from Pediatric Academic Society meetings and other paediatric and neonatal conference proceedings were searched in January 2017.

ELIGIBILITY CRITERIA

RCTs comparing probiotics versus placebo/no probiotic in preterm neonates (gestation<37 weeks) conducted in LMICs.

RESULTS

Total 23 (n=4783) RCTs from 4 continents and 10 LMICs were eligible for inclusion in the meta-analysis using fixed effect model. The risk of necrotising enterocolitis (NEC greater than or equal to stage II) (risk ratio (RR) 0.46 (95% CI 0.34 to 0.61), P<0.00001, numbers needed to treat (NNT) 25 (95% CI 20 to 50)), late-onset sepsis (LOS) (RR 0.80 (95% CI 0.71 to 0.91), P=0.0009, NNT 25 (95% CI 17 to 100)) and all-cause mortality (RR 0.73 (95% CI 0.59 to 0.90), P=0.003, NNT 50 (95% CI 25 to 100)) were significantly lower in probiotic supplemented neonates. The results were significant on random effects model analysis and after excluding studies with high risk of bias. No significant adverse effects were reported.

CONCLUSION

Probiotics have significant potential to reduce mortality and morbidity (eg, NEC, LOS) in preterm neonates in LMICs.

Probiotic Supplementation and Late-Onset Sepsis in Preterm Infants: A Meta-analysis

CONTEXT

Late-onset sepsis (LOS) is a major cause of mortality and morbidity in preterm infants. Despite various preventive measures, its incidence continues to remain high, hence the urgent need for additional approaches. One such potential strategy is supplementation with probiotics. The updated Cochrane Review (2014) did not find benefits of probiotics in reducing the risk of LOS in preterm infants (19 studies, N = 5338). Currently there are >30 randomized controlled trials (RCTs) of probiotics in preterm infants that have reported on LOS.

OBJECTIVES

To conduct a systematic review including all relevant RCTs.

DATA SOURCES

PubMed, Embase, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature, and E-abstracts from the Pediatric Academic Society meetings and other pediatric and neonatal conference proceedings were searched in June and August 2015.

STUDY SELECTION

RCTs comparing probiotics versus placebo/no probiotic were included.

DATA EXTRACTION

Relevant data were extracted independently by 3 reviewers.

RESULTS

Pooled results from 37 RCTs (N = 9416) using fixed effects model meta analysis showed that probiotics significantly decreased the risk of LOS (675/4852 [13.9%] vs 744/4564 [16.3%]; relative risk, 0.86; 95% confidence interval, 0.78-0.94; P = .0007; I(2) = 35%; number needed to treat, 44). The results were significant even after excluding studies with high risk of bias.

CONCLUSIONS

Probiotic supplementation reduces the risk of LOS in preterm infants.

Evaluation of the expression of I-FABP and L-FABP in a necrotizing enterocolitis model after the use of Lactobacillus acidophilus

BACKGROUND/PURPOSE

Necrotizing enterocolitis (NEC) is a severe intestinal disease that primarily affects premature babies, leading to high mortality and morbidity. Probiotics represent an important alternative prophylaxis for NEC but its mechanism of action is poorly understood. Moreover, intestinal and liver-type fatty acid-binding proteins (I-FABP and L-FABP) may be utilized because markers of intestinal injury, including NEC. We aimed to evaluate the protection induced by the Lactobacillus acidophilus on the intestines of newborn rats submitted to experimental NEC using I-FABP and L-FABP as biomarkers.

METHODS

Sprague-Dawley newborn rats were divided into three groups: (1) C (control)-breast-fed; (2) NEC-subjected to NEC protocol and (3) NECP-NEC+probiotic. Morphometric, intestinal lesion, immunohistochemistry and Western blotting analysis were performed. Statistical significant differences were considered when p<0.05.

RESULTS

Intestinal weight was lower in NEC and NECP compared to C (p<0.05). Intestinal injury was lower in NECP compared to NEC. Prophylactic probiotic recovered mucosa and muscular layers' thickness to C levels (p<0.05). I-FABP and L-FABP expressions in NECP showed intermediate values between C and NEC.

