Genome plasticity shapes the ecology and evolution of Phocaeicola dorei and Phocaeicola vulgatus.

Phocaeicola dorei and Phocaeicola vulgatus are very common and abundant members of the human gut microbiome and play an important role in the infant gut microbiome. These species are closely related and often confused for one another; yet, their genome comparison, interspecific diversity, and evolutionary relationships have not been studied in detail so far. Here, we perform phylogenetic analysis and comparative genomic analyses of these two Phocaeicola species. We report that P. dorei has a larger genome yet a smaller pan-genome than P. vulgatus. We found that this is likely because P. vulgatus is more plastic than P. dorei, with a larger repertoire of genetic mobile elements and fewer anti-phage defense systems. We also found that P. dorei directly descends from a clade of P. vulgatus¸ and experienced genome expansion through genetic drift and horizontal gene transfer. Overall, P. dorei and P. vulgatus have very different functional and carbohydrate utilisation profiles, hinting at different ecological strategies, yet they present similar antimicrobial resistance profiles.

Bifidobacterium longum Subsp. infantis Promotes IgA Level of Growing Mice in a Strain-Specific and Intestinal Niche-Dependent Manner.

Throughout infancy, IgA is crucial for maintaining gut mucosal immunity. This study aims to determine whether supplementing newborn mice with eight different strains of Bifidobacterium longum subsp. infantis might regulate their IgA levels. The strains were gavaged to BALB/C female (n = 8) and male (n = 8) dams at 1-3 weeks old. Eight strains of B. longum subsp. infantis had strain-specific effects in the regulation of intestinal mucosal barriers. B6MNI, I4MI, and I10TI can increase the colonic IgA level in females and males. I8TI can increase the colonic IgA level in males. B6MNI was also able to significantly increase the colonic sIgA level in females. B6MNI, I4MI, I8TI, and I10TI regulated colonic and Peyer's patch IgA synthesis genes but had no significant effect on IgA synthesis pathway genes in the jejunum and ileum. Moreover, the variety of sIgA-coated bacteria in male mice was changed by I4MI, I5TI, I8TI, and B6MNI. These strains also can decrease the relative abundance of Escherichia coli. These results indicate that B. longum subsp. infantis can promote IgA levels but show strain specificity. Different dietary habits with different strains of Bifidobacterium may have varying effects on IgA levels when supplemented in early infancy.

Exopolysaccharides Produced by Bifidobacterium longum subsp. longum YS108R Ameliorates DSS-Induced Ulcerative Colitis in Mice by Improving the Gut Barrier and Regulating the Gut Microbiota.

Ulcerative colitis (UC) is a major disease that has endangered human health. Our previous study demonstrated that Bifidobacterium longum subsp. longum YS108R, a ropy exopolysaccharide (EPS)-producing bacterium, could alleviate UC in mice, but it is unclear whether EPS is the key substance responsible for its action. In this study, we proposed to investigate the remitting effect of EPS from B. longum subsp. longum YS108R on UC in a DSS-induced UC mouse model. Water extraction and alcohol precipitation were applied to extract EPS from the supernatant of B. longum subsp. longum YS108R culture. Then the animal trial was performed, and the results indicated that YS108R EPS ameliorated colonic pathological damage and the intestinal barrier. YS108R EPS suppressed inflammation via NF-κB signaling pathway inhibition and attenuated oxidative stress via the Nrf2 signaling pathway activation. Remarkably, YS108R EPS regulated gut microbiota, as evidenced by an increase in short-chain fatty acid (SCFA)-producing bacteria and a decline in Gram-negative bacteria, resulting in an increase of propionate and butyrate and a reduction of lipopolysaccharide (LPS). Collectively, YS108R EPS manipulated the intestinal microbiota and its metabolites, which further improved the intestinal barrier and inhibited inflammation and oxidative stress, thereby alleviating UC.

Planococcus notacanthi sp. nov., isolated from the skin of a deep-sea snub-nosed spiny eel.

