title: The impact of breastfeeding on nasopharyngeal microbial communities in infants.
abstract: BACKGROUND
  Breastfeeding elicits significant protection against respiratory tract infections in infancy. Modulation of respiratory microbiota might be part of the natural mechanisms of protection against respiratory diseases induced by breastfeeding.
  
  
  OBJECTIVE
  To study the association between breastfeeding and nasopharyngeal microbial communities, including all cultivable and noncultivable bacteria.
  
  
  METHODS
  In this observational study, we analyzed the microbiota of infants that had received exclusive breastfeeding (n = 101) and exclusive formula feeding (n = 101) at age 6 weeks and 6 months by 16S-based GS-FLX-titanium-pyrosequencing.
  
  
  RESULTS
  At 6 weeks of age the overall bacterial community composition was significantly different between breastfed and formula-fed children (nonmetric multidimensional scaling, P = 0.001). Breastfed children showed increased presence and abundance of the lactic acid bacterium Dolosigranulum (relative effect size [RES], 2.61; P = 0.005) and Corynebacterium (RES, 1.98; P = 0.039) and decreased abundance of Staphylococcus (RES, 0.48; P 0.03) and anaerobic bacteria, such as Prevotella (RES, 0.25; P < 0.001) and Veillonella (RES, 0.33; P < 0.001). Predominance (>50% of the microbial profile) of Corynebacterium and Dolosigranulum was observed in 45 (44.6%) breastfed infants compared with 19 (18.8%) formula-fed infants (relative risk, 2.37; P = 0.006). Dolosigranulum abundance was inversely associated with consecutive symptoms of wheezing and number of mild respiratory tract infections experienced. At 6 months of age associations between breastfeeding and nasopharyngeal microbiota composition had disappeared.
  
  
  CONCLUSIONS
  Our data suggest a strong association between breastfeeding and microbial community composition in the upper respiratory tract of 6-week-old infants. Observed differences in microbial community profile may contribute to the protective effect of breastfeeding on respiratory infections and wheezing in early infancy. Clinical trial registered with www.clinicaltrials.gov (NCT 00189020).
authors.affiliation: 1 Department of Pediatric Immunology and Infectious Diseases, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Giske
authors.initials: G
authors.lastname: Biesbroek
authors.forename: Astrid A T M
authors.initials: AA
authors.lastname: Bosch
authors.forename: Xinhui
authors.initials: X
authors.lastname: Wang
authors.forename: Bart J F
authors.initials: BJ
authors.lastname: Keijser
authors.forename: Reinier H
authors.initials: RH
authors.lastname: Veenhoven
authors.forename: Elisabeth A M
authors.initials: EA
authors.lastname: Sanders
authors.forename: Debby
authors.initials: D
authors.lastname: Bogaert
mesh_terms: D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D001903:Bottle Feeding; D001942:Breast Feeding; D041943:Infant Formula; D064307:Microbiota / Q000276:immunology; D008895:Milk, Human / Q000276:immunology / Q000382:microbiology; D009305:Nasopharynx / Q000276:immunology / Q000382:microbiology; D009426:Netherlands; D012141:Respiratory Tract Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control
keywords: breastfeeding; infants; microbial communities; microbiota; respiratory tract