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Tarka P, Chruściel A, Hreczuch W, Kanecki K, Nitsch-Osuch A. Virucidal activity of chlorine dioxide in combination with acetic acid or citric acid and a surfactant, in presence of interfering substances, against polio-, adeno- and murine norovirus in suspension-, carrier- and four-field tests. GMS HYGIENE AND INFECTION CONTROL 2024; 19:Doc37. [PMID: 39224499 PMCID: PMC11367254 DOI: 10.3205/dgkh000492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Introduction The aim of the study was to investigate whether the virucidal effectiveness of chlorine dioxid against adenovirus and murine norovirus can be improved by combining it with carboxylic acids and surfactants. Method The virucidal efficacy against polio-, adeno- and murine norovirus has been tested in presence of interfering substances in the quantitative suspension test according to EN 14476, the carrier test without mechanical action according to EN 16777, and in the four-field test according to EN 16615.Three chlorine-dioxide-based surface disinfectants were tested: a two-component cleaning disinfectant concentrate for large surfaces, a ready-to-use (RTU) foam, and an RTU gel. Results Cleaning and disinfecting preparations based on chlorine dioxide, applied at various concentrations, in combination with acetic acid or citric acid and surfactants, are virucidally active against polio-, adeno-, and norovirus after an exposure time of 5 minutes in presence of interfering substances.
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Affiliation(s)
- Patryk Tarka
- Department of Social Medicine and Public Health, Medical University of Warsaw, Warsaw, Poland
| | | | | | - Krzysztof Kanecki
- Department of Social Medicine and Public Health, Medical University of Warsaw, Warsaw, Poland
| | - Aneta Nitsch-Osuch
- Department of Social Medicine and Public Health, Medical University of Warsaw, Warsaw, Poland
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LeChevallier MW, Prosser T, Stevens M. Opportunistic Pathogens in Drinking Water Distribution Systems-A Review. Microorganisms 2024; 12:916. [PMID: 38792751 PMCID: PMC11124194 DOI: 10.3390/microorganisms12050916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024] Open
Abstract
In contrast to "frank" pathogens, like Salmonella entrocolitica, Shigella dysenteriae, and Vibrio cholerae, that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a host with a weakened immune system and rarely in a healthy host. Historically, drinking water treatment has focused on control of frank pathogens, particularly those from human or animal sources (like Giardia lamblia, Cryptosporidium parvum, or Hepatitis A virus), but in recent years outbreaks from drinking water have increasingly been due to opportunistic pathogens. Characteristics of opportunistic pathogens that make them problematic for water treatment include: (1) they are normally present in aquatic environments, (2) they grow in biofilms that protect the bacteria from disinfectants, and (3) under appropriate conditions in drinking water systems (e.g., warm water, stagnation, low disinfectant levels, etc.), these bacteria can amplify to levels that can pose a public health risk. The three most common opportunistic pathogens in drinking water systems are Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. This report focuses on these organisms to provide information on their public health risk, occurrence in drinking water systems, susceptibility to various disinfectants, and other operational practices (like flushing and cleaning of pipes and storage tanks). In addition, information is provided on a group of nine other opportunistic pathogens that are less commonly found in drinking water systems, including Aeromonas hydrophila, Klebsiella pneumoniae, Serratia marcescens, Burkholderia pseudomallei, Acinetobacter baumannii, Stenotrophomonas maltophilia, Arcobacter butzleri, and several free-living amoebae including Naegleria fowleri and species of Acanthamoeba. The public health risk for these microbes in drinking water is still unclear, but in most cases, efforts to manage Legionella, mycobacteria, and Pseudomonas risks will also be effective for these other opportunistic pathogens. The approach to managing opportunistic pathogens in drinking water supplies focuses on controlling the growth of these organisms. Many of these microbes are normal inhabitants in biofilms in water, so the attention is less on eliminating these organisms from entering the system and more on managing their occurrence and concentrations in the pipe network. With anticipated warming trends associated with climate change, the factors that drive the growth of opportunistic pathogens in drinking water systems will likely increase. It is important, therefore, to evaluate treatment barriers and management activities for control of opportunistic pathogen risks. Controls for primary treatment, particularly for turbidity management and disinfection, should be reviewed to ensure adequacy for opportunistic pathogen control. However, the major focus for the utility's opportunistic pathogen risk reduction plan is the management of biological activity and biofilms in the distribution system. Factors that influence the growth of microbes (primarily in biofilms) in the distribution system include, temperature, disinfectant type and concentration, nutrient levels (measured as AOC or BDOC), stagnation, flushing of pipes and cleaning of storage tank sediments, and corrosion control. Pressure management and distribution system integrity are also important to the microbial quality of water but are related more to the intrusion of contaminants into the distribution system rather than directly related to microbial growth. Summarizing the identified risk from drinking water, the availability and quality of disinfection data for treatment, and guidelines or standards for control showed that adequate information is best available for management of L. pneumophila. For L. pneumophila, the risk for this organism has been clearly established from drinking water, cases have increased worldwide, and it is one of the most identified causes of drinking water outbreaks. Water management best practices (e.g., maintenance of a disinfectant residual throughout the distribution system, flushing and cleaning of sediments in pipelines and storage tanks, among others) have been shown to be effective for control of L. pneumophila in water supplies. In addition, there are well documented management guidelines available for the control of the organism in drinking water distribution systems. By comparison, management of risks for Mycobacteria from water are less clear than for L. pneumophila. Treatment of M. avium is difficult due to its resistance to disinfection, the tendency to form clumps, and attachment to surfaces in biofilms. Additionally, there are no guidelines for management of M. avium in drinking water, and one risk assessment study suggested a low risk of infection. The role of tap water in the transmission of the other opportunistic pathogens is less clear and, in many cases, actions to manage L. pneumophila (e.g., maintenance of a disinfectant residual, flushing, cleaning of storage tanks, etc.) will also be beneficial in helping to manage these organisms as well.
