Bacterial Exposures and Associations with Atopy and Asthma in Children

Maria Valkonen (1, 2) , Inge M. Wouters (3) , Martin Täubel (1) , Helena Rintala (1) , Virissa Lenters (3) , Ritva Vasara (1) , Jon Genuneit (4) , Charlotte Braun-Fahrländer (5) , Renaud Piarroux (6) , Erika von Mutius (7) , Dick Heederik (3) , Anne Hyvärinen (1)

1 Department of Health Protection
2 Department of Environmental Science
3 Division of Environmental Epidemiology
4 Institute of Epidemiology
5 Unibas - Université de Bâle = University of Basel = Basel Universität
6 IP-TPT - Infections Parasitaires : Transmission, Physiopathologie et Thérapeutiques
7 LMU - Ludwig-Maximilians University [Munich]

Background :The increase in prevalence of asthma and atopic diseases in Western countries has been linked to aspects of microbial exposure patterns of people. It remains unclear which microbial aspects contribute to the protective farm effect. Objective :The objective of this study was to identify bacterial groups associated with prevalence of asthma and atopy, and to quantify indoor exposure to some of these bacterial groups. Methods :A DNA fingerprinting technique, denaturing gradient gel electrophoresis (DGGE), was applied to mattress dust samples of farm children and control children in the context of the GABRIEL Advanced study. Associations between signals in DGGE and atopy, asthma and other allergic health outcomes were analyzed. Quantitative DNA based assays (qPCR) for four bacterial groups were applied on the dust samples to seek quantitative confirmation of associations indicated in DNA fingerprinting. Results :Several statistically significant associations between individual bacterial signals and also bacterial diversity in DGGE and health outcomes in children were observed. The majority of these associations showed inverse relationships with atopy, less so with asthma. Also, in a subsequent confirmation study using a quantitative method (qPCR), higher mattress levels of specifically targeted bacterial groups - Mycobacterium spp., Bifidobacteriaceae spp. and two different clusters of Clostridium spp. - were associated with a lower prevalence of atopy. Conclusion :DNA fingerprinting proved useful in identifying bacterial signals that were associated with atopy in particular. These findings were quantitatively confirmed for selected bacterial groups with a second method. High correlations between the different bacterial exposures impede a clear attribution of protective effects to one specific bacterial group. More diverse bacterial flora in mattress dust may link to microbial exposure patterns that protect against development of atopic diseases.

Mots clés: GRADIENT GEL-ELECTROPHORESIS; 16S RIBOSOMAL-RNA; IN-HOUSE DUST; CHILDHOOD ASTHMA; EARLY-LIFE; ALLERGY; DIVERSITY; WHEEZE; ENVIRONMENTS; PREVALENCE

Domaines: Sciences du Vivant [q-bio]; Bactériologie

Maria Valkonen, Inge M. Wouters, Martin Täubel, Helena Rintala, Virissa Lenters, et al.. Bacterial Exposures and Associations with Atopy and Asthma in Children. PLoS ONE, 2015, pp.1-14. ⟨10.1371/journal.pone.0131594⟩. ⟨hal-01201792⟩