Early administration of Bifidobacterium breve to preterm infants: randomised controlled trial

Probiotics and prebiotics in pediatrics

This clinical report reviews the currently known health benefits of probiotic and prebiotic products, including those added to commercially available infant formula and other food products for use in children. Probiotics are supplements or foods that contain viable microorganisms that cause alterations of the microflora of the host. Use of probiotics has been shown to be modestly effective in randomized clinical trials (RCTs) in (1) treating acute viral gastroenteritis in healthy children; and (2) preventing antibiotic-associated diarrhea in healthy children. There is some evidence that probiotics prevent necrotizing enterocolitis in very low birth weight infants (birth weight between 1000 and 1500 g), but more studies are needed. The results of RCTs in which probiotics were used to treat childhood Helicobacter pylori gastritis, irritable bowel syndrome, chronic ulcerative colitis, and infantile colic, as well as in preventing childhood atopy, although encouraging, are preliminary and require further confirmation. Probiotics have not been proven to be beneficial in treating or preventing human cancers or in treating children with Crohn disease. There are also safety concerns with the use of probiotics in infants and children who are immunocompromised, chronically debilitated, or seriously ill with indwelling medical devices. Prebiotics are supplements or foods that contain a nondigestible food ingredient that selectively stimulates the favorable growth and/or activity of indigenous probiotic bacteria. Human milk contains substantial quantities of prebiotics. There is a paucity of RCTs examining prebiotics in children, although there may be some long-term benefit of prebiotics for the prevention of atopic eczema and common infections in healthy infants. Confirmatory well-designed clinical research studies are necessary.

Comparative analysis of the properties of bifidobacterial isolates from fecal samples of mother-infant pairs

OBJECTIVES

The aim of the study was to evaluate the possibility of Bifidobacterium breve transfer from the mother to her infant during the perinatal period.

MATERIALS AND METHODS

Hundred isolates of B breve and 80 isolates of Bifidobacterium longum were collected from paired fecal samples of mothers and their infants. Bacterial DNA from the samples was comparatively analyzed by random amplification of polymorphic DNA. The growth of the bacteria was examined in vitro.

RESULTS

The analysis of diversity in B breve population showed that infant-derived isolates had significantly less diversity than mother-derived isolates. The analysis of the similarity between these samples revealed that the number of shared type isolates tended to be higher in infants than in their mothers. In the isolates of B longum, however, no such difference was found in the diversity between mother- and infant-derived isolates. Examination of the growth of B breve strains revealed that the shared type strains have a significantly higher growth than nonshared strains both in the presence of galactooligosaccharides and at a higher redox potential.

CONCLUSIONS

These results suggested that subpopulations of B breve strains in the mothers may be transferred to their infants. Such populations may become dominant in the gut of infants at an early time after birth, during which time the transmission of the bifidobacteria of environmental origin is not yet established. B breve strain possessing a higher growth advantage in these conditions may be advantageous for colonization in the infant gut.

Effects of four Bifidobacteria on obesity in high-fat diet induced rats

AIM: To compare the effects of four Bifidobacteria strains (Bifidobacteria L66-5, L75-4, M13-4 and FS31-12, originated from normal human intestines) on weight gain, lipid metabolism, glucose metabolism in an obese murine model induced by high-fat diet.

METHODS: Forty-eight Sprague-Dawley rats were randomly divided into six groups. Control group received standard chow, model group received high-fat diet, and intervention groups received high-fat diet added with different Bifidobacteria strains isolated from healthy volunteers’ fresh feces. All rats were executed at the 6th weekend. Body weight (BW), obese indexes, oral glucose tolerance test, serum and liver lipid and serum insulin (INS) were tested. Liver lipid deposition was classified pathologically.

RESULTS: Compared with the model group, B. M13-4 improved BW gains (264.27 ± 26.91 vs 212.55 ± 18.54, P = 0.001) while B. L66-5 induced a decrease in BW (188.47 ± 11.96 vs 212.55 ± 18.54, P = 0.043). The rest two strains had no significant change in BW. All the four strains can reduce serum and liver triglyceride and significantly alleviate the lipid deposition in liver. All strains showed a trend of lowing serum and liver total cholesterol while B. L66-5 and B. FS31-12 did so more significantly. In addition, all the four strains showed no significant differences in serum INS and glucose level.

CONCLUSION: The response of energy metabolism to administration of Bifidobacteria is strain dependent. Different strains of Bifidobacteria might drive different directions of fat distribution.

Probiotics and prebiotics in preterm infants: where are we? Where are we going?

BACKGROUND

Uncertainty exists regarding the efficacy and safety of using probiotics and prebiotics in preterm infants.

AIM

To review the evidence on the effects of administering probiotics and/or prebiotics to preterm infants.

METHODS

MEDLINE and the Cochrane Library were searched in August 2008. A supplemental search was conducted in July 2009. Only systematic reviews/meta-analyses and randomized controlled trials (RCTs) that evaluated the effects of probiotics and/or prebiotics on relevant short- and long-term primarily clinically important health outcomes published in the English language were included.

RESULTS

One systematic review and 2 well-performed meta-analyses suggest that probiotics reduce the risk of necrotizing enterocolitis (NEC) (stage > or =2). One subsequently published RCT reported similar results. The 2 meta-analyses also demonstrated that probiotics reduce the risk of death due to all causes, but do not have an effect on the risk of sepsis or death due to NEC. Regarding prebiotics, one meta-analysis of 4 RCTs demonstrated that prebiotic-supplemented formula increases stool colony counts of bifidobacteria and lactobacilli in preterm neonates without adversely affecting weight gain. Because of the limited data regarding synbiotics, the relationship between their use and clinical outcomes in preterm infants remains unclear.

CONCLUSIONS

The findings from the 2 meta-analyses of the effects of probiotic administration on the prevention of NEC show potential for such dietary supplementation. However, they must be interpreted with caution because the beneficial effects of probiotics seem to be strain specific, thus, pooling data from different strains may result in misleading conclusions. Before the routine use of probiotics and/or prebiotics in preterm infants, data regarding which products should be administered, at what dose, and for how long are needed.

