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What's new and notable in bacterial spore killing! World J Microbiol Biotechnol 2021; 37:144. [PMID: 34351499 PMCID: PMC8342367 DOI: 10.1007/s11274-021-03108-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/05/2021] [Indexed: 02/08/2023]
Abstract
Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called “germinate to eradicate” strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable.
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McEvoy B, Eveland R. Vaporized Hydrogen Peroxide: A Well-Known Technology with a New Application. Biomed Instrum Technol 2021; 54:74-79. [PMID: 34169978 DOI: 10.2345/0899-8205-54.s3.74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hydrogen peroxide has a multitude of uses and the vapor form was first identified as a sterilant in late 1970s. Following a number of developments, vaporized hydrogen peroxide (VHP) became widely adopted in early 90s as a substitute for ethylene oxide (EO) in device and instrument processing and reprocessing in healthcare facilities. Often VHP was hailed as the replacement technology for EO. Because of key limitations such as scale, penetration, and compatibility with packaging materials, adoption to terminal sterilization of single-use devices has not commenced to any significant level. However, recent developments in sterilization chamber design and process development provide new opportunity for consideration. For future products, such as those that require "end of production line sterilization," such limitations may be reconsidered and overcome. This article describes those challenges and how they have been addressed, with practical examples. The development of global consensus standards and leveraging the well-established knowledge of VHP sterilization with regard to microorganism inactivation and material compatibility will help facilitate wider consideration of VHP technology as a true alternative to EO in certain product applications.
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McEvoy B, Lynch M, Rowan NJ. Opportunities for the application of real-time bacterial cell analysis using flow cytometry for the advancement of sterilization microbiology. J Appl Microbiol 2020; 130:1794-1812. [PMID: 33155740 DOI: 10.1111/jam.14876] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/10/2020] [Accepted: 09/21/2020] [Indexed: 01/11/2023]
Abstract
Medical devices provide critical care and diagnostic applications through patient contact. Sterility assurance level (SAL) may be defined as the probability of a single viable micro-organism occurring on an item after a sterilization process. Sterilization microbiology often relies upon using an overkill validation method where a 12-log reduction in recalcitrant bacterial endospore population occurs during the process that exploits conventional laboratory-based culture media for enumeration. This timely review explores key assumptions underpinning use of conventional culture-based methods in sterilization microbiology. Consideration is given to how such methods may limit the ability to fully appreciate the inactivation kinetics of a sterilization process such as vaporized hydrogen peroxide (VH2O2) sterilization, and consequently design efficient sterilization processes. Specific use of the real-time flow cytometry (FCM) is described by way of elucidating the practical relevance of these limitation factors with implications and opportunities for the sterilization industry discussed. Application of FCM to address these culture-based limitation factors will inform real-time kinetic inactivation modelling and unlock potential to embrace emerging opportunities for pharma, medical device and sterilization industries including potentially disruptive applications that may involve reduced usage of sterilant.
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Affiliation(s)
- B McEvoy
- STERIS Applied Sterilization Technologies, IDA Business and Technology Park, Tullamore, Ireland
| | - M Lynch
- Centre for Disinfection, Sterilization and Biosecurity, Athlone Institute of Technology, Athlone, Ireland
| | - N J Rowan
- Centre for Disinfection, Sterilization and Biosecurity, Athlone Institute of Technology, Athlone, Ireland
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McEvoy B, Rowan NJ. Terminal sterilization of medical devices using vaporized hydrogen peroxide: a review of current methods and emerging opportunities. J Appl Microbiol 2019; 127:1403-1420. [PMID: 31410952 DOI: 10.1111/jam.14412] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/03/2019] [Accepted: 07/25/2019] [Indexed: 01/08/2023]
Abstract
Medical devices are an important and growing aspect of healthcare provision and are increasing in complexity to meet established and emerging patient needs. Terminal sterilization plays a vital role in the provision of safe medical devices. While terminal sterilization technologies for medical devices include multiple radiation options, ethylene oxide remains the predominant nonthermal gaseous option, sterilizing c. 50% of all manufactured devices. Vaporized hydrogen peroxide (abbreviated VH2O2 by the International Organization for Standardization) is currently deployed for clinical sterilization applications, where its performance characteristics appear aligned to requirements, constituting a viable alternative low-temperature process for terminal processing of medical devices. However, VH2O2 has operational limitations that create technical challenges for industrial-scale adoption. This timely review provides a succinct overview of VH2O2 in gaseous sterilization and addresses its applicability for terminal sterilization of medical devices. It also describes underappreciated factors such as the occurrence of nonlinear microbial inactivation kinetic plots that may dictate a need to develop a new standard approach to validate VH2O2 for terminal sterilization of medical devices.
