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Mikelonis AM, Fuller C, Ratliff K, Touati A, Calfee MW. Influence of wash aids on Bacillus spore removal from an asphalt parking lot using two spray-based washing methods. J Appl Microbiol 2022; 132:2773-2780. [PMID: 34878661 PMCID: PMC9808591 DOI: 10.1111/jam.15405] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/23/2021] [Accepted: 12/06/2021] [Indexed: 01/07/2023]
Abstract
AIMS The goal of this study was to measure the removal efficacy of Bacillus atrophaeus spores from a parking lot using spray-based washing methods (a pressure washer and a garden hose) and wash aids. B. atrophaeus is a commonly used nonpathogenic surrogate for B. anthracis, the causative agent of anthrax and a deadly bioterrorism agent that would cause major disruptions and damage to public health should it be disseminated over an urban area. METHODS AND RESULTS Five wash aids (1 mM sodium chloride, an Instant Ocean® seawater solution, 0.01% Tween 20, 0.01% sodium dodecyl sulfate, and unamended tap water) were used along with two different spray sequences in this study. Across all treatment conditions, 3.7-6.4 log10 colony forming unit were recovered in the runoff water, and 0.15%-23% of spores were removed from the surface of the parking lot. CONCLUSIONS Pressure washing removed more spores than the garden hose, and for both types of washing methods, the first pass removed more spores than the subsequent passes. The Instant Ocean and Tween 20 wash aids were found to significantly increase the percentage of spore removal when using the pressure washer, but the overall increase was only 1%-2% compared to the tap water alone. SIGNIFICANCE AND IMPACT OF STUDY This study provides public officials and emergency responders with baseline spore physical removal information for situations where a corrosive disinfectant might have a negative impact on the environment and washing is being considered as an alternative remediation approach.
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Affiliation(s)
- Anne M. Mikelonis
- Homeland Security Materials Management Division, Center for Environmental Solutions and Emergency Response, U.S. EPA Office of Research and Development, Durham, North Carolina, USA
| | - Christopher Fuller
- Watershed & Ecosystem Characterization Division, Center for Environmental Measurement and Modeling, U.S. EPA Office of Research and Development, Durham, North Carolina, USA
| | - Katherine Ratliff
- Homeland Security Materials Management Division, Center for Environmental Solutions and Emergency Response, U.S. EPA Office of Research and Development, Durham, North Carolina, USA
| | | | - Michael W. Calfee
- Homeland Security Materials Management Division, Center for Environmental Solutions and Emergency Response, U.S. EPA Office of Research and Development, Durham, North Carolina, USA
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2
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Haupert LM, McDonnell J, Martel K, Miles MD, Magnuson ML. Informing remediation of benzene contamination in drinking water distribution systems through multi-criteria decision analysis. JOURNAL OF HAZARDOUS MATERIALS ADVANCES 2021; 3:1-9. [PMID: 37850064 PMCID: PMC10581403 DOI: 10.1016/j.hazadv.2021.100013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
When contamination incidents occur in drinking water distribution systems, utilities need to select the remediation technologies most suited to their system-specific conditions and the contaminants of concern. Technology selection often involves balancing competing priorities. Multi-Criteria Decision Analysis (MCDA) is a promising approach that has been used extensively in other industries but not yet in drinking water system remediation. This paper discusses development of a computer-based tool that allows practitioners to leverage the Analytical Hierarchy Process (AHP), a well-established method of MCDA, to select remediation technologies based on their effectiveness and their compatibility with the practitioner's project objectives. This paper focuses on benzene, a contaminant implicated for many years in contamination incidents following spills and, more recently, wildfires.
