Indoor Microbial Exposure Differences between Urban and Rural Homes in Central Texas

JUAN PEDRO MAESTRE, David Jarma, Evan Williams, Sharon Horner, Kerry Kinney, University of Texas at Austin

     Abstract Number: 501
     Working Group: Bioaerosols

Abstract
The indoor microbiome composition and structure is often a reflection of the outdoor microbiome in the case of fungi, which in turn is affected by global external factors such as latitude but also by more localized factors such as home conditions or the presence of outdoor vegetation, whereas is more a reflection of the human occupancy in the case of bacteria. The influences of urbanization and other localized features on the home mycobiome are still not fully understood. In this study, the fungal assemblages recovered from rural and urban homes in Central Texas were analysed to evaluate their relationship with features of their immediate surroundings and land cover characteristics.

Home information such as household materials, surrounding features, and occupants was collected with an online REDCap survey. Bacterial and fungal communities and semi-volatile organic compound (SVOC) concentrations found in indoor dust the dust were analyzed. Microbial DNA was extracted using the Applied Biosystems, MagMAX Microbiome Ultra Nucleic Acid Isolation Kit and the resultant bacterial and fungal DNA were analyzed, 16S and ITS, on the MiSeq genomic sequencing platform. SVOCs were analyzed with an Agilent GC-MS. The 2016 National Land Cover Data (NLCD) was used to categorize the type of land cover around each participant within a 0.5mi radius.

Findings to date suggest that the degree of development of the land surrounding the homes and the type of land cover could have an impact on the fungal and bacterial diversity inside homes as well as on the community structure. LEfSe analysis indicates that homes in the more developed areas were more enriched in human associated taxa whereas those in less developed areas were enriched with plant-associated taxa. The proximity to cultivation fields also seems to have an impact on the home microbiome diversity and structure. However, the proximity to higher vegetation was not found to have an impact on the diversity and structure of the home microbiome. Finally, the plasticizer DEHP was found to be relevant for the fungal community structure and composition. This study is ongoing, and the relationships between these factors and specific taxa are also being evaluated.