The Composition of Human Milk and Infant Faecal Microbiota Over the First Three Months of Life: A Pilot Study.
ABSTRACT: Human milk contains a diverse array of bioactives and is also a source of bacteria for the developing infant gut. The aim of this study was to characterize the bacterial communities in human milk and infant faeces over the first 3 months of life, in 10 mother-infant pairs. The presence of viable Bifidobacterium and Lactobacillus in human milk was also evaluated. MiSeq sequencing revealed a large diversity of the human milk microbiota, identifying over 207 bacterial genera in milk samples. The phyla Proteobacteria and Firmicutes and the genera Pseudomonas, Staphylococcus and Streptococcus were the predominant bacterial groups. A core of 12 genera represented 81% of the microbiota relative abundance in milk samples at week 1, 3 and 6, decreasing to 73% at week 12. Genera shared between infant faeces and human milk samples accounted for 70-88% of the total relative abundance in infant faecal samples, supporting the hypothesis of vertical transfer of bacteria from milk to the infant gut. In addition, identical strains of Bifidobacterium breve and Lactobacillus plantarum were isolated from the milk and faeces of one mother-infant pair. Vertical transfer of bacteria via breastfeeding may contribute to the initial establishment of the microbiota in the developing infant intestine.
Project description:<h4>Scope</h4>Understanding biological functions of different free human milk oligosaccharides (HMOs) in shaping gastrointestinal tract microbiota during infancy is of great interest. We examined a link between HMOs in maternal milk and infant faecal microbiota composition and investigated the role of microbiota in degrading HMOs within the GI tract of healthy, breastfed, one-month old infants.<h4>Methods and results</h4>Maternal breast milk and corresponding infant faeces originated from the KOALA Birth Cohort. HMOs were quantified in milk and infant faecal samples using PGC-UPLC-MS and HPAEC-PAD. Faecal microbiota composition was characterised using Illumina HiSeq amplicon 16S rRNA sequencing. The composition associated with gender, mode of delivery, and milk HMOs: Lacto-N-fucopentaose I and 2'-Fucosyllactose. Overall, Bifidobacterium, Bacteroides, Escherichia-Shigella and Parabacteroides were predominating genera. We detected three different patterns in the infant faecal microbiota structure. Gastrointestinal degradation of HMOs was strongly associated with faecal microbiota composition, and there was a link between utilisation of specific HMOs and abundance of various phylotypes (OTUs).<h4>Conclusions</h4>HMOs in maternal milk are among important factors shaping GI tract microbiota composition in one-month old breastfed infants. Infant's ability to metabolise different HMOs strongly correlate with faecal microbiota composition, and with phylotypes within genera Bifidobacterium, Bacteroides and Lactobacillus. This article is protected by copyright. All rights reserved.
Project description:Much evidence suggests a role for human milk oligosaccharides (HMOs) in establishing the infant microbiota in the large intestine, but the response of particular bacteria to individual HMOs is not well known. Here twelve bacterial strains belonging to the genera Bifidobacterium, Enterococcus, Limosilactobacillus, Lactobacillus, Lacticaseibacillus, Staphylococcus and Streptococcus were isolated from infant faeces and their growth was analyzed in the presence of the major HMOs, 2'-fucosyllactose (2'FL), 3-fucosyllactose (3FL), 2',3-difucosyllactose (DFL), lacto-N-tetraose (LNT) and lacto-N-neo-tetraose (LNnT), present in human milk. Only the isolated Bifidobacterium strains demonstrated the capability to utilize these HMOs as carbon sources. Bifidobacterium infantis Y538 efficiently consumed all tested HMOs. Contrarily, Bifidobacterium dentium strains Y510 and Y521 just metabolized LNT and LNnT. Both tetra-saccharides are hydrolyzed into galactose and lacto-N-triose (LNTII) by B. dentium. Interestingly, this species consumed only the galactose moiety during growth on LNT or LNnT, and excreted the LNTII moiety. Two β-galactosidases were characterized from B. dentium Y510, Bdg42A showed the highest activity towards LNT, hydrolyzing it into galactose and LNTII, and Bdg2A towards lactose, degrading efficiently also 6'-galactopyranosyl-N-acetylglucosamine, N-acetyl-lactosamine and LNnT. The work presented here supports the hypothesis that HMOs are mainly metabolized by Bifidobacterium species in the infant gut.