Updated meta-analysis of probiotics for preventing necrotizing enterocolitis in preterm neonates

OBJECTIVE

Systematic reviews of randomized, controlled trials (RCTs) indicate lower mortality and necrotizing enterocolitis (NEC) and shorter time to full feeds after probiotic supplementation in preterm (<34 weeks' gestation) very low birth weight (VLBW; birth weight <1500 g) neonates. The objective of this study was to update our 2007 systematic review of RCTs of probiotic supplementation for preventing NEC in preterm VLBW neonates.

METHODS

We searched in March 2009 the Cochrane Central register; Medline, Embase, and Cinahl databases; and proceedings of the Pediatric Academic Society meetings and gastroenterology conferences. Cochrane Neonatal Review Group search strategy was followed. Selection criteria were RCTs of any enteral probiotic supplementation that started within first 10 days and continued for > or =7 days in preterm VLBW neonates and reported on stage 2 NEC or higher (Modified Bell Staging).

RESULTS

A total of 11 (N = 2176), including 4 new (n = 783), trials were eligible for inclusion in the meta-analysis by using a fixed-effects model. The risk for NEC and death was significantly lower. Risk for sepsis did not differ significantly. No significant adverse effects were reported. Trial sequential analysis) showed 30% reduction in the incidence of NEC (alpha = .05 and .01; power: 80%).

CONCLUSIONS

The results confirm the significant benefits of probiotic supplements in reducing death and disease in preterm neonates. The dramatic effect sizes, tight confidence intervals, extremely low P values, and overall evidence indicate that additional placebo-controlled trials are unnecessary if a suitable probiotic product is available.

Bifidobacterium septicemia associated with postoperative probiotic therapy in a neonate with omphalocele

We report the one case of sepsis caused by Bifidobacterium breve administered as probiotic therapy. Probiotics can be a potential cause of an invasive disease and should be used with care in vulnerable patients.

Lack of effects of oral probiotics on growth and neurodevelopmental outcomes in preterm very low birth weight infants

OBJECTIVE

To evaluate growth and neurodevelopmental outcomes in preterm very low birth weight (PVLBW) infants treated with oral probiotics for the prevention of necrotizing enterocolitis (NEC).

STUDY DESIGN

A prospective follow-up study was performed in a cohort of PVLBW infants enrolled in a single center with a masked randomized control trial to evaluate the efficacy of oral probiotics in preventing NEC. Growth measures included weight, length, and head circumference. Neurologic and sensory performance was evaluated with standard techniques. Psychometric parameters were measured used the Bayley Scales of Infant Development II (BSID-II). The studies were performed at 3 years corrected age. The primary outcome was death or neurodevelopmental impairment.

RESULTS

Of the 367 subjects enrolled in trial, 301 (89.9%) were evaluated (153 in the probiotics group and 148 in the control group). There were no significant differences in growth or in any of the neurodevelopmental and sensory outcomes between the 2 groups.

CONCLUSIONS

Oral probiotics given to PVLBW infants at 1 week after birth to reduce the incidence of NEC did not affect growth and neurodevelopmental and sensory outcomes at 3 years corrected age.

Safety of probiotics in patients receiving nutritional support: a systematic review of case reports, randomized controlled trials, and nonrandomized trials

BACKGROUND

Probiotics are increasingly used in patients receiving nutritional support; however, some case reports and trials have questioned their safety in such patients.

OBJECTIVE

The objective was to investigate the safety of probiotics in patients receiving nutritional support through a systematic review of case reports, randomized controlled trials (RCTs), and nonrandomized trials.

DESIGN

The systematic review followed Cochrane and PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations. Six electronic databases were searched, a hand search of conference proceedings and reference lists was performed, and experts were contacted. Case reports, RCTs, and nonrandomized trials of probiotic use in patients also receiving enteral or parenteral nutrition were included in the review. Two reviewers independently screened the relevant articles and extracted the data.

RESULTS

In total, 1966 articles were identified, of which 72 fulfilled the inclusion criteria. There were 20 case reports of adverse events in 32 patients, all of which were infections due to Lactobacillus rhamnosus GG or Saccharomyces boulardii; the risk factors included central venous catheters and disorders associated with increased bacterial translocation. There were 52 articles reporting 53 trials in which 4131 patients received probiotics. Most trials showed either no effect or a positive effect on outcomes related to safety (eg, mortality and infections). Only 3 trials showed increased complications, which were largely noninfectious in nature and in specific patient groups (eg, transplant and pancreatitis). In 2 of these trials, the probiotic was administered through a postpyloric tube.

CONCLUSION

Many probiotics have been used safely in patients receiving nutritional support, although some probiotic products (strains or combinations) have been shown to increase the risk of complications in specific patient groups.

Intestinal microbiota and blue baby syndrome: probiotic therapy for term neonates with cyanotic congenital heart disease

Necrotizing enterocolitis (NEC) is the most common intestinal emergency among premature infants. Risk factors in premature infants include immature intestinal immunity and an intestinal microbiota dominated by hospital-acquired bacteria. Some probiotics have been shown to decrease the incidence of NEC in premature infants. Among term infants, NEC is rare. However, among term infants with cyanotic congenital heart disease (CCHD), the incidence of NEC is similar to that of premature infants but with even greater mortality rates. Mechanisms by which NEC occurs in term infants with CCHD are unknown. Of central interest is the potential role of changes in the intestinal microbiota and whether these can be modified with probiotic bacteria; accordingly, we review the literature, propose hypotheses and present the rationale for future studies involving preliminary probiotic clinical trials.

Effects of the enteral administration of Bifidobacterium breve on patients undergoing chemotherapy for pediatric malignancies

PURPOSE

Probiotics are expected to be effective in prophylaxis of infection in cancer patient, since infections in neutropenics are mainly caused by endogenous flora through the intestinal mucosa. However, the experience with the use of probiotics in immunocompromised patients is limited, and precise fecal bacteria analysis has not been reported. The aim of the study was to evaluate the effects of the enteral administration of the probiotic, Bifidobacterium breve strain Yakult, on its ability to prevent infection, fecal micro flora, and intestinal environments in cancer patients on chemotherapy.

METHODS

A placebo-controlled trial was performed at Juntendo University Hospital. Patients with malignancies admitted for chemotherapy (n = 42) were randomized into two groups receiving probiotic or placebo. The effects on infectious complications, natural killer cells, fecal micro flora, fecal organic acid concentrations, and fecal pH were studied.

