Colonization Of Gastrointestinal Tract Research Articles

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.

BMP signaling pathway member expression is enriched in enteric neural progenitors and required for zebrafish enteric nervous system development

AbstractBackgroundThe vertebrate enteric nervous system (ENS) consists of a series of interconnected ganglia within the gastrointestinal (GI) tract, formed during development following migration of enteric neural crest cells (ENCCs) into the primitive gut tube. Much work has been done to unravel the complex nature of extrinsic and intrinsic factors that regulate processes that direct migration, proliferation, and differentiation of ENCCs. However, ENS development is a complex process, and we still have much to learn regarding the signaling factors that regulate ENCC development.ResultsHere in zebrafish, through transcriptomic, in situ transcript expression, immunohistochemical analysis, and chemical attenuation, we identified a time‐dependent role for bone morphogenetic protein (BMP) in the maintenance of Phox2bb+ enteric progenitor numbers and/or time of differentiation of the progenitor pool. In support of our in silico transcriptomic analysis, we identified expression of a novel ENS ligand‐encoding transcript, bmp5, within developmental regions of ENCCs. Through generation of a novel mutant bmp5wmr2 and bmp5 crispants, we identified a functional role for BMP5 in proper GI tract colonization, whereby phox2bb+ enteric progenitor numbers were reduced.ConclusionAltogether, this work identified time‐dependent roles for BMP signaling and a novel extrinsic factor, BMP5, that is necessary for vertebrate ENS formation.

Basic Research on Candida Species.

Candida species are common human pathogens that cause a wide range of diseases ranging from superficial to invasive candidiasis. However, basic studies focusing on the mechanisms underlying these diseases are limited. This article reviews our previous research on the mechanisms of superficial and invasive candidiasis, the virulence of Candida species, and Candida species fitness to hosts. Regarding invasive candidiasis, we focused on two types of infections: ocular candidiasis and endogenous candidiasis from the gastrointestinal tract. Using an established ocular candidiasis mouse model, along with retrospective epidemiological research, we found a strong association between Candida albicans and ocular candidiasis. Regarding endogenous candidiasis, research using Candida auris indicated that invasive strains had a higher capability for gastrointestinal tract colonization and showed greater dissemination compared with non-invasive strains. In terms of superficial candidiasis, we focused on the defense mechanism in vulvovaginal candidiasis. The results suggested that stimulated invariant natural killer T cells played a protective role against C. albicans vaginal infection and might be a therapeutic target for vulvovaginal candidiasis. Concerning Candida species fitness, we focused on environmental factors, particularly oxygen concentration, and evaluated biofilm formation under various oxygen concentrations, revealing that each Candida species favored different oxygen concentrations. In particular, Candida tropicalis showed greater biofilm formation under hypoxic conditions. Our research revealed several insights for understanding the exact mechanisms of candidiasis, which might lead to better control of Candida species infections and appropriate treatment.

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.

Relative dispersion ratios following fecal microbiota transplant elucidate principles governing microbial migration dynamics

Microorganisms frequently migrate from one ecosystem to another. Yet, despite the potential importance of this process in modulating the environment and the microbial ecosystem, our understanding of the fundamental forces that govern microbial dispersion is still lacking. Moreover, while theoretical models and in-vitro experiments have highlighted the contribution of species interactions to community assembly, identifying such interactions in vivo, specifically in communities as complex as the human gut, remains challenging. To address this gap, here we introduce a robust and rigorous computational framework, termed Relative Dispersion Ratio (RDR) analysis, and leverage data from well-characterized fecal microbiota transplant trials, to rigorously pinpoint dependencies between taxa during the colonization of human gastrointestinal tract. Our analysis identifies numerous pairwise dependencies between co-colonizing microbes during migration between gastrointestinal environments. We further demonstrate that identified dependencies agree with previously reported findings from in-vitro experiments and population-wide distribution patterns. Finally, we explore metabolic dependencies between these taxa and characterize the functional properties that facilitate effective dispersion. Collectively, our findings provide insights into the principles and determinants of community dynamics following ecological translocation, informing potential opportunities for precise community design.

