10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Exposure Assessment by Measuring Microbial DNA in House Dust using digital Polymerase Chain Reaction (dPCR)
ASHLEIGH BOPE, Samuel Cochran, David Kormos, Karen C. Dannemiller, Ohio State University
Abstract Number: 1648 Working Group: Indoor Aerosols
Abstract We spend 90% of our time indoors where we are exposed to diverse microbial communities. Much of this exposure results from house dust, which is resuspended from the floor due to occupant motion. This exposure may be assessed using quantitative Polymerase Chain Reaction (qPCR) using primers to specific microbial species of interest. Here, we explore the use of a new technology, digital Polymerase Chain Reaction (dPCR), as an advancement for measurement of this microbial DNA. Benefits of dPCR over qPCR include that it is less prone to inhibition and provides results in number of strands of DNA measured, potentially reducing the need for standards. To test measurement accuracy, we spiked known concentrations of Aspergillus fumigatus, Escherichia coli and Bacillus atrophaeus into carpet, vacuumed the dust, extracted DNA, and measured the quantity with dPCR. We determined that DNA was lost at each stage of the process, including vacuuming and DNA extraction. For instance, for A. fumigatus, 5% of DNA was lost in vacuuming from low pile carpet and 44% of DNA was lost in vacuuming from medium pile carpet. An additional 70% of DNA may be lost during DNA extraction. DNA extraction losses may be accounted for in qPCR through the use of appropriate standard, but could potentially be overlooked during dPCR. These results demonstrate the need to account for recovery efficiencies when using dPCR to measure microbial exposure from dust, or final results may be grossly underestimated.