RESULTS

The frequency of fever and the use of intravenous antibiotics were lower in the probiotic group than the placebo group. The probiotic administration enhanced the habitation of anaerobes. Disruption of the intestinal microbiota after chemotherapy such as the increase in the population levels of Enterobacteriaceae was observed at more pronounced manner in the placebo group in comparison to the probiotic group. The concentrations of total organic acids were maintained most of the time at the normal level, which constantly maintained the pH below 7.0 only in the probiotic group.

CONCLUSION

These data, although based on a limited number of patients and samples, suggest that administration of B. breve strain Yakult could be an effective approach for achieving clinical benefits in immunocompromised hosts by improving their intestinal environments.

Bifidobacterium mongoliense sp. nov., from airag, a traditional fermented mare's milk product from Mongolia

Two novel micro-organisms, designated strains YIT 10443(T) and YIT 10738, were isolated from airag, a traditional fermented mare's milk from Mongolia. The two strains were Gram-positive-staining, non-motile, asporogenous, catalase-negative, facultatively anaerobic rods of various shapes. Comparative analyses of 16S rRNA and ClpC ATPase (clpC) gene sequences and the presence of fructose-6-phosphate phosphoketolase (F6PPK) demonstrated that the novel strains were members of the genus Bifidobacterium. On the basis of 16S rRNA gene sequence similarity, the type strains of Bifidobacterium minimum (96.6 %) and Bifidobacterium psychraerophilum (95.7 %) were the closest neighbours of the novel strains, and DNA-DNA reassociation values with these strains were found to be lower than 15 %. The phenotypic and genotypic features demonstrated that the two strains represent a single, novel Bifidobacterium species, for which the name Bifidobacterium mongoliense sp. nov. is proposed. The type strain is YIT 10443(T) (=JCM 15461(T) =DSM 21395(T)).

Oral supplementation with probiotics in very-low-birth-weight preterm infants: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Although recent reports suggest that supplementation with probiotics may enhance intestinal function in premature infants, the mechanisms are unclear, and questions remain regarding the safety and efficacy of probiotics in extremely low-birth-weight infants.

OBJECTIVE

The objective was to evaluate the efficacy of probiotics on the digestive tolerance to enteral feeding in preterm infants born with a very low or extremely low birth weight.

DESIGN

In a bicentric, double-blind, randomized controlled clinical trial that was stratified for center and birth weight, 45 infants received enteral probiotics (Bifidobacterium longum BB536 and Lactobacillus rhamnosus GG; BB536-LGG) and 49 received placebo. The primary endpoint was the percentage of infants receiving >50% of their nutritional needs via enteral feeding on the 14th day of life. A triangular test was used to perform sequential analysis.

RESULTS

The trial was discontinued after the fourth sequential analysis concluded a lack of effect. The primary endpoint was not significantly different between the probiotic (57.8%) and placebo (57.1%) groups (P = 0.95). However, in infants who weighed >1000 g, probiotic supplementation was associated with a shortening in the time to reach full enteral feeding (P = 0.04). Other than colonization by the probiotic strains, no alteration in the composition of intestinal microbiota or changes in the fecal excretion of calprotectin was observed. No colonization by probiotic strains was detected in infants who weighed < or =1000 g, presumably because of more frequent suspensions of enteral feeding, more courses of antibiotic treatment, or both.

CONCLUSIONS

Supplementation with BB536-LGG may not improve the gastrointestinal tolerance to enteral feeding in very-low-birth-weight infants but may improve gastrointestinal tolerance in infants weighing >1000 g. This trial was registered at clinicaltrials.gov as NCT 00290576.

Influence of maternal bifidobacteria on the establishment of bifidobacteria colonizing the gut in infants

The aim of this study was to examine the influence of maternal intestinal and vaginal bifidobacteria on the establishment of bifidobacteria colonizing the gut in infants. Fecal samples from 110 healthy pregnant mothers within 1 mo before delivery and their babies at 1 mo of age and 100 vaginal swabs from the mother within 7 d before delivery were collected at a maternity hospital in Fukuoka city, Japan. The fecal and vaginal samples were assayed by PCR to detect Bifidobacterium species and by real-time PCR assays to estimate the bifidobacterial number. The detection of Bifidobacterium breve in the mothers' feces was significantly associated with increases in both the bifidobacterial counts and number of Bifidobacterium species in the babies' feces. In addition, a cesarean section was significantly associated with both a decrease in the counts and diversity of bifidobacteria in the babies' feces. The number of Bifidobacterium species detected in the vaginal swabs of mothers were not associated with either the bifidobacterial counts or the diversity of bifidobacteria in the babies' feces. The most important determinants of intestinal bifidobacteria in infants were the colonization of B. breve in the mothers' gut and vaginal delivery.

A randomized placebo-controlled comparison of 2 prebiotic/probiotic combinations in preterm infants: impact on weight gain, intestinal microbiota, and fecal short-chain fatty acids

OBJECTIVE

To compare the effect of 2 prebiotic/probiotic products on weight gain, stool microbiota, and stool short-chain fatty acid (SCFA) content of premature infants.

PATIENTS AND METHODS

This randomized, blinded, placebo-controlled trial included 90 premature infants treated with either a dietary supplement containing 2 lactobacillus species plus fructooligosaccharides (CUL, Culturelle, ConAgra, Omaha, NE), a supplement containing several species of lactobacilli and bifidobacteria plus fructooligosaccharides (PBP, ProBioPlus DDS, UAS Laboratories, Eden Prairie, MN), or placebo (a dilute preparation of Pregestamil formula) twice daily for 28 days or until discharge if earlier. The primary outcome was weight gain. Secondary outcomes were stool bacterial analysis by culture and 16S rDNA quantitative polymerase chain reaction and stool SCFA content measured by high performance liquid chromatography.

RESULTS

Both prebiotic/probiotic combinations contained more bacterial species than noted on the label. No significant effect on infant growth of either prebiotic/probiotic supplement was observed. By cultures, 64% of infants receiving PBP became colonized with bifidobacteria, compared with 18% of infants receiving CUL and 27% of infants receiving placebo (chi-square, P = 0.064). No differences were noted between groups in colonization rates for lactobacilli, Gram-negative enteric bacteria, or staphylococci. By 16S rDNA polymerase chain reaction analysis, the bifidobacteria content in the stools of the infants receiving PBP was higher than in the infants receiving CUL or placebo (Kruskal-Wallis, P = 0.011). No significant differences in stool SCFA content were detected between groups. No adverse reactions were noted.