Breast milk – a living superfood. Review of current knowledge

Introduction: Breastfeeding is considered the best nutrition for infants, including born preterm due to containing optimal ingredients for development and growth. Breast milk is a rich source of nutrients, it also contains diverse types of bacteria, which play a role in infant’s gastrointestinal tract colonization and preserving mammary health. Composition of human milk varies depending on numerous maternal and infant factors. Aim of the study: The aim of the study was to summarize the current knowledge about the content of nutrients, bioactive factors and microbiota diversity in human milk depending on various factors. Materials and methods: The work is a review of 26 mainly English-language scientific publications from 1989-2024 posted on the PubMed platform. Results: Milk composition changes in addition to several factors. Depending on postnatal age: preterm milk has higher content of protein, fat and immunological factors and lower concentration of lactose than term milk. Depending on milk maturity: Colostrum is higher in protein but lower in lactose, fat and energy than mature milk. Human milk is also a source of viable bacteria important for developing infant’s gut microbiota, but the diversity of bacterial strains in milk may vary. Depending on mode of delivery: milk of mothers after spontaneous labour contents more probiotic vaginal- and enteric-associated bacteria, while milk of mothers after C-section has more skin-associated microbiota. Depending on mother’s weight: milk of overweight mothers is lower in probiotic- and higher in pathogenic bacteria. Alcohol, nicotine, and some medications also have negative impact on produced milk. Conclusions: Human milk varies from woman to woman and its composition depends on several factors. Postnatal and gestational stage, delivery mode, mother's weight and certain substances have been found to be important factors influencing the constitution of breast milk, including nutrients, microbiota and volume of milk.

Comparative analysis of the antimicrobial resistance and virulence traits in ESBL-producing-Klebsiella pneumoniae ST307 strains colonizing the gastrointestinal tract and causing a fatal bloodstream infection in a leukemia patient

Klebsiella pneumoniae is an opportunistic pathogen that can colonize the gastrointestinal tract (GIT) of humans. The mechanisms underlying the successful translocation of this pathogen to cause extra-intestinal infections remain unknown, although virulence and antimicrobial resistance traits likely play significant roles in the establishment of infections. We investigated K. pneumoniae strains isolated from GIT colonization (strains Kp_FZcol-1, Kp_FZcol-2 and Kp_FZcro-1) and from a fatal bloodstream infection (strain Kp_HM-1) in a leukemia patient. All strains belonged to ST307, carried a transferable IncF plasmid containing the blaCTX-M-15 gene (pKPN3–307 TypeA-like plasmid) and showed a multidrug-resistance phenotype. Phylogenetic analysis demonstrated that Kp_HM-1 was more closely related to Kp_FZcro-1 than to the other colonizing strains. The Kp_FZcol-2 genome showed 81 % coverage with the Kp_HM-1 246,730 bp plasmid (pKp_HM-1), lacking most of its putative virulence genes. Searching public genomes with similar coverage, we observed the occurrence of this deletion in K. pneumoniae ST307 strains recovered from human colonization and infection in different countries. Our findings suggest that strains lacking the putative virulence genes found in the pKPN3–307 TypeA plasmid are still able to colonize and infect humans, highlighting the need to further investigate the role of these genes for the adaptation of K. pneumoniae ST307 in distinct human body sites.

Probiotics: Health benefits, food application, and colonization in the human gastrointestinal tract

AbstractProbiotics have become increasingly popular over the past two decades due to the continuously expanding scientific evidence indicating their beneficial effects on human health. Therefore, they have been applied in the food industry to produce functional food, which plays a significant role in human health and reduces disease risk. However, maintaining the viability of probiotics and targeting the successful delivery to the gastrointestinal tract remain two challenging tasks in food applications. Specifically, this paper reviews the potentially beneficial properties of probiotics, highlighting the use and challenges of probiotics in food application and the associated health benefits. Of foremost importance, this paper also explores the potential underlying molecular mechanisms of the enhanced effect of probiotics on gastrointestinal epithelial cells, including a discussion on various surface adhesion‐related proteins on the probiotic cell surface that facilitate colonization.

