Colonization Of Infants Research Articles

SOME POTENTIAL PREREQUISITES FOR THE FORMATION OF THE GUT MICROBIOTA IN PREMATURE BABIES: PART III

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 infants. 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.

Mobile genetic elements: the hidden puppet masters underlying infant gut microbiome assembly?

The gut microbiota is important for healthy infant development. Part of the initial colonizing microbial strains originate from the maternal gut, and undergo a selective event, termed the “colonization bottleneck”. While vertical mother-to-infant inheritance and subsequent colonization of bacteria have previously been studied, the role of mobile genetic elements (MGEs) in the infant gut microbiota assembly is unclear. In this perspective article, we discuss how horizontally and vertically transmitted phages and conjugative elements potentially have important roles in infant gut microbiota assembly and colonization through parasitic and mutualistic interactions with their bacterial hosts. While some of these MGEs are likely to be detrimental to their host survival, in other contexts, they may help bacteria colonize new niches, antagonize other bacteria, or protect themselves from other parasitic MGEs in the infant gut. As a result, the horizontal transfer of MGEs likely occurs at high rates in the infant gut, contributing to gene transfer between bacteria and affecting which bacteria can pass the colonization bottleneck. We conclude by highlighting the potential in silico , in vitro , and in vivo methodological approaches that could be employed to study the transmission and colonization dynamics of MGEs and bacteria in the infant gut.

Metal availability shapes early life microbial ecology and community succession.

The gut microbiota plays a critical role in human health and disease. Microbial community assembly and succession early in life are influenced by numerous factors. In turn, assembly of this microbial community is known to influence the host, including immune system development, and has been linked to outcomes later in life. To date, the role of host-mediated nutritional immunity and metal availability in shaping microbial community assembly and succession early in life has not been explored in depth. Using a human infant cohort, we show that the metal-chelating protein calprotectin is highly abundant in infants. Taxa previously shown to be successful early colonizers of the infant gut, such as Enterococcus, Enterobacteriaceae, and Bacteroides, are highly resistant to experimental metal starvation in culture. Lactobacillus, meanwhile, is highly susceptible to metal restriction, pointing to a possible mechanism by which host-mediated metal limitation shapes the fitness of early colonizing taxa in the infant gut. We further demonstrate that formula-fed infants harbor markedly higher levels of metals in their gastrointestinal tract compared to breastfed infants. Formula-fed infants with high levels of metals harbor distinct microbial communities compared to breastfed infants, with higher levels of Enterococcus, Enterobacter, and Klebsiella, taxa which show increased resistance to the toxic effects of high metal concentrations. These data highlight a new paradigm in microbial community assembly and suggest an unappreciated role for nutritional immunity and dietary metals in shaping the earliest colonization events of the microbiota.IMPORTANCEEarly life represents a critical window for microbial colonization of the human gastrointestinal tract. Surprisingly, we still know little about the rules that govern the successful colonization of infants and the factors that shape the success of early life microbial colonizers. In this study, we report that metal availability is an important factor in the assembly and succession of the early life microbiota. We show that the host-derived metal-chelating protein, calprotectin, is highly abundant in infants and successful early life colonizers can overcome metal restriction. We further demonstrate that feeding modality (breastmilk vs formula) markedly impacts metal levels in the gut, potentially influencing microbial community succession. Our work suggests that metals, a previously unexplored aspect of early life ecology, may play a critical role in shaping the early events of microbiota assembly in infants.

Development of an infant colon simulating in vitro model, I-TIM-2, to study the effects of modulation strategies on the infant gut microbiome composition and function.