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Affiliation(s)
- Levi M. Haupert
- Office of Research and Development, Center for Environmental Solutions and Emergency Response, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, United States
| | - Jon McDonnell
- The Cadmus Group, 100 Fifth Avenue Suite 100, Waltham, MA 02451, United States
| | - Kathy Martel
- The Cadmus Group, 100 Fifth Avenue Suite 100, Waltham, MA 02451, United States
| | - Michael D. Miles
- The Cadmus Group, 100 Fifth Avenue Suite 100, Waltham, MA 02451, United States
| | - Matthew L. Magnuson
- Office of Research and Development, Center for Environmental Solutions and Emergency Response, U.S. Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, United States
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3
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Fu Y, Peng H, Liu J, Nguyen TH, Hashmi MZ, Shen C. Occurrence and quantification of culturable and viable but non-culturable (VBNC) pathogens in biofilm on different pipes from a metropolitan drinking water distribution system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:142851. [PMID: 33097267 DOI: 10.1016/j.scitotenv.2020.142851] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 06/11/2023]
Abstract
Waterborne pathogens have been found in biofilms grown in drinking water distribution system (DWDS). However, there is a lack of quantitative study on the culturability of pathogens in biofilms from metropolitan DWDS. In this study, we quantified culturable and viable but non-culturable (VBNC) Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa and Vibrio cholerae in biofilms collected from five kinds of pipes (galvanized steel pipe, steel pipe, stainless steel clad pipe, ductile cast iron pipe and polyethylene pipe) and associated drinking water at an actual chlorinated DWDS in use from China. The results of these comprehensive analyses revealed that pipe material is a significant factor influencing the culturability of pathogen and microbial communities. Network analysis of the culturable pathogens and 16S rRNA gene inferred potential interactions between microbiome and culturability of pathogens. Although the water quality met the Chinese national standard of drinking water, however, VBNC pathogens were detected in both biofilms and water from the DWDS. This investigation suggests that stainless steel clad pipe (SSCP) was a better choice for pathogen control compared with other metal pipes. To our knowledge, this is the first study on culturable and VBNC pathogens in biofilms of different pipe materials in metropolitan DWDS.
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Affiliation(s)
- Yulong Fu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China
| | - Hongxi Peng
- Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
| | - Jingqing Liu
- Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | | | - Chaofeng Shen
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China.
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4
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Mikelonis AM, Ratliff K, Youn S. Laboratory results and mathematical modeling of spore surface interactions in stormwater runoff. JOURNAL OF CONTAMINANT HYDROLOGY 2020; 235:103707. [PMID: 32916588 PMCID: PMC7704712 DOI: 10.1016/j.jconhyd.2020.103707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Development of numerical models to predict stormwater-mediated transport of pathogenic spores in the environment depends on an understanding of adhesion forces that dictate detachment after rain events. Zeta potential values were measured in the laboratory for Bacillus globigii and Bacillus thuringiensis kurstaki, two common surrogates used to represent Bacillus anthracis, in synthetic baseline ultrapure water and laboratory prepared stormwater. Zeta potential curves were also determined for materials representative of urban infrastructure (concrete and asphalt). These data were used to predict the interaction energy between the spores and urban materials using Derjaguin-Landau-Verwey-Overbeek (DLVO) modeling. B. globigii and B. thuringiensis kurstaki sourced from Yakibou Inc., were found to have similar zeta potential curves, whereas spores sourced from the U.S. military's Dugway laboratory were found to diverge. In the ultrapure water, the modeling results use the laboratory data to demonstrate that the energy barriers between the spores and the urban materials were tunable through compression of the electrical double layer of the spores via changes of ionic strength and pH of the water. In the runoff water, charge neutralization dominated surface processes. The cations, metals, and natural organic matter (NOM) in the runoff water contributed to equalizing the zeta potential values for Dugway B. globigii and B. thuringiensis kurstaki, and drastically modified the surface of the concrete and asphalt. All DLVO energy curves using the runoff water were repulsive. The highest energy barrier predicted in this study was for Dugway B. globigii spores interacting with a concrete surface in runoff water, suggesting that this would be the most challenging combination to detach through water-based decontamination.
