Gut Microbiota In Preterm Infants Research Articles

Gut microbiota in preterm infants with late-onset sepsis and pneumonia: a pilot case-control study

BackgroundLate-onset sepsis (LOS) and pneumonia are common infectious diseases, with high morbidity and mortality in neonates. This study aimed to investigate the differences in the gut microbiota among preterm infants with LOS, or pneumonia, and full-term infants. Furthermore, this study aimed to determine whether there is a correlation between intestinal pathogenic colonization and LOS.MethodsIn a single-center case‒control study, 16 S rRNA gene sequencing technology was used to compare gut microbiota characteristics and differences among the LOS group, pneumonia group, and control group.ResultsOur study revealed that the gut microbiota in the control group was more diverse than that in the LOS group and pneumonia group (P < 0.05). No significant differences in diversity were detected between the LOS and pneumonia groups (P > 0.05). Compared with the control group, the abundances of Akkermansia, Escherichia/Shigella, and Enterococcus increased, while the abundances of Bacteroides and Stenotrophomonas decreased in the LOS and pneumonia groups. The pathogenic bacteria in infants with LOS were consistent with the distribution of the main bacteria in the intestinal microbiota. An increase in Escherichia/Shigella abundance may predict a high risk of LOS occurrence, with an area under the curve (AUC) of 0.773.ConclusionChanges in the gut microbiota composition were associated with an increased risk of LOS and pneumonia. The dominant bacteria in the gut microbiota of the LOS group were found to be associated with the causative pathogen of LOS. Moreover, preterm infants exhibiting an elevated abundance of Escherichia/Shigella may be considered potential candidates for predicting the onset of LOS.

Linking preterm infant gut microbiota to nasograstric enteral feeding tubes: exploring potential interactions and microbial strain transmission

IntroductionPreterm birth is a growing problem worldwide. Staying at a neonatal intensive care unit (NICU) after birth is critical for the survival of preterm infants whose feeding often requires the use of nasogastric enteral feeding tubes (NEFT). These can be colonized by hospital-associated pathobionts that can access the gut of the preterm infants through this route. Since the gut microbiota is the most impactful factor on maturation of the immune system, any disturbance in this may condition their health. Therefore, the aim of this study is to assess the impact of NEFT-associated microbial communities on the establishment of the gut microbiota in preterm infants.Material and methodsA metataxonomic analysis of fecal and NEFT-related samples obtained during the first 2 weeks of life of preterm infants was performed. The potential sharing of strains isolated from the same set of samples of bacterial species involved in NICU's outbreaks, was assessed by Random Amplification of Polymorphic DNA (RAPD) genotyping.ResultsIn the samples taken 48 h after birth (NEFT-1 and Me/F1), Staphylococcus spp. was the most abundant genera (62% and 14%, respectively) and it was latter displaced to 5.5% and 0.45%, respectively by Enterobacteriaceae. Significant differences in beta diversity were detected in NEFT and fecal samples taken at day 17 after birth (NEFT-3 and F3) (p = 0.003 and p = 0.024, respectively). Significant positive correlations were found between the most relevant genera detected in NEFT-3 and F3. 28% of the patients shared at least one RAPD-PCR profile in fecal and NEFT samples and 11% of the total profiles were found at least once simultaneously in NEFT and fecal samples from the same patient.ConclusionThe results indicate a parallel bacterial colonization of the gut of preterm neonates and the NEFTs used for feeding, potentially involving strain sharing between these niches. Moreover, the same bacterial RAPD profiles were found in neonates hospitalized in different boxes, suggesting a microbial transference within the NICU environment. This study may assist clinical staff in implementing best practices to mitigate the spread of pathogens that could threaten the health of preterm infants.

Dynamic impact of delivery modes on gut microbiota in preterm infants hospitalized during the initial 4 weeks of life

Preterm infants face a high risk of various complications, and their gut microbiota plays a pivotal role in health. Delivery modes have been reported to affect the development of gut microbiota in term infants, but its impact on preterm infants remains unclear. Here, we collected fecal samples from 30 preterm infants at five-time points within the first four weeks of life. Employing 16 S rRNA sequencing, principal coordinates analysis, the analysis of similarities, and the Wilcoxon rank-sum test, we examined the top dominant phyla and genera, the temporal changes in specific taxa abundance, and their relationship with delivery modes, such as Escherichia-Shigella and Enterococcus based on vaginal delivery and Pluralibacter related to cesarean section. Moreover, we identified particular bacteria, such as Taonella, Patulibacter, and others, whose proportions fluctuated among preterm infants born via different delivery modes at varying time points, as well as the microbiota types and functions. These results indicated the influence of delivery mode on the composition and function of the preterm infant gut microbiota. Importantly, these effects are time-dependent during the early stages of life. These insights shed light on the pivotal role of delivery mode in shaping the gut microbiota of preterm infants and have significant clinical implications for their care and management.