Clinical use of tigecycline may contribute to the widespread dissemination of carbapenem-resistant hypervirulent Klebsiella pneumoniae strains

ABSTRACT The emergence of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) poses grave threats to human health. These strains increased dramatically in clinical settings in China in the past few years but not in other parts of the world. Four isogenic K. pneumoniae strains, including classical K. pneumoniae, carbapenem-resistant K. pneumoniae (CRKP), hypervirulent K. pneumoniae (hvKP) and CR-hvKP, were created and subjected to phenotypic characterization, competition assays, mouse sepsis model and rat colonization tests to investigate the mechanisms underlying the widespread nature of CR-hvKP in China. Acquisition of virulence plasmid led to reduced fitness and abolishment of colonization in the gastrointestinal tract, which may explain why hvKP is not clinically prevalent after its emergence for a long time. However, tigecycline treatment facilitated the colonization of hvKP and CR-hvKP and reduced the population of Lactobacillus spp. in animal gut microbiome. Feeding with Lactobacillus spp. could significantly reduce the colonization of hvKP and CR-hvKP in the animal gastrointestinal tract. Our data implied that the clinical use of tigecycline to treat carbapenem-resistant K. pneumoniae infections facilitated the high spread of CR-hvKP in clinical settings in China and demonstrated that Lactobacillus spp. was a potential candidate for anticolonization strategy against CR-hvKP.

Effects of spore-forming Bacillus probiotics on growth performance, intestinal morphology, and immune system of broilers housed on deep litter

Aim of the study: to evaluate the effects of feed supplementation of Bacillus subtilis KATMIRA1933, B. subtilis KB41, and Bacillus amyloliquefaciens KB54 probiotics on growth performance, biochemical blood parameters, intestinal morphology, and the immune system of Ross 308 broilers housed on deep litter. Methods and Results: a total of 160 newly hatched Ross 308 broilers were involved in the 42-day-long study with evaluation of growth performance at 7, 14, 21, 28, 35, and 42 days and biochemical blood analysis, histological investigation of jejunum tissues and analysis of IL-6 and IL-10 gene expression of broilers at 42 days. As a result, probiotic KB41 significantly improved growth performance on the 42nd day of the experiment (p<0.01), increased the number of Lactobacillus bacteria in the ceca (p=0.03), and promoted IL-6 and IL-10 genes expression in the spleen of the chickens (p<0.01). The results of this study generally correspond to our previous study, which included an evaluation of Bacillus-based KB41 and KB54 probiotics on production performance and the immune system of broilers housed in cages, although the effects are less prominent. Conclusions: less prominent effects are probably linked to the colonization of the broilers' gastrointestinal tract with unknown bacilli of apparent environmental origin, as the broilers were housed in standard conditions. Significance and Impact of Study: this study provides more evidence of B. subtilis KB41 and B. amyloliquefaciens KB54 effectiveness in poultry.

Decolonization of asymptomatic carriage of multi-drug resistant bacteria by bacteriophages?

Antimicrobial resistance is a major threat to human and animal health and accounted for up to 4.5 million deaths worldwide in 2019. Asymptomatic colonization of the digestive tract by multidrug resistant (multi-resistant) bacteria such as extended-spectrum beta-lactamase-, or carbapenemase- producing Enterobacterales is (i) a risk factor for infection by these multi-resistant bacteria, (ii) a risk factor of dissemination of these multi-resistant bacteria among patients and in the community, and (iii) allows the exchange of resistance genes between bacteria. Hence, decolonization or reduction of the gastrointestinal tract colonization of these multi-resistant bacteria needs to be urgently explored. Developing new non-antibiotic strategies to limit or eradicate multi-resistant bacteria carriage without globally disrupting the microbiota is considered a priority to fight against antibiotic resistance. Probiotics or Fecal Microbiota Transplantation are alternative strategies to antibiotics that have been considered to decolonize intestinal tract from MDR bacteria but there is currently no evidence demonstrating their efficacy. Lytic bacteriophages are viruses that kill bacteria and therefore could be considered as a promising strategy to combat antibiotic resistance. Successful decolonization by bacteriophages has already been observed clinically. Here, we discuss the current alternative strategies considered to decolonize the digestive tract of multidrug resistant bacteria, briefly describing probiotics and fecal microbiota transplantation approaches, and then detail the in vivo and in vitro studies using bacteriophages, while discussing their limits regarding the animal models used, the characteristics of phages used and their activity in regards of the gut anatomy.

