Search Results (298)

Human milk bacteria contribute to gut microbiome establishment in breastfed infants. Although breastfeeding is recommended throughout infancy, temporal variation in the milk microbiome—particularly beyond solid food introduction—remains understudied. We analyzed 539 milk samples from 83 mother–infant dyads between 1 week and 12 months postpartum using full-length 16S rRNA gene sequencing. The microbiota was dominated by Streptococcus (34%), Cutibacterium (12%), and Staphylococcus (9%), with marked inter-individual variation. Microbiome profiles remained largely stable across lactation, with only six taxa showing temporal fluctuations, including increases in typical oral bacteria such as Streptococcus salivarius, Streptococcus lactarius, Rothia mucilaginosa, and Granulicatella adiacens. Richness and evenness were higher at 1 week compared to 1 month postpartum (p = 0.00003 and p = 0.007, respectively), then stabilized. Beta diversity also remained stable over time. Maternal pre-pregnancy BMI was positively associated with Gemella haemolysans (p = 0.016), while Haemophilus parainfluenzae was more abundant in milk from mothers with allergies (p = 0.003) and those who gave birth in autumn or winter (p = 0.006). The introduction of solid food was linked to minor taxonomic shifts. Overall, the milk microbiome remained robustly stable over the first year of lactation, with limited but notable fluctuations in specific taxa. This study supports the role of human milk as a consistent microbial source for infants and identifies maternal BMI, allergy status, and birth season as key variables warranting further investigation. Full article

Hydrogen sulfide (H₂S) can be produced from the metabolism of foods containing sulfur in the gastrointestinal tract (GIT). At low doses, H₂S regulates the gut microbial community and supports GIT health, but depending on dose, age, and individual health conditions, it may also contribute to inflammatory responses and gut barrier dysfunction. Controlling H₂S production in the GIT is important for maintaining a healthy gut microbiome. However, research on this subject is limited due to the gaseous nature of the chemical and the difficulty of accessing the GIT in situ. In the present ex vivo experiment, we used a single-dose sodium sulfide preparation (SSP) as a H₂S precursor to test the effect of H₂S on the human gut microbiome across different age groups, including breastfed infants, toddlers, adults, and older adults. Metagenomic sequencing and metabolite measurements revealed that the development of the gut microbial community and the production of short-chain fatty-acids (SCFAs) were age-dependent; that the infant and the older adult groups were more sensitive to SSP exposure; that exogeneous SSP suppressed SCFA production across all age groups, except for butyrate in the older adult group, suggesting that H₂S selectively favors specific gut microbial processes. Full article

The first few days following the birth are a vulnerable time for the neonate. Sick infants experience various interventions during their stay in the neonatal unit in order to stay alive and grow. Acquisition of gut microbes is critical for the short- and long-term health of the neonate. At a time when the gut microbiome is starting to take shape, crucial interventions directed at improving the growth, development and survival of the neonate impact its development. Events prior to and after the birth of the neonate, such as maternal conditions, antibiotic exposure, type of feeds, supplemental probiotics, and neonatal intensive care environment, contribute significantly to shaping the gut microbiome over the first few weeks and maintain its healthy balance crucial for long-term health. In this comprehensive review, we address common interventions the neonate is exposed to in its journey and their impact on gut microbiome, and discuss various interventions that minimize the dysbiosis of the gut. Full article

