Combining spore germination and heat inactivation to decontaminate materials contaminated with Bacillus anthracis spores

• Published in: Journal of applied microbiology 2020-01, Vol.128 (1), p.124-137
• Main Authors: Buhr, T.L., Minter, Z.A., Kennihan, N.L., Young, A.A., Borgers‐Klonkowski, E.L., Osborn, E.B., Bohmke, M.D., Hamilton, S.M., Kimani, M.B., Miller, C.T., Mackie, R.S., Innocenti, J.M., Bensman, M.D., Lilly, S.D.
• Format: Article
• Language: English
• Subjects: Air temperature; Aircraft industry; Aircraft performance; Alanine; Alanine - pharmacology; alanine racemase; Bacillus anthracis; Bacillus anthracis - drug effects; Bacillus anthracis - growth & development; Bacillus anthracis - physiology; Calcium; Deactivation; Decontamination; Decontamination - methods; Germination; germination inhibition; Heat inactivation; hot humid air; Hot Temperature; Inactivation; Inosine - pharmacology; inosine hydrolase; persister; Picolinic Acids - pharmacology; spore; Spore germination; Spores; Spores, Bacterial - drug effects; Spores, Bacterial - growth & development; Spores, Bacterial - physiology; surrogate; Temperature requirements; Time Factors
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.14474

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°C, ≥72 h, 70–90% RH, down to ≤60°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°C, several time points and spore concentrations of 5–9 log10 per ml. Germination efficiency at 0–40°C was >99% at 2 log10 (>99%) of spores. However, a repeat application of germinant was needed to achieve the objective of ≥6 log10 spore inactivation out of a 7 log10 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.