The effect of probiotic supplementation on the gut microbiota of preterm infants

Bovine colostrum prevents formula-induced gut microbiota dysbiosis in preterm pigs

BACKGROUND

Preterm birth and formula feeding increase the risk of necrotizing enterocolitis (NEC), a gut inflammatory disease known to be associated with gut microbiota (GM) changes in infants. Supplemental bovine colostrum may protect against formula-induced NEC via GM changes. We hypothesised that feeding colostrum before, after, or during formula feeding affects NEC sensitivity via changes to GM.

METHODS

Colonic GM (profiled by 16S ribosomal RNA gene amplicon sequencing) was compared in preterm pigs fed colostrum for 4 days, either before, after, or together with formula feeding for 4 days. Correlations between GM and gut parameters were assessed on day 5 or 9.

RESULTS

Both exclusive and partial colostrum feeding induced higher GM diversity, lower Enterococcus abundance, and improved intestinal maturation parameters (villus structure, digestive enzyme activities, permeability), relative to exclusive formula feeding (all p < 0.05). Across feeding regimens, Enterococcus abundance was inversely correlated with intestinal maturation parameters. Conversely, there was no correlation between GM changes and early NEC lesions.

CONCLUSION

Bovine colostrum inhibits formula-induced Enterococcus overgrowth and gut dysfunctions just after preterm birth but these effects are not causally linked. Optimising diet-related host responses, not GM, may be critical to prevent NEC in preterm newborn pigs and infants.

IMPACT

Supplement of bovine colostrum to formula feeding modified the gut microbiota by increasing species diversity and reducing Enterococcus abundance, while concurrently improving intestinal functions in preterm pigs. Diet-related changes to the gut microbiota were not clearly associated with development of necrotizing enterocolitis (NEC) in preterm pigs, suggesting that diet-related gut microbiota effects are not critical for diet-related NEC protection. The study highlights the potential to use bovine colostrum as a supplement to formula feeding for preterm infants lacking human milk.

Effect of probiotic supplementation on the gut microbiota in very preterm infants: a systematic review

OBJECTIVE

There is increasing evidence that probiotic supplementation in very preterm infants decreases the risk of necrotising enterocolitis (NEC), sepsis and mortality. The underlying mechanisms, including effects on the gut microbiota, are largely unknown. We aimed to systematically review the available literature on the effects of probiotic supplementation in very preterm infants on gut microbiota development.

DESIGN

A systematic review in Medline, Embase, Cochrane Library, CINAHL and Web of Science.

SETTING

Neonatal intensive care unit.

PATIENTS

Premature infants.

INTERVENTION

Probiotic supplementation.

MAIN OUTCOME MEASURES

Gut microbiota.

RESULTS

A total of 1046 articles were screened, of which 29 were included. There was a large heterogeneity in study design, dose and type of probiotic strains, timepoints of sample collection and analysing techniques. Bifidobacteria and lactobacilli were the most used probiotic strains. The effects of probiotics on alpha diversity were conflicting; however, beta diversity was significantly different between probiotic-supplemented infants and controls in the vast majority of studies. In most studies, probiotic supplementation led to increased relative abundance of the supplemented strains and decreased abundance of genera such as Clostridium, Streptococcus, Klebsiella and Escherichia.

CONCLUSIONS

Probiotic supplementation to preterm infants seems to increase the relative abundance of the supplemented strains with a concurrent decrease of potentially pathogenic species. These probiotic-induced microbial alterations may contribute to the decreased risk of health complications such as NEC. Future trials, including omics technologies to analyse both microbiota composition and function linked to health outcomes, are warranted to identify the optimal mixture and dosing of probiotic strains.

PROSPERO REGISTRATION NUMBER

CRD42023385204.

Fermented foods, their microbiome and its potential in boosting human health

Fermented foods (FFs) are part of the cultural heritage of several populations, and their production dates back 8000 years. Over the last ~150 years, the microbial consortia of many of the most widespread FFs have been characterised, leading in some instances to the standardisation of their production. Nevertheless, limited knowledge exists about the microbial communities of local and traditional FFs and their possible effects on human health. Recent findings suggest they might be a valuable source of novel probiotic strains, enriched in nutrients and highly sustainable for the environment. Despite the increasing number of observational studies and randomised controlled trials, it still remains unclear whether and how regular FF consumption is linked with health outcomes and enrichment of the gut microbiome in health-associated species. This review aims to sum up the knowledge about traditional FFs and their associated microbiomes, outlining the role of fermentation with respect to boosting nutritional profiles and attempting to establish a link between FF consumption and health-beneficial outcomes.