The early life stages are critical for the development of the gut microbiome. Variables such as antibiotics exposure, birth-mode via Cesarean section, and formula feeding are associated with disruptions in microbiome development and are related to adverse health effects later in life. Studying the effects of microbiome-modulating strategies in infants is challenged by appropriate ethical constraints. Therefore, we developed I-TIM-2, an infant in vitro colonic model based on the validated, computer-controlled, dynamic model of the colon, TIM-2. The system, consisting of four separate compartments, was inoculated with feces from four healthy, primarily breastfed infants, displaying distinctive microbiome profiles. For each infant's fecal sample, a 96-h experiment was performed, with two compartments receiving an infant diet adapted medium and two compartments additionally receiving five human milk oligosaccharides (HMOs) in physiological concentrations and proportions. Bacterial composition was determined by shotgun metagenomics and qPCR. Concentrations of short-chain fatty acids (SCFAs) and HMOs were determined by LC-MS. Microbial diversity and high amounts of inoculum-derived species were preserved in the model throughout each experiment. Microbiome composition and SCFA concentrations were consistent with published data from infants. HMOs strongly modulated the microbiome composition by stimulating relative proportions of Bifidobacterium. This affected the metabolic output and resulted in an increased production of acetic and formic acid, characteristic of bifidobacterial HMO metabolism. In conclusion, these data demonstrate the development of a valid model to study the dynamics and modulations of the infant gut microbiome and metabolome.IMPORTANCEThe infant gut microbiome is intricately linked to the health of its host. This is partly mediated through the bacterial production of metabolites that interact with the host cells. Human milk shapes the establishment of the infant gut microbiome as it contains human milk sugars that select for primarily bifidobacteria. The establishment can be disrupted by modern interventions such as formula feeding. This can alter the microbiome composition and metabolite production profile, which can affect the host. In this article, we set up an infant in vitro colonic model to study microbiome interactions and functions. In this model, we investigated the effects of human milk sugars and their promotion of bifidobacteria at the expense of other bacteria. The model is an ideal system to assess the effects of various modulating strategies on the infant gut microbiome and its interactions with its host.

Mother’s milk microbiota is associated with the developing gut microbial consortia in very-low-birth-weight infants

Mother's milk contains diverse bacterial communities, although their impact on microbial colonization in very-low-birth-weight (VLBW, <1,500 g) infants remains unknown. Here, we examine relationships between the microbiota in preterm mother's milk and the VLBW infant gut across initial hospitalization (n= 94 mother-infant dyads, 422 milk-stool pairs). Shared zero-radius operational taxonomic units (zOTUs) between milk-stool pairs account for ∼30%-40% of zOTUs in the VLBW infant's gut. We show dose-response relationships between intakes of several genera from milk and their concentrations in the infant's gut. These relationships and those related to microbial sharing change temporally and are modified by in-hospital feeding practices (especially direct breastfeeding) and maternal-infant antibiotic use. Correlations also exist between milk and stool microbial consortia, suggesting that multiple milk microbes may influence overall gut communities together. These results highlight that the mother's milk microbiota may shape the gut colonization of VLBW infants by delivering specific bacteria and through intricate microbial interactions.

Streptococcus agalactiae glycolipids promote virulence by thwarting immune cell clearance.

Streptococcus agalactiae [group B Streptococcus (GBS)] is a leading cause of neonatal meningitis, with late-onset disease (LOD) occurring after gastrointestinal tract colonization in infants. Bacterial membrane lipids are essential for host-pathogen interactions, and the functions of glycolipids are yet to be fully elucidated. GBS synthesizes three major glycolipids: glucosyl-diacylglycerol (Glc-DAG), diglucosyl-DAG (Glc2-DAG), and lysyl-Glc-DAG (Lys-Glc-DAG). Here, we identify the enzyme, IagB, as responsible for biosynthesis of Glc-DAG, the precursor for the two other glycolipids in GBS. To examine the collective role of glycolipids to GBS virulence, we adapted a murine model of neonatal meningitis to simulate LOD. The GBS∆iagB mutant traversed the gut-epithelial barrier comparable to wild type but was severely attenuated in bloodstream survival, resulting in decreased bacterial loads in the brain. The GBS∆iagB mutant was more susceptible to neutrophil killing and membrane targeting by host antimicrobial peptides. This work reveals an unexplored function of GBS glycolipids with their ability to protect the bacterial cell from host antimicrobial killing.

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.

Preterm Infants' Airway Microbiome: A Scoping Review of the Current Evidence.