Background/Objectives: Caesarean section (CS) accounts for over 20% of global births and routinely involves perioperative antibiotic prophylaxis (PAP) to reduce surgical site infections. While the impact of such prophylaxis on neonatal microbiome development is well described, effects on the maternal gut microbiome remain underexplored. This systematic review synthesizes current evidence on how antibiotic prophylaxis during CS affects maternal gut microbiome composition and diversity—an underrepresented, but clinically relevant aspect of maternal–fetal medicine. Methods: A systematic literature search was conducted in Medline (PubMed), the Cochrane Library, and the WHO International Clinical Trials Registry Platform (ICTRP) through November 2024. Inclusion criteria were defined according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eligible studies used molecular techniques to report maternal gut microbiome outcomes (alpha- and beta-diversity). The search concentrated on beta-lactam antibiotics. Reference lists were screened, but no additional grey literature was searched. Synthesis followed the Synthesis Without meta-analysis (SWiM) approach. No review protocol was registered. The review received no external funding. Results: Out of 1011 records, three studies (total 286 mothers) met the inclusion criteria. All reported maternal microbiome outcomes secondarily to infant-focused research. Only one study provided pre- and post-birth stool samples. Applied antibiotic regimens, sequencing methods, and reported microbiome metrics for alpha- and beta-diversity varied considerably, thus limiting comparability of results. Due to high heterogeneity, no formal risk of bias was assessed. While taxonomic diversity changes were inconsistent, significant shifts in functional diversity metrics were observed postpartum. Conclusions: Evidence on maternal microbiome disruption following perioperative antibiotic prophylaxis in CS is methodologically fragmented and limited by small sample sizes and inconsistent antibiotic protocols. Nonetheless, functional diversity appears sensitive to antibiotic exposure. To improve clinical understanding and safety, maternal-focused studies using standardized protocols are urgently needed. The maternal microbiome may play a key role in both recovery and shaping the newborn’s early microbial environment. Full article

Overuse of antibiotics is a concern in ‘culture-negative sepsis’ but it is unclear whether this is due to infection with viruses, fungi or other microbes that are not easily cultured, or whether it results from inflammatory processes. In a prospective study, we enrolled 50 preterm neonates with culture-positive sepsis (CP), culture-negative sepsis (CN), and asymptomatic preterm controls (CO). The microbiome of stool, skin, and blood, including bacterial, viral and fungal components and serum cytokine profiles were evaluated. The microbiome alpha or beta diversity did not differ between CN and CO groups. A MaAsLin analysis revealed increased relative abundances of specific bacterial and fungal genera in stool and skin samples in the CN group compared to CO. The virome analysis identified 24 viruses from skin samples, but they were not statistically different among the three groups. The cytokine and chemokine biomarker profiles were elevated in the CP group but were not statistically different between the CN and CO groups. Although the CN group had a longer hospital stay and higher BPD rates than the controls in unadjusted analyses, these differences were not significant after adjusting for gestational age and birth weight. The CN infants demonstrated microbial shifts without systemic immune activation or significantly worse clinical outcomes, supporting the rationale for discontinuing antibiotics in the absence of positive cultures. Full article

Background and Objectives: Infant feeding practices play a crucial role in shaping the oral microbiome, modulating inflammatory responses, and maintaining epithelial health during the first year of life. Breastfeeding promotes the growth of beneficial bacteria and supports a diverse, stable microbial community. In contrast, formula feeding is associated with increased colonization by potentially pathogenic bacteria, such as Staphylococcus and Escherichia coli, which may elevate the risk of infections, oral diseases, and inflammation. This study investigates the effects of breastfeeding versus formula feeding on oral bacterial growth, epithelial cell integrity, and interleukin-17 (IL-17) expression in infants aged 1–12 months. Materials and Methods: A total of 60 infants (30 breastfed and 30 formula-fed) were recruited from pediatric clinics in the Qassim region. Microbial cultures quantified bacterial colony-forming units (CFUs), and epithelial cell morphology was assessed through the microscopic analysis of mucosal scrapings. IL-17 concentrations were quantified from the oral mucosa through enzyme-linked immunosorbent assay. Statistical analyses, including t-tests and chi-square tests, compared bacterial loads, IL-17 levels, and indicators of epithelial health between groups. Adjustment for potential confounders was achieved through multivariate statistical analysis. Results: Formula-fed infants showed significantly higher IL-17 levels than breastfed infants (p < 0.001), indicating a stronger pro-inflammatory profile. Breastfed infants exhibited lower inflammation, improved epithelial health, and reduced cellular debris compared to formula-fed infants, who had higher bacterial loads. A significant correlation was found between epithelial health and bacterial clustering, with clearer epithelial cells associated with lower bacterial colonization. Conclusions: Formula feeding was associated with increased salivary IL-17 levels, greater bacterial colonization, and compromised epithelial integrity, indicating a heightened pro-inflammatory state and potential vulnerability to mucosal irritation or infection. Breastfeeding appeared to confer protective effects by promoting healthier microbial balance, epithelial integrity, and reducing inflammatory responses. These findings underscore the immunological and microbial benefits of breastfeeding in supporting oral health during infancy. Full article