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Affiliation(s)
- Anne M Mikelonis
- Office of Research and Development, Center for Environmental Solutions and Emergency Response, Homeland Security and Materials Management Division, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
| | - Katherine Ratliff
- Office of Research and Development, Center for Environmental Solutions and Emergency Response, Homeland Security and Materials Management Division, U.S. Environmental Protection Agency, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Sungmin Youn
- Marshall University, Department of Civil Engineering, College of Engineering and Computer Sciences, 1 John Marshall Drive, Huntington, WV 25755, United States
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5
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Prasad A, Du L, Zubair M, Subedi S, Ullah A, Roopesh MS. Applications of Light-Emitting Diodes (LEDs) in Food Processing and Water Treatment. FOOD ENGINEERING REVIEWS 2020. [PMCID: PMC7223679 DOI: 10.1007/s12393-020-09221-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Light-emitting diode (LED) technology is an emerging nonthermal food processing technique that utilizes light energy with wavelengths ranging from 200 to 780 nm. Inactivation of bacteria, viruses, and fungi in water by LED treatment has been studied extensively. LED technology has also shown antimicrobial efficacy in food systems. This review provides an overview of recent studies of LED decontamination of water and food. LEDs produce an antibacterial effect by photodynamic inactivation due to photosensitization of light absorbing compounds in the presence of oxygen and DNA damage; however, such inactivation is dependent on the wavelength of light energy used. Commercial applications of LED treatment include air ventilation systems in office spaces, curing, medical applications, water treatment, and algaculture. As low penetration depth and high-intensity usage can challenge optimal LED treatment, optimization studies are required to select the right light wavelength for the application and to standardize measurements of light energy dosage.
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Affiliation(s)
- Amritha Prasad
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
| | - Lihui Du
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
| | - Muhammad Zubair
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
| | - Samir Subedi
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
| | - Aman Ullah
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
| | - M. S. Roopesh
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5 Canada
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Oder M, Koklič T, Umek P, Podlipec R, Štrancar J, Dobeic M. Photocatalytic biocidal effect of copper doped TiO2 nanotube coated surfaces under laminar flow, illuminated with UVA light on Legionella pneumophila. PLoS One 2020; 15:e0227574. [PMID: 31940328 PMCID: PMC6961935 DOI: 10.1371/journal.pone.0227574] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 12/20/2019] [Indexed: 11/18/2022] Open
Abstract
Legionella pneumophila can cause a potentially fatal form of humane pneumonia (Legionnaires' disease), which is most problematic in immunocompromised and in elderly people. Legionella species is present at low concentrations in soil, natural and artificial aquatic systems and is therefore constantly entering man-made water systems. The environment temperature for it's ideal growth range is between 32 and 42°C, thus hot water pipes represent ideal environment for spread of Legionella. The bacteria are dormant below 20°C and do not survive above 60°C. The primary method used to control the risk from Legionella is therefore water temperature control. There are several other effective treatments to prevent growth of Legionella in water systems, however current disinfection methods can be applied only intermittently thus allowing Legionella to grow in between treatments. Here we present an alternative disinfection method based on antibacterial coatings with Cu-TiO2 nanotubes deposited on preformed surfaces. In the experiment the microbiocidal efficiency of submicron coatings on polystyrene to the bacterium of the genus Legionella pneumophila with a potential use in a water supply system was tested. The treatment thus constantly prevents growth of Legionella pneumophila in presence of water at room temperature. Here we show that 24-hour illumination with low power UVA light source (15 W/m2 UVA illumination) of copper doped TiO2 nanotube coated surfaces is effective in preventing growth of Legionella pneumophila. Microbiocidal effects of Cu-TiO2 nanotube coatings were dependent on the flow of the medium and the intensity of UV-A light. It was determined that tested submicron coatings have microbiocidal effects specially in a non-flow or low-flow conditions, as in higher flow rates, probably to a greater possibility of Legionella pneumophila sedimentation on the coated polystyrene surfaces, meanwhile no significant differences among bacteria reduction was noted regarding to non or low flow of medium.