SOME POTENTIAL REQUIREMENTS FOR THE FORMATION OF THE GUT MICROBIOTA IN PRETERM INFANTS: PART 1

Abnormal microbial colonization of the gut from birth in newborns aff ects growth, development, and health, leading to short- and long-term adverse eff ects. The microbiota of preterm infants diff ers from that of term ones. This is because preterm infants and their mothers have more complicated prenatal and postnatal health conditions and anatomically- functional immaturity of organs and systems depending on gestational age. Maternal conditions, antibiotics, type of feeding, and use of probiotics can signifi cantly aff ect the gut microbiota of preterm infants in the early neonatal period; however, these eff ects decrease with age. Although some factors and processes are diffi cult to intervene or avoid, understanding the potential factors and determinants will help to develop timely strategies to promote a healthy gut microbiota in preterm infants. This review discusses potential determinants of gut microbial colonization in preterm infants,the underlying mechanisms, and recommendations for addressing adverse eff ects.

Gut microbiota of preterm infants in the neonatal intensive care unit: a study from a tertiary care center in northern India.

Disruptions of the gut microbiota of preterm infants admitted to the neonatal intensive care unit (NICU) during the first 2 weeks of life are of critical importance. These infants are prone to various complications, including necrotizing enterocolitis (NEC) and sepsis. Studying the gut microbiota will improve outcomes in preterm infants. In the present study, we examined the gut microbiota of preterm infants admitted to the NICU in the first month of life. Neonates admitted to the NICU were recruited, and stool samples were collected weekly from the seventh day of the infant's life until the 30th day of life. DNA was extracted using a DNeasy Powersoil DNA isolation kit. 16S rRNA gene sequencing targeting the V3-V4 region was performed using the MiSeq platform. Sequenced reads were processed on DADA2 pipeline to obtain an amplicon sequence variant (ASV) table. All bioinformatic and statistical analyses were performed using different packages in the R statistical framework. Fourteen preterm infants were recruited, and 48 samples were collected. Alpha diversity metrics, observed ASV count, and Shannon index were found to have no differences in any clinical variables. Permutational multivariate analysis of variance (PERMANOVA) showed discrimination of neonates by gestational age and administration of probiotics. Differential abundance analysis showed a decreased abundance of Bifidobacterium Breve in extremely preterm infants (gestational age <28 weeks) compared to moderate preterm infants (gestational age 29-32 weeks). Supplementation with probiotics decreased Acinetobacter and increased Bifidobacterium in the gut of preterm neonates regardless of gestational age. Gestational age and probiotic supplementation alter the gut microbiota of preterm infants admitted to the NICU.

The effect of in-hospital breast milk intake on the gut microbiota of preterm infants

The aim of this study was to explore the effect of in-hospital breast milk intake on the development of early gut microbiota in preterm infants in two dimensions: longitudinal over time and cross-sectional between groups. Researchers collected preterm infants' general data baseline characteristics, recorded their daily breast milk intake, probiotics, and antibiotics use, and collected their stool specimens at 1st week, 2ndweek, 3rd week and 4th week after birth. The researchers analyzed the effect of breast milk on gut microbiota of preterm infants by bioinformatics methods of intra-group longitudinal variation of gut microbiota structure and diversity in preterm infants and cross-sectional differences between >70% in-hospital breast milk intake (BM) group and ≤70% (PF) group. A total of 60 preterm infants were included in this study, and a total of 213 stool specimens were retained. BM had statistically different Shannon and Simpson indices between the first and fourth week after admission (P<0.05), both of them showed a lower diversity in the later week than in the previous week. The Shannon index and Simpson index of BM from week 3 onwards were statistically different from PF (P<0.05), and the Shannon index and Simpson index of BM were lower than those of PF. Significantly statistical differences (P<0.05) were found in the beta diversity of gut microbiota in preterm infants as time progressed, and both showed a lower beta diversity in the later week than in the preceding week. The dominant taxa of PF in the first postnatal week were Bifidobacterium animalis, etc., the dominant taxa of BM in the third postnatal week were Clostridium_sensu_stricto _1, etc. CONCLUSIONS: The development and evolution of gut microbiota in preterm infants' in-hospital period was a continuous, non-random process, and similar trends in species composition and changes in gut microbes emerged in preterm infants with different ratio of breast milk intake. In the NICU setting, alpha diversity was lower in preterm infants in the >70% breast milk intake group than in the ≤70% group when compared between groups at the same time, which may be related to delayed maturation of gut microbes and represents a more developmental gut time window.

