Colonization Of Gut Microbiota Research Articles

Probiotics Application in the Treatment of Autoimmune Diseases and Enhancement of Efficacy Through Genetic Engineering

The development of multidrug resistance in most pathogenic microorganisms and the rapidly increasing prevalence of non-communicable diseases are becoming major health concerns worldwide. Among non-communicable diseases, autoimmune diseases are caused mainly by imbalances in the gut microbiota (dysbiosis). Gut microbiota colonization and immune system establishment started in the early years of life. A defect in the gut microbiota predominantly affects the proper functioning of immune cells. Hence, restoring gut dysbiosis has received considerable attention for the last few decades as a potential therapeutic option. In this regard, probiotics have been the focus of research during recent decades because of their safe history of use along with fermented foods and beverages. Currently, advanced research is being conducted on the use of probiotics as immunomodulatory mediators and for the amelioration of gut dysbiosis as therapeutic adjuncts in the treatment of autoimmune diseases. In addition, probiotics are genetically engineered to enhance treatment efficacy and to develop live biotherapeutics (LBP). In this review, research articles summarizing findings in autoimmune disease treatment via probiotic strains, emphasizing type 1 diabetes, rheumatoid arthritis, Graves' disease, systemic lupus erythematosus and inflammatory bowel disease in both clinical trials and animal models, were reviewed. Finally, promising results of genetic engineering of probiotics for use as biosensors, delivery of therapeutic proteins, and diagnosis of infections were reported.

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.

Host genetics and gut microbiota influence lipid metabolism and inflammation: potential implications for ALS pathophysiology in SOD1G93A mice

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disorder characterized by the progressive loss of motor neurons, with genetic and environmental factors contributing to its complex pathogenesis. Dysregulated immune responses and altered energetic metabolism are key features, with emerging evidence implicating the gut microbiota (GM) in disease progression. We investigated the interplay among genetic background, GM composition, metabolism, and immune response in two distinct ALS mouse models: 129Sv_G93A and C57Ola_G93A, representing rapid and slow disease progression, respectively.Using 16 S rRNA sequencing and fecal metabolite analysis, we characterized the GM composition and metabolite profiles in non-transgenic (Ntg) and SOD1G93A mutant mice of both strains. Our results revealed strain-specific differences in GM composition and functions, particularly in the abundance of taxa belonging to Erysipelotrichaceae and the levels of short and medium-chain fatty acids in fecal samples. The SOD1 mutation induces significant shifts in GM colonization in both strains, with C57Ola_G93A mice showing changes resembling those in 129 Sv mice, potentially affecting disease pathogenesis. ALS symptom progression does not significantly alter microbiota composition, suggesting stability.Additionally, we assessed systemic immunity and inflammatory responses revealing strain-specific differences in immune cell populations and cytokine levels.Our findings underscore the substantial influence of genetic background on GM composition, metabolism, and immune response in ALS mouse models. These strain-specific variations may contribute to differences in disease susceptibility and progression rates. Further elucidating the mechanisms underlying these interactions could offer novel insights into ALS pathogenesis and potential therapeutic targets.

Aerobic exercise remodels gut microbiota to alleviate cerebral ischemia-reperfusion injury.

Aerobic exercise exhibits a neuroprotective role against cerebral ischemia-reperfusion (I/R) injury, and the present study explored the underlying mechanisms. Adult Sprague-Dawley rats (n=87) were used in the study, and cerebral I/R injury in rats was modeled using middle cerebral artery occlusion and reperfusion (MCAOR), followed by interval aerobic exercise training at a moderate intensity. Colonization with gut microbiota from the trained rats was performed on MCAOR rats. Neurobehavioral assessments were performed. Cerebral infarction and neuronal damage were detected by tissue staining and molecular experiments. Gut microbiota composition was analyzed by 16S rRNA gene sequencing. Neuroinflammation was detected using an enzyme-linked immunosorbent assay. Aerobic exercise ameliorated neurological deficit, spontaneous locomotor activity, and spatial learning and memory impairment in MCAOR rats (P<0.001). Further, aerobic exercise decreased infarct volume, attenuated neuronal damage, increased SYN1 and PSD95 expression, as well as reduced neuroinflammation by upregulating IL-10 and downregulating IL-6, TNF-α, IL-17, and TGF-β in MCAOR rats (P<0.05). Aerobic exercise altered gut microbiota composition in MCAOR rats. Gut microbiota colonization in rats alleviated cerebral I/R injury by reducing neurological deficit scores, promoting spontaneous locomotor activity, decreasing infarct volume, elevating SYN1 and PSD95 expression, and improving neuroinflammation (P<0.05). In conclusion, aerobic exercise remodeled the gut microbiota in rats to attenuate cognitive dysfunction and neuroinflammation after cerebral I/R.