CONCLUSIONS

Infants receiving PBP were more likely to become colonized with bifidobacteria. No significant differences in weight gain or stool SCFA content were detected.

Prolonged duration of initial empirical antibiotic treatment is associated with increased rates of necrotizing enterocolitis and death for extremely low birth weight infants

OBJECTIVES

Our objectives were to identify factors associated with the duration of the first antibiotic course initiated in the first 3 postnatal days and to assess associations between the duration of the initial antibiotic course and subsequent necrotizing enterocolitis or death in extremely low birth weight infants with sterile initial postnatal culture results.

METHODS

We conducted a retrospective cohort analysis of extremely low birth weight infants admitted to tertiary centers in 1998-2001. We defined initial empirical antibiotic treatment duration as continuous days of antibiotic therapy started in the first 3 postnatal days with sterile culture results. We used descriptive statistics to characterize center practice, bivariate analyses to identify factors associated with prolonged empirical antibiotic therapy (> or =5 days), and multivariate analyses to evaluate associations between therapy duration, prolonged empirical therapy, and subsequent necrotizing enterocolitis or death.

RESULTS

Of 5693 extremely low birth weight infants admitted to 19 centers, 4039 (71%) survived >5 days, received initial empirical antibiotic treatment, and had sterile initial culture results through the first 3 postnatal days. The median therapy duration was 5 days (range: 1-36 days); 2147 infants (53%) received prolonged empirical therapy (center range: 27%-85%). Infants who received prolonged therapy were less mature, had lower Apgar scores, and were more likely to be black. In multivariate analyses adjusted for these factors and center, prolonged therapy was associated with increased odds of necrotizing enterocolitis or death and of death. Each empirical treatment day was associated with increased odds of death, necrotizing enterocolitis, and the composite measure of necrotizing enterocolitis or death.

CONCLUSION

Prolonged initial empirical antibiotic therapy may be associated with increased risk of necrotizing enterocolitis or death and should be used with caution.

Rationale for Using of Bifidobacterium Probiotic Strains-Fermented Milk Against Colitis Based on Animal Experiments and Clinical Trials

Probiotic foods such as probiotic strain-fermented milk or supplements proposing various health claims are now available. The beneficial effects of these probiotic foods on the digestive system are expected for not only healthy persons but also patients with diseases of the alimentary tract. This review focused on the rationale of using our Bifidobacterium strains-fermented milk as an adjunct for the prevention of recurrence or exacerbation of colitis. Animal experiments using gnotobiotic colitis or spontaneously colitis models and also human clinical trials of ulcerative colitis patients showed the potential of Bifidobacterium strains-fermented milk as a beneficial anti-colitis adjunct.

Effects of Bifidobacterium lactis Bb12 supplementation on body weight, fecal pH, acetate, lactate, calprotectin, and IgA in preterm infants

Preterm infants are prone to abnormal bacterial colonization of the intestine with ensuing adverse health effects. To examine whether the oral application of Bifidobacterium lactis Bb12 (probiotic) may improve selected indicators of health status in preterm infants, a double blind, placebo controlled randomized clinical study was performed on 69 preterm infants (<37 gestation wk). Weight gain was defined as the primary outcome measure. In antibiotic-treated infants, probiotic supplementation resulted in a higher body weight compared with placebo (p < 0.001). In the probiotic group, the fecal pH was significantly lower than in the placebo group. The fecal concentrations of acetate and lactate were 42 and 38% higher, respectively, in the probiotic group than in the placebo group. Fecal calprotectin was lower in the probiotic group (p = 0.041), while fecal IgA was higher in this group compared with the placebo group (p = 0.021).

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.

Bacterial colonization, probiotics, and necrotizing enterocolitis

The intestinal microflora has a significant role in intestinal health and gut function. The neonatal population is unique in that intestinal colonization is not established and is known to be influenced by delivery method, feeding, gestational age, and medical interventions. The preterm infant is particularly sensitive to colonization patterns as inherent intestinal defense mechanisms are immature and immature intestinal epithelial cells are known to have exaggerated inflammatory responses to both commensal and pathogenic bacteria. These responses contribute to the development of neonatal necrotizing enterocolitis in this patient population. As certain bacteria are known to influence intestinal maturation and down-regulate intestinal inflammation, it has been suggested that influencing the intestinal flora of preterm infants may be beneficial. Clinical studies indicate that probiotic therapy may decrease the incidence of necrotizing enterocolitis and studies are ongoing to elucidate the mechanism of action of different probiotic organisms. Although concerns remain and further study is necessary, probiotics are a plausible means of optimizing intestinal colonization and influencing outcome of these vulnerable infants.

Probiotics for the prevention of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) remains a significant cause of morbidity and mortality for low birth weight premature infants. Prematurity, ischemia, formula feeding, and bacterial colonization are risk factors for the self-perpetuating cycle of damaged intestinal epithelia, inflammation, bacterial entry, sepsis, and shock that characterizes NEC. Probiotics are food supplements containing live bacteria that benefit the recipient by improving the microflora balance within the intestine. Several studies suggest that the administration of probiotics may have a prophylactic effect for NEC and may reduce morbidity and mortality rates for low birth weight infants.

Probiotics: role in pathophysiology and prevention in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease largely affecting low birth weight, premature infants. Once acquired, NEC is accompanied by significant mortality and morbid sequelae. Our understanding of the pathophysiology of NEC continues to evolve, and the development of NEC is likely multifactorial with resultant bowel injury mediated through a final, common inflammatory pathway. The predisposition for NEC appears to involve the interplay between intestinal integrity and function, enteral feeding and bacterial colonization, and regulation of the gastrointestinal and systemic inflammatory response. Commensal organisms or probiotics have been shown to be crucial in the development and modulation of each of these factors within the intestinal epithelium. As a result, probiotic supplementation has been proposed as a promising new intervention for the prevention of NEC. To understand the potential utility of probiotics in NEC, we will discuss: the components of gut defense; the role of the intestinal ecosystem in modulating immunity and inflammation; bacterial colonization patterns in the preterm infant compared with patterns seen in the healthy, full-term infant; the evidence for probiotic use in other populations and diseases; and finally, the evidence of probiotic use specific to the preterm infant and NEC.

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.