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Affiliation(s)
- Martina Oder
- Department of Sanitary Engineering, University of Ljubljana, Faculty of Health Sciences, Ljubljana, Slovenia
| | - Tilen Koklič
- Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Polona Umek
- Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Rok Podlipec
- Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana, Slovenia
- Helmholz Zentrum Dresden Rossendorf, Ion Beam Center, Dresden, Germany
| | - Janez Štrancar
- Laboratory of Biophysics, “Jožef Stefan” Institute, Ljubljana, Slovenia
| | - Martin Dobeic
- Institute of Food Safety Feed and Environment, University of Ljubljana, Veterinary Faculty, Ljubljana, Slovenia
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7
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Evaluation of Legionella pneumophila Decrease in Hot Water Network of Four Hospital Buildings after Installation of Electron Time Flow Taps. WATER 2020. [DOI: 10.3390/w12010210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Legionella spp. control is a critical issue in hospital with old water networks. Chemical disinfection methods are applied as a control measure over prolonged time periods, but Legionella may be resistant to chemical agents in pipeworks with low flow and frequent water stagnation. We evaluated Legionella spp. colonization in the hot water network of Italian hospitals after the installation of time flow taps (TFTs). In the period between 2017 and 2019, TFTs were installed in four hospital water networks. They were programmed in order to obtain a hot water flow of 192 L/day from each TFTs. A continuous chlorination system (chlorine dioxide) and a cold water pre-filtration device were applied in all the buildings. Before and after TFT installation, Legionella spp. was investigated at scheduled times. Before TFT installation, Legionella pneumophila was detected in all the hospitals with counts ranging from 2 × 102 to 1.4 × 105 CFU/L. After TFT installation, a loss in Legionella pneumophila culturability was always achieved in the period between 24 h and 15 days. Total chlorine concentration (Cl2) was detected in the range between 0.23 and 0.36 mg/L while temperature values were from 44.8 to 53.2 °C. TFTs together with chemical disinfection represent a method which improve water quality and disinfectant efficacy, reducing Legionella colonization in dead-end sections.
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8
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Zhu Z, Shan L, Hu F, Li Z, Zhong D, Yuan Y, Zhang J. Biofilm formation potential and chlorine resistance of typical bacteria isolated from drinking water distribution systems. RSC Adv 2020; 10:31295-31304. [PMID: 35520667 PMCID: PMC9056398 DOI: 10.1039/d0ra04985a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 08/17/2020] [Indexed: 11/30/2022] Open
Abstract
Biofilms are the main carrier of microbial communities throughout drinking water distribution systems (DWDSs), and strongly affect the safety of drinking water. Understanding biofilm formation potential and chlorine resistance is necessary for exploring future disinfection strategies and preventing water-borne diseases. This study investigated biofilm formation of five bacterial strains isolated from a simulated DWDS at different incubation times (24 h, 48 h, and 72 h), then evaluated chlorine resistance of 72 h incubated biofilms under chlorine concentrations of 0.3, 0.6, 1, 2, 4, and 10 mg L−1. All five bacterial strains had biofilm formation potential when incubated for 72 h. The biofilm formation potential of Acinetobacter sp. was stronger than that of Bacillus cereus, Microbacterium sp. and Sphingomonas sp. were moderate, and that of Acidovorax sp. was weak. In contrast, the order of chlorine resistance was Bacillus sp. > Sphingomonas sp. > Microbacterium sp. > Acidovorax sp. > Acinetobacter sp. Thus, the chlorine resistance of a single-species biofilm has little relation with the biofilm formation potential. The biofilm biomass is not a major factor affecting chlorine resistance. Moreover, the chlorine resistance of a single-species biofilm is highly related to the physiological state of bacterial cells, such as their ability to form spores or secrete extracellular polymeric substances, which could reduce the sensitivity of the single-species biofilm to a disinfectant or otherwise protect the biofilm. Biofilms are the main carrier of microbial communities throughout drinking water distribution systems (DWDSs), and strongly affect the safety of drinking water.![]()
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Affiliation(s)
- Zebing Zhu
- School of Civil Engineering and Architecture
- East China Jiao Tong University
- Nanchang
- China
- State Key Laboratory of Urban Water Resource and Environment
| | - Lili Shan
- School of Civil Engineering and Architecture
- East China Jiao Tong University
- Nanchang
- China