Postnatal supplementation with alarmins S100a8/a9 ameliorates malnutrition-induced neonate enteropathy in mice.

Malnutrition is linked to 45% of global childhood mortality, however, the impact of maternal malnutrition on the child's health remains elusive. Previous studies suggested that maternal malnutrition does not affect breast milk composition. Yet, malnourished children often develop a so-called environmental enteropathy, assumed to be triggered by frequent pathogen uptake and unfavorable gut colonization. Here, we show in a murine model that maternal malnutrition induces a persistent inflammatory gut dysfunction in the offspring that establishes during nursing and does not recover after weaning onto standard diet. Early intestinal influx of neutrophils, impaired postnatal development of gut-regulatory functions, and expansion of Enterobacteriaceae were hallmarks of this enteropathy. This gut phenotype resembled those developing under deficient S100a8/a9-supply via breast milk, which is a known key factor for the postnatal development of gut homeostasis. We could confirm that S100a8/a9 is lacking in the breast milk of malnourished mothers and the offspring's intestine. Nutritional supply of S100a8 to neonates of malnourished mothers abrogated the aberrant development of gut mucosal immunity and microbiota colonization and protected them lifelong against severe enteric infections and non-infectious bowel diseases. S100a8 supplementation after birth might be a promising measure to counteract deleterious imprinting of gut immunity by maternal malnutrition.

Colonization profiles of gut microbiota in goat kids from neonatal to weaning period.

Understanding the colonization and change patterns of gut microbiota is pivotal for comprehending host health. As a newly cultured breed, the studies on the gut microbiota of Tianfu goats remain limited. This study aimed to address this gap by analyzing the microbial composition and colonization patterns of fecal samples collected from goat kids from birth to weaning. Fecal samples were collected on days 0, 7, 14, 21, 28, 35, 42, 49, 53, 55, 57, and 64, and the changes and colonization patterns of microorganisms were analyzed through high-throughput 16S rRNA sequencing. The results showed that the abundance of fecal microbiota in goat kids gradually increased over time, followed by a decrease after weaning and stabilization, with reduced individual differences. The colonization of fecal microorganisms mainly presented three different stages: days 0-14, days 21-49, and days 53-64. During the suckling period, the relative abundance of Proteobacteria (72.34%) was the highest, followed by Firmicutes (21.66%). From 21 days old, the microbiota in goat kids gradually to be diverse, with Lachnospiraceae and Ruminococcaceae being dominant. During post-weaning, Ruminococcaceae (30.98-33.34%) was becoming prominence which helpful for cellulose decomposition. LEfSe analyzed three important time points (d0 vs. d7, d7 vs. d14, d49 vs. d53, LDA score > 4 and p < 0.05), 53 microbial communities with stage differences were identified. Functional prediction using PICRUSt revealed that differential microbial communities are mainly related to carbohydrate and amino acid metabolism pathways. Overall, this study addresses the intricate relationship between ages, diets, and microbiota compositions in Tianfu goat kids, and also offering insights into microorganisms-host interactions.

Prenatal PM2.5 Exposure Associated with Neonatal Gut Bacterial Colonization and Early Children's Cognitive Development.