Probiotics for prevention of necrotizing enterocolitis in preterm infants

BACKGROUND

Necrotizing enterocolitis (NEC) and nosocomial sepsis are associated with increased morbidity and mortality in preterm infants. Through prevention of bacterial migration across the mucosa, competitive exclusion of pathogenic bacteria, and enhancing the immune responses of the host, prophylactic enteral probiotics (live microbial supplements) may play a role in reducing NEC and associated morbidity.

OBJECTIVES

To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC and/or sepsis in preterm infants.

SEARCH STRATEGY

The standard search strategy for the Cochrane Neonatal Review Group was performed by two review authors. Searches were made of MEDLINE (1966 to December 2006), EMBASE (1980 to December 2006), Cochrane Library Controlled Trials Register (CENTRAL, The Cochrane Library Issue 3, 2006), and abstracts of annual meetings of the Society for Pediatric Research (1995 - 2006). The authors of published articles were contacted.

SELECTION CRITERIA

Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age and/or < 2500 g birth weight were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials. Retrieved articles were assessed for eligibility and data abstracted independently by two review authors. Where data were incomplete, the primary investigator were contacted for further information and clarification. Where appropriate, data of individual trials were combined using meta-analytic techniques to provide a pooled estimate of effect assuming a fixed effect model.

MAIN RESULTS

Nine eligible trials randomizing 1425 infants were included. Included trials were highly variable with regard to enrollment criteria (i.e. birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. Data regarding extremely low birth weight infants (ELBW) could not be extrapolated. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) [typical RR 0.32 (95% CI 0.17, 0.60)] and mortality [typical RR 0.43 (95% CI 0.25, 0.75]. There was no evidence of significant reduction of nosocomial sepsis [typical RR 0.93 (95% CI 0.73, 1.19)] or days on total parenteral nutrition (TPN) [WMD -1.9 (95% CI -4.6, 0.77)]. The included trials reported no systemic infection with the probiotics supplemental organism. The statistical test of heterogeneity for NEC, mortality and sepsis was insignificant.

AUTHORS' CONCLUSIONS

Enteral supplementation of probiotics reduced the risk of severe NEC and mortality in preterm infants. This analysis supports a change in practice in premature infants > 1000 g at birth. Data regarding outcome of ELBW infants could not be extracted from the available studies; therefore, a reliable estimate of the safety and efficacy of administration of probiotic supplements cannot be made in this high risk group. A large randomized controlled trial is required to investigate the potential benefits and safety profile of probiotics supplementation in ELBW infants.

Probiotic bacteria change Escherichia coli-induced gene expression in cultured colonocytes: Implications in intestinal pathophysiology

AIM: To investigate the change in eukaryotic gene expression profile in Caco-2 cells after infection with strains of Escherichia coli and commensal probiotic bacteria.

METHODS: A 19200 gene/expressed sequence tag gene chip was used to examine expression of genes after infection of Caco-2 cells with strains of normal flora E. coli, Lactobacillus plantarum, and a combination of the two.

RESULTS: The cDNA microarray revealed up-regulation of 155 and down-regulation of 177 genes by E. coli. L. plantarum up-regulated 45 and down-regulated 36 genes. During mixed infection, 27 genes were up-regulated and 59 were down-regulated, with nullification of stimulatory/inhibitory effects on most of the genes. Expression of several new genes was noted in this group.

CONCLUSION: The commensal bacterial strains used in this study induced the expression of a large number of genes in colonocyte-like cultured cells and changed the expression of several genes involved in important cellular processes such as regulation of transcription, protein biosynthesis, metabolism, cell adhesion, ubiquitination, and apoptosis. Such changes induced by the presence of probiotic bacteria may shape the physiologic and pathologic responses they trigger in the host.

Probiotics for necrotizing enterocolitis: a systematic review

BACKGROUND

Necrotizing enterocolitis (NEC) is the most commonly acquired neonatal intraabdominal emergency and causes significant morbidity and mortality. A proposed strategy for the prevention of NEC is the administration of oral probiotics. Probiotics have been shown to reduce NEC in experimental rat models and have been used in clinical trials. The authors aimed to review the existing data on the use of oral probiotics for the prevention of NEC in preterm infants (age <33 weeks) and those with very low birth weight (VLBW).

MATERIALS AND METHODS

Systematic review of randomized controlled trials (RCTs) and quasi-RCTs was performed to find outcome measures of incidence, severity, need for surgery, and mortality in NEC. Electronic searches were performed on Medline and CINAHL databases using key word and subject headings with combinations of the terms "infant, preterm"; "infant, VLBW"; "enterocolitis, necrotizing"; and "probiotics." In addition, citation searches were performed for all potential studies.

RESULTS

Six potential RCTs were identified for inclusion, but there were no systematic or Cochrane database reviews identified. One study was discounted because of the use of historical controls, so 5 studies were selected for analysis. Cumulatively, 640 infants were treated with probiotics and 627 were used as control subjects. All of the studies showed a trend toward less NEC in the treatment group. The heterogeneity of probiotic formulations and the timing and methods of interventions in the identified studies made synthesis and comparison of data inappropriate.

CONCLUSIONS

The data appear to lend support to the use of oral probiotics for the prevention of NEC in preterm infants and those with VLBW. However, the data are insufficient to comment on their short- and long-term safety. Type of probiotics used, as well as the timing and dosage, are still to be optimized. Further understanding of the pathogenesis of NEC and the mechanisms by which probiotics prevent it may lead to evidence-based treatment strategies.

The effect of a bifidobacter supplemented bovine milk on intestinal permeability of preterm infants

BACKGROUND

Preterm infants have increased intestinal permeability which can render them susceptible to infections from enterobacteriae.

OBJECTIVES

The primary objective was to investigate whether probiotic administration to preterm infants decreases intestinal permeability. Secondary outcomes studied were: somatic growth, tolerance, rates of sepsis and necrotizing enterocolitis.

METHODS

In a prospective randomized case-control study 41 stable preterm infants of 27 to 36 weeks gestation and 34 matched comparison infants consecutively admitted to the neonatal unit were studied. The study group received a preterm formula supplemented with Bifidobacter lactis (2 x 10(7) cfu/g of dry milk) while the control group received the same formula but without supplementation. Intestinal permeability was measured within two days of birth and then seven and thirty days later using the sugar absorption test. Additionally anthropometric parameters were recorded throughout the study as well as acceptance and tolerance of the formula.

