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Comparison of Sampling Methods for an Extended Duration Outdoor Biological Study Presentation
Citation:
Mikelonis, A., W. Calfee, K. Ratliff, L. Mickelsen, S. Serre, S. Taft, D. Aslett, A. Abdel-Hady, AND A. Touati. Comparison of Sampling Methods for an Extended Duration Outdoor Biological Study Presentation. EPA International Decontamination Research and Development Conference, Norfolk, Virginia, November 19 - 21, 2019.
Impact/Purpose:
The environmental issue discussed in this presentation is sampling for biological agent contamination after a terrorist attack. The work presented is a comparative sampling study of 5 different methods on outdoor surfaces over 6 months. The data is important for emergency responders to be able to efficiently characterize a site.
Description:
Following a bioterrorist attack, materials contaminated with a biological agent pose significant health threats. A six-month outdoor sampling study was conducted using Bacillus globigii (Bg) to compare the spore recovery of traditional vs. emerging sampling methods over time. Bg is a surrogate for the Center for Disease Control (CDC) select agent Bacillus anthracis, the causative agent for anthrax. Traditional sampling methods included sponge wipes, grab samples, and vacuum sampling with 37 mm cassettes and emerging sampling methods included commercially available wet vacuums and automated robotic floor vacuums. An asphalt and a concrete parking lot (each area approximately 800 ft2) were gridded and inoculated with 106 CFU/ft2 as well as adjacent areas of soil, grass, and leaves. Samples were collected in triplicate at 1, 4, 37, 99, and 210 days after inoculation. For all sampling methods, higher spore recoveries were observed for concrete vs. asphalt samples. Only the emerging methods (wet vacuums and robots) recovered spores at 99 and 210 days for asphalt whereas all methods recovered spores at 99 days and wet vacuums, robots, and 37 mm vacuums recovered spores at 210 days for concrete samples. Spores were recovered from the grass, leaves, and soil grab samples up until the 37-day point, but only soil samples had recoverable spores past this point (at 99 days only). Methods for collecting and processing the samples as well as a statistical analysis of the results will be discussed in this presentation.