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Affiliation(s)
| | - Toby Prosser
- Melbourne Water, Melbourne, VIC 3001, Australia; (T.P.); (M.S.)
| | - Melita Stevens
- Melbourne Water, Melbourne, VIC 3001, Australia; (T.P.); (M.S.)
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Goudot S, Mathieu L, Herbelin P, Soreau S, Jorand FPA. Growth dynamic of biofilm-associated Naegleria fowleri in freshwater on various materials. Front Microbiol 2024; 15:1369665. [PMID: 38511008 PMCID: PMC10951111 DOI: 10.3389/fmicb.2024.1369665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 02/08/2024] [Indexed: 03/22/2024] Open
Abstract
In industrial water systems, the occurrence of biofilm-associated pathogenic free-living amoebae (FLA) such as Naegleria fowleri is a potential hygienic problem, and factors associated with its occurrence remain poorly understood. This study aimed to evaluate the impact of four cooling circuit materials on the growth of N. fowleri in a freshwater biofilm formed at 42°C and under a hydrodynamic shear rate of 17 s-1 (laminar flow): polyvinyl chloride, stainless steel, brass, and titanium. Colonization of the freshwater biofilms by N. fowleri was found to be effective on polyvinyl chloride, stainless steel, and titanium. For these three materials, the ratio of (bacterial prey)/(amoeba) was found to control the growth of N. fowleri. All materials taken together, a maximum specific growth rate of 0.18 ± 0.07 h-1 was associated with a generation time of ~4 h. In contrast, no significant colonization of N. fowleri was found on brass. Therefore, the contribution of copper is strongly suspected.
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Affiliation(s)
- Sébastien Goudot
- EDF Recherche et Développement, Laboratoire National d'Hydraulique et Environnement, Chatou, France
- Université de Lorraine, CNRS, LCPME, Nancy, France
| | | | - Pascaline Herbelin
- EDF Recherche et Développement, Laboratoire National d'Hydraulique et Environnement, Chatou, France
| | - Sylvie Soreau
- EDF Recherche et Développement, Laboratoire National d'Hydraulique et Environnement, Chatou, France
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4
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Tsagkari E, Sloan W. The Role of Chlorine in the Formation and Development of Tap Water Biofilms under Different Flow Regimes. Microorganisms 2023; 11:2680. [PMID: 38004692 PMCID: PMC10673482 DOI: 10.3390/microorganisms11112680] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/19/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
Water companies make efforts to reduce the risk of microbial contamination in drinking water. A widely used strategy is to introduce chlorine into the drinking water distribution system (DWDS). A subtle potential risk is that non-lethal chlorine residuals may select for chlorine resistant species in the biofilms that reside in DWDS. Here, we quantify the thickness, density, and coverage of naturally occurring multi-species biofilms grown on slides in tap water with and without chlorine, using fluorescence microscopy. We then place the slides in an annular rotating reactor and expose them to fluid-wall shears, which are redolent of those on pipe walls in DWDS. We found that biofilms in chlorine experiment were thicker, denser and with higher coverage than in non-chlorine conditions under all flow regimes and during incubation. This suggests that the formation and development of biofilms was promoted by chlorine. Surprisingly, for both chlorinated and non-chlorinated conditions, biofilm thickness, density and coverage were all positively correlated with shear stress. More differences were detected in biofilms under the different flow regimes in non-chlorine than in chlorine experiments. This suggests a more robust biofilm under chlorine conditions. While this might imply less mobilization of biofilms in high shear events in pipe networks, it might also provide refuge from chlorine residuals for pathogens.
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Affiliation(s)
- Erifyli Tsagkari
- School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK;
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Farjami A, Jalilzadeh S, Siahi-Shadbad M, Lotfipour F. The anti-biofilm activity of hydrogen peroxide against Escherichia coli strain FL-Tbz isolated from a pharmaceutical water system. JOURNAL OF WATER AND HEALTH 2022; 20:1497-1505. [PMID: 36308494 DOI: 10.2166/wh.2022.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Biofilms are considered a significant reason for the failure of disinfection strategies in industrial water systems due to their resistance to antimicrobial agents. This study is designed to investigate the anti-biofilm activity of hydrogen peroxide (H2O2) at combinations of temperatures and contact times. For this purpose, an in vitro microtiter plate (MTP)-based model system was used for biofilm formation using Escherichia coli (E. coli) strain FL-Tbz isolated from the water system of a pharmaceutical plant. To investigate the anti-biofilm activity of H2O2, it was added at different concentrations (2-7% v/v) to biofilms and incubated at different temperatures (20-60 °C) for 10-40 min to find effective conditions to eradicate biofilms. Maximum biofilms were formed when bacterial suspensions were incubated at 37 °C for 96 h. The rate of biofilm formation using an environmental isolate was higher than that of standard strain. H2O2 at concentrations of ≥6.25% (v/v) at temperatures of ≥40 °C incubated for ≥25 min significantly eradicated the biofilms.