RESULTS

All infants tolerated the study formula well. Median counts of stool bifidobacteria and lactulose/mannitol ratios at baseline were comparable. After 7 days of supplementation median bifidobacteria counts were significantly higher in the study group than in the control group (p=0.0356) and they remained higher to the end of the study (p at day 30=0.075). The L/M ratio in the study group was significantly lower at day 30 of the study as compared to the control group (p=0.003). Head growth was significantly higher in the study group (p=0.001).

CONCLUSIONS

The administration of a bifidobacter supplemented infant formula decreases intestinal permeability of preterm infants and leads to increased head growth.

Development of bacterial and bifidobacterial communities in feces of newborn babies

Microbial 16S rDNA from babies' fecal samples were amplified by PCR, and analysed by denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. PCR-DGGE profiles were used to follow in time the colonization of the intestine by bacteria. Four healthy babies, one baby who received antibiotics and their parents participated to the present study to determine the extent to which administration of antibiotics can modify the bacterial colonization of neonatal human gut and verify the influence of parental factors on the formation of the fecal bacterial community. In the healthy babies, Escherichia coli or bacteria belonging to Clostridium spp. were the initial colonizers rapidly followed by Bifidobacterium, Bacteroides, Clostridium, Streptococcus, Enterococcus and Actinomyces. Bifidobacterium species appeared already after five days in the breast-fed babies while there was a delay in the baby who received a formula based diet during only one day after birth. In each baby two or three bifidobacterial species including B. infantis were found. The observed variations in species were not associated with the feeding changes. The comparison of DGGE profiles of the babies and their parents patterns showed bands with equal migration suggesting a vertical transmission determined by genetic and environmental factors. The brief appearance of pioneer bacteria determined as being E. coli and Enterococcus spp. in the profile from the baby under antibiotic therapy, was succeeded by a small stable community consisting of Ruminococcus species. No Bifidobacterium sequences were detectable in this antibiotic-treated baby in spite of a partly breast-milk diet.

Probiotics for prevention of necrotising enterocolitis in preterm neonates with very low birthweight: a systematic review of randomised controlled trials

BACKGROUND

Results of recent clinical trials suggest that probiotic supplementation reduces the risk of necrotising enterocolitis in preterm neonates. We aimed to systematically review randomised controlled trials evaluating efficacy and safety of any probiotic supplementation (started within first 10 days, duration > or =7 days) in preventing stage 2 or greater necrotising enterocolitis in preterm neonates (gestation <33 weeks) with very low birthweight (<1500 g).

METHODS

We followed the standard search strategy of the Cochrane Neonatal Review Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, CINAHL databases, and proceedings of the Pediatric Academic Society meetings (from 1980) and Pediatric Gastroenterology conferences (from 1980) in November, 2006.

RESULTS

Seven of 12 randomised controlled trials retrieved (n=1393) were eligible for inclusion in the analysis. Meta-analysis using a fixed effects model estimated a lower risk of necrotising enterocolitis (relative risk 0.36, 95% CI 0.20-0.65) in the probiotic group than in controls. Risk of sepsis did not differ significantly between groups (0.94, 0.74-1.20). Risk of death was reduced in the probiotic group (0.47, 0.30-0.73). The time to full feeds was significantly shorter in the probiotic group (weighted mean difference -2.74 days, 95% CI -4.98 to -0.51) than in controls.

CONCLUSION

Probiotics might reduce the risk of necrotising enterocolitis in preterm neonates with less than 33 weeks' gestation. However, the short-term and long-term safety of probiotics needs to be assessed in large trials. Unanswered questions include the dose, duration, and type of probiotic agents (species, strain, single or combined, live or killed) used for supplementation.

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.

Immunonutritional effects during synbiotics therapy in pediatric patients with short bowel syndrome

The aim of this study was to evaluate the effects of synbiotic therapy in patients with short bowel syndrome (SBS). Four pediatric patients with SBS, who were receiving synbiotics therapy including Bifidobacterium breve, Lactobacillus casei and galactooligosaccharides, were enrolled in this study. We evaluated changes in immunonutritional parameters before and after receiving synbiotics therapy. Four normal, healthy, age-matched children were enrolled as controls. Fecal samples from patients and controls were collected and analyzed for fecal bacterial flora and organic acid (OA) contents. Levels of short chain fatty acids (SCFA) such as butyrate, propionate, and acetate increased in one patient, and SCFA/total OA levels increased in three patients. Serum lymphocyte counts and concentrations of pre-albumin increased after beginning synbiotics therapy, reaching a statistically significant level at the ninth month compared to the pre-treatment level. There was an increasing trend in height and weight gain velocity during the study compared with the pre-treatment period. The patients' fecal bacterial flora improved as a result of synbiotics therapy. Synbiotics therapy may be very effective at improving the intestinal flora and systemic immunonutritional status of patients with SBS.

The postnatal maturation of the immunoglobulin heavy chain IgG repertoire in human preterm neonates is slower than in term neonates

During the perinatal period the development of the IgH chain CDR3 (CDR-H3) repertoire of IgM transcripts is maturity-dependent and not influenced by premature exposure to Ag. To study whether maturity-dependent restrictions also predominate in the perinatal IgG repertoire we compared 1000 IgG transcripts from cord blood and venous blood of extremely preterm neonates (24-28 wk of gestation) and of term neonates from birth until early infancy with those of adults. We found the following. First, premature contact with the extrauterine environment induced the premature development of an IgG repertoire. However after preterm birth the diversification of the IgG repertoire was slower than that after term birth. Second, the IgG repertoire of preterm neonates retained immature characteristics such as short CDR-H3 regions and overrepresentation of D(H)7-27. Third, despite premature exposure to the extrauterine environment, somatic mutation frequency in IgG transcripts of preterm infants remained low until they reached a postconceptional age corresponding to the end of term gestation. Thereafter, somatic mutations accumulated with age at similar rates in preterm and term neonates and reached 30% of the adult level after 6 mo. In conclusion, class switch was inducible already at the beginning of the third trimester of gestation, but the developing IgG repertoire was characterized by similar restrictions as those of the developing IgM repertoire. Those B cells expressing more "mature" H chain sequences were not preferentially selected into the IgG repertoire. Therefore, the postnatal IgG repertoire of preterm infants until the expected date of delivery differs from the postnatal repertoire of term neonates.