OPN is a phosphorylated glycoprotein found in all vertebrate organisms and expressed in many tissues and secretions. It is a pleiotropic protein that plays diverse roles in various pathological and physiological processes. OPN is involved in many tissue transformation events such as intestinal and brain development, the regulation of immune system activity, immune cell activation, and inflammatory responses. This protein increases the functionality of the digestive system by regulating the intestinal microbiome and may help strengthen the intestinal barrier. OPN can also influence cognitive development and behavior. In addition, its recent association with cancer has gained critical importance. The increased expression of OPN has been observed in many cancer types, which may promote tumor cell metastasis. OPN is also effective in bacterial interaction and infections; it can prevent bacterial adhesion, supporting the development of new therapeutic approaches for oral care. Furthermore, the supplementation of OPN in infant formula has positively influenced the immune and intestinal health of infants. Many recent studies have focused on these aspects. This article provides a review and comparison of the existing knowledge on the structure and functions of OPN. It emphasizes how milk-derived OPN impacts human and infant health and disease. Full article

Although Cesarean section (C-section) delivery is often a necessary medical intervention, it also increases the risk of the infant developing chronic inflammatory, metabolic, and neurodevelopmental disorders. The association of C-section with the development of these conditions is thought to be partially mediated by the effects of the C-section on the infant’s microbiome development and subsequent immune regulation. C-section-delivered infants acquire a different set of microbes compared with infants who are vaginally delivered. “Vaginal seeding” exposes C-section-delivered infants to the maternal vaginal microbiome directly after birth, partly replicating the microbial exposures they would have received during a vaginal delivery. Studies have shown that vaginal seeding at birth partially restores the infant microbiome towards that of a vaginally delivered infant. More recently, preliminary studies have shown a potential benefit of vaginal seeding on health outcomes. Here, we examine the evidence from observational studies and randomized controlled trials that have evaluated microbiome restoration after C-section, and we discuss new research assessing the potential impact of vaginal seeding on immune, metabolic, and neurodevelopmental outcomes and the underlying mechanisms. Collectively, we review the potential health benefits, safety risks, regulatory implications, and future directions for the use of vaginal seeding in infants delivered by C-section. Full article

Background/Objectives: There is growing interest in the benefits of probiotic supplementation during pregnancy and lactation, but evidence supporting the beneficial effects for mother–infant dyads remains scarce. This study assessed the effects of probiotic supplementation on infection frequency and immunity in pregnant women and infants, and on microbiome establishment during the first month of life. Methods: At 28 weeks of gestation, 180 healthy pregnant women were randomized to receive either a placebo (n = 90) or a probiotic supplement (n = 90), Prenatis™, containing 5 billion CFU/day of Lacticaseibacillus rhamnosus Rosell^®-11 and Bifidobacterium bifidum HA-132. Results: There was a significantly lower number of women with one or more infections during the study in the probiotics group (8 vs. 18, p = 0.05) and a trend for a lower number of infections during pregnancy (primary outcome) in the probiotics group (p = 0.07). Regarding infants, a lower number of days with infections during the first month of life was observed in the probiotics group (4.7 days on average vs. 10.5 days, p = 0.03). The vaginal microbiota composition during pregnancy and after childbirth showed no significant differences between groups while the infants’ gut microbiome demonstrated a significantly higher abundance/prevalence of beneficial taxa in the probiotics group. The benefits conferred by probiotics were especially notable when considering birth by C-section. Probiotics promoted the vertical transmission of beneficial species and the induction of a highly interconnected microbiota, structured around key species. Conclusions: Probiotic supplementation during the third trimester of pregnancy and lactation is a valid strategy for conferring benefits to mothers and infants. Full article