A novel bacterial strain, APC 4016T, was previously isolated from the skin of a snub-nosed spiny eel, Notacanthus chemnitzii, from a depth of 1000 m in the northern Atlantic Ocean. Cells were aerobic, cocci, motile, Gram-positive to Gram-variable staining, and gave rise to orange-pigmented colonies. Growth occurred at 4-40 °C (optimum, 25-28 °C), pH 5.5-12 (optimum, pH 7-7.5), and 0-12 % (w/v) NaCl (optimum, 1 %). 16S rRNA gene phylogenetic analysis confirmed that strain APC 4016T belonged to the genus Planococcus and was most closely related to Planococcus okeanokoites IFO 12536T (98.98 % 16S similarity). However, digital DNA-DNA hybridization and average nucleotide identity values between these two strains were low, at 20.1 and 83.8 %, respectively. Major (>10 %) cellular fatty acids of strain APC 4016T were iso-C14 : 0, anteiso-C15 : 0 and C16 : 1-ω-Alc. The predominant respiratory quinones were menaquinones 5, 6, 7 and 8. The major cellular polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine, and three unknown lipids were also present. The draft genome sequence is 3.6 Mb with a G+C content of 45.25 mol%. This strain was previously shown to have antimicrobial activity and to encode bacteriocin and secondary metabolite biosynthetic gene clusters. Based on the phylogenetic analysis and its distinct phenotypic characteristics, strain APC 4016T is deemed to represent a novel species of the genus Planococcus, and for which the name Planococcus notacanthi sp. nov. is proposed. The type strain of this species is APC 4016T (=DSM 115753T=NCIMB 15463T).

A metagenomic catalog of the early-life human gut virome.

Early-life human gut microbiome is a pivotal driver of gut homeostasis and infant health. However, the viral component (known as "virome") remains mostly unexplored. Here, we establish the Early-Life Gut Virome (ELGV), a catalog of 160,478 non-redundant DNA and RNA viral sequences from 8130 gut virus-like particles (VLPs) enriched or bulk metagenomes in the first three years of life. By clustering, 82,141 viral species are identified, 68.3% of which are absent in existing databases built mainly from adults, and 64 and 8 viral species based on VLPs-enriched and bulk metagenomes, respectively, exhibit potentials as biomarkers to distinguish infants from adults. With the largest longitudinal population of infants profiled by either VLPs-enriched or bulk metagenomic sequencing, we track the inherent instability and temporal development of the early-life human gut virome, and identify differential viruses associated with multiple clinical factors. The mother-infant shared virome and interactions between gut virome and bacteriome early in life are further expanded. Together, the ELGV catalog provides the most comprehensive and complete metagenomic blueprint of the early-life human gut virome, facilitating the discovery of pediatric disease-virome associations in future.

Harnessing the endogenous Type I-C CRISPR-Cas system for genome editing in Bifidobacterium breve.

Bifidobacterium breve, one of the main bifidobacterial species colonizing the human gastrointestinal tract in early life, has received extensive attention for its purported beneficial effects on human health. However, exploration of the mode of action of such beneficial effects exerted by B. breve is cumbersome due to the lack of effective genetic tools, which limits its synthetic biology application. The widespread presence of CRISPR-Cas systems in the B. breve genome makes endogenous CRISPR-based gene editing toolkits a promising tool. This study revealed that Type I-C CRISPR-Cas systems in B. breve can be divided into two groups based on the amino acid sequences encoded by cas gene clusters. Deletion of the gene coding uracil phosphoribosyl-transferase (upp) was achieved in five B. breve strains from both groups using this system. In addition, translational termination of uracil phosphoribosyl-transferase was successfully achieved in B. breve FJSWX38M7 by single-base substitution of the upp gene and insertion of three stop codons. The gene encoding linoleic acid isomerase (bbi) in B. breve, being a characteristic trait, was deleted after plasmid curing, which rendered it unable to convert linoleic acid into conjugated linoleic acid, demonstrating the feasibility of successive editing. This study expands the toolkit for gene manipulation in B. breve and provides a new approach toward functional genome editing and analysis of B. breve strains.IMPORTANCEThe lack of effective genetic tools for Bifidobacterium breve is an obstacle to studying the molecular mechanisms of its health-promoting effects, hindering the development of next-generation probiotics. Here, we introduce a gene editing method based on the endogenous CRISPR-Cas system, which can achieve gene deletion, single-base substitution, gene insertion, and successive gene editing in B. breve. This study will facilitate discovery of functional genes and elucidation of molecular mechanisms of B. breve pertaining to health-associated benefits.

