Objective
Dysbiosis of the infant gut microbiota may have long‐term health consequences. This study aimed to determine the impact of maternal intrapartum antibiotic prophylaxis (IAP) on infant gut ...microbiota, and to explore whether breastfeeding modifies these effects.
Design
Prospective pregnancy cohort of Canadian infants born in 2010–2012: the Canadian Healthy Infant Longitudinal Development (CHILD) Study.
Setting
General community.
Sample
Representative sub‐sample of 198 healthy term infants from the CHILD Study.
Methods
Maternal IAP exposures and birth method were documented from hospital records and breastfeeding was reported by mothers. Infant gut microbiota was characterised by Illumina 16S rRNA sequencing of faecal samples at 3 and 12 months.
Main outcome measures
Infant gut microbiota profiles.
Results
In this cohort, 21% of mothers received IAP for Group B Streptococcus prophylaxis or pre‐labour rupture of membranes; another 23% received IAP for elective or emergency caesarean section (CS). Infant gut microbiota community structures at 3 months differed significantly with all IAP exposures, and differences persisted to 12 months for infants delivered by emergency CS. Taxon‐specific composition also differed, with the genera Bacteroides and Parabacteroides under‐represented, and Enterococcus and Clostridium over‐represented at 3 months following maternal IAP. Microbiota differences were especially evident following IAP with emergency CS, with some changes (increased Clostridiales and decreased Bacteroidaceae) persisting to 12 months, particularly among non‐breastfed infants.
Conclusions
Intrapartum antibiotics in caesarean and vaginal delivery are associated with infant gut microbiota dysbiosis, and breastfeeding modifies some of these effects. Further research is warranted to explore the health consequences of these associations.
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Maternal #antibiotics during childbirth alter the infant gut #microbiome.
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Maternal #antibiotics during childbirth alter the infant gut #microbiome.
Summary
Background
The gut microbiota is established during infancy and plays a fundamental role in shaping host immunity. Colonization patterns may influence the development of atopic disease, but ...existing evidence is limited and conflicting.
Objective
To explore associations of infant gut microbiota and food sensitization.
Methods
Food sensitization at 1 year was determined by skin prick testing in 166 infants from the population‐based Canadian Healthy Infant Longitudinal Development (CHILD) study. Faecal samples were collected at 3 and 12 months, and microbiota was characterized by Illumina 16S rRNA sequencing.
Results
Twelve infants (7.2%) were sensitized to ≥ 1 common food allergen at 1 year. Enterobacteriaceae were overrepresented and Bacteroidaceae were underrepresented in the gut microbiota of food‐sensitized infants at 3 months and 1 year, whereas lower microbiota richness was evident only at 3 months. Each quartile increase in richness at 3 months was associated with a 55% reduction in risk for food sensitization by 1 year (adjusted odds ratio 0.45, 95% confidence interval 0.23–0.87). Independently, each quartile increase in Enterobacteriaceae/Bacteroidaceae ratio was associated with a twofold increase in risk (2.02, 1.07–3.80). These associations were upheld in a sensitivity analysis among infants who were vaginally delivered, exclusively breastfed and unexposed to antibiotics. At 1 year, the Enterobacteriaceae/Bacteroidaceae ratio remained elevated among sensitized infants, who also tended to have decreased abundance of Ruminococcaceae.
Conclusions and Clinical Relevance
Low gut microbiota richness and an elevated Enterobacteriaceae/Bacteroidaceae ratio in early infancy are associated with subsequent food sensitization, suggesting that early gut colonization may contribute to the development of atopic disease, including food allergy.
Using operando X-ray diffraction, crystal structure variation of high-purity spinel cathode LiMn1.5Ni0.5O4 at voltages of 2.1–3.5 V vs. Li anode was studied. Results showed that the low-voltage Li+ ...extraction–insertion reaction proceeded in a two-phase reaction with a long voltage plateau around 2.8 V, where cubic and tetragonal spinel phases coexist. Their lattice volume difference was approximately 4.9%. That difference, which is small compared to that of ordinary LiMn2O4 spinel compound, implies that the Jahn-Teller distortion can slightly influence Li+ extraction-insertion reaction reversibility. Therefore, the redox reaction occurred over the wide voltage range of 2.5–4.9 V, at which simultaneous calorimetric measurements were conducted. Capacity fading during redox cycling was sufficiently small, but not negligible. A large exothermic reaction was detected at both charge and discharge stages, although only a small exothermic reaction was observed in both 2.8 V and 4.7 V plateau regions. The irreversibility can be attributed to the reaction at the transition region between high-voltage redox and low-voltage redox.
•High-purity micron-sized spinel cathode LiMn1.5Ni0.5O4 was synthesized.•Operando diffraction carried out the crystal structure variation at 2.1–3.5 V.•A two-phase reaction between cubic and tetragonal phases was identified.•Lattice volume difference between cubic and tetragonal phase was about 4.9%.
High-voltage cathode LiMn1.5Ni0.5O4 particles with average size of approximately 2 μm were prepared using a two-step process. Low-temperature magnetic measurements indicated them as ferrimagnetic ...materials with high Neel temperature (146.5 K) and high magnetization (107 emu/g at 4.5 K) that closely approximates the theoretical value of the stoichiometric LiMn1.5Ni0.5O4 compound. Because of their high-purity and high crystallinity, their redox signals were observed only around 4.7 V. Their low-rate capacity was sufficiently high (about 140 mAh/g at 0.1 C). Their capacity retention after the 100th cycle was higher than 95%. In spite of the low specific surface area of the LiMn1.5Ni0.5O4 particles, they exhibited high reversible capacity even at a high-current rate. Additionally, the in-situ X-ray diffraction was conducted to elucidate the reaction process, which indicated that the electrochemical reaction progresses reversibly with two consecutive two-phase reactions. The lattice parameters of three corresponding phases remained almost unchanged on the reactions (0.8165, 0.8087, and 0.8000 nm). The presence of the intermediate phase might give the relaxation of the structural variation during the electrochemical reaction.
