Combining Spore Germination And Heat Inactivation To Decontaminate Materials Contaminated With Bacillus Anthracis Spores

Aims: To add a spore germination step in order to reduce decontamination temperature and time requirements compared to the current hot, humid air decontamination parameters, which are 75-80 degrees C, >= 72 h, 70-90% RH, down to <= 60 degrees C and <= 24 h total decontamination time.Methods and Results: Bacillus anthracis spore germination with L-alanine+inosine+calcium dipicolinate (CaDPA) was quantified at 0-40 degrees C, several time points and spore concentrations of 5-9 log(10) per ml. Germination efficiency at 0-40 degrees C was >99% at <8 log(10) spores per ml. The temperature optimum was 20 degrees C. Germination efficiency was significantly higher but slower at 0 degrees C compared to >= 30 degrees C at >= 8 log(10) spores per ml. A single germinant application followed by 60 degrees C, 1-h treatment consistently inactivated >2 log(10) (>99%) of spores. However, a repeat application of germinant was needed to achieve the objective of >= 6 log10 spore inactivation out of a 7 log(10) challenge (>= 99.9999%) for <= 24 h total decontamination time for nylon and aircraft performance coating.Conclusions: L-alanine+inosine+CaDPA stimulated germination across wide temperature and spore concentration ranges.Significance and Impact of the Study: Germination expands the scope of spore decontamination to include materials from any industry sector that can be sprayed with an aqueous germinant solution.