Production, Composition and Nutritional Properties of Organic Milk: A Critical Review.

Milk is one of the most valuable products in the food industry with most milk production throughout the world being carried out using conventional management, which includes intensive and traditional systems. The intensive use of fertilizers, antibiotics, pesticides and concerns regarding animal health and the environment have given increasing importance to organic dairy and dairy products in the last two decades. This review aims to compare the production, nutritional, and compositional properties of milk produced by conventional and organic dairy management systems. We also shed light on the health benefits of milk and the worldwide scenario of the organic dairy production system. Most reports suggest milk has beneficial health effects with very few, if any, adverse effects reported. Organic milk is reported to confer additional benefits due to its lower omega-6-omega-3 ratio, which is due to the difference in feeding practices, with organic cows predominantly pasture fed. Despite the testified animal, host, and environmental benefits, organic milk production is difficult in several regions due to the cost-intensive process and geographical conditions. Finally, we offer perspectives for a better future and highlight knowledge gaps in the organic dairy management system.

Early life exposure of infants to benzylpenicillin and gentamicin is associated with a persistent amplification of the gut resistome.

BACKGROUND: Infant gut microbiota is highly malleable, but the long-term longitudinal impact of antibiotic exposure in early life, together with the mode of delivery on infant gut microbiota and resistome, is not extensively studied. METHODS: Two hundred and eight samples from 45 infants collected from birth until 2 years of age over five time points (week 1, 4, 8, 24, year 2) were analysed. Based on shotgun metagenomics, the gut microbial composition and resistome profile were compared in the early life of infants divided into three groups: vaginal delivery/no-antibiotic in the first 4 days of life, C-section/no-antibiotic in the first 4 days of life, and C-section/antibiotic exposed in first 4 days of life. Gentamycin and benzylpenicillin were the most commonly administered antibiotics during this cohort's first week of life. RESULTS: Newborn gut microbial composition differed in all three groups, with higher diversity and stable composition seen at 2 years of age, compared to week 1. An increase in microbial diversity from week 1 to week 4 only in the C-section/antibiotic-exposed group reflects the effect of antibiotic use in the first 4 days of life, with a gradual increase thereafter. Overall, a relative abundance of Actinobacteria and Bacteroides was significantly higher in vaginal delivery/no-antibiotic while Proteobacteria was higher in C-section/antibiotic-exposed infants. Strains from species belonging to Bifidobacterium and Bacteroidetes were generally persistent colonisers, with Bifidobacterium breve and Bifidobacterium bifidum species being the major persistent colonisers in all three groups. Bacteroides persistence was dominant in the vaginal delivery/no-antibiotic group, with species Bacteroides ovatus and Phocaeicola vulgatus found to be persistent colonisers in the no-antibiotic groups. Most strains carrying antibiotic-resistance genes belonged to phyla Proteobacteria and Firmicutes, with the C-section/antibiotic-exposed group presenting a higher frequency of antibiotic-resistance genes (ARGs). CONCLUSION: These data show that antibiotic exposure has an immediate and persistent effect on the gut microbiome in early life. As such, the two antibiotics used in the study selected for strains (mainly Proteobacteria) which were multiple drug-resistant (MDR), presumably a reflection of their evolutionary lineage of historical exposures-leading to what can be an extensive and diverse resistome. Video Abstract.

Alleviative effects of exopolysaccharides from Limosilactobacillus mucosae CCFM1273 against ulcerative colitis via modulation of gut microbiota and inhibition of Fas/Fasl and TLR4/NF-κB pathways.