The aim of this scoping review was to investigate and synthesize existing evidence on the airway microbiome of preterm infants to outline the prognostic and therapeutic significance of these microbiomes within the preterm population and identify gaps in current knowledge, proposing avenues for future research. We performed a scoping review of the literature following the Arskey and O'Malley framework. In accordance with our inclusion criteria and the intended purpose of this scoping review, we identified a total of 21 articles. The investigation of the airway microbiome in preterm infants has revealed new insights into its unique characteristics, highlighting distinct dynamics when compared to term infants. Perinatal factors, such as the mode of delivery, chorioamnionitis, the respiratory support, and antibiotic treatment, could impact the composition of the airway microbiome. The 'gut-lung axis', examining the link between the lung and gut microbiome as well as modifications in respiratory microbiome across different sites and over time, has also been explored. Furthermore, correlations between the airway microbiome and adverse outcomes, such as bronchopulmonary dysplasia (BPD), have been established. Additional research in neonatal care is essential to understand the early colonization of infants' airways and explore methods for its optimization. The critical opportunity to shape long-term health through microbiome-mediated effects likely lies within the neonatal period.

Association between Ureaplasma urealyticum colonization and bronchopulmonary dysplasia in preterm infants: a systematic review and meta-analysis.

Bronchopulmonary dysplasia (BPD) is the most prevalent chronic lung disease in preterm infants. Studies have shown that Ureaplasma urealyticum (UU) infection is linked to its pathogenesis. However, it remains controversial whether UU colonization in preterm infants increases the risk of developing BPD. This study aimed to conduct a systematic review and meta-analysis to summarize the correlation between UU and BPD. We searched PubMed, Embase, the Cochrane Library, Web of Science, Wanfang Database, Chinese National Knowledge Infrastructure Database, Chinese Science and Technique Journal Database, and the China Biology Medicine disc from their inception to March 15, 2024. We included cohort and case-control studies investigating the association between UU infections and BPD in preterm infants, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Newcastle-Ottawa Scale was used for quality assessment. The outcome was defined as the continued need for oxygen or respiratory support at 28 days after birth (BPD28) or at 36 weeks postmenstrual age (BPD36). Considering the potential publication bias in observational studies, we used a random-effects meta-analysis model, assessed heterogeneity (I2), performed subgroup analyses, evaluated publication bias, and graded the quality of evidence. The meta-analysis included 36 cohort studies encompassing 5,991 participants. Among these, 20 reported on BPD28, 13 on BPD36, and 3 on both. The results indicated a significant association between UU colonization and BPD28 (odds ratio (OR): 2.26, 95% confidence interval (CI): 1.78-2.85, P < 0.00001, 23 studies, very low certainty of evidence) and BPD36 (OR: 2.13, 95% CI: 1.47-3.07, P < 0.0001, 16 studies, very low certainty of evidence). There is a correlation between UU colonization and the development of BPD in preterm infants. Future research should prioritize well-designed, large-scale, high-quality randomized controlled trials (RCTs) to comprehensively assess the risk of BPD in neonates following UU infection and to provide stronger evidence for clinical screening and prevention strategies to improve the prognosis of affected newborns. https://www.crd.york.ac.uk/, identifier (CRD42024524846).

First year of life: the Golden Age of gut microbiota

During the first year of life, development and balance of newborn gut microbiota are strongly influenced by external factors such as delivery mode, breastfeeding, duration of pregnancy, mother diet and lifestyle, siblings and pets, environment, and antibiotics administration. Gut microbiota colonization starts with facultative anaerobes and continues with the establishment of anaerobic genera of which Bifidobacteria are the gold standard of a healthy gut neonatal microbiota. Scientific literature traditionally describes the fetus as sterile in the womb and identifies the membranes rupture as the beginning of microbial colonization. Vaginal delivery is an important source for the onset of infant colonization which will then continue with the transfer of a new selection of intestinal bacteria with breastfeeding. During cesarean delivery a direct contact of the mouth of newborn with the vaginal and intestinal microbiota is absent, and environmental bacteria play an important role for infants intestinal colonization. Nature has ensured that newborns receive other specific maternal bacteria, through a subsequent method of transfer: breastfeeding. We present a brief and comprehensive state-of-the-art in order to encourage natural childbirth and breastfeeding whenever possible and discuss innovative directions for develop new ad hoc personalized treatments in order to restore physiological microbiota.

Treatment of preterm brain injury via gut-microbiota-metabolite-brain axis.