| | - Fengping Hu
- School of Civil Engineering and Architecture
- East China Jiao Tong University
- Nanchang
- China
| | - Zehua Li
- School of Civil Engineering and Architecture
- East China Jiao Tong University
- Nanchang
- China
| | - Dan Zhong
- State Key Laboratory of Urban Water Resource and Environment
- School of Environment
- Harbin Institute of Technology
- Harbin
- China
| | - Yixing Yuan
- State Key Laboratory of Urban Water Resource and Environment
- School of Environment
- Harbin Institute of Technology
- Harbin
- China
| | - Jie Zhang
- State Key Laboratory of Urban Water Resource and Environment
- School of Environment
- Harbin Institute of Technology
- Harbin
- China
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9
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Polo AMS, Lopez-Peñalver JJ, Rivera-Utrilla J, Von Gunten U, Sánchez-Polo M. Halide removal from waters by silver nanoparticles and hydrogen peroxide. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 607-608:649-657. [PMID: 28709099 DOI: 10.1016/j.scitotenv.2017.05.144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 06/07/2023]
Abstract
The objective of this study was to remove halides from waters by silver nanoparticles (AgNPs) and hydrogen peroxide (H2O2). The experimental parameters were optimized and the mechanism involved was also determined. The AgNP/H2O2 process proved efficacious for bromide and chloride removal from water through the selective precipitation of AgCl and AgBr on the AgNP surface. The optimal AgNP and H2O2 concentrations to be added to the solution were determined for the halide concentrations under study. The removal of Cl- and Br- anions was more effective at basic pH, reaching values of up to 100% for both ions. The formation of OH, O2-, radicals was detected during the oxidation of Ag(0) into Ag(I), determining the reaction mechanism as a function of solution pH. Moreover, the results obtained show that: i) the efficacy of the oxidation of Ag(0) into Ag(I) is higher at pH11, ii) AgNPs can be generated by the O2- radical formation, and iii) the presence of NaCl and dissolved organic matter (tannic acid [TAN]) on the solution matrix reduces the efficacy of bromide removal from the medium due to: i) precipitation of AgCl on the AgNP surface, and ii) the radical scavenger capacity of TAN. AgNPs exhausted can be regenerated by using UV or solar light, and toxicity test results show that AgNPs inhibit luminescence of Vibrio fischeri bacteria.
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Affiliation(s)
- A M S Polo
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Campus Fuentenueva s/n, ES18071 Granada, Spain
| | - J J Lopez-Peñalver
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Campus Fuentenueva s/n, ES18071 Granada, Spain
| | - J Rivera-Utrilla
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Campus Fuentenueva s/n, ES18071 Granada, Spain
| | - U Von Gunten
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; EPFL, École Polytechnique Féderale de Lausanne, Route Cantonale, 1015 Lausanne, Switzerland
| | - M Sánchez-Polo
- Department of Inorganic Chemistry, Faculty of Science, University of Granada, Campus Fuentenueva s/n, ES18071 Granada, Spain; EPFL, École Polytechnique Féderale de Lausanne, Route Cantonale, 1015 Lausanne, Switzerland.
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10
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Pelleieux S, Mathieu L, Block JC, Gantzer C, Bertrand I. The effect of chlorination and hydrodynamic shear stress on the persistence of bacteriophages associated with drinking water biofilms. J Appl Microbiol 2016; 121:1189-97. [PMID: 27452787 DOI: 10.1111/jam.13243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 11/30/2022]
Abstract
AIMS This work aimed to assess at pilot scale the effect of chlorination and water flushing on 2-month-old drinking water biofilms and, above all, on biofilm-associated F-specific RNA bacteriophages MS2, GA and Qβ. METHODS AND RESULTS Chlorination (4 mg l(-1) ) was applied first with a hydrodynamic shear stress of 1 Pa and second with an increase in hydrodynamic shear stress to 10 Pa. Despite a rapid decrease in the number of biofilm bacteria and associated phages, infectious phages were still detected on surfaces after completion of the 150 min cleaning procedure. The resulting sequence of phage removal was: GA > Qβ ≫ MS2. CONCLUSIONS The effect of chlorine on biofilm bacteria and biofilm-associated phages was limited to the upper layers of the biofilm and was not enhanced by an increase in hydrodynamic shear stress. A smaller decrease was observed for MS2 than for GA or Qβ after completion of the cleaning procedure. SIGNIFICANCE AND IMPACT OF THE STUDY The differences observed between the three phages suggest that the location of the viral particles in the biofilm, which is related to their surface properties, affects the efficiency of chlorine disinfection.