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Affiliation(s)
- Afsaneh Farjami
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sina Jalilzadeh
- Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammadreza Siahi-Shadbad
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran E-mail: ; Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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Characterization of a Novel Regulator of Biofilm Formation in the Pathogen Legionella pneumophila. Biomolecules 2022; 12:biom12020225. [PMID: 35204726 PMCID: PMC8961574 DOI: 10.3390/biom12020225] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/23/2022] [Accepted: 01/24/2022] [Indexed: 12/22/2022] Open
Abstract
Legionella pneumophila is a Gram-negative, facultative intracellular pathogen that causes severe pneumonia known as Legionnaires’ disease. The bacterium causes disease when contaminated water is aerosolized and subsequently inhaled by individuals, which allows the bacteria to gain access to the lungs, where they infect alveolar macrophages. L. pneumophila is ubiquitous in the environment, where it survives by growing in biofilms, intracellularly within protozoa, and planktonically. Biofilms are a major concern for public health because they provide a protective niche that allows for the continuous leaching of bacteria into the water supply. In addition, biofilms enhance the survival of the bacteria by increasing resistance to temperature fluctuations and antimicrobial agents. Currently, there is little known about biofilm formation and regulation by L. pneumophila. Here, we present evidence of a specific gene, bffA, which appears to be involved in the regulation of motility, biofilm formation, cellular replication, and virulence of L. pneumophila. A strain lacking bffA has an enhanced biofilm formation phenotype, forming biofilms that are both faster and thicker than wild type. Additionally, the knockout strain has significantly reduced motility, enhanced uptake into amoebae, and altered growth kinetics on solid media. Our data suggest a potential role for bffA in signaling pathways that govern changes in growth rate and motility in response to environmental conditions.
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Farjami A, Hatami MS, Siahi-Shadbad M, Lotfipour F. Peracetic acid Activity on Biofilm Formed by Escherichia coli Isolated from an Industrial Water System. Lett Appl Microbiol 2022; 74:613-621. [PMID: 34984695 DOI: 10.1111/lam.13647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 12/26/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022]
Abstract
One of the major problems in industrial water systems is the generation of biofilm, which is resistant to antimicrobial agents and causes failure of sanitization policy. This work aimed to study the anti-biofilm activity of peracetic acid (PAA) at contact times and temperatures combinations. To this end, a 96 well microtiter-based calorimetric method was applied in in vitro biofilm production using Ecsherichia coli, isolated from the water supply system of a pharmaceutical plant. The phenotypic and phylogenetic tests confirmed the isolated bacteria belong to strains of Ecsherichia coli. The anti-biofilm activity of peracetic acid on formed biofilm was investigated at concentrations of 0.15-0.5% for a contact time of 5-15 min at 20°C to 60°C. The maximum biofilm formation by MTP method using an Ecsherichia coli isolate was achieved in 96 h incubation in TSB containing wells at 37°C. Biofilm formation rate showed to be high by the environmental isolate compared with that of standard strain. PAA at concentrations above 0.25%, the temperature of 40°C, and a minimum of 10 minutes of contact time was effective in the eradication of biofilm in an MPT-based system.
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Affiliation(s)
- Afsaneh Farjami
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Pharmaceutical Analysis Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Mohammadreza Siahi-Shadbad
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzaneh Lotfipour
- Food and Drug Safety Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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8
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Zhang C, Lu J. Legionella: A Promising Supplementary Indicator of Microbial Drinking Water Quality in Municipal Engineered Water Systems. FRONTIERS IN ENVIRONMENTAL SCIENCE 2021; 9:1-22. [PMID: 35004706 PMCID: PMC8740890 DOI: 10.3389/fenvs.2021.684319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Opportunistic pathogens (OPs) are natural inhabitants and the predominant disease causative biotic agents in municipal engineered water systems (EWSs). In EWSs, OPs occur at high frequencies and concentrations, cause drinking-water-related disease outbreaks, and are a major factor threatening public health. Therefore, the prevalence of OPs in EWSs represents microbial drinking water quality. Closely or routinely monitoring the dynamics of OPs in municipal EWSs is thus critical to ensuring drinking water quality and protecting public health. Monitoring the dynamics of conventional (fecal) indicators (e.g., total coliforms, fecal coliforms, and Escherichia coli) is the customary or even exclusive means of assessing microbial drinking water quality. However, those indicators infer only fecal contamination due to treatment (e.g., disinfection within water utilities) failure and EWS infrastructure issues (e.g., water main breaks and infiltration), whereas OPs are not contaminants in drinking water. In addition, those indicators appear in EWSs at low concentrations (often absent in well-maintained EWSs) and are uncorrelated with OPs. For instance, conventional indicators decay, while OPs regrow with increasing hydraulic residence time. As a result, conventional indicators are poor indicators of OPs (the major aspect of microbial drinking water quality) in EWSs. An additional or supplementary indicator that can well infer the prevalence of OPs in EWSs is highly needed. This systematic review argues that Legionella as a dominant OP-containing genus and natural inhabitant in EWSs is a promising candidate for such a supplementary indicator. Through comprehensively comparing the behavior (i.e., occurrence, growth and regrowth, spatiotemporal variations in concentrations, resistance to disinfectant residuals, and responses to physicochemical water quality parameters) of major OPs (e.g., Legionella especially L. pneumophila, Mycobacterium, and Pseudomonas especially P. aeruginosa), this review proves that Legionella is a promising supplementary indicator for the prevalence of OPs in EWSs while other OPs lack this indication feature. Legionella as a dominant natural inhabitant in EWSs occurs frequently, has a high concentration, and correlates with more microbial and physicochemical water quality parameters than other common OPs. Legionella and OPs in EWSs share multiple key features such as high disinfectant resistance, biofilm formation, proliferation within amoebae, and significant spatiotemporal variations in concentrations. Therefore, the presence and concentration of Legionella well indicate the presence and concentrations of OPs (especially L. pneumophila) and microbial drinking water quality in EWSs. In addition, Legionella concentration indicates the efficacies of disinfectant residuals in EWSs. Furthermore, with the development of modern Legionella quantification methods (especially quantitative polymerase chain reactions), monitoring Legionella in ESWs is becoming easier, more affordable, and less labor-intensive. Those features make Legionella a proper supplementary indicator for microbial drinking water quality (especially the prevalence of OPs) in EWSs. Water authorities may use Legionella and conventional indicators in combination to more comprehensively assess microbial drinking water quality in municipal EWSs. Future work should further explore the indication role of Legionella in EWSs and propose drinking water Legionella concentration limits that indicate serious public health effects and require enhanced treatment (e.g., booster disinfection).