Probiotic supplementation modifies the gut microbiota profile of very low birth weight preterm infants during hospitalization

BACKGROUND

Probiotic supplementation is increasingly being given to very low birth weight (VLBW) preterm infants. This preliminary observational study aimed to investigate the effects of multiple-strain probiotics on the gut microbiota of VLBW preterm infants.

METHODS

We collected meconium and stool samples on days 14, 30, and 60 after birth from 49 VLBW infants with a gestational age of <32 weeks. The infants were divided into the probiotics (n = 24) and control (n = 25) groups. The microbial composition and diversity in the gut of the two groups were analyzed using 16 S rRNA gene sequencing.

RESULTS

The relative abundance of Bifidobacterium and Lactobacillus was significantly higher in the probiotics group than in the control group on days 14, 30, and 60 (Bifidobacterium: p = 0.002, p < 0.0001, and p < 0.0001, respectively; Lactobacillus: p = 0.012, p < 0.0001, and p < 0.0001, respectively). The control group exhibited a significantly higher proportion of participants with a low abundance (<1%) of Bifidobacterium or Lactobacillus on days 14, 30, and 60 than those in the probiotic group. Moreover, the probiotics group exhibited a significantly lower abundance of Klebsiella on days 14 and 30 (2.4% vs. 11.6%, p = 0.037; and 7.9% vs. 16.6%, p = 0.032, respectively) and of Escherichia-Shigella on day 60 than the control group (6.1% vs. 12.3%, p = 0.013). Beta diversity analysis revealed that the microbiota profile was clearly divided into two groups on days 30 and 60 (p = 0.001).

CONCLUSION

Probiotic supplementation significantly increased the relative abundance of Bifidobacterium and Lactobacillus and inhibited the growth of potential pathogens. Furthermore, probiotic supplementation led to a distinct gut microbiota profile. Further research is needed to identify probiotic strains that exert significant influence on the gut microbiome and their long-term health implications in preterm infants.

Early gut microbiota intervention in premature infants: Application perspectives

BACKGROUND

Preterm birth is the leading cause of death in children under the age of five. One of the major factors contributing to the high risk of diseases and deaths in premature infants is the incomplete development of the intestinal immune system. The gut microbiota has been widely recognized as a critical factor in promoting the development and function of the intestinal immune system after birth. However, the gut microbiota of premature infants is at high risk of dysbiosis, which is highly associated with adverse effects on the development and education of the early life immune system. Early intervention can modulate the colonization and development of gut microbiota and has a long-term influence on the development of the intestinal immune system.

AIM OF REVIEW

This review aims to summarize the characterization, interconnection, and underlying mechanism of gut microbiota and intestinal innate immunity in premature infants, and to discuss the status, applicability, safety, and prospects of different intervention strategies in premature infants, thus providing an overview and outlook of the current applications and remaining gaps of early intervention strategies in premature infants.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key concepts. Firstly, the gut microbiota of premature infants is at high risk of dysbiosis, resulting in dysfunctional intestinal immune system processes. Secondly, contributing roles of early intervention have been observed in improving the intestinal environment and promoting gut microbiota colonization, which is significant in the development and function of gut immunity in premature infants. Thirdly, different strategies of early intervention, such as probiotics, fecal microbiota transplantation, and nutrients, show different safety, applicability, and outcome in premature infants, and the underlying mechanism is complex and poorly understood.

Determinants of microbial colonization in the premature gut

Abnormal microbial colonization in the gut at an early stage of life affects growth, development, and health, resulting in short- and long-term adverse effects. Microbial colonization patterns of preterm infants differ from those of full-term infants in that preterm babies and their mothers have more complicated prenatal and postnatal medical conditions. Maternal complications, antibiotic exposure, delivery mode, feeding type, and the use of probiotics may significantly shape the gut microbiota of preterm infants at an early stage of life; however, these influences subside with age. Although some factors and processes are difficult to intervene in or avoid, understanding the potential factors and determinants will help in developing timely strategies for a healthy gut microbiota in preterm infants. This review discusses potential determinants of gut microbial colonization in preterm infants and their underlying mechanisms.

