Comparison of Bacillus Anthracis to the Surrogate Bacillus Atrophaeus for Spore Inactivation on a Novel Antimicrobial Fabric
Abstract
Military fabric amended with an antimicrobial compound may reduce the viability of biological threat agents that could be encountered in contaminated environments. Bacillus atrophaeus (formerly Baclllus sub tills var. niger) is typically employed in the evaluation of antimicrobial compounds and has been reported to be less susceptible to disinfection than Baclllus anthracis, and thus is commonly used as a surrogate whenever direct evaluation with B. anthracis may not be feasible. In this study, a direct comparison of the sporicidal activity of a novel antimicrobial fabric was evaluated for B. anthracis and the surrogate B. atrophaeus. Fabric amended with a chlorine-based compound and fabric minus this compound were inoculated with a liquid suspension of dormant spores of either B. anthracis or B. atrophaeus and incubated at 300C for one hour at relative humilities ranging from 60 to greater than 90 percent relative humidity (RH). Spores were eluted from their respective fabrics and enumerated by direct microscopic count. The number of viable spores was determined by cultivation on Nutrient Agar and the percent of cultivable spores were calculated as the ratio of cultivable spores to total spores as a function of exposure time. Cultivability of B. anthracis spores on fabric amended with the antimicrobial compound decreased significantly with an increase in the percent of relative humidity (R2 = 0.97) with approximately five logarithms (5.5 i 0.4) in reduction at 90 percent RH. Baclllus atrophaeus spores were not correlated with the percent RH (R2 = 0.31) and only experienced about a one logarithm reduction (0.9 i 0.3) in cultivability at 90 percent RH. Additionally, spores eluted fiom control fabric with no antimicrobial maintained cultivability under the same exposure conditions.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2006
- Accession Number
- ADA457831
Entities
People
- Christopher C. Thornburg
- Jon J. Calomiris
Organizations
- Henry M. Jackson Foundation for the Advancement of Military Medicine