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Affiliation(s)
- Chiqian Zhang
- Pegasus Technical Services, Inc., Cincinnati, OH, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH, United States
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Lytle DA, Pfaller S, Muhlen C, Struewing I, Triantafyllidou S, White C, Hayes S, King D, Lu J. A comprehensive evaluation of monochloramine disinfection on water quality, Legionella and other important microorganisms in a hospital. WATER RESEARCH 2021; 189:116656. [PMID: 33249307 PMCID: PMC8133025 DOI: 10.1016/j.watres.2020.116656] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 05/22/2023]
Abstract
Opportunistic pathogens such as Legionella are of significant public health concern in hospitals. Microbiological and water chemistry parameters in hot water throughout an Ohio hospital were monitored monthly before and after the installation of a monochloramine disinfection system over 16 months. Water samples from fifteen hot water sampling sites as well as the municipal water supply entering the hospital were analyzed using both culture and qPCR assays for specific microbial pathogens including Legionella, Pseudomonas spp., nontuberculous Mycobacteria [NTM], as well as for heterotrophic bacteria. Legionella culture assays decreased from 68% of all sites being positive prior to monochloramine addition to 6% positive after monochloramine addition, and these trends were parallel to qPCR results. Considering all samples, NTMs by culture were significantly reduced from 61% to 14% positivity (p<0.001) after monochloramine treatment. Mycobacterium genus-specific qPCR positivity was reduced from 92% to 65%, but the change was not significant. Heterotrophic bacteria (heterotrophic bacteria plate counts [HPCs]) exhibited large variability which skewed statistical results on a per room basis. However, when all samples were considered, a significant decrease in HPCs was observed after monochloramine addition. Lastly, Pseudomonas aeruginosa and Vermamoeba vermiformis demonstrated large and significant decrease of qPCR signals post-chloramination. General water chemistry parameters including monochloramine residual, nitrate, nitrite, pH, temperature, metals and total trihalomethanes (TTHMs) were also measured. Significant monochloramine residuals were consistently observed at all sampling sites with very little free ammonia present and no water quality indications of nitrification (e.g., pH decrease, elevated nitrite or nitrate). The addition of monochloramine had no obvious impact on metals (lead, copper and iron) and disinfection by-products.
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Affiliation(s)
- Darren A Lytle
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States.
| | - Stacy Pfaller
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Christy Muhlen
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Ian Struewing
- U.S. Environmental Protection Agency, ORD, Center for Environmental Measurement and Modelling (CEMM), 26 W. Martin Luther King Drive, Cincinnati, OH 45268, United States
| | - Simoni Triantafyllidou
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Colin White
- Ohio Environmental Protection Agency, Emerging Contaminants Section, Division of Drinking and Ground Waters, 50 West Town Street, Suite 700 Columbus, OH 43215, United States
| | - Sam Hayes
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Dawn King
- U.S. Environmental Protection Agency, ORD, Center for Environmental Solutions and Emergency Response (CESER), 26 W. Martin Luther King Drive, Cincinnati, OH, 45268, United States
| | - Jingrang Lu
- U.S. Environmental Protection Agency, ORD, Center for Environmental Measurement and Modelling (CEMM), 26 W. Martin Luther King Drive, Cincinnati, OH 45268, United States
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Lu MC, Chen PL, Huang DJ, Liang CK, Hsu CS, Liu WT. Disinfection efficiency of hospital infectious disease wards with chlorine dioxide and hypochlorous acid. AEROBIOLOGIA 2020; 37:29-38. [PMID: 33169045 PMCID: PMC7642575 DOI: 10.1007/s10453-020-09670-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
The disinfection efficiencies of two chemical disinfectants, chlorine dioxide and weak acid hypochlorous water (WAHW), were examined in the soiled room and dishwashing room of a hospital infectious disease ward in Taiwan. The investigations were conducted in two seasons, namely winter and summer, in order to examine the correlation between the bioaerosol concentration and the environmental factors. In addition, a single-daily disinfection mode (SM) and a twice-daily disinfection mode (TM) were applied in this study. The results showed that the bacteria and fungi colony counts were strongly correlated with the temperature. Both disinfectants reduced the bacteria and fungi concentrations in the considered rooms. However, of the two disinfectants, the ClO2 showed a stronger disinfection effect than the WAHW. It means that when using ClO2 as the disinfectant, the disinfection efficiency of the TM treatment mode is significantly better than that of the SM treatment mode. But, when using WAHW as the disinfectant, no significant difference is found between the disinfection efficiencies of the two methods. Overall, the results showed that the application of ClO2 twice daily provided the most effective means of satisfying the Taiwan EPA guidelines for the indoor air quality of hospital medical wards.
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Affiliation(s)
- Ming-Chun Lu
- Department of Environmental Resources Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710 Taiwan
| | - Po-Lin Chen
- Center for Infection Control and Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, 70101 Taiwan
| | - Da-Ji Huang
- Department of Environmental Resources Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710 Taiwan
| | - Chih-Kuo Liang
- Department of Electrical Engineering, National Taitung Junior College, Taitung, 95045 Taiwan
| | - Ching-Shan Hsu
- Department of Environmental Resources Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710 Taiwan
| | - Wei-Ting Liu
- Department of Environmental Resources Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710 Taiwan
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Nisar MA, Ross KE, Brown MH, Bentham R, Whiley H. Legionella pneumophila and Protozoan Hosts: Implications for the Control of Hospital and Potable Water Systems. Pathogens 2020; 9:pathogens9040286. [PMID: 32326561 PMCID: PMC7238060 DOI: 10.3390/pathogens9040286] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 04/10/2020] [Accepted: 04/14/2020] [Indexed: 12/12/2022] Open
Abstract
Legionella pneumophila is an opportunistic waterborne pathogen of public health concern. It is the causative agent of Legionnaires’ disease (LD) and Pontiac fever and is ubiquitous in manufactured water systems, where protozoan hosts and complex microbial communities provide protection from disinfection procedures. This review collates the literature describing interactions between L. pneumophila and protozoan hosts in hospital and municipal potable water distribution systems. The effectiveness of currently available water disinfection protocols to control L. pneumophila and its protozoan hosts is explored. The studies identified in this systematic literature review demonstrated the failure of common disinfection procedures to achieve long term elimination of L. pneumophila and protozoan hosts from potable water. It has been demonstrated that protozoan hosts facilitate the intracellular replication and packaging of viable L. pneumophila in infectious vesicles; whereas, cyst-forming protozoans provide protection from prolonged environmental stress. Disinfection procedures and protozoan hosts also facilitate biogenesis of viable but non-culturable (VBNC) L. pneumophila which have been shown to be highly resistant to many water disinfection protocols. In conclusion, a better understanding of L. pneumophila-protozoan interactions and the structure of complex microbial biofilms is required for the improved management of L. pneumophila and the prevention of LD.