Ulcerative colitis (UC) has become a public health challenge as its global prevalence increases annually. The use of prebiotics in healthcare has grown in recent years. Thus, the present study was designed to explore the alleviating effects and mechanisms of exopolysaccharides (EPS) produced by Limosilactobacillus mucosae CCFM1273 on UC. The results indicated that CCFM1273 EPS mitigated the disease symptoms and colonic pathologic damage in DSS-induced colitis mice. Moreover, CCFM1273 EPS improved the intestinal barrier by restoring goblet cell numbers and MUC2 production, enhancing intercellular junctions, and inhibiting epithelial cell apoptosis. In addition, CCFM1273 EPS inhibited colonic inflammation and oxidative stress. Importantly, CCFM1273 EPS augmented short-chain fatty acid (SCFA) producers, leading to increased levels of SCFAs (especially propionic acid), which inhibited the Fas/Fasl pathway and consequently inhibited epithelial apoptosis, and diminished Gram-negative bacteria, further decreasing lipopolysaccharides (LPS), which suppressed the TLR4/NF-κB pathway and consequently suppressed colonic inflammation, eventually relieving UC in mice. This study provides theoretical support for the use of prebiotics in clinical practice for UC.

Influence of age, socioeconomic status, and location on the infant gut resistome across populations.

Antibiotic resistance is a growing global concern, with many ecological niches showing a high abundance of antibiotic resistance genes (ARGs), including the human gut. With increasing indications of ARGs in infants, this study aims to investigate the gut resistome profile during early life at a wider geographic level. To achieve this objective, we utilized stool samples data from 26 studies involving subjects aged up to 3 years from different geographical locations. The 32,277 Metagenome Assembled Genomes (MAGs) previously generated from shotgun sequencing reads from these studies were used for resistome analysis using RGI with the CARD database. This analysis showed that the distribution of ARGs across the countries in our study differed in alpha diversity and compositionally. In particular, the abundance of ARGs was found to vary by socioeconomic status and healthcare access and quality (HAQ) index. Surprisingly, countries having lower socioeconomic status and HAQ indices showed lower ARG abundance, which was contradictory to previous reports. Gram-negative genera, including Escherichia, Enterobacter, Citrobacter, and Klebsiella harbored a particularly rich set of ARGs, which included antibiotics that belong to the Reserve, Access or Watch category, such as glycopeptides, fluoroquinolones, sulfonamides, macrolides, and tetracyclines. We showed that ARG abundance exponentially decreased with time during the first 3 years of life. Many highly ARG-abundant species including Escherichia, Klebsiella, Citrobacter species that we observed are well-known pathobionts found in the infant gut in early life. High abundance of these species and a diverse range of ARGs in their genomes point toward the infant gut, acting as an ARG reservoir. This is a concern and further studies are needed to examine the causal effect and its consequences on long-term health.

Existing and Future Strategies to Manipulate the Gut Microbiota With Diet as a Potential Adjuvant Treatment for Psychiatric Disorders.

Nutrition and diet quality play key roles in preventing and slowing cognitive decline and have been linked to multiple brain disorders. This review compiles available evidence from preclinical studies and clinical trials on the impact of nutrition and interventions regarding major psychiatric conditions and some neurological disorders. We emphasize the potential role of diet-related microbiome alterations in these effects and highlight commonalities between various brain disorders related to the microbiome. Despite numerous studies shedding light on these findings, there are still gaps in our understanding due to the limited availability of definitive human trial data firmly establishing a causal link between a specific diet and microbially mediated brain functions and symptoms. The positive impact of certain diets on the microbiome and cognitive function is frequently ascribed with the anti-inflammatory effects of certain microbial metabolites or a reduction of proinflammatory microbial products. We also critically review recent research on pro- and prebiotics and nondietary interventions, particularly fecal microbiota transplantation. The recent focus on diet in relation to brain disorders could lead to improved treatment outcomes with combined dietary, pharmacological, and behavioral interventions.