The impact of neonatal intensive care unit antibiotics on gut bacterial microbiota of preterm infants: a systematic review

Preterm infants encounter an unnatural beginning to life, with housing in neonatal intensive care units (NICUs) where they are exposed to antibiotics. Although the effectiveness of antibiotics in infection control is well established, the short- and long-term unintended effects on the microbiota of preterm infants receiving antibiotic treatment are yet to be quantified. Our aim was to investigate the unintended consequences of NICU antibiotics on preterm infants’ gut microbiota. We searched three electronic databases—Embase, PubMed, and Scopus—for records from 2010 to October 2022. Eligibility criteria included intervention and observational studies that collected stool samples and analyzed microbiota data on the effect of antibiotics on the gut microbiota of preterm infants using 16S rRNA sequencing. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the quality of the studies was judged using the Cochrane Collaboration Tool for assessing risk of bias (RoB2) for clinical trials, while non-randomized studies were assessed using the Newcastle–Ottawa Scale (NOS). The initial searches yielded 7,605 papers, of which 21 were included in the review. The selected studies examined 3,669 stool samples that were collected longitudinally from 878 preterm infants in seven different countries. Preterm infants exposed to antibiotics had a reduced bacterial diversity, an increased relative abundance of pathogenic bacteria such as Enterobacteriaceae, and a decrease or absence of symbiotic bacteria such as Bifidobacterium spp., which have been shown to assist in immunity development. Antibiotic discontinuation restored diversity, with variances linked to the antibiotic spectrum and treatment duration in some but not all cases. Breastfeeding confounded the association between antibiotic use and dysbiosis. Intriguingly, the reduction of γ-aminobutyric acid (GABA), a crucial neurotransmitter for early brain development, was linked to the depletion of Veillonella spp. Despite the apparent benefits of using antibiotics on preterm infants, we conclude that they should be used only when absolutely necessary and for a short period of time. Mothers’ milk is recommended to hasten the restoration of disrupted microbiota.

Пробіотики, кишкова мікробіота та захворювання, пов’язані з незрілістю травного каналу, у значно недоношених немовлят

Interruption of the formation of gut microbiota in preterm infants increases the probability of necrotizing enterocolitis (NEC) and late-onset neonatal sepsis (LOS). The use of probiotics can reduce the corresponding risk. Purpose - to evaluate the clinical effectiveness of enteral administration of Lactobacillus reuteri DSM 17938 in reducing the incidence of NEC, LOS, and overall mortality in infants with gestational age (GA) ≤32 weeks, as well as the effect of the probiotic on the formation of the gut microbiota. Materials and methods. 100 newborns with GA ≤32 weeks and birth weight ≤1500 g were enrolled in the open randomized study. 50 infants in the probiotic group until reaching postmenstrual age (PMA) of 36 weeks received Lactobacillus reuteri DSM 17938 at a dose of 108 CFU/day with enteral feeding (EF), and 50 infants in the comparison group received standard treatment. The primary effectiveness criteria were the incidence of NEC, LOS, and overall mortality. As the secondary criteria, the duration of the period to reach the full EF, the number of episodes of feeding intolerance, duration of antibacterial therapy, weight at PMA of 36 weeks, and length of hospital stay were used. Results. The administration of Lactobacillus reuteri DSM 17938 at a dose of 108 CFU/day neither reduced the incidence of NEC and LOS nor overall mortality. This intervention, however, significantly reduced the length of hospital stay in infants with GA ≥28 weeks (56.0 (46.0-71.0) days vs 65.0 (60.0-87.9) days; р=0.03), and was associated with the earlier achievement of full enteral volume (23.0 (16.0-37.0) days vs 30.0 (18.0-37.0) days; р=0.26) and fewer episodes of feeding intolerance in infants with GA &lt;28 weeks (1.0 (1.0-3.0) vs 3.0 (3.0-4.0); р=0.19). No effect of the probiotic therapy on the gut colonization by Lactobacillus spp. and Bifidobacterium spp. was observed. Conclusions. Enteral administration of Lactobacillus reuteri DSM 17938 improves tolerance to EF and reduces the period to achieve full EF and the total length of hospital stay in preterm infants. The effect of this probiotic on the incidence of NEC and LOS, as well as the postnatal formation of the gut microbiota, requires further study. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Dynamic changes of the gut microbial colonization in preterm infants with different time points after birth.