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Carlson KM, Boczek LA, Chae S, Ryu H. Legionellosis and Recent Advances in Technologies for Legionella Control in Premise Plumbing Systems: A Review. WATER 2020; 12:1-676. [PMID: 32704396 PMCID: PMC7377215 DOI: 10.3390/w12030676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review discusses Legionella, among the most prolific and publicly well-known waterborne pathogens, and advances in potential treatment technologies. The number of cases associated with Legionella continues to rise, as does its public awareness. Currently, cases associated with premise plumbing account for the largest number of legionellosis cases in the United States. So, while it is important to understand Legionella as such, it is also important to investigate how to treat drinking water in premise plumbing for Legionella and other waterborne pathogens. While there are currently several methods recognized as potential means of inactivating waterborne pathogens, several shortcomings continue to plague its implementation. These methods are generally of two types. Firstly, there are chemical treatments such as chlorine, chlorine dioxide, monochloramine, ozone, and copper-silver ionization. Secondly, there are physical treatments such as thermal inactivation and media filtration. Their shortcomings range from being labor-intensive and costly to having negative health effects if not properly operated. Recently developed technologies including ultraviolet (UV) irradiation using light emitting diodes (LEDs) and innovative carbon nanotube (CNT) filters can better control waterborne pathogens by allowing for the simultaneous use of different treatment measures in plumbing systems.
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Affiliation(s)
- Kelsie M. Carlson
- United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45268, USA
| | - Laura A. Boczek
- United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
| | - Soryong Chae
- Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45268, USA
| | - Hodon Ryu
- United States Environmental Protection Agency, Office of Research and Development, 26 W. Martin Luther King Dr., Cincinnati, OH 45268, USA
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13
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Cortés-Sánchez ADJ. Legionella, water and biotechnology. REGULATORY MECHANISMS IN BIOSYSTEMS 2019. [DOI: 10.15421/021918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Legionella spp. are microorganisms that are generally found in the aquatic environment (rivers, streams, lakes, among others). The importance in public health is in the fact that this bacterium is capable of multiplying and propagating in artificial aquatic systems (piping systems, storage tanks, fountains, and cooling towers), giving rise to diseases in humans called legionellosis, transmitted by inhalation of contaminated water droplets or aerosols and whose complications can lead to the death of the patient. Legionellosis is of worldwide distribution, Legionella pneumophila being the most commonly involved species in outbreaks and reported cases. The people most at risk are the elderly, people with weakened immune systems, and people with a history of smoking. Around the world, regulatory agencies and health organizations have issued and established recommendations with the purpose of controlling and preventing the risk of contracting this disease, which include the sanitation of water supplies, maintenance through regular cleaning and disinfection of facilities and devices for reducing the presence of this pathogen. The main objective of this review is to present in a general manner, aspects related to the disease known as legionellosis, its casual agents, habitat, transmission form, and phenotypic and metabolic characteristics. Likewise, the methods of control and prevention of these pathogens are presented, including a potential biotechnological alternative that can contribute to actions in favour of the protection of public health through the use of compounds with surface activity called biosurfactants.
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Chlorine and Monochloramine Disinfection of Legionella pneumophila Colonizing Copper and Polyvinyl Chloride Drinking Water Biofilms. Appl Environ Microbiol 2019; 85:AEM.02956-18. [PMID: 30683743 DOI: 10.1128/aem.02956-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 01/09/2019] [Indexed: 11/20/2022] Open
Abstract
Building water systems promote the regrowth and survival of opportunistic pathogens, such as Legionella pneumophila, especially within biofilms, where most drinking water microbes reside. However, compared to their planktonic form, disinfection efficacy for the biofilm-associated forms of water-based pathogens is unclear. The aim of this study was to determine the effectiveness of free chlorine and monochloramine in the inactivation of biofilm-associated L. pneumophila strain Philadelphia-1 serogroup 1 (LpP1s1). Mature (1.5- to 2-year-old) drinking water biofilms were developed on copper (Cu) and polyvinyl chloride (PVC) slides within biofilm annular reactors, then colonized with LpP1s1 at approximately 4 log10 CFU cm-2 and exposed to 2 mg liter-1 of free chlorine or monochloramine. Ct (disinfectant concentration × time, expressed as mg min liter-1) inactivation values for 2-, 3-, and 4-log10 reductions of planktonic and biofilm LpP1s1 were determined. For planktonic LpP1s1, free chlorine was more effective at inactivation than was monochloramine treatment, and for biofilm-associated LpP1s1, monochloramine was more effective on Cu biofilms while free chlorine was more effective on PVC biofilms. In contrast to monochloramine, free chlorine treatment of Cu and PVC biofilms, negatively impacted LpP1s1 16S rRNA gene transcript levels and may act synergistically with Cu surfaces to further reduce transcript levels. Moreover, LpP1s1 cells shed from biofilms into the bulk water were more resistant to disinfection than were prepared planktonic LpP1s1 cells. Results from this study indicate that biofilm association, disinfectant type, and substratum play an important role in the survival of Legionella pneumophila in building water systems.IMPORTANCE Microbial regrowth within building water systems are promoted by water stagnation, low disinfectant residual, high surface-to-volume ratio, amenable growth temperatures, and colonization of drinking water biofilms. Moreover, biofilms provide protection from environmental stresses, access to higher levels of nutrients, and opportunities for symbiotic interactions with other microbes. Disinfectant efficacy information is historically based on inactivation of pathogens in their planktonic, free-floating forms. However, due to the ecological importance of drinking water biofilms for pathogen survival, this study evaluated the efficacy of two common disinfectants, free chlorine and monochloramine, on Legionella pneumophila colonizing mature, drinking water biofilms established on copper and PVC surfaces. Results showed that inactivation was dependent on the disinfectant type and biofilm substratum. Overall, this, and other related research, will provide a better understanding of Legionella ecological stability and survival and aid policy makers in the management of exposure risks to water-based pathogens within building water systems.
