title: Bacterial microbiota of the upper respiratory tract and childhood asthma.
abstract: BACKGROUND
  Patients with asthma and healthy controls differ in bacterial colonization of the respiratory tract. The upper airways have been shown to reflect colonization of the lower airways, the actual site of inflammation in asthma, which is hardly accessible in population studies.
  
  
  OBJECTIVE
  We sought to characterize the bacterial communities at 2 sites of the upper respiratory tract obtained from children from a rural area and to relate these to asthma.
  
  
  METHODS
  The microbiota of 327 throat and 68 nasal samples from school-age farm and nonfarm children were analyzed by 454-pyrosequencing of the bacterial 16S ribosomal RNA gene.
  
  
  RESULTS
  Alterations in nasal microbiota but not of throat microbiota were associated with asthma. Children with asthma had lower α- and β-diversity of the nasal microbiota as compared with healthy control children. Furthermore, asthma presence was positively associated with a specific operational taxonomic unit from the genus Moraxella in children not exposed to farming, whereas in farm children Moraxella colonization was unrelated to asthma. In nonfarm children, Moraxella colonization explained the association between bacterial diversity and asthma to a large extent.
  
  
  CONCLUSIONS
  Asthma was mainly associated with an altered nasal microbiota characterized by lower diversity and Moraxella abundance. Children living on farms might not be susceptible to the disadvantageous effect of Moraxella. Prospective studies may clarify whether Moraxella outgrowth is a cause or a consequence of loss in diversity.
authors: Dr von Hauner Children's Hospital, LMU Munich, Munich, Germany. Electronic address: martin.depner@med.uni-muenchen.de.
authors: Martin
authors: M
authors: Depner
authors: Dr von Hauner Children's Hospital, LMU Munich, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany.
authors: Markus J
authors: MJ
authors: Ege
authors: National Heart & Lung Institute, Imperial College London, London, United Kingdom.
authors: Michael J
authors: MJ
authors: Cox
authors: National Heart & Lung Institute, Imperial College London, London, United Kingdom.
authors: Sarah
authors: S
authors: Dwyer
authors: Pathogen Genomics Group, Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom.
authors: Alan W
authors: AW
authors: Walker
authors: Dr von Hauner Children's Hospital, LMU Munich, Munich, Germany.
authors: Lena T
authors: LT
authors: Birzele
authors: Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany.
authors: Jon
authors: J
authors: Genuneit
authors: Division of Cardiology and Pulmonology, Department of Pediatrics and Adolescents, Innsbruck Medical University, Innsbruck, Austria.
authors: Elisabeth
authors: E
authors: Horak
authors: Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors: Charlotte
authors: C
authors: Braun-Fahrländer
authors: Department of Pediatrics, Allergology and Cardiology, Wroclaw Medical University, Wroclaw, Poland.
authors: Hanna
authors: H
authors: Danielewicz
authors: Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Ariz.
authors: Raina M
authors: RM
authors: Maier
authors: National Heart & Lung Institute, Imperial College London, London, United Kingdom.
authors: Miriam F
authors: MF
authors: Moffatt
authors: National Heart & Lung Institute, Imperial College London, London, United Kingdom.
authors: William O
authors: WO
authors: Cookson
authors: Institute for Risk Assessment Sciences, Division of Environmental Epidemiology, University of Utrecht, Utrecht, The Netherlands.
authors: Dick
authors: D
authors: Heederik
authors: Dr von Hauner Children's Hospital, LMU Munich, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany.
authors: Erika
authors: E
authors: von Mutius
authors: Dr von Hauner Children's Hospital, LMU Munich, Munich, Germany.
authors: Antje
authors: A
authors: Legatzki
mesh_terms: D001249:Asthma / Q000382:microbiology*; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D002648:Child; D004269:DNA, Bacterial / Q000235:genetics; D000072480:Farms; D005260:Female; D006801:Humans; D008297:Male; D064307:Microbiota; D009666:Nose / Q000382:microbiology*; D010614:Pharynx / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA gene; Asthma; childhood; microbiota; nose; throat; upper respiratory tract