Previous research indicated that fine particulate matter (PM2.5) exposure affected both offspring neurodevelopment and the colonization of gut microbiota (GM), while the underlying mechanism remained unclear. Our study aimed to evaluate the impacts of prenatal PM2.5 exposure on child cognitive development and investigate the role of neonatal GM colonization in the association. Based on the Shanghai Maternal-Child Pairs Cohort, 361 maternal-child pairs were recruited. Prenatal PM2.5 exposure concentrations were estimated using a high-spatial-resolution prediction model, and child neurodevelopment was assessed by the Ages and Stages Questionnaire. Multivariable linear regression models, logistic regression models, linear discriminant analysis effect size, and random forest model were applied to explore the associations among PM2.5 exposure, GM colonization, and children's neurodevelopment. The present study revealed a negative correlation between PM2.5 exposure throughout pregnancy and child neurodevelopment. Prenatal PM2.5 exposure was associated with an increased risk of suspected developmental delay (SDD) (OR = 1.683, 95% CI: 1.138, 2.489) in infants aged 2 months. Additionally, potential operational taxonomic unit markers were identified for PM2.5-related neurotoxicity, demonstrating promising classification potential for early SDD screening (AUC = 71.27%). Prenatal PM2.5 exposure might disrupt the composition, richness, and evenness of meconium GM, thereby influencing cognitive development and the occurrence of SDD in offspring. Seven PM2.5-related genera, Ruminococcus gnavus group, Romboutsia, Burkholderiaceae Caballeronia Paraburkholderia, Blautia, Alistipes, Parabacteroides, and Bacteroides, were validated as correlated with prenatal PM2.5 exposure and the occurrence of SDD. Moreover, alterations of GM related to PM2.5 exposure and SDD might be accompanied by changes in functional pathways of amino acid, lipid, and vitamin metabolism as indicated by differentially enriched species in the Kyoto Encyclopedia of Genes and Genomes.

Effects of maternal hawthorn-leaf flavonoid supplementation on the intestinal development of offspring chicks

Metabolic disorders in maternal generation during the late egg-laying period have adverse effects on neonatal development. The study was conducted to clarify the effects of maternal feeding of hawthorn-leaf flavonoid (HF) on the microbial community and intestinal development of chicks. Breeder hens were fed a basic corn-soybean diet, while the treatment groups were supplemented with 30 or 60 mg/kg HF. The offspring chicks were divided into CON, LHF, and HHF groups according to the maternal treatments. Maternal HF supplementation at 60 mg/kg increased the average daily gain and decreased the feed conversion rate of chicks (P < 0.05), but did not affect the average daily feed intake. HF treatments increased the villus height to crypt depth ratio and up-regulated the protein expressions of PCNA, IGF-1R, PI3K and p-mTOR in the jejunum (P < 0.05) of 1-day-old and 14-day-old chicks. Additionally, maternal HF treatment up-regulated the mRNA expression of tight junction transmembrane proteins (occludin) and scaffolding proteins (ZO-1 and ZO-2) in the jejunum of 1-day-old chicks (P < 0.05). Moreover, the maternal effects of HF on ZO-1 expression could last for 14 d (P < 0.05). Interestingly, dietary HF supplementation altered the vertically transmitted microbial community from breeder hens to chicks, especially increased the relative abundance of probiotics (i.e., Clostridium_sensu_stricto_1) in the meconium of chicks (P < 0.05), which may help with early gut microbiota colonization and intestinal development. In summary, dietary HF supplementation for breeder hens altered the bacterial community of neonates and might promote intestinal development of chicks through the IGF-1R/AKT/mTOR signaling pathway.

Effects of ciprofloxacin and levofloxacin on initial colonization of intestinal microbiota in Bufo gargarizans at embryonic stages

Ciprofloxacin (CIP) and levofloxacin (LEV) are broad-spectrum antibiotics with potent antibacterial activity. Although many studies have shown that antibiotics can lead to gut microbiota disruption, the effects of CIP and LEV on gut microbial colonization at the embryonic stage remain poorly characterized. Here, we evaluated the response of Bufo gargarizans embryos in terms of gut microbiota colonization, growth and developmental stages to CIP and LEV exposure. Embryos treated with 100 μg/L CIP and LEV exhibited significantly reduced diversity and richness of the gut microbiota, as well as altered community structure. Both CIP and LEV treatments resulted in an increase in the pathogenic bacteria Bosea and Aeromonas, and they appeared to be more resistant to CIP than LEV. Additionally, CIP exposure caused reduced total length and delayed the development in B. gargarizans embryos, while LEV increased the total length and promoted embryonic development. The present study revealed the adverse effects of CIP and LEV exposure on host gut microbiota, growth and development during the embryonic stage, and contributed new perspectives to the evaluation of early aquatic ecological risk under CIP and LEV exposure.

Delayed colonization of Bifidobacterium spp. and low prevalence of B. infantis among infants of Asian ancestry born in Singapore: insights from the GUSTO cohort study.