Breast milk is vital for infant survival, protecting against infections and strengthening the immune system. In addition to nutrients, breast milk contains beneficial microorganisms, antimicrobial peptides and proteins (APPs), including lactoferrin and lysozyme, and peptides such as defensins and cathelicidins that destroy harmful bacteria and regulate the neonatal immune response. Breast milk also promotes the growth of beneficial gut bacteria (Bacteroidaceae and Bifidobacteriaceae) while reducing harmful pathogens, fostering a healthy gut microbiome, and supporting long-term infant health. Traditionally, research on antimicrobial proteins and milk microbiota has been conducted in isolation. However, at the molecular level, these components do not function independently; they interact synergistically, influencing immunomodulation, inflammation, and the composition of the gut microbiome. Therefore, this review aims to provide an overview of the discovery and identification of APPs in breast milk, the dynamic relationship between the breast milk microbiota, and the potentiation of artificial feeding with supplemented formulas when breastfeeding is impossible, benefits on newborn immune systems, and even the benefits to breast tissue. Full article

Background/Objectives: In recent years, due to the emergence of antimicrobial resistance, probiotics have been increasingly used during pregnancy and lactation with real maternal–fetal benefits. Probiotic intervention, especially multi-strain probiotics, due to their anti-inflammatory, metabolic, and immunomodulatory actions, can be performed prophylactically and therapeutically with promising results regarding maternal, fetal, and neonatal health. The administration of probiotics can modulate the maternal microbiome, regulate microflora imbalance in various conditions (overweight/obesity, gestational diabetes mellitus (GDM), preeclampsia, allergic diseases), and influence several reactions such as modulating the non-specific cellular immune system, metabolic processes, and inhibition of pathogens. This study aimed to analyze, based on available data, how the administration of probiotic supplements to women during pregnancy can modify immunometabolic responses to microbial dysbiosis to limit weight gain and the risk of obesity, to improve glucose homeostasis and reduce the risk of GDM, to prevent preeclampsia and its effects on maternal–fetal outcomes, and to reduce rates of atopic eczema and allergic diseases in infants. Methods: We performed a systematic search in MEDLINE/PubMed to identify studies that have investigated the effects of probiotic intervention on the immunometabolic response in pregnancy and lactation, especially in women with diabetes, overweight/obesity, preeclampsia, and allergic conditions. Results: Fifty-six RCT studies, totaling 15,044 women, matched the inclusion criteria, of which eight were for interventions on the immune response, twenty on allergic conditions, seven on obesity and excess weight gain in pregnancy, and twenty-one on GDM. Conclusions: Due to the heterogeneous structure and the size of the samples, the methodologies, formulations, moment of initiation, and study durations, future research is needed to establish their effectiveness and safety in pregnancy and lactation regarding maternal-fetal health and outcomes in childhood and adult life. Full article

Early-life establishment of the gut microbiota plays a role in lifelong health, with disruptions linked to heightened risks of metabolic and immune disorders. Probiotic supplementation may be used to modulate the infant gut microbiome to promote favourable development. Here, we evaluate how Lab4B probiotic supplementation shapes the development of the infant gut microbiome over the first 6 months. Faecal samples collected from infants enrolled in PROBAT (ISRCTN26287422), a randomised, double-blind, placebo-controlled trial, were analysed using culture-dependent and -independent (16S rDNA and metagenomic shotgun sequencing) techniques to examine the composition, diversity, and metabolic capabilities of the microbiome, as well as the abundance of antimicrobial resistance genes (ARGs). Probiotic supplementation encouraged the development of a microbiome with a distinct composition characterised by elevated abundances of Bifidobacteriaceae in the first 6 weeks (p = 0.006) and Lactobacillaceae throughout the first 6 months (p < 0.05 at every 6-week time point), accelerated microbial diversification, reduced abundance of beta-lactam- and cephalosporin-resistance genes, and differences in predicted metabolic capabilities at the start and end points. Supplementation of this neonatal population, which is at high risk of atopy, with the Lab4B probiotic significantly influenced the development of the infant gut microbiota during the first 6 months. Full article