Project description:Several factors affect gut microbiota development in early life, among which breastfeeding plays a key role. We followed 24 mother-infant pairs to investigate the associations between concentrations of selected human milk oligosaccharides (HMOs) in breastmilk, infant faeces, and the faecal microbiota composition in healthy, breastfed infants at two, six and 12 weeks of age. Lactation duration had a significant effect on breastmilk HMO content, which decreased with time, except for 3-fucosyllactose (3FL) and Lacto-N-fucopentaose III (LNFP III). We confirmed that microbiota composition was strongly influenced by infant age and was associated with mode of delivery and breastmilk LNFP III concentration at two weeks, with infant sex, delivery mode, and concentrations of 3'sialyllactose (3'SL) in milk at six weeks, and infant sex and Lacto-N-hexaose (LNH) in milk at 12 weeks of age. Correlations between levels of individual breastmilk HMOs and relative abundance of OTUs found in infant faeces, including the most predominant Bifidobacterium OTUs, were weak and varied with age. The faecal concentration of HMOs decreased with age and were strongly and negatively correlated with relative abundance of OTUs within genera Bifidobacterium, Parabacteroides, Escherichia-Shigella, Bacteroides, Actinomyces, Veillonella, Lachnospiraceae Incertae Sedis, and Erysipelotrichaceae Incertae Sedis, indicating the likely importance of these taxa for HMO metabolism in vivo.
Project description:<h4>Objective</h4>The objective of this work was to study the lactobacilli and bifidobacteria population in human milk of healthy women, and to investigate the influence that several factors (including antibioteraphy during pregnancy and lactation, country and date of birth, delivery mode, or infant age) may exert on such population.<h4>Methods</h4>A total of 160 women living in Germany or Austria provided the breast milk samples. Initially, 66 samples were randomly selected and cultured on MRS-Cys agar plates. Then, the presence of DNA from the genera Lactobacillus and Bifidobacterium, and from most of the Lactobacillus and Bifidobacterium species that were isolated, was assessed by qualitative polymerase chain reaction (PCR) using genus- and species-specific primers.<h4>Results</h4>Lactobacilli and bifidobacteria could be isolated from the milk of 27 (40.91%) and 7 (10.61%), respectively, of the 66 cultured samples. On the contrary, Lactobacillus and Bifidobacterium sequences were detected by PCR in 108 (67.50%) and 41 (25.62%), respectively, of the 160 samples analyzed. The Lactobacillus species most frequently isolated and detected was L salivarius (35.00%), followed by L fermentum (25.00%) and L gasseri (21.88%), whereas B breve (13.75%) was the bifidobacterial species most commonly recovered and whose DNA was most regularly found. The number of lactobacilli- or bifidobacteria-positive samples was significantly lower in women who had received antibiotherapy during pregnancy or lactation.<h4>Conclusions</h4>Our results suggest that either the presence of lactobacilli and/or bifidobacteria or their DNA may constitute good markers of a healthy human milk microbiota that has not been altered by the use of antibiotics.
Project description:<h4>Background</h4>Human milk and infant gut microbiota are essential for the immune system maturation and protection against infections. There is scarce information on the microbiological composition of breast milk in general, and none from developing countries. The objective of the study was to characterize the breast milk and gut microbiota from mothers and infants from southern Mozambique, where infections and breastfeeding are prevalent.<h4>Methods</h4>A community-based study was undertaken among 121 pairs of women and infants. Breast milk and infant's faeces were analyzed by bacterial culture and molecular methods. Breast milk samples were screened for HIV RNA by RT-PCR.<h4>Results</h4>The most frequent bacterial groups isolated by culture media in breast milk were Staphylococci (96.4%), Streptococci (92.7%) and Lactobacilli (56.4%). HIV RNA was detected in 24% of the samples. Staphylococcus hominis, S. aureus, and S.parasanguis were more frequently isolated in infants ?14 days of life. Women on exclusive breastfeeding presented higher proportion of S. parasanguis in breast milk than those on mixed infant feeding (36.4% versus 11.1%, p?=?0.035). Bacterial diversity (mean number of bacterial species isolated by sample: 10.4 versus 8.5; p?=?0.004) and the frequency of Lactobacillus spp (75.9% versus 36%, p?=?0.003) were higher in the specimens with HIV RNA than in those without it. The main bacterial groups found in infant's faeces were Bifidobacterium, Streptococci and Enterococci.<h4>Conclusions</h4>Women with HIV RNA in breast milk had a different pattern of microbiological composition, suggesting specific immunopathological phenomena in HIV-infected women. Both breast milk and faecal microbiota composition varied with lactation period, which might be related to changes in the type of feeding over time and/or in the milk's biochemical characteristics. These findings provide insights into interactions between commensal bacteria and HIV infection in human milk and the role of these bacteria in mucosal protection against infections in breastfed infants.
