Home Dust Microbiota is Disordered in Homes of Asthmatic Children

BACKGROUND:  Exposure to microorganisms has repeatedly been found to influence the development of atopic diseases, such as asthma.  This relationship has been best understood as an inverse correlation between microbial diversity and atopic disease.  The aim of this study was to determine if the home microbiome of asthmatics differs from that of healthy children by utilizing 16S rRNA based phylogenetic analysis by microarray technology.

METHODS:  This cross-sectional study utilized dust samples collected as part of the Kansas City Safe and Healthy Homes Program.  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:  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 of homes (p=0.025).  All of the top 12 OTUs with significant abundance differences were increased in homes of asthmatic children and belonged to one of the five phyla (p=0.001 to p=7.2 x 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.