Home dust microbiota is disordered in homes of low-income asthmatic children

Abstract

OBJECTIVE Exposure to microorganisms has repeatedly been found to influence development of atopic diseases, such as asthma. Innovative techniques have been developed that can comprehensively characterize microbial communities. The objective of this study was to characterize the home microbiota of asthmatic children utilizing 16S rRNA based phylogenetic analysis by microarray. METHODS In this cross-sectional study DNA was extracted from home dust and bacterial 16S rRNA genes amplified. Bacterial products were hybridized to the PhyloChip Array and scanned using a GeneArray scanner. The Adonis test was used to determine significant differences in the whole microbiome. Welch’s t-test was used to determine significant abundance differences and genus-level richness differences. RESULTS Nineteen homes were included in the analysis (14 asthma, 5 no asthma). 1741 operational taxonomic units (OTUs) were found in at least one sample. Bacterial genus richness did not differ in the homes of asthmatics and non-asthmatics (p=0.09). The microbial profile was significantly different between the two groups (p=0.025). All of the top 12 OTUs with significant abundance differences were increased in homes of asthmatics and belonged to one of the five phyla (p=0.001 to p=7.2 × 10−6). Nearly half of significant abundance differences belonged to the phylum Cyanobacteria or Proteobacteria. CONCLUSIONS These results suggest that home dust has a characteristic microbiota which is disturbed in the homes of asthmatics, resulting in a particular abundance of Cyanobacteria and Proteobacteria. Further investigations are needed which utilize high throughput technology to further clarify how home microbial exposures influence human health and disease.

Building upon current knowledge and techniques of indoor microbiology to construct the next era of theory into microorganisms, health, and the built environment

“…Despite the differences in outcome, both studies concluded that the overall community was significantly altered. In addition to reports of decreased abundance of members of the phyla Firmicutes and Bacteroidetes in homes with children who suffer from wheezing or atopy [201], members of the phyla Cyanobacteria and Proteobacteria were increased in asthmatic homes [200]. Many human pathobionts, microorganisms capable of pathogenicity but not inherently infectious [202], belong to the Proteobacteria phylum.…”

“…Different indoor bacterial communities are commonly reported in the homes of dermal or asthmatic atopy or nonatopic asthma sufferers [56,200] in comparison with otherwise healthy homes. One study found the urban homes of young children with atopic dermatitis or wheezing had lower bacterial richness than homes with healthy children [201] while another study found there was no difference in bacterial richness of asthmatic vs. nonasthmatic homes [200]. Despite the differences in outcome, both studies concluded that the overall community was significantly altered.…”

Contributions of the intestinal microbiome in lung immunity

“…Asthma was inversely related to bacterial species in mattress dust and to a lower extent in nasal samples , suggesting that inhalation of bacteria that do not colonize nasal passages contribute to airway inflammation. Another study found that Cyanobacteria and Proteobacteria were abundant in dust from the homes of patients with asthma . Although this does not demonstrate a cause‐effect relationship, the data suggest environmental triggers may contribute to the initiation or development of asthma in susceptible individuals.…”

Indoor microbiota in severely moisture damaged homes and the impact of interventions

“…High throughput sequencing approaches have been applied to indoor environments to improve our understanding of the microbial ecology in buildings and to ultimately assess health implications of exposure to the indoor microbiome. Only few of these sequencing studies have addressed at least to some extent the effect of moisture damage and indoor dampness on indoor microbiota [ 12 , 30 – 35 ], and to date there are no clear patterns of microbial response to water damage.…”