Background/Objectives: Severe infection (sInfection; either late-onset culture-proven sepsis or necrotizing enterocolitis) in very low birth weight (VLBW) infants increases mortality rates and may show long-term progression. The fecal microbiome composition in VLBW infants with and without sInfection was classified in the sInfection and non-sInfection groups. Methods: Gut microbiomes, secondary information from a previous randomized trial, were analyzed using QIIME 2 software. The biodiversity and abundance of the gut microbiota between the sInfection and non-sInfection groups were compared. Results: Fifty-one neonates were included in the sInfection (n = 9) and non-sInfection (n = 42) groups; no significant differences in the fecal microbiome were observed in both alpha and beta diversities. Analysis of relative abundance revealed that in both groups, the predominant gut microbiota phylum, class, and genus were Proteobacteria, Gammaproteobacteria, and Klebsiella, respectively. The main fecal microbiome in the non-sInfection group included Faecalibacterium, Clostridium butyricum, and Bacteroides fragilis. Clostridium_sensu_stricto _1 was significantly more abundant in the non-sInfection group than in the sInfection group. Conclusions: Clostridium_sensu_stricto_1 was the main gut microbiota in the non-sInfection group. Considering the potential taxa as synbiotics (correlations among prebiotics, probiotics, and postbiotics), therapeutics may be useful for preventing and managing necrotizing enterocolitis or late-onset culture-proven sepsis in VLBW infants. Full article

Background: The impact of maternal obesity on offspring health remains a major and pressing issue. We investigated its impact on the development of the infant gut microbiome during the first six months of life, examining the taxonomic composition, metabolic pathways, and antibiotic resistance genes. Methods: Twenty-four mother–infant pairs were divided into maternally obese (OB, BMI > 36) and normal weight (BM) groups. Shotgun metagenomic sequencing was performed on stool samples collected at birth and at 1, 3, and 6 months. A total of 12 maternal samples and 23 infant samples (n = 35) in the obese group and 12 maternal samples and 30 infant samples (n = 42) in the control group were sequenced. The analysis included taxonomic profiling (MetaPhlAn 4), metabolic pathway analysis (HUMAnN 3), and antibiotic resistance gene screening (CARD/ABRicate). Results: The OB group showed reduced alpha diversity in the first month (p ≤ 0.01) and an increased Firmicutes/Bacteroidetes ratio, peaking at 3 months (p ≤ 0.001). The metabolic profiling revealed enhanced carbohydrate breakdown (p ≤ 0.001) in the BM group and lipid biosynthesis (p ≤ 0.0001) in the OB group pathways. Strong correlations emerged between Lactobacillales and fatty acid biosynthesis (r = 0.7, p ≤ 0.0001) and between Firmicutes and lincosamide (r = 0.8, p ≤ 0.0001). Conclusions: The infants of obese mothers had significantly altered development of the infant gut microbiome, affecting both composition and metabolic potential. These changes may have long-term health consequences and suggest potential therapeutic targets for intervention. Full article

The human milk (HM) microbiome is variable and depends on maternal, perinatal, and cultural–environmental factors. The diversity of the HM microbiome is crucial in the development of the child. The aim of the study was to assess the prevalence of bacteria (using culture-based methods) of Polish women with normal BMI, giving birth on time through vaginal delivery. Methods: The research material consisted of human milk and swabs from the areola and nipple, before and after breastfeeding, derived from Polish women (n = 86). Classic culture methods were used to obtain multiple bacteria. Species identification of the grown colonies was performed using MALDI TOF MS (Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry). Results: 120 species of bacteria were isolated, mainly from the genus Streptococcus and Staphylococcus. Species specific only to human milk were identified (belonging to the following genera: Microbacterium, Shewanella, Psychrobacter, Aeromonas, Serratia, Buttiauxella, Lactobacillus, Bifidobacterium) as well as species specific only to areola and nipple swabs after breastfeeding (Acinetobacter lactucae, Moraxella catarrhalis, Corynebacterium pseudodiphtheriticum, Corynebacterium propinquim). It was confirmed that most species were present in all tested materials collected from one patient. Conclusions: The analysis carried out showed the presence of bacteria in the human milk of Polish women, including strains of lactic acid bacteria. The human milk microbiota may significantly influence the formation of the infant’s intestinal microbiota, including some key genera, i.e., Lactobacillus, Bifidobacterium, and Limosilactobacillus, which were also isolated from the tested samples. The data presented here provide new data on culturable bacterial species isolated from breast milk from Polish women giving birth via vaginal delivery and potential routes of transmission from the neonate’s oral cavity. Full article