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Affiliation(s)
- S Pelleieux
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, Nancy, France.,LCPME, UMR 7564, Université de Lorraine, Nancy, France
| | - L Mathieu
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, Nancy, France.,EPHE, UL, CNRS, UMR 7564 LCPME, PSL Research University, Nancy, France
| | - J-C Block
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, Nancy, France.,LCPME, UMR 7564, Université de Lorraine, Nancy, France
| | - C Gantzer
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, Nancy, France.,LCPME, UMR 7564, Université de Lorraine, Nancy, France
| | - I Bertrand
- CNRS, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), UMR 7564, Institut Jean Barriol, Nancy, France. .,LCPME, UMR 7564, Université de Lorraine, Nancy, France.
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11
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Nganvongpanit K, Buddhachat K, Klinhom S, Kaewmong P, Thitaram C, Mahakkanukrauh P. Determining comparative elemental profile using handheld X-ray fluorescence in humans, elephants, dogs, and dolphins: Preliminary study for species identification. Forensic Sci Int 2016; 263:101-106. [PMID: 27093230 DOI: 10.1016/j.forsciint.2016.03.056] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 03/03/2016] [Accepted: 03/29/2016] [Indexed: 11/15/2022]
Abstract
Species identification is a crucial step in forensic anthropological studies. The aim of this study was to determine elemental profiles in bones from four mammal species, to be used for species discrimination. Human, elephant, dog, and dolphin bones were scanned by X-ray fluorescence (XRF); the differences in elemental profiles between species were determined using discriminant analysis. Dogs had the greatest number of elements (23), followed by humans (22) and elephants (20). Dolphins had the lowest number of elements (16). The accuracy rate of species identification in humans, elephants, dogs, and dolphins was 98.7%, 100%, 94.9%, and 92.3%, respectively. We conclude that element profiles of bones based on XRF analyses can serve as a tool for determining species.
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Affiliation(s)
- Korakot Nganvongpanit
- Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Elephant Research and Education Center, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand; Excellence Center in Osteology Research and Training Center, Chiang Mai University, Chiang Mai 50200, Thailand.
| | - Kittisak Buddhachat
- Animal Bone and Joint Research Laboratory, Department of Veterinary Biosciences and Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
| | - Sarisa Klinhom
- Elephant Research and Education Center, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
| | | | - Chatchote Thitaram
- Elephant Research and Education Center, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.
| | - Pasuk Mahakkanukrauh
- Excellence Center in Osteology Research and Training Center, Chiang Mai University, Chiang Mai 50200, Thailand.
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12
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Zhou W, Orr MW, Lee VT, Zachariah MR. Synergistic effects of ultrafast heating and gaseous chlorine on the neutralization of bacterial spores. Chem Eng Sci 2016. [DOI: 10.1016/j.ces.2016.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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13
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Abstract
The global crisis of antibiotic resistance has reached a point where, if action is not taken, human medicine will enter a postantibiotic world and simple injuries could once again be life threatening. New antibiotics are needed urgently, but better use of existing agents is just as important. More appropriate use of antibiotics in medicine is vital, but the extensive use of antibiotics outside medical settings is often overlooked. Antibiotics are commonly used in animal husbandry, bee-keeping, fish farming and other forms of aquaculture, ethanol production, horticulture, antifouling paints, food preservation, and domestically. This provides multiple opportunities for the selection and spread of antibiotic-resistant bacteria. Given the current crisis, it is vital that the nonmedical use of antibiotics is critically examined and that any nonessential use halted.