CONCLUSION

L. acidophilus had a protective effect on the development of NEC and FABPs could demonstrate the degree of tissular damage of the intestine.

Cohort study of probiotics in a North American neonatal intensive care unit

OBJECTIVE

To determine whether routine probiotic administration to very preterm infants would reduce the incidence of necrotizing enterocolitis (NEC) without adverse consequences.

STUDY DESIGN

Since the end of July 2011, we have administered a probiotic mixture to all admitted infants of <32 weeks' gestation. We give 0.5 g of a mixture of 4 bifidobacteria (Bifidobacterium breve, bifidum, infantis, and longum) and Lactobacillus rhamnosus HA-111 [corrected] (2 × 10(9) colony-forming units) per day, starting with the first feed, until the infant reaches 34 weeks. We compared complications among infants admitted during the first 17 months of routine use with those admitted during the previous 17 months.

RESULTS

Two hundred ninety-four infants received probiotics, and 317 infants formed the comparison group. Introduction of probiotics was associated with a reduction in NEC (from 9.8% to 5.4%, P < .02), a nonsignificant decrease in death (9.8% to 6.8%), and a significant reduction in the combined outcome of death or NEC (from 17% to 10.5%, P < .05). After adjustment for gestational age, intrauterine growth restriction, and sex, the improvements remained significant (OR for NEC, 0.51; 95% CI, 0.26-0.98; OR for death or NEC, 0.56; 95% CI, 0.33-0.93). There was no effect of probiotics on health care-associated infection.

DISCUSSION

A product that is readily available in North America, that has excellent quality control, and that contains strains similar to those that have been shown effective in randomized controlled trials substantially reduced the frequency of NEC in our neonatal intensive care unit.

Controversies in the management of the critically ill: the role of probiotics

Probiotics are commercially available, viable, non-pathogenic micro-organisms that, when ingested in sufficient quantities, exert a health benefit to the host derived through modification of the gut flora, local release of antimicrobial factors, maintenance of integrity of the gut barrier, competition for epithelial adherence, prevention of bacterial translocation, and modulation of the local immune response. In critically ill patients, probiotics appear to lead to decreased susceptibility to antibiotic-associated diarrhoea, Clostridium difficile infections, ventilator-associated pneumonia, necrotising enterocolitis, acute severe pancreatitis, sepsis and multiple organ dysfunction syndrome as well as a shortened duration of infections. Current scientific evidence supporting the use of probiotics is not conclusive and is mainly derived from single-centre, not very well designed trials that are limited by many factors including small sample sizes, heterogeneity in the probiotic strains used, effectiveness of the combined strains, optimum dose regimens, frequency and duration of administration, and certainly incomplete knowledge of the mechanism of action of each strain. Probiotics appear to be well tolerated, whilst adverse events are very rare. The most commonly reported adverse events include bacteraemia, fungaemia and sepsis. At present, based on the available evidence and although helpful and relatively safe for certain disease conditions, routine use of probiotics in the critically ill is not recommended.

Probiotic, prebiotic, and synbiotic use in critically ill patients

PURPOSE OF REVIEW

To summarize the existing data regarding the use of probiotics, prebiotics, and synbiotics in select disorders encountered in the intensive care unit setting.

RECENT FINDINGS

Recent systematic reviews and meta-analyses have more rigorously aggregated the fragmented primary data which suffers from multiple limitations.