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LeChevallier MW. Monitoring distribution systems for
Legionella pneumophila
using Legiolert. ACTA ACUST UNITED AC 2019. [DOI: 10.1002/aws2.1122] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Bertelli C, Courtois S, Rosikiewicz M, Piriou P, Aeby S, Robert S, Loret JF, Greub G. Reduced Chlorine in Drinking Water Distribution Systems Impacts Bacterial Biodiversity in Biofilms. Front Microbiol 2018; 9:2520. [PMID: 30405577 PMCID: PMC6205969 DOI: 10.3389/fmicb.2018.02520] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 10/03/2018] [Indexed: 12/14/2022] Open
Abstract
In drinking water distribution systems (DWDS), a disinfectant residual is usually applied to limit bacterial regrowth. However, delivering water with no or reduced chlorine residual could potentially decrease the selection for antimicrobial resistant microorganisms, favor bacterial regrowth and result in changes in bacterial populations. To evaluate the feasibility of water reduction in local DWDS while ensuring water safety, water quality was measured over 2 months in two different networks, each of them harboring sub-areas with normal and reduced chlorine. Water quality remained good in chlorine reduced samples, with limited development of total flora and absence of coliforms. Furthermore, 16S rRNA amplicon-based metagenomics was used to investigate the diversity and the composition of microbial communities in the sub-networks. Taxonomic classification of sequence reads showed a reduced bacterial diversity in sampling points with higher chlorine residuals. Chlorine disinfection created more homogeneous bacterial population, dominated by Pseudomonas, a genus that contains some major opportunistic pathogens such as P. aeruginosa. In the absence of chlorine, a larger and unknown biodiversity was unveiled, also highlighted by a decreased rate of taxonomic classification to the genus and species level. Overall, this experiment in a functional DWDS will facilitate the move toward potable water delivery systems without residual disinfectants and will improve water taste for consumers.
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Affiliation(s)
- Claire Bertelli
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | - Marta Rosikiewicz
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | - Sébastien Aeby
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | | | | | - Gilbert Greub
- Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
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Grunert A, Frohnert A, Selinka HC, Szewzyk R. A new approach to testing the efficacy of drinking water disinfectants. Int J Hyg Environ Health 2018; 221:1124-1132. [PMID: 30098909 DOI: 10.1016/j.ijheh.2018.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 12/29/2022]
Abstract
New disinfection procedures are being developed and proposed for use in drinking-water production. Authorising their use requires an effective test strategy that can simulate conditions in practice. For this purpose, we developed a test rig working in a flow-through mode similar to the disinfection procedures in waterworks, but under tightly defined conditions, including very short contact times. To quantify the influence of DOC, temperature and pH on the efficacy of two standard disinfectants, chlorine and chlorine dioxide, simulated use tests were systematically performed. This test rig enabled quantitative comparison of the reduction of four test organisms, two viruses and two bacteria, in response to disinfection. Chlorine was substantially more effective against Enterococcus faecium than chlorine dioxide whereas the latter was more effective against the bacteriophage MS2, especially at pH values of >7.5 at which chlorine efficacies already decline. Contrary to expectation, bacteria were not generally reduced more quickly than viruses. Overall, the results confirm a high efficacy of chlorine and chlorine dioxide, validating them as standard disinfectants for assessing the efficacy of new disinfectants. Furthermore, these data demonstrate that the test rig is an appropriate tool for testing new disinfectants as well as disinfection procedures.
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Affiliation(s)
- Andreas Grunert
- Federal Environment Agency, Section Drinking Water Treatment, Schichauweg 58, D-12307, Berlin, Germany.
