NCT01111864.

Breast milk has recently been recognized as source of commensal and potential probiotic bacteria. The present study investigated whether viable strains of gut-associated obligate anaerobes are shared between the maternal and neonatal gut ecosystem via breastfeeding. Maternal faeces, breast milk and corresponding neonatal faeces collected from seven mothers-neonate pairs at three neonatal sampling points were analyzed by culture-independent (pyrosequencing) and culture-dependent methods (16S rRNA gene sequencing, pulsed field gel electrophoresis, random amplified polymorphic DNA and repetitive extragenic palindromic polymerase chain reaction. Pyrosequencing allowed identifying gut-associated obligate anaerobic genera, like Bifidobacterium, Bacteroides, Parabacteroides and members of the Clostridia (Blautia, Clostridium, Collinsella and Veillonella) shared between maternal faeces, breast milk and neonatal faeces. Using culture, a viable strain of Bifidobacterium breve was shown to be shared between all three ecosystems within one mother-neonate pair. Furthermore, pyrosequencing revealed that several butyrate-producing members of the Clostridia (Coprococcus, Faecalibacterium, Roseburia and Subdoligranulum) were shared between maternal faeces and breast milk. This study shows that (viable) obligate gut-associated anaerobes may be vertically transferred from mother to neonate via breastfeeding. Thus, our data support the recently suggested hypothesis of a novel way of mother-neonate communication, in which maternal gut bacteria reach breast milk via an entero-mammary pathway to influence neonatal gut colonization and maturation of the immune system.

Anemic African children carry an unfavorable ratio of fecal enterobacteria to bifidobacteria and lactobacilli, which is increased by iron fortification. Thus, iron fortification in this population produces a potentially more pathogenic gut microbiota profile, and this profile is associated with increased gut inflammation. This trial was registered at controlled-trials.com as ISRCTN21782274.

BackgroundDietary changes are suggested to play a role in the increasing prevalence of allergic diseases and asthma. Short‐chain fatty acids (SCFAs) are metabolites present in certain foods and are produced by microbes in the gut following fermentation of fibers. SCFAs have been shown to have anti‐inflammatory properties in animal models. Our objective was to investigate the potential role of SCFAs in the prevention of allergy and asthma.MethodsWe analyzed SCFA levels by high‐performance liquid chromatography (HPLC) in fecal samples from 301 one‐year‐old children from a birth cohort and examined their association with early life exposures, especially diet, and allergy and asthma later in life. Data on exposures and allergic diseases were collected by questionnaires. In addition, we treated mice with SCFAs to examine their effect on allergic airway inflammation.ResultsSignificant associations between the levels of SCFAs and the infant's diet were identified. Children with the highest levels of butyrate and propionate (≥95th percentile) in feces at the age of one year had significantly less atopic sensitization and were less likely to have asthma between 3 and 6 years. Children with the highest levels of butyrate were also less likely to have a reported diagnosis of food allergy or allergic rhinitis. Oral administration of SCFAs to mice significantly reduced the severity of allergic airway inflammation.ConclusionOur results suggest that strategies to increase SCFA levels could be a new dietary preventive option for allergic diseases in children.

Initial neonatal gut colonisation is a crucial stage for developing a healthy physiology, beneficially influenced by breast-feeding. Breast milk has been shown not only to provide nutrients and bioactive/immunological compounds, but also commensal bacteria, including gut-associated anaerobic Bifidobacterium spp. The aim of the present study was to investigate bacterial diversity in breast milk, with emphasis on identifying gut-associated obligate anaerobes. Breast milk collected from seven mothers at three sampling points (days 3-6, 9 -14 and 25 -30 postpartum) was analysed by combined culture-dependent and state-of-the-art, culture-independent methods (Sanger sequencing and 454-pyrosequencing). In addition to the predominance of facultative anaerobes such as Staphylococcus, Streptococcus and Propionibacterium (.90 % of isolated strains and 23·7 % relative abundance using pyrosequencing), significant populations of obligate anaerobes, including Bifidobacterium and Veillonella, were detected using pyrosequencing and confirmed by the isolation of viable strains (3·4 % of isolates and 1·4 % relative abundance). Pyrosequencing also revealed the presence of DNA of multiple major gut-associated obligate anaerobes (6·2 % relative abundance) such as Bacteroides and, for the first time, several members of the Clostridia, including butyrate producers, such as Faecalibacterium and Roseburia, which are important for colonic health. The present study suggests that breast milk may be a major source of bacterial diversity to the neonatal gut, including gut-associated obligate anaerobes, and may thus significantly influence gut colonisation and maturation of the immune system.