The loss of ancestral microbes, or the "disappearing microbiota hypothesis" has been proposed to play a critical role in the rise of inflammatory and immune diseases in developed nations. The effect of this loss is most consequential during early-life, as initial colonizers of the newborn gut contribute significantly to the development of the immune system. In this longitudinal study (day 3, week 3, and month 3 post-birth) of infants of Asian ancestry born in Singapore, we studied how generational immigration status and common perinatal factors affect bifidobacteria and Bifidobacterium longum subsp. infantis (B. infantis) colonization. Cohort registry identifier: NCT01174875. Our findings show that first-generation migratory status, perinatal antibiotics usage, and cesarean section birth, significantly influenced the abundance and acquisition of bifidobacteria in the infant gut. Most importantly, 95.6% of the infants surveyed in this study had undetectable B. infantis, an early and beneficial colonizer of infant gut due to its ability to metabolize the wide variety of human milk oligosaccharides present in breastmilk and its ability to shape the development of a healthy immune system. A comparative analysis of B. infantis in 12 countries by their GDP per capita showed a remarkably low prevalence of this microbe in advanced economies, especially Singapore. This study provides new insights into infant gut microbiota colonization, showing the impact of generational immigration on early-life gut microbiota acquisition. It also warrants the need to closely monitor the declining prevalence of beneficial microbes such as B. infantis in developed nations and its potential link to increasing autoimmune and allergic diseases.

Study on Changes in Gut Microbiota and Microbiability in Rabbits at Different Developmental Stages.

This study used feces from 0-day-old (36 rabbits), 10-day-old (119 rabbits), and 60-day-old (119 rabbits) offspring rabbits and their corresponding female rabbits (36 rabbits) as experimental materials. Using 16s rRNA sequencing, the study analyzed the types and changes of gut microbiota in rabbits at different growth and development stages, as well as the correlation between gut microbiota composition and the weight of 60-day-old rabbits. All experimental rabbits were placed in the same rabbit shed. Juvenile rabbits were fed solid feed at 18 days of age and weaned at 35 days of age. In addition to identifying the dominant bacterial phyla of gut microbiota in rabbits at different age stages, it was found that the abundance of Clostridium tertium and Clostridium paraputrificum in all suckling rabbits (10-day-old) was significantly higher than that in rabbits fed with whole feed (60-day-old) (p < 0.05), while the abundance of Gram-negative bacterium cTPY13 was significantly lower (p < 0.05). In addition, Fast Expected Maximum Microbial Source Tracing (FEAST) analysis showed that the contribution of female rabbits' gut microbiota to the colonization of offspring rabbits' gut microbiota was significantly higher than that of unrelated rabbits' gut microbiota (p < 0.05). The contribution of female rabbits' gut microbiota to the colonization of gut microbiota in 0-day-old rabbits was significantly higher than that to the colonization of gut microbiota in the 10- and 60-day-old rabbits (p < 0.05). Finally, the correlation between gut microbiota composition and body weight of 60-day-old rabbits was analyzed based on a mixed linear model, and six ASVs significantly affecting body weight were screened. The above results provide important theoretical and practical guidance for maintaining gut health, improving growth and development performance, and feeding formulation in rabbits.

Early-life factors shaping the gut microbiota of Common buzzard nestlings

BackgroundExploring the dynamics of gut microbiome colonisation during early-life stages is important for understanding the potential impact of microbes on host development and fitness. Evidence from model organisms suggests a crucial early-life phase when shifts in gut microbiota can lead to immune dysregulation and reduced host condition. However, our understanding of gut microbiota colonisation in long-lived vertebrates, especially during early development, remains limited. We therefore used a wild population of common buzzard nestlings (Buteo buteo) to investigate connections between the early-life gut microbiota colonisation, environmental and host factors.ResultsWe targeted both bacterial and eukaryotic microbiota using the 16S and 28S rRNA genes. We sampled the individuals during early developmental stages in a longitudinal design. Our data revealed that age significantly affected microbial diversity and composition. Nest environment was a notable predictor of microbiota composition, with particularly eukaryotic communities differing between habitats occupied by the hosts. Nestling condition and infection with the blood parasite Leucocytozoon predicted microbial community composition.ConclusionOur findings emphasise the importance of studying microbiome dynamics to capture changes occurring during ontogeny. They highlight the role of microbial communities in reflecting host health and the importance of the nest environment for the developing nestling microbiome. Overall, this study contributes to understanding the complex interplay between microbial communities, host factors, and environmental variables, and sheds light on the ecological processes governing gut microbial colonisation during early-life stages.