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Affiliation(s)
- B McEvoy
- STERIS Applied Sterilization Technologies, IDA Business and Technology Park, Tullamore, Ireland
| | - N J Rowan
- Bioscience Research Institute, Athlone Institute of Technology, Athlone, Ireland
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Le Toquin E, Faure S, Orange N, Gas F. New Biocide Foam Containing Hydrogen Peroxide for the Decontamination of Vertical Surface Contaminated With Bacillus thuringiensis Spores. Front Microbiol 2018; 9:2295. [PMID: 30319592 PMCID: PMC6171482 DOI: 10.3389/fmicb.2018.02295] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 09/07/2018] [Indexed: 01/23/2023] Open
Abstract
Despite scientific advances, bacterial spores remain a major preoccupation in many different fields, such as the hospital, food, and CBRN-E Defense sector. Although many disinfectant technologies exist, there is a lack for the decontamination of difficult to access areas, outdoor sites, or large interior volumes. This study evaluates the decontamination efficiency of an aqueous foam containing hydrogen peroxide, with the efficiency of disinfectant in the liquid form on vertical surfaces contaminated by Bacillus thurengiensis spores. The decontamination efficiency impact of the surfactant and stabilizer agents in the foam and liquid forms was evaluated. No interferences were observed with these two chemical additives. Our results indicate that the decontamination kinetics of both foam and liquid forms are similar. In addition, while the foam form was as efficient as the liquid solution at 4°C, it was even more so at 30°C. The foam decontamination reaction follows the Arrhenius law, which enables the decontamination kinetic to be predicted with the temperature. Moreover, the foam process used via spraying or filling is more attractive due to the generation of lower quantity of liquid effluents. Our findings highlight the greater suitability of foam to decontaminate difficult to access and high volume facilities compared to liquid solutions.
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Affiliation(s)
- Esther Le Toquin
- Laboratoire Innovations technologiques pour la Détection et le Diagnostic, Service de Pharmacologie et Immunoanalyse, DRF, CEA, INRA, Bagnols-sur-Cèze, France.,Laboratoire de Microbiologie Signaux et Microenvironnement, Université de Rouen, Evreux, France
| | - Sylvain Faure
- Laboratoire des Procédés Supercritiques et Décontamination, Service d'études des technologies pour l'assainissement démantèlement et l'étanchéité, Univ. Montpellier, DEN, CEA, Bagnols-sur-Cèze, France
| | - Nicole Orange
- Laboratoire de Microbiologie Signaux et Microenvironnement, Université de Rouen, Evreux, France
| | - Fabienne Gas
- Laboratoire Innovations technologiques pour la Détection et le Diagnostic, Service de Pharmacologie et Immunoanalyse, DRF, CEA, INRA, Bagnols-sur-Cèze, France
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Wand ME. Bacterial Resistance to Hospital Disinfection. MODELING THE TRANSMISSION AND PREVENTION OF INFECTIOUS DISEASE 2017. [DOI: 10.1007/978-3-319-60616-3_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Zheng L, Abhyankar W, Ouwerling N, Dekker HL, van Veen H, van der Wel NN, Roseboom W, de Koning LJ, Brul S, de Koster CG. Bacillus subtilis Spore Inner Membrane Proteome. J Proteome Res 2016; 15:585-94. [PMID: 26731423 DOI: 10.1021/acs.jproteome.5b00976] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The endospore is the dormant form of Bacillus subtilis and many other Firmicutes. By sporulation, these spore formers can survive very harsh physical and chemical conditions. Yet, they need to go through germination to return to their growing form. The spore inner membrane (IM) has been shown to play an essential role in triggering the initiation of germination. In this study, we isolated the IM of bacterial spores, in parallel with the isolation of the membrane of vegetative cells. With the use of GeLC-MS/MS, over 900 proteins were identified from the B. subtilis spore IM preparations. By bioinformatics-based membrane protein predictions, ca. one-third could be predicted to be membrane-localized. A large number of unique proteins as well as proteins common to the two membrane proteomes were identified. In addition to previously known IM proteins, a number of IM proteins were newly identified, at least some of which are likely to provide new insights into IM physiology, unveiling proteins putatively involved in spore germination machinery and hence putative germination inhibition targets.