Functional and Probiotic Characterization of Newly Isolated Strains from Infant Feces and Breast Milk

Infant feces and breast milk are sources of lactic acid bacteria with interesting functional and technological properties. Therefore, we focused on the isolation and characterization of new potential probiotic strains from infant feces and breast milk. Nine strains were identified based on 16S rRNA sequences of Lacticaseibacillus rhamnosus, Limosilactobacillus reuteri, and Lactobacillus gasseri. Subsequently, these isolates were evaluated for their safety (antibiotic resistance, hemolytic, and enzymatic activity) and functional properties (gastrointestinal condition tolerance, hydrophobicity, auto-aggregation, adhesion to Caco-2/HT-29 cell lines, antimicrobial and antioxidant properties, and the production of exopolysaccharides). All the isolates were non-hemolytic and resistant to streptomycin, kanamycin, and vancomycin. They also demonstrated antimicrobial activity against five selected pathogens (Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella sp., and Enterococcus faecalis) and the production of exopolysaccharides. Isolates Lacticaseibacillus rhamnosus S1F and S6C together with Lactobacillus gasseri M8C showed the highest ability to survive 3.0 g/L of bile salts and a good adhesion property, which is important for gastrointestinal tract (GIT) colonization or the inhibition of pathogens. Following in vivo characterization, three strains S1F and S6C from infant feces, and M6C from breast milk, showed probiotic properties with potential applications in the food industry.

A-251 Comparison of Antimicrobial Susceptibility Profiles of Enterobacteriaceae spp. Isolates from Retail Meat Products Imported from USA and Brazil or Domestically Produced on Caribbean Islands of St. Kitts and Grenada

Abstract Background Enterobacteriaceae species, including Escherichia coli, Klebsiella and Salmonella, are endogenous colonizers of gastrointestinal tract of livestock animals, which pose potential health threats to humans, particularly for individuals with compromised immune systems (Guentzel 1996). The emergence of drug-resistant strains due to the overuse of antibiotics in agricultural practices have increased the urgency to evaluate zoonotic bacteria and to assess potential impact on human and animal health (Llor 2014). Project Aim and Methods The aim of this study is to compare the microbial prevalence and antimicrobial resistance profiles of Enterobacteriaceae isolates present on pork and poultry products domestically produced in the Caribbean Islands, St. Kitts and Grenada as compared to poultry imported from USA and Brazil. This study was conducted over a 4-year time period at University of Medicine and Health Sciences (UMHS) in St Kitts and at St. George’s University (SGU), Grenada. Microbial colonies were isolated on MacConkey agar after 24-hour incubation at 36°C in Buffered Peptone Water and identified using standard biochemical assays and API-20E test kit. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion on Mueller-Hinton plates. Results A total of 44 meat products from Caribbean Islands and 49 meat samples from Brazil and USA were processed to yield 64 and 60 bacterial isolates, respectively. Bacterial colonies isolated from imported meat products displayed higher incidence of antibiotic susceptibility to multiple classes of drugs (MDR = Multiple Drug Resistant) as compared to domestically produced meats. The prevalence of MDR bacteria was 45% MDR isolates from USA-imported chicken as compared to 13% MDR bacteria isolated from chicken domestically raised. Conclusions Imported meats exhibit a higher prevalence of antimicrobial resistance, particularly in the beta-lactam class of antibiotics, including amoxicillin and cephalosporins and fluroquinolones. The overuse of subtherapeutic antibiotics in mass scale livestock production is likely creating selective pressure for the overabundance of MDR strains in the gastrointestinal tract of animals. The findings of this study will be communicated to relevant community leaders and organizations in order to inform the development of strategies aimed at reducing the prevalence of antimicrobial resistance and identifying appropriate treatment options for associated infections.

Evaluation of single-strain Prevotella histicola on KLH-driven immune responses in healthy volunteers: A randomized controlled trial with EDP1815

IntroductionEDP1815 is a single-strain of Prevotella histicola with preclinical immunomodulatory properties. The aim of this study was to evaluate pharmacodynamic effects of EDP1815 on the immune response following immunization with keyhole limpet hemocyanin (KLH) and dermal rechallenge. MethodsThirty-two healthy subjects (median 30, range 18–59 years) were randomized over two cohorts to EDP1815 or placebo (12:4). Both cohorts received 8.0 × 1011 total cells daily for 28 days, reconstituted in 10 (A formulation) or 5 (B formulation) capsules. KLH-specific antibodies and circulating regulatory T cells were evaluated. Skin response after rechallenge was assessed with imaging. Immune cell subsets from blister exudates were assessed in the B cohort only. Ex vivo phytohemagglutinin and lipopolysaccharide whole blood challenges were performed to evaluate cytokine release. Gastrointestinal tract persistence, prevalence, and colonization of EDP1815 were assessed by fecal qPCR and microbiome assays. Data were analyzed using repeated measures analysis of covariances. ResultsThere was a trend toward a treatment effect on the KLH-induced skin rechallenge response (CIELab a* estimated difference (ED) −1.50 arbitrary unit (AU), 95% CI −3.47–0.47 AU, P = .13, and average redness ED −0.14 AU, 95% CI −0.31–0.03 AU, P = .10 in B cohort) and, to a lesser extent, on the humoral KLH response. No notable EDP1815 effects were observed on gut persistence, microbiome, and other safety parameters. ConclusionBased on our findings and the clinical benefit observed in the phase 2 study in psoriasis, further investigation of the immunomodulatory effects and potential clinical benefit of EDP1815 is warranted.

