Signatures in the gut microbiota of Japanese infants who developed food allergies in early childhood

Abstract

Bacterial colonization in infancy is considered crucial for the development of the immune system. Recently, there has been a drastic increase in childhood allergies in Japan. Therefore, we conducted a prospective study with 56 infants on the relationship between gut microbiota in the first year of life and the development of allergies during the first 3 years. In the lactation period, organic acid producers such as Leuconostoc, Weissella and Veillonella tended to be underrepresented in subjects who developed food allergies (FA, n = 14) within the first two years. In the weaning period, children in the FA group were highly colonized by unclassified Enterobacteriaceae and two Clostridium species closely related to Clostridium paraputrificum and C. tertium, and the whole tree phylogenetic diversity index was significantly lower in the FA group. All of these differences in the weaning period were statistically significant, even after adjusting for potential confounding factors. A higher abundance of unclassified Enterobacteriaceae was also found in the other allergic group (n = 15), whereas the two Clostridium species were highly specific to the FA group. The mode of action of these Clostridium species in childhood food allergies remains unknown, warranting further investigation.

The association between gut microbiota development and maturation of intestinal bile acid metabolism in the first 3 y of healthy Japanese infants

“…Both PCRs were performed as described previously. 8 Amplicons from the second PCR were purified using FastGene Gel/PCR Extraction Kit (Nippon Genetics Co., Ltd.), and the DNA concentrations were measured using PicoGreen® ds DNA Assay Kit (Life Technologies) in a Tecan M200 (excitation at 480 nm and emission at 520 nm). A pool of equal amounts (200 ng) of amplicons from each sample was purified by electrophoresis in 2% (w/v) agarose gel, followed by extraction from the gel using FastGene Gel/PCR Extraction Kit.…”

“…1,[4][5][6] The developing microbiota has a great impact on infant health and subsequent host physiology, notably through the development of the digestive tract, immune system, and metabolic homeostasis. 6,7 Therefore, failure in gut microbiota development may lead to diseases such as food allergies, 8,9 asthma, 10 atopic dermatitis, 11 and childhood obesity. 12,13 Bile acids (BAs) constitute the primary component of bile.…”

Cultural isolation of spore-forming bacteria in human feces using bile acids

“…The amplified products were then used as templates in a second PCR for further amplification using barcode-tagged primers. Both PCRs were performed as described previously 39 . PCR products were pooled and combined in equimolar amounts for sequencing using the Illumina MiSeq platform, generating 300 bp paired-end reads.…”

The gut microbiome in food allergy

“…Compared with germ-free controls, the mice colonized with Clostridium clusters showed reduced levels of peanut-specific and total IgE and no drop in rectal temperature on allergen challenge. 27 Although many studies in murine models have found that taxa from Clostridia confer an overall protective effect on the host, their association with atopic risk has been more variable in human studies 5,8,9,11,28,29…”