SUMMARY

Probiotics are living microorganisms which, when ingested in adequate amounts, provide health benefits to the host. The mechanisms of these benefits include improved gastrointestinal barrier function, modification of the gut flora by inducing host cell antimicrobial peptides, releasing probiotic antimicrobial factors, competing for epithelial adherence, and immunomodulation to the advantage of the host. In the intensive care unit, probiotics appear to provide benefits in antibiotic-associated diarrhea, ventilator-associated pneumonia, and necrotizing enterocolitis. With increasing rates of antibiotic resistance among common nosocomial pathogens and fewer new antibiotics in the research pipeline, increasing attention has been placed on nonantibiotic approaches to the prevention and treatment of nosocomial infections. Existing studies of probiotics in critically ill patients are limited by heterogeneity in probiotic strains, dosages, duration of administration, and small sample sizes. Although probiotics are generally well tolerated and adverse events are very rare, the results of the PROPATRIA (Probiotics Prophylaxis in Patients with Predicted Severe Acute Pancreatitis) trial highlight the need for meticulous attention to safety monitoring. Better identification of the ideal characteristics of effective probiotics coupled with improved understanding of mechanisms of action will help to delineate the true beneficial effects of probiotics in various disorders.

Adherence inhibition of Cronobacter sakazakii to intestinal epithelial cells by prebiotic oligosaccharides

Cronobacter sakazakii is an opportunistic pathogen that has been implicated in meningitis, NEC, and sepsis in neonates. Colonization and subsequent infection and invasion of C. sakazakii require that the organism adheres to host cell surfaces. Agents that inhibit or block attachment of the pathogen to epithelial cells could be useful in reducing infections. The goal of this research was to assess the ability of prebiotic galactooligosaccharides (GOS) and polydextrose (PDX) to inhibit adherence of C. sakazakii 4603 to a HEp-2 human cell line. Adherence experiments were performed in the presence or absence of prebiotics using HEp-2 cells grown to confluency on glass coverslips. Prebiotics and bacteria were added and incubated for 3 h. Coverslips were washed, and adherence was determined by cultural and microscopic methods. When measured microscopically or by cultural methods, significant reductions in adherence (56 and 71%, respectively) of C. sakazakii were observed in the presence of GOS (16 mg/ml). Adherence inhibition also occurred (48%) when a GOS-PDX blend (8 mg/ml each) was tested, although PDX by itself had less effect. Similar results were also observed for Caco-2 cells and also for another strain of C. sakazakii (29004). These results suggest that GOS and PDX, alone and in combination, may have an anti-adhesive effect on C. sakazakii and directly inhibit the adherence to gastrointestinal epithelial cells.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Lactobacillus reuteri DSM 17938 in infantile colic: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To test the efficacy of Lactobacillus reuteri on infantile colic and to evaluate its relationship to the gut microbiota.

STUDY DESIGN

Fifty exclusively breastfed colicky infants, diagnosed according to modified Wessel's criteria, were randomly assigned to receive either L reuteri DSM 17 938 (10(8) colony-forming units) or placebo daily for 21 days. Parental questionnaires monitored daily crying time and adverse effects. Stool samples were collected for microbiologic analysis.

RESULTS

Forty-six infants (L reuteri group: 25; placebo group: 21) completed the trial. Daily crying times in minutes/day (median [interquartile range]) were 370 (120) vs 300 (150) (P=.127) on day 0 and 35.0 (85) vs 90.0 (148) (P=.022) on day 21, in the L reuteri and placebo groups, respectively. Responders (50% reduction in crying time from baseline) were significantly higher in the L reuteri group versus placebo group on days 7 (20 vs 8; P=.006), 14 (24 vs 13; P=.007), and 21 (24 vs 15; P=.036). During the study, there was a significant increase in fecal lactobacilli (P=.002) and a reduction in fecal Escherichia coli and ammonia in the L reuteri group only (P=.001). There were no differences in weight gain, stooling frequency, or incidence of constipation or regurgitation between groups, and no adverse events related to the supplementation were observed.

CONCLUSION

L. reuteri DSM 17 938 at a dose of 10(8) colony-forming units per day in early breastfed infants improved symptoms of infantile colic and was well tolerated and safe. Gut microbiota changes induced by the probiotic could be involved in the observed clinical improvement.