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Affiliation(s)
| | | | | | | | - Henk van Veen
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
| | - Nicole N van der Wel
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
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Mechanism of Sporicidal Activity for the Synergistic Combination of Peracetic Acid and Hydrogen Peroxide. Appl Environ Microbiol 2015; 82:1035-1039. [PMID: 26637595 PMCID: PMC4751845 DOI: 10.1128/aem.03010-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/20/2015] [Indexed: 11/20/2022] Open
Abstract
There is still great interest in controlling bacterial endospores. The use of chemical disinfectants and, notably, oxidizing agents to sterilize medical devices is increasing. With this in mind, hydrogen peroxide (H2O2) and peracetic acid (PAA) have been used in combination, but until now there has been no explanation for the observed increase in sporicidal activity. This study provides information on the mechanism of synergistic interaction of PAA and H2O2 against bacterial spores. We performed investigations of the efficacies of different combinations, including pretreatments with the two oxidizers, against wild-type spores and a range of spore mutants deficient in the spore coat or small acid-soluble spore proteins. The concentrations of the two biocides were also measured in the reaction vessels, enabling the assessment of any shift from H2O2 to PAA formation. This study confirmed the synergistic activity of the combination of H2O2 and PAA. However, we observed that the sporicidal activity of the combination is largely due to PAA and not H2O2. Furthermore, we observed that the synergistic combination was based on H2O2 compromising the spore coat, which was the main spore resistance factor, likely allowing better penetration of PAA and resulting in the increased sporicidal activity.
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Guo MT, Yuan QB, Yang J. Distinguishing effects of ultraviolet exposure and chlorination on the horizontal transfer of antibiotic resistance genes in municipal wastewater. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:5771-8. [PMID: 25853586 DOI: 10.1021/acs.est.5b00644] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Growing attention has been paid to the dissemination of antibiotic resistance genes (ARGs) in wastewater microbial communities; however, the disinfection processes, as microbial control technologies, have not been evaluated for their impacts on ARGs transfer. In this study, the effects of ultraviolet (UV) disinfection and chlorination on the frequency of ARGs transfer have been explored based on the conjugative transfer model between Gram-negative strains of E. coli. The results indicated that UV disinfection and chlorination exhibit distinct influences on the conjugative transfer. Low UV doses (up to 8 mJ/cm2) had little influence on the frequency of conjugative transfer, and UV exposure only decreased the bacterial number but did not change the cell permeability. By comparison, low chlorine doses (up to 40 mg Cl min/L) significantly promoted the frequency of conjugative transfer by 2-5-fold. The generated chloramine stimulated the bacteria and improved the cell permeability. More pilus were induced on the surface of conjugative cells, which acted as pathways for ARGs transfer. The frequency of ARG transfers was greatly suppressed by high doses of UV (>10 mJ/cm2) or chlorine (>80 mg Cl min/L).
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Affiliation(s)
- Mei-Ting Guo
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Qing-Bin Yuan
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Jian Yang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
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Leggett MJ, Schwarz JS, Burke PA, Mcdonnell G, Denyer SP, Maillard JY. Resistance to and killing by the sporicidal microbicide peracetic acid. J Antimicrob Chemother 2014; 70:773-9. [DOI: 10.1093/jac/dku445] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Leggett MJ, McDonnell G, Denyer SP, Setlow P, Maillard JY. Bacterial spore structures and their protective role in biocide resistance. J Appl Microbiol 2012; 113:485-98. [PMID: 22574673 DOI: 10.1111/j.1365-2672.2012.05336.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The structure and chemical composition of bacterial spores differ considerably from those of vegetative cells. These differences largely account for the unique resistance properties of the spore to environmental stresses, including disinfectants and sterilants, resulting in the emergence of spore-forming bacteria such as Clostridium difficile as major hospital pathogens. Although there has been considerable work investigating the mechanisms of action of many sporicidal biocides against Bacillus subtilis spores, there is far less information available for other species and particularly for various Clostridia. This paucity of information represents a major gap in our knowledge given the importance of Clostridia as human pathogens. This review considers the main spore structures, highlighting their relevance to spore resistance properties and detailing their chemical composition, with a particular emphasis on the differences between various spore formers. Such information will be vital for the rational design and development of novel sporicidal chemistries with enhanced activity in the future.
