title: Maternal breast-milk and intestinal bifidobacteria guide the compositional development of the Bifidobacterium microbiota in infants at risk of allergic disease.
abstract: BACKGROUND
  The sources and the impact of maternal bacteria on the initial inoculum of the intestinal microflora of newborn infants remain elusive.
  
  
  OBJECTIVE
  To assess the association between maternal breast-milk and fecal bifidobacteria and infants' fecal bifidobacteria.
  
  
  METHODS
  Sixty-one mother-infant pairs were included, special emphasis being placed on the maternal allergic status. Bifidobacteria were analysed by a direct PCR method in fecal samples from mothers at 30-35 weeks of gestation and from infants at 1 month of age and from breast-milk samples 1 month post-partum.
  
  
  RESULTS
  Fecal Bifidobacterium adolescentis and Bifidobacterium bifidum colonization frequencies and counts among mother-infant pairs correlated significantly (P=0.005 and 0.02 for frequencies, respectively, and P=0.002 and 0.01 for counts, respectively). Only infants of allergic, atopic mothers were colonized with B. adolescentis. Each of the breast-milk samples contained bifidobacteria [median 1.4 x 10(3) bacterial cells/mL; interquartile range (IQR) 48.7-3.8 x 10(3)]. Bifidobacterium longum was the most frequently detected species in breast-milk. Allergic mothers had significantly lower amounts of bifidobacteria in breast-milk compared with non-allergic mothers [median 1.3 x 10(3) bacterial cells/mL (IQR 22.4-3.0 x 10(3)) vs. 5.6 x 10(3) bacterial cells/mL (1.8 x 10(3)-1.8 x 10(4)), respectively, (P=0.004)], and their infants had concurrently lower counts of bifidobacteria in feces [3.9 x 10(8) bacterial cells/g (IQR 6.5 x 10(6)-1.5 x 10(9)) in infants of allergic mothers, vs. 2.5 x 10(9) bacterial cells/g (6.5 x 10(8)-3.2 x 10(10)) in infants of non-allergic mothers, P=0.013].
  
  
  CONCLUSIONS
  Breast-milk contains significant numbers of bifidobacteria and the maternal allergic status further deranges the counts of bifidobacteria in breast-milk. Maternal fecal and breast-milk bifidobacterial counts impacted on the infants' fecal Bifidobacterium levels. Breast-milk bacteria should thus be considered an important source of bacteria in the establishment of infantile intestinal microbiota.
authors.affiliation: Department of Pediatrics, Turku University Central Hospital, Turku, Finland. mingro@utu.fi
authors.forename: M-M
authors.initials: MM
authors.lastname: Grönlund
authors.forename: M
authors.initials: M
authors.lastname: Gueimonde
authors.forename: K
authors.initials: K
authors.lastname: Laitinen
authors.forename: G
authors.initials: G
authors.lastname: Kociubinski
authors.forename: T
authors.initials: T
authors.lastname: Grönroos
authors.forename: S
authors.initials: S
authors.lastname: Salminen
authors.forename: E
authors.initials: E
authors.lastname: Isolauri
mesh_terms: D039941:Bifidobacteriales Infections / Q000382:microbiology / Q000635:transmission; D001644:Bifidobacterium / Q000502:physiology*; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology / Q000382:microbiology*; D007223:Infant; D007231:Infant, Newborn; D007422:Intestines / Q000382:microbiology*; D008895:Milk, Human / Q000382:microbiology*; D009035:Mothers; D012307:Risk Factors