Review of Decontamination Techniques for the Inactivation of Bacillus anthracis and Other Spore-Forming Bacteria Associated with Building or Outdoor Materials
Abstract:Since the intentional release of Bacillus anthracis spores through the U.S. Postal Service in the fall of 2001, research and development related to decontamination for this biological agent have increased substantially. This review synthesizes the advances made relative to B. anthracis spore decontamination science and technology since approximately 2002, referencing the open scientific literature and publicly available, well-documented scientific reports. In the process of conducting this review, scientific k… Show more
“…But when accounting for material interactions in the model, the species does have a significant effect (p <0.0001). This observed similarity or increase in resistance of B. subtilis to ozone gas as compared to B. anthracis is consistent with the literature in which the resistance of B. subtilis or B. atrophaeus is comparable to B. anthracis with the use of several other decontaminants [3]. We believe our study is the first to make the direct comparison between the two species relative to their resistance to ozone gas inactivation and supports the use of B. subtilis as a surrogate for B. anthracis for this decontaminant.…”
Section: Plos Onesupporting
confidence: 91%
“…Postal Service [2]. Since this 2001 attack, a large body of research and development has been undertaken to evaluate decontamination techniques for this bioterrorism agent, and is reviewed here [3]. The present study builds on that research and supports the National Biodefense Strategy by verifying the efficacy of ozone gas as a decontaminant for inactivating B. anthracis spores deposited on various types of building materials.…”
Section: Introductionmentioning
confidence: 91%
“…Generally, inorganic, nonporous materials such as glass, laminate, or galvanized metal are typically easier to effectively decontaminate compared to porous and organic materials such as carpet and wood, especially when using oxidation-based sporicides such as ozone. [3] The observation that B. anthracis spores were relatively more difficult to inactivate with ozone gas on glass, galvanized metal and laminate indicates the possibility of a different inactivation mechanism involved. Ozone gas is known to react with organic matter to produce ROS (which may include hydroxyl and peroxyl radicals, and peroxides [34][35][36]), and these ROS may be sporicidal themselves.…”
Section: Plos Onementioning
confidence: 99%
“…Other research groups [12,15,16] have corroborated the finding that increasing RH levels (> 80%) improves efficacy with ozone gas. Indeed, a higher RH during fumigation with other gases [3] or with hot air [17][18][19][20] is usually associated with improved decontamination efficacy for B. anthracis spores.…”
A study was conducted to assess the efficacy of ozone gas in inactivating spores of both Bacillus anthracis and Bacillus subtilis inoculated onto six building materials (glass, wood, carpet, laminate, galvanized metal, and wallboard paper). Testing conditions consisted of ozone gas concentrations ranging from 7,000-12,000 parts per million (ppm), contact times from 4 to 12 h, and two relative humidity (RH) levels of 75 and 85%. Results showed that increasing the ozone concentration, contact time, and RH generally increased decontamination efficacy. The materials in which the highest decontamination efficacy was achieved for B. anthracis spores were wallboard paper, carpet, and wood with � 6 log 10 reduction (LR) occurring with 9,800 ppm ozone, 85% RH, for 6 h. The laminate and galvanized metal materials were generally more difficult to decontaminate, requiring 12,000 ppm ozone, 85% RH, and 9-12 h contact time to achieve �6 LR of B. anthracis. Lastly, overall, there were no significant differences in decontamination efficacy between the two species.
“…But when accounting for material interactions in the model, the species does have a significant effect (p <0.0001). This observed similarity or increase in resistance of B. subtilis to ozone gas as compared to B. anthracis is consistent with the literature in which the resistance of B. subtilis or B. atrophaeus is comparable to B. anthracis with the use of several other decontaminants [3]. We believe our study is the first to make the direct comparison between the two species relative to their resistance to ozone gas inactivation and supports the use of B. subtilis as a surrogate for B. anthracis for this decontaminant.…”
Section: Plos Onesupporting
confidence: 91%
“…Postal Service [2]. Since this 2001 attack, a large body of research and development has been undertaken to evaluate decontamination techniques for this bioterrorism agent, and is reviewed here [3]. The present study builds on that research and supports the National Biodefense Strategy by verifying the efficacy of ozone gas as a decontaminant for inactivating B. anthracis spores deposited on various types of building materials.…”
Section: Introductionmentioning
confidence: 91%
“…Generally, inorganic, nonporous materials such as glass, laminate, or galvanized metal are typically easier to effectively decontaminate compared to porous and organic materials such as carpet and wood, especially when using oxidation-based sporicides such as ozone. [3] The observation that B. anthracis spores were relatively more difficult to inactivate with ozone gas on glass, galvanized metal and laminate indicates the possibility of a different inactivation mechanism involved. Ozone gas is known to react with organic matter to produce ROS (which may include hydroxyl and peroxyl radicals, and peroxides [34][35][36]), and these ROS may be sporicidal themselves.…”
Section: Plos Onementioning
confidence: 99%
“…Other research groups [12,15,16] have corroborated the finding that increasing RH levels (> 80%) improves efficacy with ozone gas. Indeed, a higher RH during fumigation with other gases [3] or with hot air [17][18][19][20] is usually associated with improved decontamination efficacy for B. anthracis spores.…”
A study was conducted to assess the efficacy of ozone gas in inactivating spores of both Bacillus anthracis and Bacillus subtilis inoculated onto six building materials (glass, wood, carpet, laminate, galvanized metal, and wallboard paper). Testing conditions consisted of ozone gas concentrations ranging from 7,000-12,000 parts per million (ppm), contact times from 4 to 12 h, and two relative humidity (RH) levels of 75 and 85%. Results showed that increasing the ozone concentration, contact time, and RH generally increased decontamination efficacy. The materials in which the highest decontamination efficacy was achieved for B. anthracis spores were wallboard paper, carpet, and wood with � 6 log 10 reduction (LR) occurring with 9,800 ppm ozone, 85% RH, for 6 h. The laminate and galvanized metal materials were generally more difficult to decontaminate, requiring 12,000 ppm ozone, 85% RH, and 9-12 h contact time to achieve �6 LR of B. anthracis. Lastly, overall, there were no significant differences in decontamination efficacy between the two species.