Risks associated with preterm birth are unevenly distributed across all gestations. At earlier gestational ages, complications such as necrotizing enterocolitis (NEC) and late-onset sepsis (LOS) conditions are significantly more common and are associated with a shift in the composition of the gut microbiome. Conventional bacterial culture techniques demonstrate that the colonization of the gut microbiota of preterm infants differs significantly from that of healthy-term infants. The current study aimed to investigate the impact of preterm infancy on the dynamic changes of fecal microbiota in preterm infants at different time points (1, 7, 14, 21, 28, and 42 days) after birth. We selected 12 preterm infants hospitalized in the Sixth Affiliated Hospital of Sun Yat-sen University from January 2017 to December 2017. A total of 130 fecal specimens from preterm infants were analyzed using 16S rRNA gene sequencing. We found that the colonization process of fecal microbiota in preterm infants is highly dynamic at different time points after birth, i.e., Exiguobacterium, Acinetobacter, and Citrobacter showed a declining abundance pattern with the advancement of age, while the bacterial groups of Enterococcus (Klebsiella and Escherichia coli) gradually grew and became the main microbiota during the development of fecal microbiota in preterm infants at the age of 42 days. Furthermore, the colonization of intestinal Bifidobacteria in preterm infants was relatively late and did not rapidly become the predominant microbiota. Moreover, the results also showed the presence of Chryseobacterium bacterial group, whose colonization was different in different time point groups. Conclusively, our findings deepen our comprehension and offer new perspectives on targeting particular bacteria in the treatment of preterm infants at different time points after birth.

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.

Source of human milk (mother or donor) is more important than fortifier type (human or bovine) in shaping the preterm infant microbiome

SummaryMilk fortifiers help meet the nutritional needs of preterm infants receiving their mother’s own milk (MOM) or donor human milk. We conducted a randomized clinical trial (NCT03214822) in 30 very low birth weight premature neonates comparing bovine-derived human milk fortifier (BHMF) versus human-derived fortifier (H2MF). We found that fortifier type does not affect the overall microbiome, although H2MF infants were less often colonized by an unclassified member of Clostridiales Family XI. Secondary analyses show that MOM intake is strongly associated with weight gain and microbiota composition, including Bifidobacterium, Veillonella, and Propionibacterium enrichment. Finally, we show that while oxidative stress (urinary F2-isoprostanes) is not affected by fortifier type or MOM intake, fecal calprotectin is higher in H2MF infants and lower in those consuming more MOM. Overall, the source of human milk (mother versus donor) appears more important than the type of milk fortifier (human versus bovine) in shaping preterm infant gut microbiota.

Dysbiosis in Gut Microbiota in Children Born Preterm Who Developed Autism Spectrum Disorder: A Pilot Study.

The gut microbiota was reported to differ between children with autism spectrum disorder (ASD) and typically developing (TD) children, and dysbiosis of the gut microbiota in preterm infants is common. Here, we explored the characteristics of gut microbiota in children born preterm with ASD. We performed 16S rRNA gene sequencing using stool samples from ASD children born preterm and TD children born preterm. Alpha diversity was significantly greater in the ASD group. A comparison of beta diversity showed different clusters. Linear discriminant analysis effect size analysis revealed significantly more Firmicutes in the ASD group compared with the TD group. In conclusion, the gut microbiota in children born preterm differs between children with ASD and TD.

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.

First 1000 Days and Beyond After Birth: Gut Microbiota and Necrotizing Enterocolitis in Preterm Infants.