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Affiliation(s)
- M J Leggett
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK
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Campbell CG, Kirvel RD, Love AH, Bailey CG, Miles R, Schweickert J, Sutton M, Raber E. Decontamination After a Release ofB. anthracisSpores. Biosecur Bioterror 2012; 10:108-22. [DOI: 10.1089/bsp.2011.0095] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Chris G. Campbell
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Robert D. Kirvel
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Adam H. Love
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Christopher G. Bailey
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Robin Miles
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Jerry Schweickert
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Mark Sutton
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
| | - Ellen Raber
- Chris G. Campbell, PhD, is an Environmental Scientist; Robert D. Kirvel, PhD, is a science writer; Christopher G. Bailey, PhD, is a scientist in the Biosciences and Biotechnology Division; Robin Miles, MSME, MBA, is Group Leader for the Center for Micro and Nano Technology; Jerry Schweickert, MPH, is an Environmental Scientist; Mark Sutton, PhD, is a scientist in the Chemical Sciences Division; and Ellen Raber, MS, is Deputy Program Director for Counterterrorism in the Global Security Principal
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Origin of bacterial spores contaminating foods. Food Microbiol 2011; 28:177-82. [DOI: 10.1016/j.fm.2010.07.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Revised: 07/07/2010] [Accepted: 07/08/2010] [Indexed: 11/22/2022]
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Greenberg DL, Busch JD, Keim P, Wagner DM. Identifying experimental surrogates for Bacillus anthracis spores: a review. INVESTIGATIVE GENETICS 2010; 1:4. [PMID: 21092338 PMCID: PMC2988482 DOI: 10.1186/2041-2223-1-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 09/01/2010] [Indexed: 01/05/2023]
Abstract
Bacillus anthracis, the causative agent of anthrax, is a proven biological weapon. In order to study this threat, a number of experimental surrogates have been used over the past 70 years. However, not all surrogates are appropriate for B. anthracis, especially when investigating transport, fate and survival. Although B. atrophaeus has been widely used as a B. anthracis surrogate, the two species do not always behave identically in transport and survival models. Therefore, we devised a scheme to identify a more appropriate surrogate for B. anthracis. Our selection criteria included risk of use (pathogenicity), phylogenetic relationship, morphology and comparative survivability when challenged with biocides. Although our knowledge of certain parameters remains incomplete, especially with regards to comparisons of spore longevity under natural conditions, we found that B. thuringiensis provided the best overall fit as a non-pathogenic surrogate for B. anthracis. Thus, we suggest focusing on this surrogate in future experiments of spore fate and transport modelling.
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Affiliation(s)
- David L Greenberg
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
| | - Joseph D Busch
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
| | | | - David M Wagner
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
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Decontamination options for Bacillus anthracis-contaminated drinking water determined from spore surrogate studies. Appl Environ Microbiol 2010; 76:6631-8. [PMID: 20709855 DOI: 10.1128/aem.01136-10] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Five parameters were evaluated with surrogates of Bacillus anthracis spores to determine effective decontamination alternatives for use in a contaminated drinking water supply. The parameters were as follows: (i) type of Bacillus spore surrogate (B. thuringiensis or B. atrophaeus), (ii) spore concentration in suspension (10(2) and 10(6) spores/ml), (iii) chemical characteristics of the decontaminant (sodium dichloro-S-triazinetrione dihydrate [Dichlor], hydrogen peroxide, potassium peroxymonosulfate [Oxone], sodium hypochlorite, and VirkonS), (iv) decontaminant concentration (0.01% to 5%), and (v) exposure time to decontaminant (10 min to 1 h). Results from 138 suspension tests with appropriate controls are reported. Hydrogen peroxide at a concentration of 5% and Dichlor or sodium hypochlorite at a concentration of 2% were highly effective at spore inactivation regardless of spore type tested, spore exposure time, or spore concentration evaluated. This is the first reported study of Dichlor as an effective decontaminant for B. anthracis spore surrogates. Dichlor's desirable characteristics of high oxidation potential, high level of free chlorine, and a more neutral pH than that of other oxidizers evaluated appear to make it an excellent alternative. All three oxidizers were effective against B. atrophaeus spores in meeting the EPA biocide standard of greater than a 6-log kill after a 10-min exposure time and at lower concentrations than typically reported for biocide use. Solutions of 5% VirkonS and Oxone were less effective as decontaminants than other options evaluated in this study and did not meet the EPA's efficacy standard for a biocide, although they were found to be as effective for concentrations of 10(2) spores/ml. Differences in methods and procedures reported by other investigators make quantitative comparisons among studies difficult.