The Establishment of Fibrolytic Bacteria in the Foal Gastrointestinal Tract Is Related to the Occurrence of Coprophagy by Foals.

The consumption of maternal feces (coprophagy) is commonly observed in healthy foals and is a proposed contributor to microbial colonization of the foal's gastrointestinal tract (GIT). This study investigated the role of coprophagy in the establishment of fibrolytic bacteria in the foal GIT. Nine thoroughbred mares were dosed with chromic oxide, an indigestible marker, as a method to detect the occurrence of coprophagy by their foals. Foal fecal samples were collected from 12 h to 21 d after birth to measure chromic oxide and neutral detergent fiber (NDF) and to enumerate cellulolytic bacteria using culture-based techniques. Milk yield was estimated at 7 and 14 d postpartum. Coprophagy was detected as early as 3 d after birth and detected in all foals by 7 d of age. There were strong relationships between coprophagy and cellulolytic bacteria and NDF in foal feces at 7 d of age (r = 0.9703 and r = 0.7878, respectively; p < 0.05). Fecal NDF and chromic oxide concentrations were negatively related to milk yield (r = -0.8144 and r = -0.6966, respectively; p < 0.05), suggesting milk availability affected the incidence of coprophagy. Based on the relationships identified, maternal feces are an important source of fiber and live microbes for the foal, contributing to the development of the microbial community.

Homeostatic control of an iron repressor in a GI tract resident.

The transition metal iron plays a crucial role in living cells. However, high levels of iron are potentially toxic through the production of reactive oxygen species (ROS), serving as a deterrent to the commensal fungus Candida albicans for colonization in the iron-rich gastrointestinal tract. We observe that the mutant lacking an iron-responsive transcription factor Hap43 is hyper-fit for colonization in murine gut. We demonstrate that high iron specifically triggers multiple post-translational modifications and proteasomal degradation of Hap43, a vital process guaranteeing the precision of intestinal ROS detoxification. Reduced levels of Hap43 de-repress the expression of antioxidant genes and therefore alleviate the deleterious ROS derived from iron metabolism. Our data reveal that Hap43 functions as a negative regulator for oxidative stress adaptation of C. albicans to gut colonization and thereby provide a new insight into understanding the interplay between iron homeostasis and fungal commensalism.

Chemoreceptors from the commensal gut Roseburia rectibacter bind to mucin and trigger chemotaxis.

Chemotaxis is crucial for bacterial adherence and colonization of the host gastrointestinal tract. Previous studies have demonstrated that chemotaxis affects the virulence of causative pathogens and the infection in the host. However, the chemotactic abilities of non-pathogenic and commensal gut bacteria have rarely been explored. We observed that Roseburia rectibacter NSJ-69 exhibited flagella-dependent motility and chemotaxis to a variety of molecules, including mucin and propionate. A genome-wide analysis revealed that NSJ-69 has 28 putative chemoreceptors, 15 of which have periplasmic ligand-binding domains (LBDs). These LBD-coding genes were chemically synthesized and expressed heterologously in Escherichia coli. Intensive screening of ligands revealed four chemoreceptors bound to mucin and two bound to propionate. When expressed in Comamonas testosteroni or E. coli, these chemoreceptors elicited chemotaxis toward mucin and propionate. Hybrid chemoreceptors were constructed, and results showed that the chemotactic responses to mucin and propionate were dependent on the LBDs of R. rectibacter chemoreceptors. Our study identified and characterized R. rectibacter chemoreceptors. These results will facilitate further investigations on the involvement of microbial chemotaxis in host colonization.