Preterm birth remains a major maternal and infant health issue worldwide particularly with an increase in the global preterm birth rate, which requires more interventions to manage the consequences of preterm birth. In addition to traditional complications, recent studies have shown that the succession of gut microbiota of preterm infants is disordered due to the systemic physiological immaturity, which confers negative influences on the growth, development, and health of infants. In the present study, we briefly discussed the prevalence of preterm birth worldwide and then highlighted the signatures of gut microbiota in preterm infants within the first 1000 days of life after the birth categorized into birth, infancy, and childhood. Afterward, we focused on the potential association of clinical phenotypes typically associated with preterm birth (i.e., necrotizing enterocolitis) with gut microbiota, and the potential directions for future studies in this field are finally discussed.

Profiling Growth Patterns of Human Gut Microbes in Response to Preterm Human Milk and Formula

BackgroundThe infant gut microbiota undergoes significant fluxes in microbial composition during the first few years of life. The intestine is colonized shortly after birth with facultative anaerobes, like as Enterococcus, Enterobacter, Streptococcus, and Staphylococcus, which reduce the intestinal oxygen content and create niches for strict anaerobes, like Bifidobacteria, Bacteroides, and Clostridia. The dominant factors which influence the infant gut composition are gestational age and diet. The gut microbiota of preterm infants is characterized by limited microbial diversity and increased levels of facultative anaerobes such as Enterococci, Staphylococci, and Enterbacteriacea (Enterobacter, Escherichia, and Klebsiellaspp.). The gut microbiota is also highly influenced by diet, specifically formula and human milk use. The intake of human milk is associated with increased Bifidobacteria, while the intake of formula correlates with increased Enterobacteriaceae. This study aimed to analyze next‐generation products including preterm formula, human milk‐oligosaccharide term formula, and preterm breastmilk using a culture‐based model.Methods &amp; ResultsWe cultured 8 different Bifidobacteria, 8 Lactobacilli, 8 Streptococcus, 3 Enterococci and 4 Klebsiella strains in a fully defined bacteria media and monitored growth and pH after 20 hrs of anaerobic incubation. Significant differences were identified in strain growth and culture pH between human milk and formula. Human milk significantly elevated the growth of all Bifidobacteria and Lactobacilli. In contrast, human milk supported the growth of three Streptococci and only nominally supported pathobiont Enterococci and Klebsiella strains. Preterm formula elevated the majority of Bifidobacteria and Lactobacilli, as well as several Streptococci. Interestingly, preterm and full‐term formula significantly enhanced the growth of pathobiont strains. Full‐term formula only supported the growth certain commensal microbes, which was in marked contrast to human milk and preterm formula. Using computational modeling, a correlation was observed with human milk oligosaccharide (HMO) degrading glycosyl hydrolase profiles in the genomes of commensal microbes with human milk, but not with formula; confirming the HMO preference of our representative infant commensal microbes.ConclusionsThese findings indicate a unique profile of growth in response to human milk and formula. Since alterations in the infant gut microbiota have linked to childhood health and development, understanding how bacteria differentially utilize whole milk or formula may provide insights into which microbes drive diet‐related microbiota shifts.

Association Between Trajectory Patterns of Body Mass Index Change Up to 10 Months and Early Gut Microbiota in Preterm Infants.

Recent research suggests that gut microbiota plays an important role in the occurrence and development of excessive weight and obesity, and the early-life gut microbiota may be correlated with weight gain and later growth. However, the association between neonatal gut microbiota, particularly in preterm infants, and excessive weight and obesity remains unclear. To evaluate the relationship between gut microbiota and body mass index (BMI) growth trajectories in preterm infants, we examined microbial composition by performing 16S rDNA gene sequencing on the fecal samples from 75 preterm infants within 3 months after birth who were hospitalized in the neonatal intensive care unit of Hunan Children’s Hospital from August 1, 2018 to October 31, 2019. Then, we collected their physical growth information during 0–10 months. Latent growth mixture models were used to estimate growth trajectories of infantile BMI, and the relationship between the gut microbiota and the BMI growth trajectories was analyzed. The results demonstrated that there were 63,305 and 61 operational taxonomic units in the higher BMI group (n = 18), the lower BMI group (n = 51), and the BMI catch-up group (n = 6), respectively. There were significant differences in the abundance of the gut microbiota, but no significant differences in the diversity of it between the lower and the higher BMI group. The BMI growth trajectories could not be clearly distinguished because principal component analysis showed that gut microbiota composition among these three groups was similar. The three groups were dominated by Firmicutes and Proteobacteria in gut microbiota composition, and the abundance of Lactobacillus in the higher BMI group was significantly different from the lower BMI group. Further intervention experiments and dynamic monitoring are needed to determine the causal relationship between gut microbiota differences and the BMI change.

