You are here:
Fate of Bacillus spores during indoor surface cleaning activities
Citation:
Thornburg, J., A. Dart, E. Dowell, M. Gray, J. Archer, W. Calfee, R. Yaga, W. Schoppman, AND B. Thomas. Fate of Bacillus spores during indoor surface cleaning activities. American Association for Aerosol Research (AAAR) 40th Annual Conference, Raleigh, NC, October 03 - 07, 2022.
Impact/Purpose:
This research performed an initial assessment on the efficacy of “low technology” surface cleaning methods for the inactivation and/or removal of spores from indoor surfaces with materials and chemicals readily available to the public that could minimize resuspension and overall exposure risk. Quantitative experimental data could be easily translated into qualitative, graphical guidance that the public could understand and implement when undertaking the cleaning of their homes themselves. Based on the COVID-19 response, it is likely the public would respond positively to guidance on how to use “low technology” surface cleaning techniques as risk reduction measures following a wide area biological agent release.
Description:
An outdoor, wide area release of a persistent biological agent has the potential to significantly disrupt society. An unexplored aspect of consequence management is the need to minimize risk from immediate and delayed exposure to low concentrations of a biological agent transported into the indoor environment. The possibility that “low technology” surface cleaning methods for the inactivation and/or removal of Bacillus anthracis (Ba) spores with materials and chemicals readily available to the public could minimize resuspension and overall exposure risk, requires focused research. We tested different combinations of cleaning materials, cleaning solutions, application methods, and cleaning force to cover a broad range of potential inhalation exposure risks via resuspension. Experiments were conducted on laminate flooring loaded with dry Bacillus thuringiensis var. kurstaki (Btk) spores inside a sealed glove box. Spores that were resuspended, those physically removed by the cleaning material, and those remaining on the surface were extracted from the sample, plated, incubated and enumerated. This led to the development of a risk minimization ratio, defined as the sum of the viable spores resuspended and remaining on the surface divided by the number collected by the cleaning material. This analysis determined a wet wipe with any type of cleaning liquid performed best at minimizing potential exposure from resuspension and surface contamination, a paper towel with bleach or dry was in the middle range, and a sponge dipped in bleach solution or dry was the worst at minimizing potential exposure.