New insights into the interactions between the gut microbiota and the inflammatory response to ulcerative colitisin a mouse model of dextran sodium sulfate and possible mechanisms of action for treatment with PE&AFWE.

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation. Intestinal innate immunity, including innate immune cells, defends against pathogens and excessive entry of gut microbiota, while preserving immune tolerance to resident intestinal microbiota, and may be characterized by its capacity to produce a rapid and nonspecific reaction. The association between microbiota dysbiosis and the pathogenesis of IBD is complex and dynamic. When the intestinal ecosystem is in dysbiosis, the reduced abundance and diversity of intestinal gut microbiota make the host more vulnerable to the attack of exogenous and endogenous pathogenic gut microbiota. The aim of our study was to comprehensively assess the relationship between microbial populations within UC, the signaling pathways of pathogenic gut microbe therein and the inflammatory response, as well as to understand the effects of using PE&AFWE (poppy extract [Papaver nudicaule L.] and Artemisia frigida Willd. extract) on UC modulation. A UC mouse model was established by inducing SPF-grade C57BL/6 mice using dextrose sodium sulfate (DSS). Based on metagenomic sequencing to characterize the gut microbiome, the relationship between gut microbiota dysbiosis and gut microbiota was further studied using random forest and Bayesian network analysis methods, as well as histopathological analysis. (1) We found that the 5 gut microbiota with the highest relative abundance of inflammatory bowel disease UC model gut microbiota were consistent with the top 5 ranked natural bacteria. There were three types of abundance changes in the model groups: increases (Chlamydiae/Proteobacteria and Deferribacteres), decreases (Firmicutes), and no significant changes (Bacteroidetes). The UC model group was significantly different from the control group, with 1308 differentially expressed species with abundance changes greater than or equal to 2-fold. (2) The proportion of the fecal flora in the UC group decreased by 37.5% in the Firmicutes and increased by 14.29% in the proportion of Proteobacteria compared to the control group before treatment. (3) The significantly enriched and increased signaling pathways screened were the 'arachidonic acid metabolic pathway' and the 'phagosomal pathway', which both showed a decreasing trend after drug administration. (4) Based on the causal relationship between different OTUs and the UC model/PE&AFWE administration, screening for directly relevant OTU networks, the UC group was found to directly affect OTU69, followed by a cascade of effects on OTU12, OTU121, OTU93, and OTU7, which may be the pathway of action that initiated the pathological changes in normal mice. (5) We identified a causal relationship between common differentially expressed OTUs and PE&AFWE and UC in the pre- and post-PE&AFWE-treated groups. Thereby, we learned that PE&AFWE can directly affect OTU90, after which it inhibits UC, inhibiting the activity of arachidonic acid metabolic pathway by affecting OTU118, which in turn inhibits the colonization of gut microbiota by OTU93 and OTU7. (6) Histopathological observation and scoring (HS) of the colon showed that there was a significant difference between the model group and the control group (p < 0.001), and that there was a significant recovery in both the sulfasalazine (SASP)and the PE&AFWE groups after the administration of the drug (p < 0.0001). We demonstrated causal effects and inflammatory metabolic pathways in gut microbiota dysbiosis and IBD, with five opportunistic pathogens directly contributing to IBD. PE&AFWE reduced the abundance of proteobacteria in the gut microbiota, and histopathology showed significant improvement.

Perturbed maternal microbiota shapes offspring microbiota during early colonization period in mice.

Recent studies have highlighted the impact of disrupted maternal gut microbiota on the colonization of offspring gut microbiota, with implications for offspring developmental trajectories. The extent to which offspring inherit the characteristics of altered maternal gut microbiota remains elusive. In this study, we employed a mouse model where maternal gut microbiota disruption was induced using non-absorbable antibiotics. Systematic chronological analyses of dam fecal samples, offspring luminal content, and offspring gut tissue samples revealed a notable congruence between offspring gut microbiota profiles and those of the perturbed maternal gut microbiota, highlighting the profound influence of maternal microbiota on early-life colonization of offspring gut microbiota. Nonetheless, certain dominant bacterial genera in maternal microbiota did not transfer to the offspring, indicating a bacterial taxonomy-dependent mechanism in the inheritance of maternal gut microbiota. Our results embody the vertical transmission dynamics of disrupted maternal gut microbiota in an animal model, where the gut microbiota of an offspring closely mirrors the gut microbiota of its mother.

