Rapid Determination of Endospore Viability by Hyperspectral Reflectance Following Surface Decontamination

Abstract : Bacterial spores, or endospores, such as those of Bacillus anthracis, are an asymmetrical threat. Decontamination following endospore release is costly and can be difficult and slow to confirm. Part of the constraint is because rapid and accurate means to differentiate live (viable) from dead (non-viable) bacterial endospores are lacking. Endospores have minimal metabolic activity and withstand many sterilization techniques, yet they can germinate and grow rapidly in favorable conditions, increasing the likelihood of disease. In scenarios such as post-infrastructure decontamination, a rapid and quantitative assessment of endospore viability is prerequisite to establishing health risks. Current and accepted methods for determining endospore viability require culturing, which takes several days. Scatter and depolarization signatures from polarized laser sources and micro- and nano-sensors show promise as a means of optically confirming endospore presence, but have not been shown to have the ability to distinguish viable from non-viable endospores. In the laboratory, we have exploited the oxidative alteration of the spore coat caused by decontamination solutions and used hyperspectral reflectance and appropriate post-processing to differentiate viable from non-viable endospores following endospore decontamination by oxidants.