| | - Anne Frohnert
- Federal Environment Agency, Section Microbiological Risks, Corrensplatz 1, D-14197, Berlin, Germany
| | - Hans-Christoph Selinka
- Federal Environment Agency, Section Microbiological Risks, Corrensplatz 1, D-14197, Berlin, Germany
| | - Regine Szewzyk
- Federal Environment Agency, Section Microbiological Risks, Corrensplatz 1, D-14197, Berlin, Germany
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Lu MC, Huang DJ, Hsu CS, Liang CK, Chen GM. Improvement of indoor air quality in pet shop using gaseous chlorine dioxide. ENVIRONMENTAL MONITORING AND ASSESSMENT 2018; 190:371. [PMID: 29858706 DOI: 10.1007/s10661-018-6723-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 05/11/2018] [Indexed: 05/26/2023]
Abstract
Many studies have shown that pet shops have a high concentration of bioaerosols. Thus, effective disinfection protocols are essential to protect the pet shop staff and visitors to the store. The present study examines the effectiveness of gaseous chlorine dioxide (ClO2) fogging in minimizing the residual bacteria and fungi levels in a typical pet shop in Taiwan consisting of a commodity area, a lodging area, and a grooming area. This investigation uses three disinfection modes (DMs) according to different disinfection periods, namely once every hour (1DM), once every 2 h (2DM), and once every 3 h (3DM). The bacteria and fungi concentrations are measured before and after disinfection treatment, and the effectiveness of each disinfection mode is evaluated using standard statistical techniques. To assess the effect of the environmental factors on the disinfection efficiency, measurements are taken of temperature, relative humidity, airflow velocity, the carbon dioxide concentration, the PM1, PM2.5, PM7, PM10, and TSP level at each sampling locations. The results reveal that the effectiveness of the three disinfection modes depends on both the environmental parameters and the use of the three areas (e.g., commodity, lodging, or grooming). Hence, the choice of disinfection method should be adjusted accordingly. For all three disinfection modes, a faster air velocity is beneficial in spreading the disinfectant throughout the indoor space and improving the disinfection performance. Overall, the results presented in this study confirm that gaseous chlorine dioxide disinfection improves the air quality in the pet shop interior, and thus beneficial in safeguarding the health of the pet shop staff and visitors.
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Affiliation(s)
- Ming-Chun Lu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan
| | - Da-Ji Huang
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan
| | - Ching-Shan Hsu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan.
| | - Chih-Kuo Liang
- Department of Electrical Engineering, National Taitung Junior College, Taitung, 95045, Taiwan
| | - Geng-Min Chen
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan
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19
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Stüken A, Haverkamp THA, Dirven HAAM, Gilfillan GD, Leithaug M, Lund V. Microbial Community Composition of Tap Water and Biofilms Treated with or without Copper-Silver Ionization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3354-3364. [PMID: 29461810 DOI: 10.1021/acs.est.7b05963] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Copper-silver ionization (CSI) is an in-house water disinfection method primarily installed to eradicate Legionella bacteria from drinking water distribution systems (DWDS). Its effect on the abundance of culturable Legionella and Legionella infections has been documented in several studies. However, the effect of CSI on other bacteria in DWDS is largely unknown. To investigate these effects, we characterized drinking water and biofilm communities in a hospital using CSI, in a neighboring building without CSI, and in treated drinking water at the local water treatment plant. We used 16S rDNA amplicon sequencing and Legionella culturing. The sequencing results revealed three distinct water groups: (1) cold-water samples (no CSI), (2) warm-water samples at the research institute (no CSI), and (3) warm-water samples at the hospital (after CSI; ANOSIM, p < 0.001). Differences between the biofilm communities exposed and not exposed to CSI were less clear (ANOSIM, p = 0.022). No Legionella were cultured, but limited numbers of Legionella sequences were recovered from all 25 water samples (0.2-1.4% relative abundance). The clustering pattern indicated local selection of Legionella types (Kruskal-Wallis, p < 0.001). Furthermore, one unclassified Betaproteobacteria OTU was highly enriched in CSI-treated warm water samples at the hospital (Kruskal-Wallis, p < 0.001).
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Affiliation(s)
- Anke Stüken
- Dept. Zoonotic, Food and Waterborne Infections , Norwegian Institute of Public Health , Oslo , Norway
| | - Thomas H A Haverkamp
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences , University of Oslo , Blindern, Oslo , Norway
| | - Hubert A A M Dirven
- Dept. Toxicology and Risk Assessment , Norwegian Institute of Public Health , Oslo , Norway
| | - Gregor D Gilfillan
- Dept. Medical Genetics , Oslo University Hospital and University of Oslo , Oslo , Norway
| | - Magnus Leithaug
- Dept. Medical Genetics , Oslo University Hospital and University of Oslo , Oslo , Norway
| | - Vidar Lund
- Dept. Zoonotic, Food and Waterborne Infections , Norwegian Institute of Public Health , Oslo , Norway
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20
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Iervolino M, Mancini B, Cristino S. Industrial Cooling Tower Disinfection Treatment to Prevent Legionella spp. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E1125. [PMID: 28954435 PMCID: PMC5664626 DOI: 10.3390/ijerph14101125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/19/2017] [Accepted: 09/22/2017] [Indexed: 01/22/2023]
Abstract
The contamination of industrial cooling towers has been identified as one cause of legionellosis, but the real risk has been underestimated. Two different disinfection treatments were tested on Legionella colonization in an industrial Cooling Tower System (CTS). Environmental monitoring of Legionella, P. aeruginosa, and a heterotrophic plate count (HPC) at 36 °C was performed from June to October 2016. The disinfection procedures adopted were based on hydrogen peroxide (H₂O₂) and silver salts (Ag⁺), in addition to an anti-algal treatment, then using hyperclorination as a shock, and then continuous treatment by sodium hypochlorite (NaClO). L. pneumophila serogroup 8 was found at a concentration of 5.06 Log cfu/L after the CTS filling; a shock treatment performed by H₂O₂/Ag⁺ produced a rapid increase in contamination up to 6.14 Log cfu/L. The CTS activity was stopped and two subsequent shock treatments were performed using NaClO, followed by continuous hyperclorination. These procedures showed a significant decrease (p < 0.05) in Legionella concentration (1.77 Log cfu/L). The same trend was observed for P. aeruginosa (0.55 Log cfu/100 mL) and HPC (1.95 Log cfu/mL) at 36 °C. Environmental monitoring and the adoption of maintenance procedures, including anti-scale treatment, and physical, chemical, and microbiological control, ensure the good performance of a CTS, reducing the Legionella risk for public health.
