title: Supercritical carbon dioxide and hydrogen peroxide cause mild changes in spore structures associated with high killing rate of Bacillus anthracis.
abstract: The present work examines chemical and structural response in B. anthracis spores killed by a mixture of supercritical carbon dioxide (SCCO(2)) and hydrogen peroxide (H(2)O(2)). Deactivation of 6-log of B. anthracis spores by SCCO(2)+H(2)O(2) was demonstrated, but changes in structure were observed in only a small portion of spores. Results from phase contrast microscopy proved that this treatment is mild and does not trigger germination-like changes. TEM imaging revealed mild damage in a portion of spores while the majority remained intact. Dipicolinic acid (DPA) analysis showed that <10% of the DPA was released from the spore core into the external milieu, further demonstrating only modest damage to the spores. Confocal fluorescent microscopy, assessing uptake of DNA-binding dyes, directly demonstrated compromise of the permeability barrier. However, the magnitude of uptake was small compared to spores that had been autoclaved. This work suggests that SCCO(2)+H(2)O(2) is quite mild compared to other sterilization methods, which has major implications in its application. These results provide some insight on the possible interactions between spores and the SCCO(2)+H(2)O(2) sterilization process.
authors.affiliation: Department of Chemical Engineering, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Nishita
authors.initials: N
authors.lastname: Dalal
authors.forename: Michael A
authors.initials: MA
authors.lastname: Matthews
authors.forename: Lashanda N
authors.initials: LN
authors.lastname: Waller
authors.forename: Clint
authors.initials: C
authors.lastname: Saunders
authors.forename: Karen F
authors.initials: KF
authors.lastname: Fox
authors.forename: Alvin
authors.initials: A
authors.lastname: Fox
mesh_terms: D001408:Bacillus anthracis / Q000187:drug effects* / Q000502:physiology; D002245:Carbon Dioxide / Q000737:chemistry / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000737:chemistry / Q000494:pharmacology*; D046529:Microscopy, Electron, Transmission / Q000295:instrumentation / Q000379:methods; D008858:Microscopy, Phase-Contrast / Q000295:instrumentation / Q000379:methods; D010848:Picolinic Acids / Q000737:chemistry; D013171:Spores, Bacterial / Q000187:drug effects; D013242:Sterilization / Q000379:methods*
chemical_list: D010848:Picolinic Acids; D002245:Carbon Dioxide; D006861:Hydrogen Peroxide; C004860:dipicolinic acid