Effects of oral administration of bifidobacterium breve on fecal lactic acid and short-chain fatty acids in low birth weight infants

OBJECTIVES

Short-chain fatty acids (SCFAs) are known to provide energy to colonocytes, whereas overproduction of SCFAs can cause mucosal injury in premature infants. Our objective was to investigate the effects of the oral administration of Bifidobacterium breve M-16V (B breve) on fecal lactic acid and SCFAs in low birth weight (LBW) infants.

PATIENTS AND METHODS

Fecal lactic, acetic, propionic, and butyric acids from 66 premature infants were analyzed by high-performance liquid chromatography at 0, 2, and 4 weeks after birth. The subjects included 22 extremely LBW (ELBW, <1000 g), 22 very LBW (VLBW, <1500 g), and 22 LBW (<2500 g) infants. The infants were divided into two groups: those with and those without B. breve supplementation.

RESULTS

In the control groups, fecal acetic acid and total SCFA concentrations were significantly increased at 2 weeks in the VLBW and LBW infants (P < 0.05) and at 4 weeks in the ELBW, VLBW, and LBW infants (P < 0.01 for each) compared with those at week 0. Fecal lactic acid concentrations showed a similar pattern during follow-up, but the differences were not significant. Four weeks after B breve administration, the fecal butyric acid concentrations were significantly decreased in the ELBW and VLBW infants (P < 0.05 each), and the ratio of the acetic acid concentrations to the total SCFAs was significantly increased compared with those of the control groups in the ELBW (P < 0.05), VLBW (P < 0.05), and LBW infants (P < 0.01).

CONCLUSIONS

Oral administration of B breve reduces the production of butyric acid, which may be helpful in protecting LBW infants from digestive diseases such as necrotizing enterocolitis.

Perioperative synbiotic treatment to prevent postoperative infectious complications in biliary cancer surgery: a randomized controlled trial

SUMMARY BACKGROUND DATA

Use of synbiotics has been reported to benefit human health, but clinical value in surgical patients remains unclear.

OBJECTIVE

To investigate the effect of perioperative oral administration of synbiotics upon intestinal barrier function, immune responses, systemic inflammatory responses, microflora, and surgical outcome in patients undergoing high-risk hepatobiliary resection.

METHODS

Patients with biliary cancer involving the hepatic hilus (n = 101) were randomized before hepatectomy, into a group receiving postoperative enteral feeding with synbiotics (group A); or another receiving preoperative plus postoperative synbiotics (group B). Lactulose-mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, natural killer (NK) cell activity, interleukin-6 (IL-6), fecal microflora, and fecal organic acid concentrations were determined before and after hepatectomy. Postoperative infectious complications were recorded.

RESULTS

Of 101 patients, 81 completed the trial. Preoperative and postoperative changes in L/M ratio and DAO activity were similar between groups. Preoperatively in group B, NK activity, and lymphocyte counts increased, while IL-6 decreased significantly (P < 0.05). Postoperative serum IL-6, white blood cell counts, and C-reactive protein in group B were significantly lower than in group A (P < 0.05). During the preoperative period, numbers of Bifidobacterium colonies cultured from and total organic acid concentrations measured in feces increased significantly in group B (P < 0.05). Postoperative concentrations of total organic acids and acetic acid in feces were significantly higher in group B than in group A (P < 0.05). Incidence of postoperative infectious complications was 30.0% (12 of 40) in group A and 12.1% (5 of 41) in group B (P < 0.05).

CONCLUSIONS

Preoperative oral administration of synbiotics can enhance immune responses, attenuate systemic postoperative inflammatory responses, and improve intestinal microbial environment. These beneficial effects likely reduce postoperative infectious complications after hepatobiliary resection for biliary tract cancer.

Bifidobacterium breve enhances transforming growth factor beta1 signaling by regulating Smad7 expression in preterm infants

OBJECTIVES

Transforming growth factor (TGF) beta1 displays a broad spectrum of activities in mucosal regulation, including induction of oral tolerance, potent anti-inflammatory effects, mucosal IgA expression and effects on epithelial cell proliferation and differentiation. The present study examined the effect of probiotics on the immunologic system of preterm infants in relation to TGF-beta signaling.

METHODS

Subjects comprised 19 preterm infants divided into 2 groups: receiving Bifidobacterium breve supplementation (B. breve group) and without supplementation (controls). Blood samples were collected from both groups on days 0, 14 and 28 after birth. Serum cytokine levels were measured using enzyme-linked immunosorbent assay, and expression levels of the TGF-beta signaling molecule, Smad, were examined using semiquantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Serum TGF-beta1 level was elevated on day 14 and remained elevated on day 28 in the B. breve group. Level of messenger RNA expression was enhanced for Smad3 and reduced for Smad7 (antagonistic Smad) after B. breve administration relative to levels in controls on day 28.

CONCLUSIONS

These results demonstrated that the administration of B. breve to preterm infants can up-regulate TGF-beta1 signaling and may possibly be beneficial in attenuating inflammatory and allergic reactions in these infants.

Probiotics and neonatal intestinal infection

PURPOSE OF REVIEW

Necrotizing enterocolitis remains an enigmatic and potentially devastating condition with high morbidity and mortality. This review explores ways in which bacterial pathogens, together with gut microflora, influence the pathophysiology of necrotizing enterocolitis. Specifically, it examines the role of gut microbial colonization and its 'normalization' with probiotics vis a vis its contribution to intestinal bacterial invasion.

RECENT FINDINGS

Recent studies have demonstrated that prophylactic administration of probiotics to preterm neonates decreases both the incidence and severity of subsequent necrotizing enterocolitis.

SUMMARY

Probiotics represent a therapeutic effort to bolster natural host defenses via the 'normalization' of abnormal gut microflora of the premature infant at risk, thereby reducing the subsequent threat of necrotizing enterocolitis. The appeal of probiotics in neonatology is threefold. First, their safety record renders them an attractive alternative to many of the more aggressive therapeutic options; second, they represent a simple, noninvasive attempt to recreate a natural or normal flora rather than a disruption of nature. Third, probiotics are used mainly for disease prevention and are naturally occurring. As such, they are not considered to be drugs, but rather food supplements. To date, very few other strategies have been proven definitively to be efficacious in decreasing the incidence of necrotizing enterocolitis.