Brain injury in preterm infants potentially disrupts critical structural and functional connective networks in the brain. It is a major cause of neurological sequelae and developmental deficits in preterm infants. Interesting findings suggest that the gut microbiota (GM) and their metabolites contribute to the programming of the central nervous system (CNS) during developmental stages and may exert structural and functional effects throughout the lifespan. To summarize the existing knowledge of the potential mechanisms related to immune, endocrine, neural, and blood-brain barrier (BBB) mediated by GM and its metabolites in neural development and function. We review the recent literature and included 150 articles to summarize the mechanisms through which GM and their metabolites work on the nervous system. Potential health benefits and challenges of relevant treatments are also discussed. This review discusses the direct and indirect ways through which the GM may act on the nervous system. Treatment of preterm brain injury with GM or related derivatives, including probiotics, prebiotics, synbiotics, dietary interventions, and fecal transplants are also included. This review summarizes mechanisms underlying microbiota-gut-brain axis and novel therapeutic opportunities for neurological sequelae in preterm infants. Optimizing the initial colonization and microbiota development in preterm infants may represent a novel therapy to promote brain development and reduce long-term sequelae.

Effect of Probiotic Dose Escalation on Gut Microbiota and Clinical Outcomes in Preterm Infants-A Systematic Review.

Probiotics are known to decrease incidences of necrotising enterocolitis, feeding intolerance, late-onset sepsis, and mortality in preterm infants. Administering an adequate dose is important for optimizing the benefits and safety of probiotics. We conducted a systematic review to assess the effect of probiotic dose escalation on clinical outcomes and gut microbiota in preterm neonates. We searched PubMed, EMBASE, EMCARE, Medline, Cochrane Library, Google Scholar, and MedNar databases in July 2023. Three studies were included. In one of the randomized studies (n = 149, gestation 27 to 33 weeks), no significant differences in faecal Lactobacillus and Bifidobacterium counts and clinical outcomes were seen between the high- and low-dose groups. There was a trend towards increased Lactobacillus and Bifidobacterium counts in the high-dose group. In the other randomized study (n = 120, birth weight 500 to 2000 gm), smaller infants (500 to 1000 gm) required higher doses to display Lactobacillus in their faeces. The cohort study (n = 12, gestation < 33 weeks) showed a trend towards an increase in faecal abundance of bifidobacteria and bacterial diversity in the B. infantis group with increasing dose/time. Limited evidence suggests a higher dose might improve gut colonization in preterm infants. Further studies are urgently needed to address this gap in the knowledge considering the increasing use of probiotics for preterm infants.

Molecular characterization of Clostridium perfringens isolates from a tertiary children’s hospital in Guangzhou, China, establishing an association between bacterial colonization and food allergies in infants

BackgroundCow’s milk protein allergy (CMPA) is one of the most common types of food allergy in infants. Faecal pathogen cultures showed that the positive rate of Clostridium perfringens was more than 30%, which was significantly higher than that for other bacteria. Therefore, it is speculated that Clostridium perfringens colonization may be one of the pathogenetic factors for CMPA in infants. We conducted a real-world evidence study. Infants aged 0–6 months with diarrhoea and mucoid and/or bloody stools were recruited from a large tertiary hospital in China. Faecal pathogen cultures for the detection of Clostridium perfringens were confirmed by flight mass spectrometry, and potential toxin genes were identified using PCR. After 12 months of follow-up, the diagnoses of CMPA and food allergy were recorded. The correlation was assessed by Pearson correlation analysis.ResultsIn this study, 358 infants aged 0–6 months with gastrointestinal symptoms and faecal pathogen cultures were recruited. A total of 270 (44.07% girls; mean age, 2.78 ± 2.84 months) infants were followed up for 12 months. Overall, the rate of positivity for Clostridium perfringens in faecal pathogen cultures was 35.75% (128/358) in infants aged ≤ 6 months. The earliest Clostridium perfringens colonization was detected within 2 days after birth. The majority of Clostridium perfringens isolates were classified as type C in 85 stool samples. In the Clostridium perfringens-positive group, 48.21% (54/112) of infants were clinically diagnosed with food allergies after 12 months, including 37.5% (42/112) with CMPA, which was significantly higher than that of the negative group, with 7.59% (12/158) exhibiting food allergies and 5.06% (8/158) presenting CMPA (P < 0.0001). Faecal Clostridium perfringens positivity was significantly correlated with CMPA, food allergy, faecal occult blood, faecal white blood cells, antibiotic use, increased peripheral blood platelet counts, and decreased haemoglobin levels (P < 0.0001).ConclusionsThis study demonstrates that intestinal colonization by Clostridium perfringens is common in infants. The majority of Clostridium perfringens isolates are classified as type C. Colonization of the intestine by Clostridium perfringens is associated with the development of CMPA and food allergy in infants.

