Evaluation of tools for environmental sampling of Bacillus anthracis spores

This study describes the validation of sampling techniques used to detect biological warfare agents used in terror attacks. For this purpose, we tested the efficiencies of different sampling media and extraction solutions for the recovery of bacterial pathogens. We first used Bacillus cereus ATCC 4342 spores as a surrogate for highly pathogenic B. anthracis to compare recovery efficiencies of spores from four different surfaces. We used three different types of sampling swabs and four different solutions to extract spores from the swabs. The most effective sampling method employed rayon swabs moistened with water. The efficencies of the four extraction solutions did not differ significantly, although yields were highest using phosphate-buffered saline containing Tween 80 (PBS-T). Using rayon swabs and sterile water, we recovered B. cereus ATCC 4342 and B. anthracis spores with equivalent efficiencies. These findings indicate that because of its reduced pathogenicity and relative ease in handling (Biosafety Level 1), use of B. cereus ATCC 4342 will facilitate further optimization of techniques to detect B. anthracis.