title: Intestinal microbiota of 6-week-old infants across Europe: geographic influence beyond delivery mode, breast-feeding, and antibiotics.
abstract: OBJECTIVE
  : There are many differences in diet and lifestyle across Europe that may influence the development of the infant gut microbiota. This work aimed to assess the impact of geographic area, mode of delivery, feeding method, and antibiotic treatment on the fecal microbiota of infants from 5 European countries with different lifestyle characteristics: Sweden, Scotland, Germany, Italy, and Spain.
  
  
  METHODS
  : Fecal samples from 606 infants (age 6 weeks) recruited within the European project INFABIO were analyzed by fluorescent in situ hybridization combined with flow cytometry using a panel of 10 rRNA targeted group- and species-specific oligonucleotide probes. Information on factors potentially affecting gut microbiota composition was collected with questionnaires and associations were evaluated with multivariate analyses.
  
  
  RESULTS
  : The Bifidobacterium genus was predominant (40% average proportion of total detectable bacteria), followed by Bacteroides (11.4%) and enterobacteria (7.5%). Northern European countries were associated with higher proportions of bifidobacteria in infant feces, whereas a more diverse microbiota with more bacteroides characterized southern countries. Bifidobacteria dominated the microbiota of breast-fed infants, whereas formula-fed babies had significantly higher proportions of Bacteroides and members of the Clostridium coccoides and Lactobacillus groups. Newborns delivered by cesarean section or from mothers treated with antibiotics perinatally had lower proportions of Bacteroides and members of the Atopobium cluster.
  
  
  CONCLUSIONS
  : Delivery mode and feeding method influenced the fecal microbiota of European infants at 6 weeks, as expected, but the effect of country of birth was more pronounced, with dominant bifidobacteria in northern countries and greater early diversification in southern European countries.
authors.affiliation: Institut National de la Recherche Agronomique, Unité d'Ecologie et de Physiologie du Système Digestif, Jouy en Josas, France.
authors.forename: Matteo
authors.initials: M
authors.lastname: Fallani
authors.forename: David
authors.initials: D
authors.lastname: Young
authors.forename: Jane
authors.initials: J
authors.lastname: Scott
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Norin
authors.forename: Sergio
authors.initials: S
authors.lastname: Amarri
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Adam
authors.forename: Marga
authors.initials: M
authors.lastname: Aguilera
authors.forename: Sheila
authors.initials: S
authors.lastname: Khanna
authors.forename: Angel
authors.initials: A
authors.lastname: Gil
authors.forename: Christine A
authors.initials: CA
authors.lastname: Edwards
authors.forename: Joël
authors.initials: J
authors.lastname: Doré
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D001903:Bottle Feeding; D001942:Breast Feeding; D002585:Cesarean Section; D003106:Colon / Q000187:drug effects / Q000382:microbiology*; D015169:Colony Count, Microbial; D003431:Cross-Cultural Comparison; D005060:Europe; D005243:Feces / Q000382:microbiology; D005260:Female; D020459:Genes, rRNA; D006801:Humans; D007223:Infant; D041943:Infant Formula; D015345:Oligonucleotide Probes; D011247:Pregnancy; D011795:Surveys and Questionnaires
chemical_list: D000900:Anti-Bacterial Agents; D015345:Oligonucleotide Probes