Advances in research on microbial conjugated linoleic acid bioconversion.

Conjugated linoleic acid (CLA) is a functional food ingredient with prebiotic properties that provides health benefits for various human pathologies and disorders. However, limited natural CLA sources in animals and plants have led microorganisms like Lactobacillus and Bifidobacterium to emerge as new CLA sources. Microbial conversion of linoleic acid to CLA is mediated by linoleic acid isomerase and multicomponent enzymatic systems, with CLA production efficiency dependent on microbial species and strains. Additionally, complex factors like LA concentration, growth status, culture substrates, precursor type, prebiotic additives, and co-cultured microbe identity strongly influence CLA production and isomer composition. This review summarizes advances in the past decade regarding microbial CLA production, including bacteria and fungi. We highlight CLA production and potential regulatory mechanisms and discuss using microorganisms to enhance CLA content and nutritional value of fermented products. We also identify primary microbial CLA production bottlenecks and provide strategies to address these challenges and enhance production through functional gene and enzyme mining and downstream processing. This review aims to provide a reference for microbial CLA production and broaden the understanding of the potential probiotic role of microbial CLA producers.

Human breastmilk-derived Bifidobacterium longum subsp. infantis CCFM1269 regulates bone formation by the GH/IGF axis through PI3K/AKT pathway.

Bifidobacterium longum subsp. infantis is a prevalent member of the gut microbiota of breastfed infants. In this study, the effects of human breastmilk-derived B.longum subsp. infantis CCFM1269 on bone formation in developing BALB/c mice were investigated. Newborn female and male mice were assigned to control group (administered saline), CCFM11269 group (administered B. longum subsp. infantis CCFM1269, 1 × 109 CFU/mouse/day) and I5TI group (administered B. longum subsp. infantis I5TI, 1 × 109 CFU/mouse/day) from 1-week-old to 3-, 4- and 5-week old. B. longum subsp. infantis I5TI served as a negative control in this study. The results demonstrated that B. longum subsp. infantis CCFM1269 promoted bone formation in growing mice by modulating the composition of the gut microbiota and metabolites. The expression of genes and proteins in the PI3K/AKT pathway was stimulated by B. longum subsp. infantis CCFM1269 through the GH/IGF-1 axis in growing mice. This finding suggests B. longum subsp. infantis CCFM1269 may be useful for modulating bone metabolism during growth.

A pilot study of dietary fibres on pathogen growth in an ex vivo colonic model reveals their potential ability to limit vancomycin-resistant Enterococcus expansion.

Aim: Dietary fibre is important for shaping gut microbiota. The aim of this pilot study was to investigate the impact of dietary fibres on pathogen performance in the presence of gut microbiota. Methods: In an ex vivo gut model, pooled faecal samples were spiked with a cocktail of representative gastrointestinal pathogens and fermented with yeast ß-glucan for 24 hours, after which 16S rRNA amplicon sequencing and short-chain and branched-chain fatty acid (SCFA and BCFA) analyses were performed. In addition, oat ß-glucan, arabinoxylan, yeast ß-glucan, and galactooligosaccharides were each tested against individual representative pathogens and pathogen growth was assessed via qPCR. Glucose served as a control carbon source. Results: Based on 16S rRNA amplicon sequencing, yeast ß-glucan selected for higher proportions of Bacteroides (P = 0.0005, ~6 fold) and Clostridia (P = 0.005, ~3.6 fold) while species of Escherichia/Shigella (P = 0.021, ~2.8 fold) and Lactobacillus (P = 0.007, ~ 15.7-fold) were higher in glucose. Pathogen relative abundance did not differ between glucose and yeast ß-glucan. In the absence of pathogens, higher production of BCFAs (P = 0.002) and SCFAs (P = 0.002) fatty acids was observed for fibre group(s). For individual pathogens, yeast ß-glucan increased growth of Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes (P < 0.05), arabinoxylan increased S. typhimurium (P < 0.05). Tested fibres decreased vancomycin-resistant Enterococcus faecium (P < 0.05), with yeast ß-glucan causing a 1-log reduction (P < 0.01), while galactooligosaccharides decreased L. monocytogenes (P < 0.05). Conclusion: Tested fibres differentially influenced the growth of pathogens, but yeast ß-glucan could represent a dietary strategy to help limit vancomycin-resistant enterococci (VRE) expansion in the gut.