Therapeutic Potential of Gut Microbiota and Its Metabolite Short-Chain Fatty Acids in Neonatal Necrotizing Enterocolitis

Short chain fatty acids (SCFAs), the principle end-products produced by the anaerobic gut microbial fermentation of complex carbohydrates (CHO) in the colon perform beneficial roles in metabolic health. Butyrate, acetate and propionate are the main SCFA metabolites, which maintain gut homeostasis and host immune responses, enhance gut barrier integrity and reduce gut inflammation via a range of epigenetic modifications in DNA/histone methylation underlying these effects. The infant gut microbiota composition is characterized by higher abundances of SCFA-producing bacteria. A large number of in vitro/vivo studies have demonstrated the therapeutic implications of SCFA-producing bacteria in infant inflammatory diseases, such as obesity and asthma, but the application of gut microbiota and its metabolite SCFAs to necrotizing enterocolitis (NEC), an acute inflammatory necrosis of the distal small intestine/colon affecting premature newborns, is scarce. Indeed, the beneficial health effects attributed to SCFAs and SCFA-producing bacteria in neonatal NEC are still to be understood. Thus, this literature review aims to summarize the available evidence on the therapeutic potential of gut microbiota and its metabolite SCFAs in neonatal NEC using the PubMed/MEDLINE database.

Bifidobacterium: Host-Microbiome Interaction and Mechanism of Action in Preventing Common Gut-Microbiota-Associated Complications in Preterm Infants: A Narrative Review

The development and health of infants are intertwined with the protective and regulatory functions of different microorganisms in the gut known as the gut microbiota. Preterm infants born with an imbalanced gut microbiota are at substantial risk of several diseases including inflammatory intestinal diseases, necrotizing enterocolitis, late-onset sepsis, neurodevelopmental disorders, and allergies which can potentially persist throughout adulthood. In this review, we have evaluated the role of Bifidobacterium as commonly used probiotics in the development of gut microbiota and prevention of common diseases in preterm infants which is not fully understood yet. The application of Bifidobacterium as a therapeutical approach in the re-programming of the gut microbiota in preterm infants, the mechanisms of host-microbiome interaction, and the mechanism of action of this bacterium have also been investigated, aiming to provide new insights and opportunities in microbiome-targeted interventions in personalized medicine.

Release of HMGB1 and Toll-like Receptors 2, 4, and 9 Signaling Are Modulated by Bifidobacterium animalis subsp. lactis BB-12 and Salmonella Typhimurium in a Gnotobiotic Piglet Model of Preterm Infants

Gnotobiotic (GN) animals with defined microbiota allow us to study host-microbiota and microbiota-microbiota interferences. Preterm germ-free (GF) piglets were mono-associated with probiotic Bifidobacterium animalis subsp. lactis BB-12 (BB12) to ameliorate/prevent the consequences of infection with the Salmonella Typhimurium strain LT2 (LT2). Goblet cell density; expression of Toll-like receptors (TLRs) 2, 4, and 9; high mobility group box 1 (HMGB1); interleukin (IL)-6; and IL-12/23p40 were analyzed to evaluate the possible modulatory effect of BB12. BB12 prevented an LT2-induced decrease of goblet cell density in the colon. TLRs signaling modified by LT2 was not influenced by the previous association with BB12. The expression of HMGB1, IL-6, and IL12/23p40 in the jejunum, ileum, and colon and their levels in plasma were all decreased by BB12, but these changes were not statistically significant. In the colon, differences in HMGB1 distribution between the GF and LT2 piglet groups were observed. In conclusion, the mono-association of GF piglets with BB12 prior to LT2 infection partially ameliorated the inflammatory response to LT2 infection.

Probiotics to prevent necrotizing enterocolitis in very low birth weight infants: A network meta-analysis

Objective

This study aims to review the evidence for the optimal regimen of probiotics for the prevention of necrotizing enterocolitis (NEC) in very low birth weight infants.

