Researchers determine the most effective means of collecting bioterror evidence

Researchers from the National Institute of Standards and Technology have completed a study on the best methods of collecting bioterror evidence after an attack or biohazard event.

The study illustrates the different methods for collecting, extracting and quantifying microbial spores to determine the most efficient method.

Different collection methods have been used in cleanup efforts following bioterrorist attack or biohazard contamination. The study found that polyester-rayon wipes in the field followed by saline-surfactant extraction and vortexing was close to 10 times more effective at recovering spores than the worst method.

"A comprehensive look at the impact of protocol variables affecting the performance of spore recovery—especially when dealing with serious threats such as anthrax—is an important national homeland security priority," Sandra Da Silva, the lead researcher on the study, said. "In this study, we used Bacillus anthracis (Sterne), a vaccine strain, as a surrogate for Bacillus anthracis (Ames), the causative agent of the anthrax disease, in order to learn how to improve the low efficiency of current protocols."

The researchers used multiple types of wipe materials, types of extraction solutions and several methods to loosen the spores from the wipe after collection. The researchers found polyester-rayon to be the most efficient material for spore collection, which they said was due to the chemistry and structure of the fibers.

A surfactant-based extraction solution worked most effectively at removing spores from the wipes and getting them into the solution, which the researchers said was a result of the detergent-like character of the surfactants to loosen the bond between the spores and wipe surface. Vortexing, or mixing by rapid spinning, removed more spores than applying the force of sound waves.

The findings from the study will be used to develop an ASTM protocol for the sampling of bacterial surfaces. Another study is being conducted with microbes like Bacillus cereus and Burkholderia thailandensis that are more sensitive to environmental conditions.