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Griffiths K, Setlow P. Effects of modification of membrane lipid composition onBacillus subtilissporulation and spore properties. J Appl Microbiol 2009; 106:2064-78. [DOI: 10.1111/j.1365-2672.2009.04176.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Rogers J, Richter W, Choi Y, Judd A. Use of superabsorbent polymer gels for surface decontamination ofBacillus anthracisspores. Lett Appl Microbiol 2009; 48:180-6. [DOI: 10.1111/j.1472-765x.2008.02506.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Rogers JV, Choi YW, Richter WR, Stone HJ, Taylor ML. Bacillus AnthracisSpore Inactivation by Fumigant Decontamination. APPLIED BIOSAFETY 2008. [DOI: 10.1177/153567600801300203] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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CRONIN ULTANP, WILKINSON MARTING. MONITORING CHANGES IN GERMINATION AND PERMEABILITY OF BACILLUS CEREUS ENDOSPORES FOLLOWING CHEMICAL, HEAT AND ENZYMATIC TREATMENTS USING FLOW CYTOMETRY. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1745-4581.2008.00124.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sánchez-Fortún S, Llorente MT, Castaño A. Cytotoxic and genotoxic effect in RTG-2 cell line exposed to selected biocides used in the disinfection of cooling towers. ECOTOXICOLOGY (LONDON, ENGLAND) 2008; 17:273-279. [PMID: 18274895 DOI: 10.1007/s10646-008-0194-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 01/17/2008] [Indexed: 05/25/2023]
Abstract
The cytotoxic and genotoxic effects induced by trichloroisocyanuric acid, Oxone, and sodium bromide, active principles included in formulations for cleaning and disinfection of cooling towers, were studied on RTG-2 cell line. Neutral red assay was used to determine the cellular viability. Toxicity ranking based on IC(50) values found that trichloroisocyanuric acid was the most cytotoxic biocide tested followed by Oxone, whereas sodium bromide resulted in a very low cytotoxicity. DNA damage has been evaluated on RTG-2 cultures by means of an in vitro assay based on the ability of PicoGreen fluorochrome to interact preferentially with dsDNA, and the results indicated that trichloroisocyanuric acid induced DNA strand breaks at concentrations above 1.2 mg/l, equivalent to 1/50-EC(50(48)), whereas exposures to Oxone and sodium bromide did not induce DNA damage at the maximal concentrations tested (1/10-EC(50(48))). These results confirm the suitability of this method for the screening of genotoxic effects of this type of aquatic pollutants, and we suggest their use in environmental risk assessment procedures.
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Affiliation(s)
- S Sánchez-Fortún
- Departamento Toxicología y Farmacología, Facultad de Veterinaria, Universidad Complutense (UCM), Madrid, Spain.
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de Benito Armas A, Padula NL, Setlow B, Setlow P. Sensitization of Bacillus subtilis spores to dry heat and desiccation by pretreatment with oxidizing agents. Lett Appl Microbiol 2008; 46:492-7. [PMID: 18331248 DOI: 10.1111/j.1472-765x.2008.02344.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To determine if pretreatment with oxidizing agents sensitizes Bacillus subtilis spores to dry heat or desiccation. METHODS Bacillus subtilis spores were killed approx. 90% by oxidizing agents, and the sensitivity of treated and untreated spores to dry heat and desiccation was determined. The effects of pyruvate on spore recovery after oxidizing agent pretreatment and then dry heat or desiccation were also determined. CONCLUSIONS Spores pretreated with Oxone or hypochlorite were not sensitized to dry heat or freeze-drying. However, hydrogen peroxide or t-butylhydroperoxide pretreatment sensitized spores to dry heat or desiccation, and the desiccation caused mutagenesis in the survivors. Pyruvate increased recovery of spores treated with hydrogen peroxide alone or plus dry heat or desiccation, and with t-butylhydroperoxide and desiccation, but not with t-butylhydroperoxide alone or plus dry heat. SIGNIFICANCE AND IMPACT OF THE STUDY Pretreatment with peroxides sensitizes bacterial spores to subsequent stress. This finding may suggest improved regimens for spore inactivation.