Bifidobacterium longum subsp. infantis B6MNI Alleviates Collagen-Induced Arthritis in Rats via Regulating 5-HIAA and Pim-1/JAK/STAT3 Inflammation Pathways.

The immunomodulatory potential of certain bacterial strains suggests that they could be beneficial in the treatment of rheumatoid arthritis (RA). In this study, we investigated the effects of Bifidobacterium longum subsp. infantis B6MNI on the progression of collagen-induced arthritis (CIA) in rats as well as its influence on the gut microbiota and fecal metabolites. Forty-eight female Wistar rats were divided into six groups that included a B6MNI group with CIA and intragastrically administered B. longum subsp. infantis B6MNI (109 CFU/day/rat), a control group (CON), and a CIA group, both of which were intracardiacally administered the same volume of saline. Rats were sacrificed after short-term (ST, 4 weeks) or long-term (LT, 6 weeks) administration. The results indicate that B. longum subsp. infantis B6MNI can modulate the gut microbiota and fecal metabolites, including 5-hydroxyindole-3-acetic acid (5-HIAA), which in turn impacts the expression of Pim-1 and immune cell differentiation, then through the JAK-STAT3 pathway affects joint inflammation, regulates osteoclast differentiation factors, and delays the progression of RA. Our results also suggest that B. longum subsp. infantis B6MNI is most efficacious for the early or middle stages of RA.

Winogradskyella bathintestinalis sp. nov., isolated from the intestine of the deep-sea loosejaw dragonfish, Malacosteus niger.

A novel bacterial strain, APC 3343T, was isolated from the intestine of a deep-sea loosejaw dragon fish, Malacosteus niger, caught at a depth of 1000 m in the Northwest Atlantic Ocean. Cells were aerobic, rod-shaped, yellow/orange-pigmented, non-motile and Gram-negative. Growth of strain APC 3343T was observed at 4-30 °C (optimum, 21-25 °C), pH 5.5-10 (optimum, pH 7-8) and 0.5-8 % (w/v) NaCl (optimum, 2-4 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain APC 3343T was most closely related to members of the genus Winogradskyella, with the most closely related type strains being Winogradskyella algae Kr9-9T (98.46 % identity), Winogradskyella damuponensis F081-2T (98.07 %), Winogradskyella eximia CECT 7946T (97.93 %), Winogradskyella litoriviva KMM 6491T (97.79 %) and Winogradskyella endarachnes HL2-2T (97.79 %). Major fatty acids (>10 % of total) were iso-C16 : 0 3-OH, iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 0 3-OH. The predominant respiratory quinone was menaquinone-6 (MK-6). Polar lipids were phosphatidylethanolamine, three unknown aminolipids and eight unknown lipids. The draft genome sequence was 3.8 Mb in length with a G+C content of 33.43 mol%. Based on the phenotypic characteristics and phylogenetic analysis, strain APC 3343T is deemed to be a novel species of the genus Winogradskyella, and for which the name Winogradskyella bathintestinalis sp. nov. is proposed. The type strain of this species is APC 3343T (=DSM 115832T=NCIMB 15464T).

Machine-learning analysis of cross-study samples according to the gut microbiome in 12 infant cohorts.

IMPORTANCE: There are challenges in merging microbiome data from diverse research groups due to the intricate and multifaceted nature of such data. To address this, we utilized a combination of machine-learning (ML) models to analyze 16S sequencing data from a substantial set of gut microbiome samples, sourced from 12 distinct infant cohorts that were gathered prospectively. Our initial focus was on the mode of delivery due to its prior association with changes in infant gut microbiomes. Through ML analysis, we demonstrated the effective merging and comparison of various gut microbiome data sets, facilitating the identification of robust microbiome biomarkers applicable across varied study populations.