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.

An Overview of the Influence of Breastfeeding on the Development of Inflammatory Bowel Disease.

The first 1000 days of life is a critical period that contributes significantly to the programming of an individual's future health. Among the many changes that occur during this period early in life, there is growing evidence that the establishment of healthy gut microbiota plays an important role in the prevention of both short- and long-term health problems. Numerous publications suggest that the quality of the gut microbiota colonisation depends on several dietary factors, including breastfeeding. In this respect, a relationship between breastfeeding and the risk of inflammatory bowel disease (IBD) has been suggested. IBDs are chronic intestinal diseases, and perinatal factors may be partly responsible for their onset. We review the existence of links between breastfeeding and IBD based on experimental and clinical studies. Overall, despite encouraging experimental data in rodents, the association between breastfeeding and the development of IBD remains controversial in humans, partly due to the considerable heterogeneity between clinical studies. The duration of exclusive breastfeeding is probably decisive for its lasting effect on IBD. Thus, specific improvements in our knowledge could support dietary interventions targeting the gut microbiome, such as the early use of prebiotics, probiotics or postbiotics, in order to prevent the disease.

Core gut microbes Cloacibacterium and Aeromonas associated with different gastropod species could be persistently transmitted across multiple generations

BackgroundStudies on the gut microbiota of animals have largely focused on vertebrates. The transmission modes of commensal intestinal bacteria in mammals have been well studied. However, in gastropods, the relationship between gut microbiota and hosts is still poorly understood. To gain a better understanding of the composition of gut microbes and their transmission routes in gastropods, a large-scale and long-term experiment on the dynamics and transmission modes of gut microbiota was conducted on freshwater snails.ResultsWe analyzed 244 microbial samples from the digestive tracts of freshwater gastropods and identified Proteobacteria and Bacteroidetes as dominant gut microbes. Aeromonas, Cloacibacterium, and Cetobacterium were identified as core microbes in the guts, accounting for over 50% of the total sequences. Furthermore, both core bacteria Aeromonas and Cloacibacterium, were shared among 7 gastropod species and played an important role in determining the gut microbial community types of both wild and cultured gastropods. Analysis of the gut microbiota at the population level, including wild gastropods and their offspring, indicated that a proportion of gut microbes could be consistently vertically transmitted inheritance, while the majority of the gut microbes resulted from horizontal transmission. Comparing cultured snails to their wild counterparts, we observed an increasing trend in the proportion of shared microbes and a decreasing trend in the number of unique microbes among wild gastropods and their offspring reared in a cultured environment. Core gut microbes, Aeromonas and Cloacibacterium, remained persistent and dispersed from wild snails to their offspring across multiple generations. Interestingly, under cultured environments, the gut microbiota in wild gastropods could only be maintained for up to 2 generations before converging with that of cultured snails. The difference observed in gut bacterial metabolism functions was associated with this transition. Our study also demonstrated that the gut microbial compositions in gastropods are influenced by developmental stages and revealed the presence of Aeromonas and Cloacibacterium throughout the life cycle in gastropods. Based on the dynamics of core gut microbes, it may be possible to predict the health status of gastropods during their adaptation to new environments. Additionally, gut microbial metabolic functions were found to be associated with the adaptive evolution of gastropods from wild to cultured environments.ConclusionsOur findings provide novel insights into the dynamic processes of gut microbiota colonization in gastropod mollusks and unveil the modes of microbial transmission within their guts.1dB18pPYxP-ygVgUJj2q9BVideo

Analysis of the gut microbiota using MALDI-TOF and cultural techniques in breastfed infants delivered vaginally and through caesarean section

Objectives: The gastrointestinal tract of newborns is colonised immediately after birth with microbes from the environment, mainly from the mother. According to studies, the early neonatal microbiota is crucial for developing the postnatal immune system. The objective of this study was to investigate the relationship between neonatal gut flora and the mode of delivery during gut microbiota colonisation. Material and Methods: A total of 30 neonates – 16 born vaginally and 14 by caesarean section – participated in this study of the intestinal bacterial composition at 3 days of age. Stool cultures and matrix-assisted laser desorption ionisation time-of-flight analyses determine aerobic and anaerobic bacterial species. Results: Neonates delivered by caesarean section appeared to have a less diverse gut microbiota regarding bacterial species than vaginally delivered neonates. Bifidobacterium species are absent from the gut microbiota after caesarean delivery. Even though every newborn vaginally born had a unique microbial profile, the most prevalent bacterial species were Streptococcus spp., Veillonella atypica, Bacteroides vulgatus and Bifidobacterium spp. Conclusion: Our results suggest that the mode of birth significantly influences the gut microbiota composition in the 1st year of human life. This study opens the path to further investigations to confirm the link between microbiota composition and enterotypes of the gut microbiome of breastfed neonates. In addition, we underline the importance of MALDI-TOF for species-level identification of organisms within a fraction of a second.