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Affiliation(s)
- A de Benito Armas
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030-3305, USA
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Abstract
A number of mechanisms are responsible for the resistance of spores of Bacillus species to heat, radiation and chemicals and for spore killing by these agents. Spore resistance to wet heat is determined largely by the water content of spore core, which is much lower than that in the growing cell protoplast. A lower core water content generally gives more wet heat-resistant spores. The level and type of spore core mineral ions and the intrinsic stability of total spore proteins also play a role in spore wet heat resistance, and the saturation of spore DNA with alpha/beta-type small, acid-soluble spore proteins (SASP) protects DNA against wet heat damage. However, how wet heat kills spores is not clear, although it is not through DNA damage. The alpha/beta-type SASP are also important in spore resistance to dry heat, as is DNA repair in spore outgrowth, as Bacillus subtilis spores are killed by dry heat via DNA damage. Both UV and gamma-radiation also kill spores via DNA damage. The mechanism of spore resistance to gamma-radiation is not well understood, although the alpha/beta-type SASP are not involved. In contrast, spore UV resistance is due largely to an alteration in spore DNA photochemistry caused by the binding of alpha/beta-type SASP to the DNA, and to a lesser extent to the photosensitizing action of the spore core's large pool of dipicolinic acid. UV irradiation of spores at 254 nm does not generate the cyclobutane dimers (CPDs) and (6-4)-photoproducts (64PPs) formed between adjacent pyrimidines in growing cells, but rather a thymidyl-thymidine adduct termed spore photoproduct (SP). While SP is formed in spores with approximately the same quantum efficiency as that for generation of CPDs and 64PPs in growing cells, SP is repaired rapidly and efficiently in spore outgrowth by a number of repair systems, at least one of which is specific for SP. Some chemicals (e.g. nitrous acid, formaldehyde) again kill spores by DNA damage, while others, in particular oxidizing agents, appear to damage the spore's inner membrane so that this membrane ruptures upon spore germination and outgrowth. There are also other agents such as glutaraldehyde for which the mechanism of spore killing is unclear. Factors important in spore chemical resistance vary with the chemical, but include: (i) the spore coat proteins that likely react with and detoxify chemical agents; (ii) the relative impermeability of the spore's inner membrane that restricts access of exogenous chemicals to the spore core; (iii) the protection of spore DNA by its saturation with alpha/beta-type SASP; and (iv) DNA repair for agents that kill spores via DNA damage. Given the importance of the killing of spores of Bacillus species in the food and medical products industry, a deeper understanding of the mechanisms of spore resistance and killing may lead to improved methods for spore destruction.
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Affiliation(s)
- P Setlow
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, 06030-3305, USA.
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Cronin UP, Wilkinson MG. The use of flow cytometry to study the germination ofBacillus cereus endospores. Cytometry A 2007; 71:143-53. [PMID: 17200957 DOI: 10.1002/cyto.a.20368] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND At present the study of endospore germination is conducted using microbiological methods which are slow and yield data based on the means of large heterogeneous populations. Flow cytometry (FCM) offers the potential to rapidly quantify and identify germination and outgrowth events for large numbers of individual endospores. METHODS Standard methods were employed to arrest the germination of Bacillus cereus endospores at defined stages. Endospores were then stained with SYTO 9 alone or carboxyfluorescein diacetate (CFDA) together with Hoechst 33342 and analysed using FCM. Comparisons were made between FCM as a method to measure germination rate and standard microbiological techniques. RESULTS Germinating endospores displayed increases in permeability to SYTO 9 and hydrolysis of CFDA compared with controls. Statistically significant correlations were found between the standard plate count method and both FCM methods for measuring the percentage of germinating and outgrowing endospores up to 75 min after addition of germinant. CONCLUSIONS Using FCM, the percentage of germinating or outgrowing endospores at various time points during germination and/or outgrowth can be quantified. FCM with CFDA/Hoechst 33342 staining may be used to estimate overall germination rate, whereas FCM with SYTO 9 staining may be used to quantify ungerminated, germinating and outgrowing endospores.