•The ferrimagnetic LiMn1.5Ni0.5O4 particles had Tc = 146.5 K and Ms = 107 emu/g at 4.5 K.•The LiMn1.5Ni0.5O4 cathode had good cycling and rate performances with high redox potential about 4.7 V.•The redox reaction of the LiMn1.5Ni0.5O4 was composed of reversible two consecutive two-phase reactions.
The human gut is host to a diverse and abundant community of bacteria that influence health and disease susceptibility. This community develops in infancy, and its composition is strongly influenced ...by environmental factors, notably perinatal anthropogenic exposures such as delivery mode (Cesarean vs. vaginal) and feeding method (breast vs. formula); however, the built environment as a possible source of exposure has not been considered. Here we report on a preliminary investigation of the associations between bacteria in house dust and the nascent fecal microbiota from 20 subjects from the Canadian Healthy Infant Longitudinal Development (CHILD) Study using high-throughput sequence analysis of portions of the 16S rRNA gene. Despite significant differences between the dust and fecal microbiota revealed by Nonmetric Multidimensional Scaling (NMDS) analysis, permutation analysis confirmed that 14 bacterial OTUs representing the classes Actinobacteria (3), Bacilli (3), Clostridia (6) and Gammaproteobacteria (2) co-occurred at a significantly higher frequency in matched dust–stool pairs than in randomly permuted pairs, indicating an association between these dust and stool communities. These associations could indicate a role for the indoor environment in shaping the nascent gut microbiota, but future studies will be needed to confirm that our findings do not solely reflect a reverse pathway. Although pet ownership was strongly associated with the presence of certain genera in the dust for dogs (Agrococcus, Carnobacterium, Exiguobacterium, Herbaspirillum, Leifsonia and Neisseria) and cats (Escherichia), no clear patterns were observed in the NMDS-resolved stool community profiles as a function of pet ownership.
Secretory immunoglobulin A (IgA) plays a critical role in gut mucosal immune defense. Initially provided by breastmilk, IgA production by the infant gut is gradually stimulated by developing gut ...microbiota. This study reports associations between infant fecal IgA concentrations 4 months after birth, breastfeeding status and other pre/postnatal exposures in 47 infants in the Canadian Healthy Infant Longitudinal Development cohort. Breastfed infants and first-born infants had higher median fecal IgA concentrations (23.11 v. 9.34 µg/g protein, P<0.01 and 22.19 v. 8.23 µg/g protein, P=0.04). IgA levels increased successively with exclusivity of breastfeeding (β-coefficient, 0.37, P<0.05). This statistical association was independent of maternal parity and household pets. In the absence of breastfeeding, female sex and pet exposure elevated fecal IgA to levels found in breastfed infants. In addition to breastfeeding, infant fecal IgA associations with pre/postnatal exposures may affect gut immunity and risk of allergic disease.
In order to clarify crystal defect effects on the physical phenomena observed for a SrTiO3 single crystal grown by Verneuil method, the optical density and photoluminescence spectra, complex ...impedance spectra, and crystal structure were fully studied for the as-grown crystal boule. The as-grown crystal boule consists of a shell (which is colorless transparent and electrically good insulator) and a core (which is dark blue and has a high electrical conductivity ( > 10-3Omega-1cm-1), and a colossal static dielectric constant ( > 106) at room temperature). The as-grown single crystal was then annealed at 973K in an Ar-H2 gas stream. With the progressing of annealing, the as-grown single crystal becomes colorless-transparent insulator and the static dielectric constant decreases down to approximately 300 at room temperature. The X-ray crystallographic studies indicate that the crystallinity is almost independent of the annealing, while the dielectric property is considerably affected by the annealing. A model on the basis of a (Ti3+-oxygen vacancy) complex defect is proposed for explaining the observed properties of SrTiO3.
High-voltage cathode LiMn1.5Ni0.5O4 particles with average size of approximately 2 μm were prepared using a two-step process. Low-temperature magnetic measurements indicated them as ferrimagnetic ...materials with high Neel temperature (146.5 K) and high magnetization (107 emu/g at 4.5 K) that closely approximates the theoretical value of the stoichiometric LiMn1.5Ni0.5O4 compound. Because of their high-purity and high crystallinity, their redox signals were observed only around 4.7 V. Their low-rate capacity was sufficiently high (about 140 mAh/g at 0.1 C). Their capacity retention after the 100th cycle was higher than 95%. In spite of the low specific surface area of the LiMn1.5Ni0.5O4 particles, they exhibited high reversible capacity even at a high-current rate. Additionally, the in-situ X-ray diffraction was conducted to elucidate the reaction process, which indicated that the electrochemical reaction progresses reversibly with two consecutive two-phase reactions. The lattice parameters of three corresponding phases remained almost unchanged on the reactions (0.8165, 0.8087, and 0.8000 nm). The presence of the intermediate phase might give the relaxation of the structural variation during the electrochemical reaction.
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