276 Investigating the Colonization History of Early-Life Microbiome of Piglets

Abstract Early-life microbiome establishment and colonization is essential for gut development, nutrient digestion and metabolism, and modulation of the immune system. Microbial colonization of the infant digestive tract begins at birth, and as such, maternal microbiota has an important influence on the early-life establishment and colonization of the infant gut microbiota. Therefore, perturbations during early life establishment of the infant gut microbiome may have long-term impact on the microbiota composition and function, and may serve as a major determinant on host health and development. To evaluate the effects of early life microbiomes on long-term colonization of the microbiome, and effect host function, we set out to quantify the percentage of the sow microbiome that contributes to early-life colonization in the piglet and how such microbiomes would persist within the piglet gut. To this end, we investigated the colonization history and the role of the sow microbiome in establishment of the piglet microbiome over time using 16S rRNA sequencing. We observed 125 amplicon sequence variants to be persistent across different sampling time points, day 0, day 14, and day 21, representing 89.73%, 68.99%, and 67.30% of the total reads on day 0, day 14 and day 21, recovered from the piglets respectively. Comparing the piglet microbiota to that of the sow, we observed 114 of the 125 persistent ASVs in the piglet microbiota to arise from the sow that account for 75% of the total reads in the sow microbiota. This core microbiome includes Bacteroides, Methanobrevibacter, Lachnoclostridium, Lactobacillus, Escherichia-Shigella, Clostridium sensu stricto 1, Christensenellaceae R-7 group, Ruminococcaceae Genus, Romboutsia, Phascolarctobacterium, Erysipelotrichaceae Genus, Muribaculaceae Genus, Streptococcus, [Eubacterium] coprostanoligenes group Genus and others. The species abundance increased for Bacteroides, Methanobrevibacter, Lachnoclostridium, Clostridium sensu stricto 1, Lactobacillus, Christensenellaceae R-7 group, Ruminococcaceae Genus, Romboutsia, Phascolarctobacterium, Erysipelotrichaceae Genus, Muribaculaceae Genus, Streptococcus, [Eubacterium] coprostanoligenes group Genus and other species over time while species abundance of pathogens or opportunistic pathogens such as Escherichia-Shigella and Salmonella species decreased over time. In conclusion, the maternal microbiota has an important role in early-life microbiome establishment and can be utilized to develop a more beneficial microbiome to increase pig health and productivity.

Cesarean section induced dysbiosis promotes type 2 immunity but not oxazolone-induced dermatitis in mice

ABSTRACT Delivery by cesarean section (CS) is associated with an altered gut microbiota (GM) colonization and a higher risk of later chronic inflammatory diseases. Studies investigating the association between CS and atopic dermatitis (AD) are contradictive and often biased by confounding factors. The aim of this study was therefore to provide experimental evidence for the association between CS and AD in a mouse model and clarify the role of the GM changes associated with CS. It was hypothesized that CS-delivered mice, and human CS-GM transplanted mice develop severe dermatitis due to early dysbiosis. BALB/c mice delivered by CS or vaginally (VD) as well as BALB/c mice transplanted with GM from CS or VD human donors were challenged with oxazolone on the ear. The severity of dermatitis was evaluated by ear thickness and clinical and histopathological assessment which were similar between all groups. The immune response was assessed by serum IgE concentration, local cytokine response, and presence of immune cells in the draining lymph node. Both CS-delivered mice and mice inoculated with human CS-GM had a higher IgE concentration. A higher proportion of Th2 cells were also found in the CS-GM inoculated mice, but no differences were seen in the cytokine levels in the affected ears. In support of the experimental findings, a human cohort analysis from where the GM samples were obtained found that delivery mode did not affect the children’s risk of developing AD. In conclusion, CS-GM enhanced a Th2 biased immune response, but had no effect on oxazolone-induced dermatitis in mice.