“…of spores of some species to cause food spoilage and human disease (1)(2)(3). Because of these spore properties, there is continuing interest in methods to inactivate spores in a safe manner while minimizing damage to either the environment or materials with which spores are associated (4)(5)(6). The need for such decontamination methods is further exacerbated by the increased prevalence of antibiotic-resistant bacteria as well as the potential use of spores of some strains of Bacillus anthracis as agents of bioterrorism or biowarfare.…”
This study examined the microbicidal activity of 222-nm UV radiation (UV222), which is potentially a safer alternative to the 254-nm UV radiation (UV254) that is often used for surface decontamination. Spores and/or growing and stationary-phase cells of Bacillus cereus, Bacillus subtilis, Bacillus thuringiensis, Staphylococcus aureus, and Clostridioides difficile and a herpesvirus were all killed or inactivated by UV222 and at lower fluences than with UV254. B. subtilis spores and cells lacking the major DNA repair protein RecA were more sensitive to UV222, as were spores lacking their DNA-protective proteins, the α/β-type small, acid-soluble spore proteins. The spore cores’ large amount of Ca2+-dipicolinic acid (∼25% of the core dry weight) also protected B. subtilis and C. difficile spores against UV222, while spores’ proteinaceous coat may have given some slight protection against UV222. Survivors among B. subtilis spores treated with UV222 acquired a large number of mutations, and this radiation generated known mutagenic photoproducts in spore and cell DNA, primarily cyclobutane-type pyrimidine dimers in growing cells and an α-thyminyl-thymine adduct termed the spore photoproduct (SP) in spores. Notably, the loss of a key SP repair protein markedly decreased spore UV222 resistance. UV222-treated B. subtilis spores germinated relatively normally, and the generation of colonies from these germinated spores was not salt sensitive. The latter two findings suggest that UV222 does not kill spores by general protein damage, and thus, the new results are consistent with the notion that DNA damage is responsible for the killing of spores and cells by UV222.
IMPORTANCE Spores of a variety of bacteria are resistant to common decontamination agents, and many of them are major causes of food spoilage and some serious human diseases, including anthrax caused by spores of Bacillus anthracis. Consequently, there is an ongoing need for efficient methods for spore eradication, in particular methods that have minimal deleterious effects on people or the environment. UV radiation at 254 nm (UV254) is sporicidal and commonly used for surface decontamination but can cause deleterious effects in humans. Recent work, however, suggests that 222-nm UV (UV222) may be less harmful to people than UV254 yet may still kill bacteria and at lower fluences than UV254. The present work has identified the damage by UV222 that leads to the killing of growing cells and spores of some bacteria, many of which are human pathogens, and UV222 also inactivates a herpesvirus.
Some bacterial species enter a dormant state in the form of spores to resist to unfavorable external conditions. Spores are resistant to a wide series of stress agents, including UV radiation, and can last for tens to hundreds of years. Due to the suspension of biological functions, such as DNA repair, they accumulate DNA damage upon exposure to UV radiation. Differently from active organisms, the most common DNA photoproducts in spores are not cyclobutane pyrimidine dimers, but rather the so‐called spore photoproducts. This noncanonical photochemistry results from the dry state of DNA and its binding to small, acid‐soluble proteins that drastically modify the structure and photoreactivity of the nucleic acid. Herein, multiscale molecular dynamics simulations, including extended classical molecular dynamics and quantum mechanics/molecular mechanics based dynamics, are used to elucidate the coupling of electronic and structural factors that lead to this photochemical outcome. In particular, the well‐described impact of the peculiar DNA environment found in spores on the favored formation of the spore photoproduct, given the small free energy barrier found for this path, is rationalized. Meanwhile, the specific organization of spore DNA precludes the photochemical path that leads to cyclobutane pyrimidine dimer formation.
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