Project description:Background:Human milk microbiota plays a role in the bacterial colonization of the neonatal gut, which has important consequences in the health and development of the newborn. However, there are few studies about the vertical transfer of bacteria from mother to infant in Latin American populations. Methods:We performed a cross-sectional study characterizing the bacterial diversity of 67 human milk-neonatal stool pairs by high-throughput sequencing of V3-16S rDNA libraries, to assess the effect of the human milk microbiota on the bacterial composition of the neonate's gut at early days. Results:Human milk showed higher microbial diversity as compared to the neonatal stool. Members of the Staphylococcaceae and Sphingomonadaceae families were more prevalent in human milk, whereas the Pseudomonadaceae family, Clostridium and Bifidobacterium genera were in the neonatal stool. The delivery mode showed association with the neonatal gut microbiota diversity, but not with the human milk microbiota diversity; for instance, neonates born by C-section showed greater richness and diversity in stool microbiota than those born vaginally. We found 25 bacterial taxa shared by both ecosystems and 67.7% of bacteria found in neonate stool were predicted to originate from human milk. This study contributes to the knowledge of human milk and neonatal stool microbiota in healthy Mexican population and supports the idea of vertical mother-neonate transmission through exclusive breastfeeding.
Project description:Bifidobacterium and Lactobacillus are beneficial for human health, and many strains of these two genera are widely used as probiotics. We used two large datasets published by the American Gut Project (AGP) and a gut metagenomic dataset (NBT) to analyze the relationship between these two genera and the community structure of the gut microbiota. The meta-analysis showed that Bifidobacterium, but not Lactobacillus, is among the dominant genera in the human gut microbiota. The relative abundance of Bifidobacterium was elevated when Lactobacillus was present. Moreover, these two genera showed a positive correlation with some butyrate producers among the dominant genera, and both were associated with alpha diversity, beta diversity, and the robustness of the gut microbiota. Additionally, samples harboring Bifidobacterium present but no Lactobacillus showed higher alpha diversity and were more robust than those only carrying Lactobacillus. Further comparisons with other genera validated the important role of Bifidobacterium in the gut microbiota robustness. Multivariate analysis of 11,744 samples from the AGP dataset suggested Bifidobacterium to be associated with demographic features, lifestyle, and disease. In summary, Bifidobacterium members, which are promoted by dairy and whole-grain consumption, are more important than Lactobacillus in maintaining the diversity and robustness of the gut microbiota.
Project description:<h4>Background</h4>Human breast milk (HBM) contains optimal nutrients for infant growth. Probiotics are used to prevent disease and, when taken by the mother, they may affect infant microbiome as well as HBM. However, few studies have specifically investigated the effect of probiotic intake by the mother on HBM and infant microbiota at genus/species level. Therefore, we present a comprehensive analysis of paired HBM and infant feces (IF) microbiome samples before and after probiotic intake by HBM-producing mothers.<h4>Methods</h4>Lactating mothers were administered with <i>Lactobacillus rhamnosus</i> (n = 9) or <i>Saccharomyces boulardii</i> capsules (n = 9), for 2 months; or no probiotic (n = 7). Paired HBM and IF samples were collected before and after treatment and analyzed by next-generation sequencing.<h4>Results</h4>Forty-three HBM and 49 IF samples were collected and sequenced. Overall, in 43 HBM samples, 1,190 microbial species belonging to 684 genera, 245 families, 117 orders, and 56 classes were detected. In 49 IF samples, 372 microbial species belonging to 195 genera, 79 families, 42 orders, and 18 classes were identified. Eight of 20 most abundant genera in both HBM and IF samples overlapped: <i>Streptococcus</i> (14.42%), <i>Lactobacillus</i>, <i>Staphylococcus</i>, and <i>Veillonella</i>, which were highly abundant in the HBM samples; and <i>Bifidobacterium</i> (27.397%), <i>Bacteroides</i>, and <i>Faecalibacterium</i>, which were highly abundant in the IF samples. Several major bacterial genera and species were detected in the HBM and IF samples after probiotic treatment, illustrating complex changes in the microbiomes upon treatment.<h4>Conclusion</h4>This is the first Korean microbiome study in which the effect of different probiotic intake by the mother on the microbiota in HBM and IF samples was investigated. This study provides a cornerstone to further the understanding of the effect of probiotics on the mother and infant microbiomes.
