Household environmental characteristics influence the house dust metagenome

Environmental exposures can shape microbial community compositions inside homes. Metagenomic sequencing methods can further elucidate the role of household exposures like indoor moisture and the surrounding landscape. To identify household environmental exposures associated with the house dust metagenome. Microbial communities in vacuumed dust from 771 homes in the Agricultural Lung Health Study were characterized using whole metagenome shotgun sequencing (5821 taxa across 45 phyla). Household characteristics (i.e. presence of leaks, de-humidifier, humidifier use) were assessed by questionnaires or field technicians. We evaluated associations between exposures and both overall microbial diversity and differentially abundant taxa (ANCOM-BC2). Additionally, we explored microbial networks based on Spearman correlations (SECOM). Microbial diversity was higher in homes with mold/mildew (p-value<0.05), leaks, humidifier use, or occupants removing shoes before entering (p-value<0.1). Examining individual species, <10 taxa were significantly differentially abundant (p-value<0.05 after Holm-Bonferroni correction) in relation to both mold/mildew and leaks. Greater than 10 species were significantly differentially abundant in relation to removing shoes and humidifier use. Additionally, the genera Clostridium, Prevotella, and Cryptobacteroides were positively associated with removing shoes. In this farming population, the house dust microbiome differed by moisture-related exposures, and removing shoes before entering the home. Many novel associations were identified between individual taxa and these exposures. Our findings further knowledge of the impact of environmental conditions inside the home on the indoor microbiome.