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

BACKGROUND

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

METHODOLOGY/PRINCIPAL FINDINGS

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

CONCLUSIONS/SIGNIFICANCE

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

Cronobacter spp. (Enterobacter sakazakii): advice, policy and research in Canada

Although the number of reported cases of Cronobacter infection in Canada is low, Health Canada has been actively studying this organism since 1991. After reviewing the situation at the national level and due to health concerns with powdered formulae and its international trade, in 2003, Health Canada raised this issue at the international level by proposing to revise the Code of Practice for Powdered Formulae for Infants and Young Children at the Codex Alimentarius Committee of Food Hygiene. Canada volunteered to chair the Working Group that would be developing the Code, and the Code was completed in four years. The Code contributed to an improvement in the hygienic conditions in plants manufacturing Powdered Infant Formula (PIF), resulting in a lower level of product contamination with Cronobacter species. Canada has produced a document detailing Good Manufacturing Practices (GMPs) for Infant Formula in Canada. Health Canada uses the GMPs as a basis for assessing the manufacturing information received in pre-market notifications for new or changed infant formulas. Health Canada does not have microbiological criteria for Cronobacter spp. in PIF; however, we are currently working on developing these criteria. At present, there are no active or passive surveillance systems for Cronobacter spp. in Canada, although this has been discussed. Health Canada has recently adapted and condensed FAO/WHO guidelines to develop a draft guidance document for the hygienic preparation and handling of PIF in home and hospitals/care settings, which outline requirements for parents, caregivers, and staff in hospitals and day-care centres. Health Canada's Bureau of Microbial Hazards conducts research on the ecology, biology and pathogenesis of Cronobacter spp. Some of the research projects include specific aspects of molecular typing, virulence studies involving animal models, as well as in vitro tissue culture work to examine adhesion and invasion. Collaborative research is also being done with the Canadian National Research Council, using NMR and mass spectroscopy to reveal the structure of the O-polysaccharide of the various Cronobacter species. This review summarizes and discusses current activities that are being undertaken in Canada with respect to Cronobacter spp.

Probiotics for the prevention of respiratory tract infections: a systematic review

We evaluated the clinical evidence regarding probiotic use for the prevention of respiratory tract infections (RTIs). Randomised controlled trials (RCTs) studying the effects of probiotics for the prevention of upper or lower RTIs were systematically identified. Fourteen RCTs (twelve involving healthy subjects and two involving patients with RTIs) were included. Various Lactobacillus strains were used in seven RCTs, combinations of Lactobacillus and Bifidobacterium strains were used in five RCTs, and a Bifidobacterium strain and a non-pathogenic Enterococcus faecalis strain were used in one RCT, respectively. In ten RCTs no difference was found regarding the incidence of RTIs in the probiotic arm compared with the control arm, whereas the remaining four RCTs favoured the use of probiotics. Reduction in the severity of symptoms related to RTIs was noted in five of six RCTs that provided relevant data. In three of nine RCTs that provided relevant data, the clinical course of RTIs was shorter in the probiotic arm, whereas no difference was found in the remaining six RCTs. In conclusion, probiotics may have a beneficial effect on the severity and duration of symptoms of RTIs but do not appear to reduce the incidence of RTIs.

Long-term colonization of a Lactobacillus plantarum synbiotic preparation in the neonatal gut

BACKGROUND

Probiotic, prebiotic, and synbiotic (a combination of pro- and prebiotic) supplements increasingly are being used to prevent and treat a variety of health conditions. Although colonization is considered a key element in the success of such treatments, few clinical studies have addressed colonizing ability. Studies are even more limited in neonates and infants, who may benefit most from such treatment. The present study was conducted to determine the colonizing ability, tolerance, and impact on the stool flora of 7 days of administration of a synbiotic supplement to a neonatal cohort, in preparation for a larger hospital-based trial.

PATIENTS AND METHODS

In this randomized, double-masked, controlled trial, healthy inborn newborns >35 weeks of gestational age and >1800 g birth weight were randomized between 1 and 3 days after birth to receive an oral synbiotic preparation (Lactobacillus plantarum and fructooligosaccharides) or a dextrose saline placebo. Two babies were treated with the synbiotic preparation for every 1 baby treated with the placebo. Duration of therapy was 7 days. Comprehensive stool cultures were done at baseline and on days 3, 7, 14, 21, and 28.