Human Milk-Based or Bovine Milk-Based Fortifiers Differentially Impact the Development of the Gut Microbiota of Preterm Infants.

Background: Preterm infants are exposed to different dietary inputs during their hospitalization in the neonatal intensive care unit (NICU). These include human milk (HM), with a human milk-based (HMF) or a bovine milk-based (BMF) fortifier, or formula. Milk consumption and the type of fortification will cause changes in the gut microbiota structure of preterm infants. This study aimed to characterize the gut microbiota of PT infant according to the type of feeding and the type of HM fortification and its possible association with infant's growth.Methods: Ninety-seven infants born ≤33 wks of gestation or <1,500 g were followed during the hospitalization period in the NICU after birth until discharge. Clinical and dietary information was collected, including mode of delivery, pregnancy complications, mechanical ventilation, use of antibiotics, weight, and type and amount of milk consumed. To characterize the gut microbiota composition, weekly stool samples were collected from study participants. The V3–V4 region of the 16S rRNA bacterial gene was Sequenced using Illumina MiSeq technology.Results: After birth, black maternal race, corrected gestational age (GA) and exposure to pregnancy complications, had a significant effect on gut microbial diversity and the abundance of Enterococcus, Veillonella, Bifidobacterium, Enterobacter, and Bacteroides. Over the course of hospitalization, corrected GA and exposure to chorioamnionitis remained to have an effect on gut microbial composition. Two different enterotypes were found in the gut microbiota of preterm infants. One enriched in Escherichia-Shigella, and another enriched in uncharacterized Enterobacteriaceae, Klebsiella and Clostridium sensu stricto 1. Overall, HM and fortification with HMF were the most common feeding strategies. When consuming BMF, PT infants had higher growth rates than those consuming HMF. Milk and type of fortification were significantly associated with the abundance of Clostridium sensu stricto 1, Bifidobacterium and Lactobacillus.Conclusions: This observational study shows the significant association between milk consumption and the exposure to HMF or BMF fortification in the fecal microbiota composition of preterm infants. Additionally, these results show the effect of other perinatal factors in the establishment and development of PT infant's gut microbiota.

How Gut Microbiota Supports Immunity, Growth and Development of Preterm Infants: A Narrative Review

ABSTRACTBackground: Gut microbiota, a complex ecosystem consisting of abundant microorganisms, plays a role in preterm infants’ immunity, growth, and development. Dysbiosis or disruption of the gut microbiota can precipitate various diseases, such as allergy or autoimmune disorders in premature infants. Purpose: This study aimed to review gut microbiota in preterm infants and its role in supporting the infants’ immunity, growth, and development. Discussion: Bifidobactericeae is the predominant microbiota in GI tract of preterm infants. However, various factors can influence this gut microbiota e.g., genetics, lifestyle of the mothers (smoking, diet, use of antibiotic, obesity), birth mode, type of feeding, and environmental factors. Gut dysbiosis can result in impaired immune system which predisposes the preterm infants to infections, even fatal adverse event. Furthermore, the growth and development might be affected as well as lead to various neurodevelopmental and psychiatric disorders. Human milk is a prebiotic source which can stimulate the growth of Baifidobactericeae and Bacteroidetes. If the human milk is inadequate or unavailable, the recommended interventions for gut dysbiosis in premature infants are probiotics, prebiotics, or both supplementations (synbiotics). The administration of prebiotics and probiotics associates with lower morbidity and death rates in preterm infants, as well as shorter duration of hospital stay and duration to achieve full enteral feeding. Conclusions: Immunity as well as growth and development of preterm infants are affected greatly by gut microbiota The less diverse microbiota in preterm infants’ gut predispose them to various health problems. Hence, this problem should be managed properly, one of which is prebiotic and probiotic supplementation Keywords: Gastrointestinal Microbiome, Premature, Immunity, Growth, Development

Evolution of Intestinal Gases and Fecal Short-Chain Fatty Acids Produced in vitro by Preterm Infant Gut Microbiota During the First 4 Weeks of Life.