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Affiliation(s)
- Ultan P Cronin
- Department of Life Sciences, University of Limerick, Castletroy, Co. Limerick, Ireland
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Paul M, Atluri S, Setlow B, Setlow P. Mechanisms of killing of spores of Bacillus subtilis by dimethyldioxirane. J Appl Microbiol 2006; 101:1161-8. [PMID: 17040240 DOI: 10.1111/j.1365-2672.2006.03000.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To determine the mechanisms of Bacillus subtilis spore resistance to and killing by a novel sporicide, dimethyldioxirane (DMDO) that was generated in situ from acetone and potassium peroxymonosulfate at neutral pH. METHODS AND RESULTS Spores of B. subtilis were effectively killed by DMDO. Rates of killing by DMDO of spores lacking most DNA protective alpha/beta-type small, acid-soluble spore proteins (alpha- beta- spores) or the major DNA repair protein, RecA, were very similar to that of wild-type spore killing. Survivors of wild-type and alpha- beta- spores treated with DMDO also exhibited no increase in mutations. Spores lacking much coat protein due either to mutation or chemical decoating were much more sensitive to DMDO than were wild-type spores, but were more resistant than growing cells. Wild-type spores killed with this reagent retained their large pool of dipicolinic acid (DPA), and the survivors of spores treated with DMDO were sensitized to wet heat. The DMDO-killed spores germinated with nutrients, albeit more slowly than untreated spores, but germinated faster than untreated spores with dodecylamine. The killed spores were also germinated by very high pressures and by lysozyme treatment in hypertonic medium, but many of these spores lysed shortly after their germination, and none of these treatments were able to revive the DMDO-killed spores. CONCLUSIONS DMDO is an effective reagent for killing B. subtilis spores. The spore coat is a major factor in spore resistance to DMDO, which does not kill spores by DNA damage or by inactivating some component needed for spore germination. Rather, this reagent appears to kill spores by damaging the spore's inner membrane in some fashion. SIGNIFICANCE AND IMPACT OF THE STUDY This work demonstrates that DMDO is an effective decontaminant for spores of Bacillus species that can work under mild conditions, and the killed spores cannot be revived. Evidence has also been obtained on the mechanisms of spore resistance to and killing by this reagent.
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Affiliation(s)
- M Paul
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06030-3305, USA
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Rogers JV, Ducatte GR, Choi YW, Early PC. A preliminary assessment ofBacillus anthracisspore inactivation using an electrochemically activated solution (ECASOL™). Lett Appl Microbiol 2006; 43:482-8. [PMID: 17032220 DOI: 10.1111/j.1472-765x.2006.02002.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM To evaluate the efficacy of electrochemically activated solution (ECASOL) in decontaminating Bacillus anthracis Ames and Vollum 1B spores, with and without changing the source water hardness and final ECASOL pH. METHODS AND RESULTS Five different ECASOL formulations were generated, in which the source water hardness and final ECASOL pH were varied, resulting in cases where significant changes in free available chlorine (FAC) and oxidative-reduction potential (ORP) were observed. B. anthracis Ames and Vollum 1B spores were suspended in the various ECASOL formulations for 30 min, and decontamination efficacy was determined; calcium hypochlorite [5% high-test hypochlorite (HTH)] was used as a positive control. The five different ECASOL formulations yielded mean FAC levels ranging from 305 to 464 ppm, and mean ORP levels ranging from +826 to +1000 mV. Exposure to all the ECASOL formulations and 5% HTH resulted in >or=7.0 log reductions in both B. anthracis Ames and Vollum 1B spores. CONCLUSIONS The present testing demonstrated that ECASOL with a minimum of c. 300-ppm FAC levels and +800-mV ORP inactivated the B. anthracis spores in suspension, similar to 5% HTH. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide information for decontaminating B. anthracis Ames and Vollum 1B spores in suspension using ECASOL.
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Affiliation(s)
- J V Rogers
- Battelle Memorial Institute, Columbus, OH, USA
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Banerjee D, Markley AL, Yano T, Ghosh A, Berget PB, Minkley EG, Khetan SK, Collins TJ. “Green” Oxidation Catalysis for Rapid Deactivation of Bacterial Spores. Angew Chem Int Ed Engl 2006; 45:3974-7. [PMID: 16673442 DOI: 10.1002/anie.200504511] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Deboshri Banerjee
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA.
