Early Life Microbiota Colonization at Six Months of Age: A Transitional Time Point

Abstract

BackgroundEarly life gut microbiota is involved in several biological processes, particularly metabolism, immunity, and cognitive neurodevelopment. Perturbation in the infant’s gut microbiota increases the risk for diseases in early and later life, highlighting the importance of understanding the connections between perinatal factors with early life microbial composition. The present research paper is aimed at exploring the prenatal and postnatal factors influencing the infant gut microbiota composition at six months of age.MethodsGut microbiota of infants enrolled in the longitudinal, prospective, observational study “A.MA.MI” (Alimentazione MAmma e bambino nei primi MIlle giorni) was analyzed. We collected and analyzed 61 fecal samples at baseline (meconium, T0); at six months of age (T2), we collected and analyzed 53 fecal samples. Samples were grouped based on maternal and gestational weight factors, type of delivery, type of feeding, time of weaning, and presence/absence of older siblings. Alpha and beta diversities were evaluated to describe microbiota composition. Multivariate analyses were performed to understand the impact of the aforementioned factors on the infant’s microbiota composition at six months of age.ResultsDifferent clustering hypotheses have been tested to evaluate the impact of known metadata factors on the infant microbiota. Neither maternal body mass index nor gestational weight gain was able to determine significant differences in infant microbiota composition six months of age. Concerning the type of feeding, we observed a low alpha diversity in exclusive breastfed infants; conversely, non-exclusively breastfed infants reported an overgrowth of Ruminococcaceae and Flavonifractor. Furthermore, we did not find any statistically significant difference resulting from an early introduction of solid foods (before 4 months of age). Lastly, our sample showed a higher abundance of clostridial patterns in firstborn babies when compared to infants with older siblings in the family.ConclusionOur findings showed that, at this stage of life, there is not a single factor able to affect in a distinct way the infants’ gut microbiota development. Rather, there seems to be a complex multifactorial interaction between maternal and neonatal factors determining a unique microbial niche in the gastrointestinal tract.

How Metabolomics Provides Novel Insights on Celiac Disease and Gluten-Free Diet: A Narrative Review

“…This is in accordance with previous studies on infants, which reported how various prenatal and perinatal factors influence the early gut microbiota development (Koenig et al, 2011;Raspini et al, 2020). In addition, although the feeding and the time of solid food introduction were demonstrated to be among the main postnatal factors affecting gut microbiota in early phases of life (Differding et al, 2020;Raspini et al, 2021;Vacca et al, 2022), the fact that only one infant showed positive antibodies before 24 months of age in Sellitto et al (2012), in our opinion, was not statistically sufficient to raise conclusions about effects related to an earlier or delayed gluten introduction in infants with genetically predisposed CD. Lipidomes, on the contrary, have provided more information as predictive tools to assess the CD onset later in life, suggesting that specific phosphatidylcholines might differentiate CD infants before gluten exposure (Auricchio et al, 2019).…”

The establishment of the gut microbiota in 1-year-aged infants: from birth to family food

“…Our previous findings on gut microbiota resulted from analyzing infants at birth (T0), 1 month (T1), and 6 months (T2) [ 20 , 25 ] and showed that prenatal and perinatal variables were the main affecting factors. Differently, the inspection of prenatal and perinatal factors at T3 revealed that these became low significance.…”

“…Alpha diversity indices were compared according to a two-tailed Mann–Whitney test computing the exact p values (qval or exact pval) after correction for multiple comparisons using GraphPad Prism version 8.0.1 (GraphPad Software, San Diego, California, USA). As previously adopted [ 25 ], the multivariable association between 16S rDNA-seq abundances and variables (metadata) was performed using the MaAsLin2 R package ( https://huttenhower.sph.harvard.edu/maaslin/ ; accessed 27 Sept 2021), which allows to investigate metadata as fixed or random effects (Tables 1 and 2 , respectively).…”

“…The 16S rDNA gene amplification was performed with primers: Forward 5′-CCT ACG GGNGGC WGC AG-3′ and Reverse 5′-GAC TAC HVGGG TAT CTA ATC C-3′, which targeted the hypervariable V3-V4 regions of the 16S rDNA gene. Followed protocols useful to obtain raw sequence files (fast files) and filter them according to a quality control check (FastQC) were previously detailed [25]. The 16S rDNA metabarcoding analysis was carried out by QIIME2, and the SILVA 138 taxonomic database used to define the bacterial taxonomy.…”

Role of Maternal Microbiota and Nutrition in Early-Life Neurodevelopmental Disorders

“…As the microbiota is shared between the mother and child, maternal diet can influence the microbiota of the offspring. In the gastrointestinal system, a complex combination of mother and offspring factors generates a unique microbiome [ 33 ]. The concept of fetal microbiome, which postulates that microbial colonization begins in utero, remains controversial [ 34 , 35 , 36 , 37 ]; however, a wealth of evidence demonstrates that the microbiota of the mother can be seeded in the offspring at the time of birth via vertical transmission from the reproductive and gastrointestinal tracts [ 38 , 39 , 40 , 41 , 42 ] and can be transmitted by breastfeeding [ 43 ].…”