Background: The production of intestinal gases and fecal short-chain fatty acids (SCFAs) by infant gut microbiota may have a significant impact on their health, but information about the composition and volume of intestinal gases and SCFA profiles in preterm infants is scarce.Objective: This study examined the change of the composition and volume of intestinal gases and SCFA profiles produced by preterm infant gut microbiota in vitro during the first 4 weeks of life.Methods: Fecal samples were obtained at five time points (within 3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks) from 19 preterm infants hospitalized in the neonatal intensive care unit (NICU) of Shanghai Children's Hospital, Shanghai Jiao Tong University between May and July 2020. These samples were initially inoculated into four different media containing lactose (LAT), fructooligosaccharide (FOS), 2′-fucosyllactose (FL-2), and galactooligosaccharide (GOS) and thereafter fermented for 24 h under conditions mimicking those of the large intestine at 37.8°C under anaerobic conditions. The volume of total intestinal gases and the concentrations of individual carbon dioxide (CO2), hydrogen (H2), methane (CH4), and hydrogen sulfide (H2S) were measured by a gas analyzer. The concentrations of total SCFAs, individual acetic acid, propanoic acid, butyric acid, isobutyric acid, pentanoic acid, and valeric acid were measured by gas chromatography (GC).Results: The total volume of intestinal gases (ranging from 0.01 to 1.64 ml in medium with LAT; 0–1.42 ml with GOS; 0–0.91 ml with FOS; and 0–0.44 ml with FL-2) and the concentrations of CO2, H2, H2S, and all six fecal SCFAs increased with age (p-trends < 0.05). Among them, CO2 was usually the predominant intestinal gas, and acetic acid was usually the predominant SCFA. When stratified by birth weight (<1,500 and ≥1,500 g), gender, and delivery mode, the concentration of CO2 was more pronounced among infants whose weight was ≥1,500 g than among those whose weight was <1,500 g (p-trends < 0.05).Conclusions: Our findings suggested that the intestinal gases and SCFAs produced by preterm infant gut microbiota in vitro increased with age during the first 4 weeks of life.

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

IntroductionProbiotic supplementation of preterm infants may prevent serious morbidities associated with prematurity.AimTo investigate the impact of probiotic supplementation on the gut microbiota and determine factors associated with detection of probiotic species in the infant gut.Hypothesis/Gap StatementProbiotic supplementation increases the long-term colonization of probiotic species in the gut of preterm infants.MethodologyLongitudinal stool samples were collected from a cohort of very preterm infants participating in a blinded randomized controlled trial investigating the impact of probiotic supplementation (containing Bifidobacterium longum subsp. infantis BB-02, Bifidobacterium animalis subsp. lactis BB-12 and Streptococcus thermophilus TH-4) for prevention of late-onset sepsis. The presence of B. longum subsp. infantis , B. animalis subsp. lactis and S. thermophilus was determined for up to 23 months after supplementation ended using real-time PCR. Logistic regression was used to investigate the impact of probiotic supplementation on the presence of each species.ResultsDetection of B. longum subsp. infantis [odds ratio (OR): 53.1; 95 % confidence interval (CI): 35.6–79.1; P < 0.001], B. animalis subsp. lactis (OR: 89.1; 95 % CI: 59.0–134.5; P < 0.001) and S. thermophilus (OR: 5.66; 95 % CI: 4.35–7.37; P < 0.001) was increased during the supplementation period in infants receiving probiotic supplementation. Post-supplementation, probiotic-supplemented infants had increased detection of B. longum subsp. infantis (OR: 2.53; 95 % CI: 1.64–3.90; P < 0.001) and B. animalis subsp. lactis (OR: 1.59; 95 % CI: 1.05–2.41; P=0.030). Commencing probiotic supplementation before 5 days from birth was associated with increased detection of the probiotic species over the study period ( B. longum subsp. infantis, OR: 1.20; B. animalis subsp. lactis, OR: 1.28; S. thermophilus, OR: 1.45).ConclusionProbiotic supplementation with B. longum subsp. infantis BB-02, B. animalis subsp. lactis BB-12 and S. thermophilus TH-4 enhances the presence of probiotic species in the gut microbiota of very preterm infants during and after supplementation. Commencing probiotic supplementation shortly after birth may be important for improving the long-term colonization of probiotic species.