title: Infant gut microbiota and food sensitization: associations in the first year of life.
abstract: 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
  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.
authors.affiliation: Department of Pediatrics, School of Public Health, University of Alberta, Edmonton, AB, Canada; Department of Pediatrics & Child Health, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, MB, Canada.
authors.forename: M B
authors.initials: MB
authors.lastname: Azad
authors.forename: T
authors.initials: T
authors.lastname: Konya
authors.forename: D S
authors.initials: DS
authors.lastname: Guttman
authors.forename: C J
authors.initials: CJ
authors.lastname: Field
authors.forename: M R
authors.initials: MR
authors.lastname: Sears
authors.forename: K T
authors.initials: KT
authors.lastname: HayGlass
authors.forename: P J
authors.initials: PJ
authors.lastname: Mandhane
authors.forename: S E
authors.initials: SE
authors.lastname: Turvey
authors.forename: P
authors.initials: P
authors.lastname: Subbarao
authors.forename: A B
authors.initials: AB
authors.lastname: Becker
authors.forename: J A
authors.initials: JA
authors.lastname: Scott
authors.forename: A L
authors.initials: AL
authors.lastname: Kozyrskyj
mesh_terms: D000367:Age Factors; D044822:Biodiversity; D002170:Canada / Q000453:epidemiology; D005260:Female; D005512:Food Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000009:adverse effects*; D007231:Infant, Newborn; D008297:Male; D054892:Metagenome; D064307:Microbiota; D011159:Population Surveillance; D012336:RNA, Ribosomal, 16S; D012882:Skin Tests
chemical_list: D012336:RNA, Ribosomal, 16S