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Affiliation(s)
- Richard William Meek
- Institute of Microbiology and Infection, University Of Birmingham, Birmingham, United Kingdom
| | - Hrushi Vyas
- Institute of Microbiology and Infection, University Of Birmingham, Birmingham, United Kingdom
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Martin NL, Bass P, Liss SN. Antibacterial Properties and Mechanism of Activity of a Novel Silver-Stabilized Hydrogen Peroxide. PLoS One 2015; 10:e0131345. [PMID: 26154263 PMCID: PMC4496041 DOI: 10.1371/journal.pone.0131345] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 06/01/2015] [Indexed: 11/18/2022] Open
Abstract
Huwa-San peroxide (hydrogen peroxide; HSP) is a NSF Standard 60 (maximum 8 mg/L(-1)) new generation peroxide stabilized with ionic silver suitable for continuous disinfection of potable water. Experiments were undertaken to examine the mechanism of HSP against planktonic and biofilm cultures of indicator bacterial strains. Contact/kill time (CT) relationships that achieve effective control were explored to determine the potential utility in primary disinfection. Inhibitory assays were conducted using both nutrient rich media and a medium based on synthetic wastewater. Assays were compared for exposures to three disinfectants (HSP, laboratory grade hydrogen peroxide (HP) and sodium hypochlorite) at concentrations of 20 ppm (therefore at 2.5 and 5 times the NSF limit for HP and sodium hypochlorite, respectively) and at pH 7.0 and 8.5 in dechlorinated tap water. HSP was found to be more or equally effective as hypochlorite or HP. Results from CT assays comparing HSP and HP at different bacterial concentrations with neutralization of residual peroxide with catalase suggested that at a high bacterial concentration HSP, but not HP, was protected from catalase degradation possibly through sequestration by bacterial cells. Consistent with this hypothesis, at a low bacterial cell density residual HSP was more effectively neutralized as less HSP was associated with bacteria and therefore accessible to catalase. Silver in HSP may facilitate this association through electrostatic interactions at the cell surface. This was supported by experiments where the addition of mono (K(+)) and divalent (Ca(+2)) cations (0.005-0.05M) reduced the killing efficacy of HSP but not HP. Experiments designed to distinguish any inhibitory effect of silver from that of peroxide in HSP were carried out by monitoring the metabolic activity of established P. aeruginosa PAO1 biofilms. Concentrations of 70-500 ppm HSP had a pronounced effect on metabolic activity while the equivalent concentrations of ionic silver (50- 375 ppb) had a negligible effect, demonstrating that the microbiocidal activity of HSP was due to peroxide rather than silver. Overall, it was found that the antimicrobial activity of HSP is enhanced over that of hydrogen peroxide; the presence of the ionic silver enhances interactions of HSP with the bacterial cell surface rather than acting directly as a biocide at the tested concentrations.
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Affiliation(s)
- Nancy L. Martin
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Paul Bass
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
| | - Steven N. Liss
- School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
- Department of Chemical Engineering, Queen's University, Kingston, Ontario, Canada
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Abstract
A relatively short list of reference viral, bacterial and protozoan pathogens appears adequate to assess microbial risks and inform a system-based management of drinking waters. Nonetheless, there are data gaps, e.g. human enteric viruses resulting in endemic infection levels if poorly performing disinfection and/or distribution systems are used, and the risks from fungi. Where disinfection is the only treatment and/or filtration is poor, cryptosporidiosis is the most likely enteric disease to be identified during waterborne outbreaks, but generally non-human-infectious genotypes are present in the absence of human or calf fecal contamination. Enteric bacteria may dominate risks during major fecal contamination events that are ineffectively managed. Reliance on culture-based methods exaggerates treatment efficacy and reduces our ability to identify pathogens/indicators; however, next-generation sequencing and polymerase chain reaction approaches are on the cusp of changing that. Overall, water-based Legionella and non-tuberculous mycobacteria probably dominate health burden at exposure points following the various societal uses of drinking water.
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Affiliation(s)
- Nicholas J. Ashbolt
- School of Public Health, University of Alberta, Edmonton, Room 3-57D, South Academic Building, Alberta, T6G 2G7 Canada
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