RESULTS

Nineteen infants received the active study supplement and 12 infants received the placebo for 7 days. L plantarum was cultured from the stools of 84% of the treated infants after 3 days of treatment, and from 95% of infants on day 28 after birth. Of the infants, 100%, 94%, 88%, 56%, and 32% remained colonized at months 2, 3, 4, 5, and 6, respectively. In both groups, the total mean number of species and the mean log colony counts increased over time. The number of bacterial species was significantly higher on days 21 and 28 in the synbiotic preparation group compared with placebo (P = 0.002 and 0.03, respectively). There was a linear increase in the mean log gram-negative colony counts in the placebo group during the 4-week period that was significantly higher than that in the Lactobacillus group on days 14, 21, and 28 (P < 0.001 for each). In contrast, the supplement group had significantly higher gram-positive colony counts on days 14 (P = 0.002) and 28 (P = 0.04). Only 1 infant in the placebo group was colonized with L fermentum during the first 28 days of life. No difference was found in the percent increase in weight between baseline and day 7, but on day 28 and months 2, 3, and 6, the percent increase from baseline was higher in the probiotic-treated group (P </= 0.05). The supplement was tolerated well.

CONCLUSIONS

The synbiotic preparation colonized quickly after 3 days of administration and the infants stayed colonized for several months after therapy was stopped. There was an increase in bacterial diversity and gram-positive organisms and a reduction of gram-negative bacterial load in the treatment group. Because a combination preparation was used, it is difficult to specifically attribute the colonization to either the probiotic or prebiotic component in this study. Larger efficacy trials are warranted to examine the mechanism of action and precise effects of these supplements.

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.

Apparently non-specific results found using a norovirus antigen immunoassay for fecal specimens from neonates

Norovirus is increasingly recognized as a frequent cause of non-bacterial gastroenteritis. Despite a 10-fold increase in the number of cases reported following the availability of enzyme immunoassays, there are no reports yet from preterm neonates. We report on a sudden clustering of antigen-positive enzyme immuno assays results in a level III neonatal intensive care unit, involving 22 of 43 infants screened. Although antigen-positive samples were significantly associated with bloody stools (P<0.001) and gastric residues (P<0.02), norovirus infection could not be confirmed by reverse-transcriptase polymerase chain reaction or electron microscopy. We question the validity of the so called norovirus-specific antigen assays and warn against overreacting to positive enzyme immunoassays results without reverse-transcriptase polymerase chain reaction confirmation especially in the neonatal setting.

Formula fortified with live probiotic culture reduces pulmonary and gastrointestinal bacterial colonization and translocation in a newborn animal model

BACKGROUND/PURPOSE

Acidified diets are protective against intestinal bacterial colonization and translocation. Probiotic diets are designed to modulate the intestinal flora to enhance mucosal immunity. This study was designed to determine if formula acidified with live probiotic decreases bacterial gut colonization and translocation, and is equally tolerated as other acidified diets.

METHODS

One hundred twenty-eight rabbit pups delivered via cesarean section [cesarean delivery, cesarean birth, abdominal delivery] were randomly assigned to 4 feeding groups: NAN Nestle (control, pH 7.0), NAN acidified with citric acid (pH 4.55), biologically acidified Pelargon (pH 4.55), and NAN with live Lactococcus lactis culture (pH 4.2). Pups were gavage fed every 12 hours with Enterobacter cloacae challenges of 10 colony-forming units/mL per feed and killed on day of life 3. Lungs, liver, spleen, mesenteric lymph nodes (MLNs), stomach, and cecum were cultured and quantitatively analyzed for target organism growth. Results were analyzed using chi(2) tests.