Oral Care in Critically Ill Infants and the Potential Effect on Infant Health: An Integrative Review.

Critically ill infants admitted to the neonatal intensive care unit are at risk for ventilator-associated pneumonia and abnormal oral colonization. Adherence to evidence-based guidelines for oral care in critically ill adults is associated with improved short- and long-term health outcomes. However, oral care guidelines for critically ill infants admitted to the neonatal intensive care unit have not been established, possibly increasing their risk of ventilator-associated pneumonia and other health complications. To describe and summarize the evidence regarding oral care for critically ill infants admitted to the neonatal intensive care unit and to identify gaps needing further investigation. The MEDLINE (through PubMed) and CINAHL databases were searched for observational studies and randomized controlled trials investigating the effect of oral care on oral colonization, ventilator-associated pneumonia, and health outcomes of infants in the neonatal intensive care unit. This review of 5 studies yielded evidence that oral care may promote a more commensal oral and endotracheal tube aspirate microbiome. It may also reduce the risk of ventilator-associated pneumonia and length of stay in the neonatal intensive care unit. However, the paucity of research regarding oral care in this population and differences in oral care procedures, elements used, and timing greatly limit any possible conclusions. Oral care in critically ill infants may be especially important because of their suppressed immunity and physiological immaturity. Further appropriately powered studies that control for potential covariates, monitor for adverse events, and use recommended definitions of ventilator-associated pneumonia are needed to make clinical recommendations.

Detection of maternal transmission of resistant Gram-negative bacteria in a Cambodian hospital setting.

Infection with Extended-spectrum beta-lactamase -producing Enterobacterales (ESBL-E) is common in infants and leads to increased intensive care unit admission and mortality, but the role of maternal transmission in colonization of infants is unclear. Using paired isolates from 50 pairs of mothers and neonates admitted to a Cambodian hospital, we investigated antimicrobial resistance in Escherichia coli and Klebsiella pneumoniae using whole genome sequencing. We detected a wide variety of ESBL-E genes present in this population along with high levels of multidrug resistance. From 21 pairs where the same organism was present in both mother and neonate, we identified eight pairs with identical or near-identical isolates from both individuals suggestive of transmission at or around birth, including a pair with transmission of multiple strains. We found no evidence for transmission of plasmids only from mother to infant. This suggests vertical transmission outside hospitals as a common cause of ESBL-E colonization in neonates.

In vivo immunomodulatory alleviating effects of animal milk oligosaccharides on murine NEC: A study

Human milk oligosaccharides may mediate prebiotic and anti-inflammatory effects on newborns. It is essential for preterm infants susceptible to intestinal dysfunction and necrotizing enterocolitis (NEC). However, the infant breastfeeding rate remains low, and there is still a great demand for suitable substitutes for HMOs prebiotic effect. In this paper, we study the new molecular insights of the protective mechanism of four animal milk oligosaccharides against developing experimental NEC from the perspective of intestinal flora balance and immunomodulatory mechanism. Studies have found that milk oligosaccharides (MOs), especially yak milk oligosaccharides, can directly affect the intestinal barrier by inhibiting the expression of inflammatory factors, restoring the abundance of Bifidobacteria, Bacteroidetes and Lactobacilli, improving the intestinal function, bacterial colonization and NEC resistance of premature infants after birth. These results emphasize that MOs, a substitute for breastfeeding, have specific preventive and alleviating effects on neonatal NEC.

Association between caesarean section and childhood asthma development

According to the World Health Organization (WHO), the rates of caesarean section delivery, which is the most common surgical procedure in gynecology and obstetrics, are increasing globally and amount to 21%. In Poland percentage of caesarean sections (CS) is one of the highest in Europe and amount to 42.2%. The reason for this is the extension of medical indications, but also an increase in the number of CS at the request of pregnant women. Although CS can be a lifesaving procedure, it can also cause many health complications for both - the woman and the child. Numerous studies indicate that caesarean delivery is associated with childhood asthma. Several hypotheses of the pathogenesis of this relationship have been presented. One of them, which is based on the hygiene hypothesis indicates that mode of delivery can cause different bacteria colonization in infants. Lack of contact of fetus with the mother’s vaginal flora during CS labor may cause improper immune system maturation. Another hypothesis is that reduced exposure to stress hormones and mechanical forces during CS labor can indicate infant respiratory complications such as respiratory distress syndrome (RDS) or transient tachypnea of the newborn (TTN). It is suggested that these abnormalities have an impact on asthma development in later life. On the other hand, there are studies which do not confirm that mode of delivery has an influence on the induction of asthma. Due to the significant heterogeneity of studies and unclear risk factors and pathomechanism of the childhood asthma it is impossible to strong confirm the association between caesarean section and asthma developing.

