AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Decay of Single and Clusters of Bacillus Anthracis Sterne Spores Exposed to UV-C and Solar Light
JANA KESAVAN, Daniel Mcgrady, Jerry Cabalo, Aime Goad, US ARMY CCDC CBC
Abstract Number: 512 Working Group: Bioaerosols
Abstract It is important to study the fate of bacteria in the environment as intentionally and unintentionally released bacteria can affect the general public, first responders, and soldiers. Bacterial spores are released in the environment as single spores and as various size clusters. Spores intentionally released from commercial sprayers or other devices will result in large particles containing multiple spores which dry down to form spore clusters. In these larger clusters, the outer layers of bacteria may protect organisms in the center from UV exposures. This study was conducted to evaluate whether single spores and clusters are affected differently when they are exposed to UV-C and solar light. Single spores were deposited on to polycarbonate membrane filters using a Sono-Tek aerosol generator and by pipetting solutions onto filters. Bacteria clusters (2.5 and 4 micron) were generated and deposited onto polycarbonate membrane filters using an ink jet aerosol generator. After exposure of the organisms to UV-C or solar light for varying lengths of time, the particles were extracted from filters and cultured. Percent kill was determined by comparing the number of culturable organisms in the exposed samples to the unexposed control samples. The results indicate that the culturable fraction decreased with increased exposure for both UV-C and solar exposure. UV-C exposure results indicate that the 4 micron particles decayed slower compared to the smaller size clusters and single spores as a result of the protection from the outer layers of particles. On the other hand, solar simulator exposure indicates that all three size particles have similar decay curves. These results agree with the mathematical predictions conducted by our collaborators.