Design

Through searching PubMed, EMBASE, Cochrane Library, and Web of Science till September 30, 2022, only randomized controlled trials were included to evaluate the optimal regimen of probiotics for the prevention of NEC in very low birth weight infants. The methodological quality of the included studies was assessed by the Cochrane risk of bias assessment tool (RoB 2), and the collected data were analyzed accordingly using Stata software.

Results

Twenty-seven RCTs were included, and the total sample size used in the study was 529. The results of the network meta-analysis showed that Bovine lactoferrin + Lactobacillus rhamnosus GG (RR 0.03; 95% CI 0.00-0.35), Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (RR 0.06; 95% CI 0.00-0.70), Bifidobacterium lactis + inulin (RR 0.16; 95% CI 0.03-0.91) were superior to the control group (Bifidobacterium lactis + Bifidobacterium longum) in reducing the incidence of NEC. The reduction in the incidence of NEC were as follows: Bovine lactoferrin + Lactobacillus rhamnosus GG (SUCRA 95.7%) > Lactobacillus rhamnosus + Lactobacillus plantarum + Lactobacillus casei + Bifidobacterium lactis (SUCRA 89.4%) > Bifidobacterium lactis + inulin (SUCRA 77.8%).

Conclusions

This network meta-analysis suggests that Lactobacillus rhamnosus GG combined with bovine lactoferrin maybe the most recommended regimen for the prevention of NEC in very low birth weight infants.

Detection of Escherichia coli, Pseudomonas aeruginosa, Salmonella paratyphoid B, and Shigella dysentery in live Bacillus licheniformis products using propidium monoazide-real-time-quantitative polymerase chain reaction

To eliminate the influences of excipients and interference of dead bacterial DNA on the detection of Escherichia coli, Pseudomonas aeruginosa, Salmonella paratyphoid B, and Shigella dysentery in live Bacillus licheniformis capsules, a polymerase chain reaction (PCR) method with high sensitivity and specificity was established. By combining bromide with propidium monoazide (PMA) -real-time quantitative PCR (qPCR) with microporous membrane filtration, excipients were removed, the filtrate was collected, and the bacteria were enriched using the centrifugal method. The optimal PMA working concentration, dark incubation time, and exposure time were determined. Specific E. coli, P. aeruginosa, S. paratyphoid B, and S. dysentery primers were selected to design different probes and a multiplex qPCR reaction system was established. The PMA-qPCR method was verified using different concentrations of dead and live bacteria. This method is efficient and accurate and can be widely applied to the detection of aforementioned pathogenic bacterial strains in live Bacillus licheniformis products.

Dynamic Changes of the Gut Microbiota in Preterm Infants With Different Gestational Age

The gut microbiota plays a key role in the pathogenesis of diseases affecting preterm infants and gestational age is one of the important factors which affect the gut microbiota of infants. To determine the characteristics of the gut microbiota in preterm infants of different gestational ages from birth to 1 year after birth, we collected 622 fecal samples from neonates of different gestational ages at different time points after birth. According to the gestational ages, the samples were divided into four groups, extremely preterm, very preterm, moderate to late preterm, and term group. Meconium and fecal samples at day 14, 28, 120, and 365 after birth were collected. 16S rRNA sequencing was performed and the composition and structure of the gut microbiota in preterm infants of different gestational age was compared with that of term infants. In our study, alpha diversity of meconium in extremely preterm group was higher than very preterm group, moderate to late preterm group and term group and alpha diversity of meconium in preterm group was decreased with increasing of gestational age. At day 14 to day 120 after birth, alpha diversity of term and moderate to late preterm group were significantly higher than other two preterm groups. However, moderate to late preterm group owned the highest alpha diversity which was higher than term group at day 365 after birth. Besides, the results shown the duration of opportunistic pathogen such as Klebsiella and Enterococcus which dominant colonization was different in different gestational age groups. As well as the probiotics, such as Bifidobacterium, which abundance enriched at different time point in different gestational age groups. We profiled the features of dynamic changes of gut microbiome from different gestational ages infants. The results of our research provide new insights for individualized interventions of specific microbes of preterm infants with different gestational ages at different time points after birth.