In silico prediction and expression analysis of vaccine candidate genes of Campylobacter jejuni

Campylobacter jejuni (C. jejuni) is the most common food-borne pathogen that causes human gastroenteritis in the United States. Consumption of contaminated poultry products is considered as the major source of human Campylobacter infection. An effective vaccine would be a promising alternative to antibiotic supplements to curb C. jejuni colonization in poultry gastrointestinal (GI) tract. However, the genetic diversity among the C. jejuni isolates makes vaccine production more challenging. Despite many attempts, an effective Campylobacter vaccine is not yet available. This study aimed to identify suitable candidates to develop a subunit vaccine against C. jejuni, which could reduce colonization in the GI tract of the poultry. In the current study, 4 C. jejuni strains were isolated from retail chicken meat and poultry litter samples and their genomes were sequenced utilizing next-generation sequencing technology. The genomic sequences of C. jejuni strains were screened to identify potential antigens utilizing the reverse vaccinology approach. In silico genome analysis predicted 3 conserved potential vaccine candidates (phospholipase A [PldA], TonB dependent vitamin B12 transporter [BtuB], and cytolethal distending toxin subunit B [CdtB]) suitable for the development of a vaccine. Furthermore, the expression of predicted genes during host-pathogen interaction was analyzed by an infection study using an avian macrophage-like immortalized cell line (HD11). The HD11 was infected with C. jejuni strains, and the RT-qPCR assay was performed to determine the expression of the predicted genes. The expression difference was analyzed using ΔΔCt methods. The results indicate that all 3 predicted genes, PldA, BtuB, and CdtB, were upregulated in 4 tested C. jejuni strains irrespective of their sources of isolation. In conclusion, in silico prediction and gene expression analysis during host-pathogen interactions identified 3 potential vaccine candidates for C. jejuni.

Development and role of intestinal microbiota in term and preterm newborn babies. Accent on breast feeding

Intestinal microbiota (IM) plays in human organism a number of various functions including a participation in metabolic procecces, stimulation of immune function, competition with pathogenic flora, fermentation activity in colon. Microbial colonization of sterile gastrointestinal tract of newborn is based on several natural principles and depends on mode of delivery, vaginal and fecal flora of own mother, external factors (hospitalization, antibiotic therapy), and as well is regulated by breast feeding or bottle feeding. Besides that there is a proven difference between term and preterm newborn babies. Microbial community (so called Microbiome) of human milk with its complicated microbial society plays a key role in IM development, especially in combination with human milk oligosaccharides evolutionary connected with human intestinal microbiota development.

Calf rumen microbiome from birth to weaning and shared microbial properties to the maternal rumen microbiome.

Optimization of host performance in cattle may be achieved through programming of the rumen microbiome. Thus, understanding maternal influences on the development of the calf rumen microbiome is critical. We hypothesized that there exists a shared microbial profile between the cow and calf rumen microbiomes from birth through weaning. Specifically, our objective was to relate the calf's meconium and rumen fluid microbiomes in early life to that of the cow rumen fluid prior to parturition and at weaning. Rumen fluid was collected from multiparous Angus crossbred cows (n = 10) prior to parturition and at weaning. Immediately following the parturition, meconium and rumen fluid were collected from the calf. Rumen fluid was collected again from the calf on day 2, day 28, and at weaning. The rumen fluid microbial profile and subsequent volatile fatty acid (VFA) profile were characterized using 16S rRNA sequencing and gas liquid chromatography, respectively. Microbial data was analyzed using QIIME2 and the GLM procedure of SAS was used to analyze the VFA profile. Alpha diversity was similar in the early gut microbiome (meconium, rumen fluid at birth and day 2; q ≥ 0.12) and between the cow and calf at weaning (q ≥ 0.06). Microbial composition, determined by beta diversity, differed in the early rumen microbiome (rumen fluid at birth, day 2, and day 28; q ≤ 0.04), and VFA profiles complimented these results. There were similarities in composition between meconium, rumen fluid at birth, and rumen fluid from the cow at weaning (q ≥ 0.09). These data indicate successive development of the rumen microbiome and stabilization over time. Similarities between meconium and rumen fluid at birth potentially indicates in utero colonization of the calf gastrointestinal tract. Similarities in composition between the early calf rumen microbiome and the cow at weaning prompt an interesting comparison and area for future consideration in terms of identifying at what stage of gestation might colonization begin. Overall, this study provides insight into similarities between the cow and calf microbiomes and may be helpful in developing hypotheses for the pathway of colonization and programming potential in the early gut.