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Rogers JV, Sabourin CLK, Choi YW, Richter WR, Rudnicki DC, Riggs KB, Taylor ML, Chang J. Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas generator. J Appl Microbiol 2006; 99:739-48. [PMID: 16162224 DOI: 10.1111/j.1365-2672.2005.02686.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To evaluate the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface materials using hydrogen peroxide gas. METHODS AND RESULTS Bacillus anthracis, B. subtilis, and G. stearothermophilus spores were dried on seven types of indoor surfaces and exposed to > or =1000 ppm hydrogen peroxide gas for 20 min. Hydrogen peroxide exposure significantly decreased viable B. anthracis, B. subtilis, and G. stearothermophilus spores on all test materials except G. stearothermophilus on industrial carpet. Significant differences were observed when comparing the reduction in viable spores of B. anthracis with both surrogates. The effectiveness of gaseous hydrogen peroxide on the growth of biological indicators and spore strips was evaluated in parallel as a qualitative assessment of decontamination. At 1 and 7 days postexposure, decontaminated biological indicators and spore strips exhibited no growth, while the nondecontaminated samples displayed growth. CONCLUSIONS Significant differences in decontamination efficacy of hydrogen peroxide gas on porous and nonporous surfaces were observed when comparing the mean log reduction in B. anthracis spores with B. subtilis and G. stearothermophilus spores. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide comparative information for the decontamination of B. anthracis spores with surrogates on indoor surfaces using hydrogen peroxide gas.
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Affiliation(s)
- J V Rogers
- Battelle Memorial Institute, Columbus, OH, OH 43201, USA.
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Driks A. From rings to layers: surprising patterns of protein deposition during bacterial spore assembly. J Bacteriol 2004; 186:4423-6. [PMID: 15231773 PMCID: PMC438608 DOI: 10.1128/jb.186.14.4423-4426.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Adam Driks
- Department of Microbiology and Immunology, Loyola University Medical Center, 2160 South First Avenue, Maywood, IL 60153, USA.
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Young SB, Setlow P. Mechanisms of Bacillus subtilis spore resistance to and killing by aqueous ozone. J Appl Microbiol 2004; 96:1133-42. [PMID: 15078531 DOI: 10.1111/j.1365-2672.2004.02236.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
AIMS To determine the mechanisms of Bacillus subtilis spore killing by and resistance to aqueous ozone. METHODS AND RESULTS Killing of B. subtilis spores by aqueous ozone was not due to damage to the spore's DNA, as wild-type spores were not mutagenized by ozone and wild-type and recA spores exhibited very similar ozone sensitivity. Spores (termed alpha-beta-) lacking the two major DNA protective alpha/beta-type small, acid-soluble spore proteins exhibited decreased ozone resistance but were also not mutagenized by ozone, and alpha-beta- and alpha-beta-recA spores exhibited identical ozone sensitivity. Killing of spores by ozone was greatly increased if spores were chemically decoated or carried a mutation in a gene encoding a protein essential for assembly of the spore coat. Ozone killing did not cause release of the spore core's large depot of dipicolinic acid (DPA), but these killed spores released all of their DPA after a subsequent normally sublethal heat treatment and also released DPA much more readily when germinated in dodecylamine than did untreated spores. However, ozone-killed spores did not germinate with either nutrients or Ca(2+)-DPA and could not be recovered by lysozyme treatment. CONCLUSIONS Ozone does not kill spores by DNA damage, and the major factor in spore resistance to this agent appears to be the spore coat. Spore killing by ozone seems to render the spores defective in germination, perhaps because of damage to the spore's inner membrane. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide information on the mechanisms of spore killing by and resistance to ozone.
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Affiliation(s)
- S B Young
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, CT 06032-3305, USA
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Russell AD. Bacterial outer membrane and cell wall penetration and cell destruction by polluting chemical agents and physical conditions. Sci Prog 2003; 86:283-311. [PMID: 15508894 PMCID: PMC10367465 DOI: 10.3184/003685003783238608] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the environment, bacteria and other microorganisms are subjected to a variety of constantly changing chemical and physical agencies. Chemical ones include antimicrobial compounds (both biocides and antibiotics), pollutants, drugs, cosmetic and pharmaceutical ingredients and pesticides. The physical agents include desiccation and drying, osmotic pressure, hydrostatic pressure, temperature and pH changes and radiations (ultraviolet, sunlight, ionizing). Bacteria must thus adapt to survive these inimicable conditions. Organisms such as bacterial spores usually survive, whereas other types of microorganisms may be much more susceptible. Depending on the type of organism, the bacterial cell wall, outer membrane or the spore outer layers may act as permeability barriers to the intracellular uptake of antibiotics and biocides. Some antibacterial agents interact with, and damage or modify, the outer components. Physical agencies are known to damage the cytoplasmic membrane or to produce alterations in DNA or proteins or enzymes. Nevertheless, significant damage to the cell wall or outer membrane may also occur. Four types of organisms are considered: cocci, mycobactria, Gram-negative bacteria and bacterial spores. The nature of the damage inflicted on, or in some cases prevented by, their outer cell layers is discussed for each type of organism.
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Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, UK
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