Prevention of infections by probiotics

'Viable bacteria that exhibit beneficial effects for health based on improvement of balance of intestinal bacterial flora' was the most common definition of probiotics, but the diversity of their action mechanisms, including immune regulation, has been clarified, and probiotics have recently been broadly defined as 'live microorganisms which when administered in adequet amounts confer a health benefit on the host'. Coined words such as prebiotics, describing non-digestible food fiber components that contribute to host health by activating proliferation and function of beneficial intestinal bacteria, and synbiotics, describing a combination of probiotics and prebiotics have also been established as medical expressions. In this report, clinical studies of probiotics, prebiotics, and synbiotics on prevention of infection by various infectious diseases in humans are reviewed. The effects of and action mechanisms against sporadic intestinal infectious diseases that are difficult to investigate in humans (enterohemorrhagic Escherichia coli and Salmonellosis) in experimental animal models are also reviewed. Finally, points necessary for clarification of the role of probiotics in health care, and their functions in health care foods are discussed.

Oral probiotics prevent necrotizing enterocolitis in very low birth weight neonates

OBJECTIVE

To test the hypothesis that normalizing the intestinal flora by administration of prophylactic probiotics would provide a natural defense, thereby reducing both the incidence and severity of necrotizing enterocolitis (NEC) in preterm neonates.

STUDY DESIGN

Neonates < or =1500 g birth weight were randomized to either receive a daily feeding supplementation with a probiotic mixture (Bifidobacteria infantis, Streptococcus thermophilus, and Bifidobacteria bifidus; Solgar, Israel) of 10(9) colony forming units (CFU)/day or to not receive feed supplements. NEC was graded according to Bell's criteria.

RESULTS

For 72 study and 73 control infants, respectively, birth weight (1152 +/- 262 g vs 1111 +/- 278 g), gestational age (30 +/- 3 weeks vs 29 +/- 4 weeks), and time to reach full feeds (14.6 +/- 8.7 days vs 17.5 +/- 13.6 days) were not different. The incidence of NEC was reduced in the study group (4% vs 16.4%; P=.03). NEC was less severe in the probiotic-supplemented infants (Bell's criteria 2.3 +/- 0.5 vs 1.3 +/- 0.5; P=.005). Three of 15 babies who developed NEC died, and all NEC-related deaths occurred in control infants.

CONCLUSION

Probiotic supplementation reduced both the incidence and severity of NEC in our premature neonatal population.

Probiotics used in human studies

GOAL

To investigate the literature from 1980 to 2004 for the types of studies and organisms used as probiotics in human studies and diseases.

METHODS

PubMed search for probiotic organisms used in studies from 1980 to August 2004. The data from those papers were evaluated for organisms used, dose, vehicle, frequency, and investigator's report of positive or negative results.

RESULTS

A total of 185 manuscripts were identified. Investigators reported results of both single and multiple organisms in the same manuscript. A single organism was used in 125 reports, and multiple organisms, ranging from 2 to 9, were used in 60 reports. Positive results were reported in 239 clinical situations and negative results reported in 49 in a total of 288 clinical conclusions drawn by the respective investigators. The studies are tabulated in this review.

CONCLUSION

There is a large literature available in credible journals that report benefit of probiotic administration using a wide range of doses, organisms, and clinical situations. Most of the studies are simple reports of a clinical situation and require additional evaluation.

Synbiotics reduce postoperative infectious complications: a randomized controlled trial in biliary cancer patients undergoing hepatectomy

BACKGROUND AND AIMS

The clinical value of synbiotics in surgical patients remains unclear. The aim of this study was to investigate the effect of synbiotics on intestinal integrity and microflora, as well as on surgical outcome, in patients undergoing high-risk hepatectomy.

METHODS

Fifty-four patients with biliary cancer were randomly allocated to two groups before hepatectomy. One group received postoperative enteral feeding that included synbiotics; the other received enteral feeding only. Lactulose/mannitol (L/M) ratio, serum diamine oxidase (DAO) activity, and fecal microflora and organic acid concentrations were determined. Postoperative infectious complications were recorded.

RESULTS

Of the 54 patients, 44 completed the trial (21 receiving synbiotics and 23 others as controls). Postoperative changes in L/M ratios and serum DAO activities were identical between the two groups. Numbers of beneficial bacteria increased in the synbiotics group after surgery but decreased in controls. Numbers of harmful microorganisms decreased in the synbiotics group but increased in controls. Total organic acid concentrations increased in the synbiotics group but decreased in controls. Incidence of infectious complications was 19% (4/21) in the synbiotics group and 52% (12/23) in controls (P<0.05). All study patients tolerated surgery (mortality 0%).

CONCLUSIONS

Synbiotics, combined with early enteral nutrition, can reduce postoperative infections. This beneficial effect presumably involves correction of an intestinal microbial imbalance induced by surgical stress.

Oral probiotics reduce the incidence and severity of necrotizing enterocolitis in very low birth weight infants

OBJECTIVE

We evaluated the efficacy of probiotics in reducing the incidence and severity of necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants.

PATIENTS AND METHODS

A prospective, masked, randomized control trial was conducted to evaluate the beneficial effects of probiotics in reducing the incidence and severity of NEC among VLBW (<1500 g) infants. VLBW infants who started to fed enterally and survived beyond the seventh day after birth were eligible for the trial. They were randomized into 2 groups after parental informed consents were obtained. The infants in the study group were fed with Infloran (Lactobacillus acidophilus and Bifidobacterium infantis) with breast milk twice daily until discharged. Infants in the control group were fed with breast milk alone. The clinicians caring for the infants were blinded to the group assignment. The primary outcome was death or NEC (>or= stage 2).

RESULTS

Three hundred sixty-seven infants were enrolled: 180 in the study group and 187 in the control group. The demographic and clinical variables were similar in both groups. The incidence of death or NEC (>or= stage 2) was significantly lower in the study group (9 of 180 vs 24 of 187). The incidence of NEC (>or= stage 2) was also significantly lower in the study when compared with the control group (2 of 180 vs 10 of 187). There were 6 cases of severe NEC (Bell stage 3) in the control group and none in the study group. None of the positive blood culture grew Lactobacillus or Bifidobacterium species.

CONCLUSION

Infloran as probiotics fed enterally with breast milk reduces the incidence and severity of NEC in VLBW infants.