A preliminarily Investigation on Oral Colonization and Counts of Streptococcus mutans and Streptococcus mitis in a Group of Predentate Infants in Relation to Some Maternal and Infant Factors (A Longitudinal Observational study).

Bacterial colonization of infants' oral cavities is a key factor for future caries risk. This study sought to longitudinally assess oral bacterial colonization in a group of predentate infants in relation to some mother and infant factors. A total of 50 mother-infant pairs were enrolled. When infants were 3-month-old, data were collected about some infant and mother factors; additionally, maternal Decayed, Missing, and Filled Teeth (DMFT) scores and salivary samples of mothers and infants were obtained. At 6 months of infant's age, another infants' salivary samples were obtained. Saliva was cultured to detect and quantify Streptococcus mutans (S. mutans) and Streptococcus mitis (S. mitis). Streptococcus mitis (S. mitis) was detected in all infants at 3 months. 74 and 96% of infants acquired S. mutans at 3 and 6 months, respectively. S. mutans detection was significantly higher with higher maternal DMFT scores, salivary S. mutans counts, and lower S. mitis counts, as well as when infants were given sugar-containing complementary foods/drinks. At 3-6 months, infants' S. mutans counts were significantly positively correlated with maternal S. mutans counts and DMFT scores and negatively correlated with maternal S. mitis counts. The opposite was evident for infants' S. mitis counts. Regression analysis showed that increased maternal DMFT scores and S. mutans counts, and Cesarean delivery were strong predictors for increased infant's S. mutans counts. While increased DMFT scores and maternal S. mutans counts were strong predictors for reduced infant's S. mitis counts. Poor maternal oral health, early introduction of sugars in the diet, and probably Cesarean delivery can negatively impact infants' oral bacterial colonization and possibly future caries risk. Understanding factors associated with oral colonization of both caries-producing and protective flora in infants of different populations is important for caries prevention. This, in turn, can aid tailoring oral health promotion programs for expectant mothers. Wassel MO, Salman NS, Metwalli NE. A preliminarily Investigation on Oral Colonization and Counts of Streptococcus mutans and Streptococcus mitis in a Group of Predentate Infants in Relation to some Maternal and Infant Factors (A Longitudinal Observational study). Int J Clin Pediatr Dent 2023;16(1):79-86.

Association of Gestational Diabetes With the Dynamic Changes of Gut Microbiota in Offspring From 1 to 6 Months of Age.

The present study aimed to prospectively evaluate the influence of gestational diabetes mellitus (GDM) on the gut microbiota in 1- and 6-month-old offspring, as well as the dynamic changes from 1 to 6 months of age. Seventy-three mother-infant dyads (34 GDM vs 39 non-GDM) were included in this longitudinal study. Two fecal samples were collected for each included infant at home by the parents at 1 month of age ("M1 phase") and again at 6 months of age ("M6 phase"). Gut microbiota were profiled by 16S rRNA gene sequencing. Although no significant differences were observed in diversity and composition between GDM and non-GDM groups in the M1 phase, we observed differential structures and composition in the M6 phase between the 2 groups (P < .05), with lower levels of diversity, 6 depleted and 10 enriched gut microbes among infants born to GDM mothers. The dynamic changes in alpha diversity from the M1 to M6 phase were also significantly different according to GDM status (P < .05). Moreover, we found that the altered gut bacteria in the GDM group were correlated with infants' growth. Maternal GDM was associated not only with the community structure and composition in the gut microbiota of offspring at a specific time point, but also with the differential changes from birth to infancy. Altered colonization of the GDM infants' gut microbiota might affect their growth. Our findings underscore the critical impact of GDM on the formation of early-life gut microbiota and on the growth and development of infants.

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.