RESULTS

NAN with live probiotic culture, when compared with Pelargon, acidified NAN, and NAN, significantly reduced the incidence of Enterobacter pulmonary colonization (P < .01), bacterial translocation (liver, P < .025; spleen and MLN, P < .05), and gastric and intestinal colonization (P < .001 for both).

CONCLUSION

Probiotic-fortified formula provides superior protection against pulmonary and gastrointestinal bacterial colonization and translocation compared with neutral and acidified formulas, and is equally tolerated.

Immunomodulation, Part V: probiotics

The five-part "Pointers in Practical Pharmacology" immunomodulation series has presented some of the agents researchers are investigating in hopes of finding the means to effectively prevent and treat infectious processes in neonates. The phosphodiesterase inhibitor pentoxifylline appears promising, but large, randomized, clinical trials are still lacking. So far, there is no clear evidence to support the use of G-CSF for either the prevention or the treatment of sepsis. The results of a large, randomized, clinical trial of G-CSF in the United Kingdom are pending. Although intravenous immunoglobulin (IVIG) therapy does not appear to be useful in the prevention of sepsis, its effectiveness in the treatment of sepsis is uncertain. It is hoped that the results of the International Neonatal Immunotherapy Study will provide definitive answers regarding treatment of sepsis with IVIG. The "conditionally essential" amino acid glutamine administered either enterally or parenterally does not make a difference in the rate of systemic infection or NEC in very low birth weight infants. Finally, probiotics appear promising as documented by at least two of the three randomized, clinical trials described here. As the search continues for agents to enhance the neonate's immune system and prevent and treat infectious diseases, remember that our best prevention tool is excellent and consistent hand hygiene.

Healthcare-associated infections in neonatal units: lessons from contrasting worlds

Neonatal intensive care units are vulnerable to outbreaks and sporadic incidents of healthcare-associated infections (HAIs). The incidence and outcome of these infections are determined by the degree of immaturity of the neonatal immune system, invasive procedures involved, the aetiological agent and its antimicrobial susceptibility pattern and, above all, infection control policies practised by the unit. It is important to raise awareness of infection control practices in resource-limited settings, since overdependence upon antimicrobial agents and co-existing lack of awareness of infection control is encouraging the emergence of multi-drug-resistant nosocomial pathogens. We reviewed 125 articles regarding HAIs from both advanced and resource-limited neonatal units in order to study risk factors, aetiological agents, antimicrobial susceptibility patterns and reported successes in infection control interventions. The articles include surveillance studies, outbreaks and sporadic incidents. Gram-positive cocci, viruses and fungi predominate in reports from the advanced units, while Gram-negative enteric rods, non-fermenters and fungi are commonly reported from resource-limited settings. Antimicrobial susceptibility patterns from surveillance studies determined the empirical therapy used in each neonatal unit. Most outbreaks, irrespective of the technical facilities available, were traced to specific lack of infection control practices. We discuss infection control interventions, with special emphasis on their applicability in resource-limited settings. Cost-effective measures for implementing these interventions, with particular reference to the recognition of the role of the microbiologist, the infection control team and antibiotic policies are presented.

Special circumstances: trophic feeds, necrotizing enterocolitis and bronchopulmonary dysplasia

There are many unresolved issues regarding how to feed the extremely-low-birth-weight (ELBW) infant. Trophic feedings of small volumes of breast milk or formula do not appear to increase the incidence of necrotizing enterocolitis (NEC). For prevention of NEC, breast milk, antenatal steroids and fluid restriction each confers a benefit. Because the incidence of NEC is relatively low, to determine if a particular prevention strategy is effective, large numbers of infants would need to be enrolled in a prospective, randomized controlled trial, and such trials are rare. Candidate therapies for NEC prevention that warrant further study include oral immunoglobulins, probiotics, long-chain polyunsaturated fatty acids and arginine. Suboptimal nutrition in ELBW infants is common in the early postnatal period. This is also the most critical time for the development of bronchopulmonary dysplasia, when even brief periods of malnutrition have significant effects on lung development and growth.