Project description:Human breast milk is recognized as one of multiple important sources of commensal bacteria for infant gut. Previous studies searched for the bacterial strains shared between breast milk and infant feces by isolating bacteria and performing strain-level bacterial genotyping, but only limited number of milk bacteria were identified to colonize infant gut, including bacteria from Bifidobacterium, Staphylococcus, Lactobacillus, and Escherichia/Shigella. Here, to identify the breast milk bacteria capable of colonizing gut without the interference of bacteria of origins other than the milk or the necessity to analyze infant feces, normal chow-fed germ-free mice were orally inoculated with the breast milk collected from a mother 2 days after vaginal delivery. According to 16S rRNA gene-based denaturant gradient gel electrophoresis and Illumina sequencing, bacteria at >1% abundance in the milk inoculum were only Streptococcus (56.0%) and Staphylococcus (37.4%), but in the feces of recipient mice were Streptococcus (80.3 ± 2.3%), Corynebacterium (10.0 ± 2.6 %), Staphylococcus (7.6 ± 1.6%), and Propionibacterium (2.1 ± 0.5%) that were previously shown as dominant bacterial genera in the meconium of C-section-delivered human babies; the abundance of anaerobic gut-associated bacteria, Faecalibacterium, Prevotella, Roseburia, Ruminococcus, and Bacteroides, was 0.01-1% in the milk inoculum and 0.003-0.01% in mouse feces; the abundance of Bifidobacterium spp. was below the detection limit of Illumina sequencing in the milk but at 0.003-0.01% in mouse feces. The human breast milk microbiota-associated mouse model may be used to identify additional breast milk bacteria that potentially colonize infant gut.
Project description:The infant gut microbiota plays a critical role in early life growth and derives mainly from maternal gut and breast milk. This study aimed to analyze the differences in the gut microbiota, namely <i>Bifidobacterium</i> and <i>Lactobacillus</i> communities at species level among breast milk as well as maternal and infant feces at different time points after delivery. Fifty-one mother-infant pairs from Indonesia were recruited, and the breast milk and maternal and infant feces were collected and analyzed by high throughput sequencing (16S rRNA, <i>Bifidobacterium</i> groEL and <i>Lactobacillus</i> groEL genes). PCoA results showed bacterial composition was different among breast milk and maternal and infant feces within the first two years. The abundance of <i>Bifidobacterium</i> and <i>Bacteroides</i> were significantly higher in infant feces compared to their maternal feces from birth to two years of age, and maternal breast milk within six months after birth (<i>p <</i> 0.05), whereas the abundance of <i>Blautia</i>, <i>Prevotella</i>, and <i>Faecalibacterium</i> was higher in maternal feces compared to that in breast milk within six months and infant feces within one year after birth, respectively (<i>p <</i> 0.05). The relative abundances of <i>Bacteroides</i> and <i>Lactobacillus</i> was higher and lower in infant feces compared to that in maternal feces only between one and two years of age, respectively (<i>p <</i> 0.05). For <i>Bifidobacterium</i> community at species level, <i>B. adolescentis, B. ruminantium, B. longum subsp. infantis, B. bifidum,</i> and <i>B. pseudolongum</i> were identified in all samples. However, the profile of <i>Bifidobacterium</i> was different between maternal and infant feces at different ages. The relative abundances of <i>B. adolescentis</i> and <i>B. ruminantium</i> were higher in maternal feces compared to those in infant feces from birth to one year of age (<i>p <</i> 0.05), while the relative abundances of <i>B. longum</i> subsp. <i>infantis</i> and <i>B. bifidum</i> were higher in infant feces compared to those in maternal feces beyond three months, and the relative abundance of <i>B. pseudolongum</i> was only higher in infant feces between three and six months (<i>p <</i> 0.05). For <i>Lactobacillus</i> community, <i>L. paragasseri</i> showed higher relative abundance in infant feces when the infant was younger than one year of age (<i>p <</i> 0.05). This study showed bacterial composition at the genus level and <i>Bifidobacterium</i> and <i>Lactobacillus</i> communities at the species level were stage specific in maternal breast milk as well as and maternal and infant feces.