Longitudinal observational study protocol - Preterm Infants: Microbiome Establishment, Neuro-CrossTalk and Origins (PIMENTO).

INTRODUCTION: Very preterm infants are at risk of abnormal microbiome colonisation in the first weeks to months of life. Several important associated factors have been identified including gestational age, mode of delivery, antibiotic exposure and feeding. Preterm infants are at risk of a number of pathologies for which the microbiome may play a central role, including necrotising enterocolitis and sepsis. The objective of this study is to determine detailed microbiome changes that occur around implementation of different management practices including empiric antibiotic use, advancement of feeds and administration of probiotics during admission to the neonatal intensive care unit. METHODS AND ANALYSIS: A single-site, longitudinal observational study of infants born less than 32 weeks gestation, including collection of maternal samples around delivery and breastmilk and infant samples from admission through discharge from the neonatal unit. ETHICS AND DISSEMINATION: The protocol was approved by the Clinical Research Ethics Committee of the Cork Teaching Hospitals.The findings from this study will be disseminated in peer-reviewed journals, during scientific conferences, and directly to the study participants. Sequencing data will be deposited in public databases. TRIAL REGISTRATION NUMBER: NCT05803577.

Microbiota and Resistome Analysis of Colostrum and Milk from Dairy Cows Treated with and without Dry Cow Therapies.

This study investigated the longitudinal impact of methods for the drying off of cows with and without dry cow therapy (DCT) on the microbiota and resistome profile in colostrum and milk samples from cows. Three groups of healthy dairy cows (n = 24) with different antibiotic treatments during DCT were studied. Colostrum and milk samples from Month 0 (M0), 2 (M2), 4 (M4) and 6 (M6) were analysed using whole-genome shotgun-sequencing. The microbial diversity from antibiotic-treated groups was different and higher than that of the non-antibiotic group. This difference was more evident in milk compared to colostrum, with increasing diversity seen only in antibiotic-treated groups. The microbiome of antibiotic-treated groups clustered separately from the non-antibiotic group at M2-, M4- and M6 milk samples, showing the effect of antibiotic treatment on between-group (beta) diversity. The non-antibiotic group did not show a high relative abundance of mastitis-causing pathogens during early lactation and was more associated with genera such as Psychrobacter, Serratia, Gordonibacter and Brevibacterium. A high relative abundance of antibiotic resistance genes (ARGs) was observed in the milk of antibiotic-treated groups with the Cephaguard group showing a significantly high abundance of genes conferring resistance to cephalosporin, aminoglycoside and penam classes. The data support the use of non-antibiotic alternatives for drying off in cows.

Neonatal outcomes following introduction of routine probiotic supplementation to very preterm infants.

AIM: To evaluate the combined outcome of death and/or severe grade necrotising enterocolitis (NEC) in very preterm infants admitted to Cork University Maternity Hospital, Ireland, before and after introduction of routine supplementation with Bifidobacterium bifidum and Lactobacillus acidophilus probiotics (Infloran®). METHODS: A retrospective study of infants <32 weeks gestation and < 1500 g surviving beyond 72 h of life was performed. Two 6-year epochs; pre-probiotics (Epoch 1: 2008-2013) and with probiotics (Epoch 2: 2015-2020), were evaluated. The primary outcome was defined as death after 72 h or NEC Bell stage 2a or greater. RESULTS: Seven-hundred-and-forty-four infants were included (Epoch 1: 391, Epoch 2: 353). The primary outcome occurred in 67 infants (Epoch 1: 37, Epoch 2: 30, p = 0.646). After adjustment, the difference was significant (OR [95% CI]: 0.53 [0.29 to 0.97], p = 0.038). Differences between epochs did not depend on gestational age group (<28 weeks; ≥28 weeks). CONCLUSION: There was an associated reduction of the composite outcome of severe grade NEC and/or death, after adjustment for confounding variables, with introduction of routine administration of a B. bifidum and L. acidophilus probiotic at our institution.