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Affiliation(s)
- Matteo Iervolino
- Department of Biological, Geological and Environmental Sciences, BiGeA, University of Bologna, via San Giacomo 12, 40126 Bologna, Italy.
| | - Benedetta Mancini
- Department of Biological, Geological and Environmental Sciences, BiGeA, University of Bologna, via San Giacomo 12, 40126 Bologna, Italy.
| | - Sandra Cristino
- Department of Biological, Geological and Environmental Sciences, BiGeA, University of Bologna, via San Giacomo 12, 40126 Bologna, Italy.
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21
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Uysal T, Yilmaz S, Turkoglu M, Sadikoglu M. Investigation of some disinfection chemicals and water quality parameters in swimming pools in the city center and districts of Canakkale, Turkey. ENVIRONMENTAL MONITORING AND ASSESSMENT 2017; 189:338. [PMID: 28620710 DOI: 10.1007/s10661-017-6031-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
In this study, the variations in concentrations of some disinfection chemicals such as cyanuric acid (CyA), free chlorine (FC), and residual chlorine (RC), which affect human health, were investigated in the water of swimming pools. In addition, quality parameters such as temperature, pH, and total alkalinity (TA) in 44 swimming pools located in the city center and districts of Canakkale, Turkey, were examined in the summer period. While FC and RC amounts were analyzed using tablet tests with N-N-diethyl phenylenediamine (DPD 1) and potassium iodine (DPD 3) using the colorimetric method in the comparator, TA and CyA levels were measured with a photometric method. Temperature and pH were measured using YSI 556 MPS. Levels of CyA, FC, RC, pH, temperature, and TA varied between 0.00 and 725.0 mg L-1 (108.0 ± 111.4 mg L-1), 0.00 and 5.00 mg L-1 (1.60 ± 0.962 mg L-1), 0 and 0.55 mg L-1 (0.087 ± 0.059), 6.40 and 8.20 mg L-1 (7.30 ± 0.038 mg L-1), 22.0 and 32.0 °C (27.6 ± 1.45 °C), and 0.00 and 391.0 mg L-1 (129.3 ± 89.0), respectively. The findings were compared to standard limit values of the Ministry of Health of the Turkish Republic and other countries. Not only maximum concentrations of CyA but also the average concentrations exceeded the standard limit values of different countries in July and August with high tourism activity in Turkey. Although there is no problem in view of average values of other quality parameters, there are some problems in view of the maximum values in pool waters compared to standard limit values.
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Affiliation(s)
- Tolga Uysal
- Faculty of Arts and Sciences, Department of Chemistry, Canakkale Onsekiz Mart University, Terzioglu Campus, 17020, Canakkale, Turkey
| | - Selehattin Yilmaz
- Faculty of Arts and Sciences, Department of Chemistry, Canakkale Onsekiz Mart University, Terzioglu Campus, 17020, Canakkale, Turkey
| | - Muhammet Turkoglu
- Faculty of Marine Sciences and Technology, Department of Hydrobiology, Canakkale Onsekiz Mart University, Terzioglu Campus, 17020, Canakkale, Turkey
| | - Murat Sadikoglu
- Faculty of Education, Department of Science Education, Gaziosmanpasa University, 60240, Tokat, Turkey.
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22
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Miller HC, Morgan MJ, Wylie JT, Kaksonen AH, Sutton D, Braun K, Puzon GJ. Elimination of Naegleria fowleri from bulk water and biofilm in an operational drinking water distribution system. WATER RESEARCH 2017; 110:15-26. [PMID: 27974249 DOI: 10.1016/j.watres.2016.11.061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/07/2016] [Accepted: 11/25/2016] [Indexed: 06/06/2023]
Abstract
Global incidence of primary amoebic meningoencephalitis cases associated with domestic drinking water is increasing. The need for understanding disinfectant regimes capable of eliminating the causative microorganism, Naegleria fowleri, from bulk water and pipe wall biofilms is critical. This field study demonstrated the successful elimination of N. fowleri from the bulk water and pipe wall biofilm of a persistently colonised operational drinking water distribution system (DWDS), and the prevention of further re-colonisation. A new chlorination unit was installed along the pipe line to boost the free chlorine residual to combat the persistence of N. fowleri. Biofilm and bulk water were monitored prior to and after re-chlorination (RCl), pre-rechlorination (pre-RCl) and post-rechlorination (post-RCl), respectively, for one year. A constant free chlorine concentration of > 1 mg/L resulted in the elimination of N. fowleri from both the bulk water and biofilm at the post-RCl site. Other amoeba species were detected during the first two months of chlorination, but all amoebae were eliminated from both the bulk water and biofilm at post-RCl after 60 days of chlorination with free chlorine concentrations > 1 mg/L. In addition, a dynamic change in the biofilm community composition and a four log reduction in biofilm cell density occurred post-RCl. The pre-RCl site continued to be seasonally colonised by N. fowleri, but the constant free chlorine residual of > 1 mg/L prevented N. fowleri from recolonising the bulk and pipe wall biofilm at the post-RCl site. To our knowledge, this is the first study to demonstrate successful removal of N. fowleri from both the bulk and pipe wall biofilm and prevention of re-colonisation of N. fowleri in an operational DWDS. The findings of this study are of importance to water utilities in addressing the presence of N. fowleri and other amoeba in susceptible DWDSs.
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Affiliation(s)
- Haylea C Miller
- CSIRO Land and Water, Private Bag No.5, Wembley, Western Australia 6913, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Matthew J Morgan
- CSIRO Land and Water, Black Mountain Laboratories, P.O. Box 1700, Canberra, ACT 2601, Australia
| | - Jason T Wylie
- CSIRO Land and Water, Private Bag No.5, Wembley, Western Australia 6913, Australia
| | - Anna H Kaksonen
- CSIRO Land and Water, Private Bag No.5, Wembley, Western Australia 6913, Australia; School of Pathology and Laboratory Medicine, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - David Sutton
- School of Pathology and Laboratory Medicine, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Kalan Braun
- Water Corporation of Western Australia, 629 Newcastle Street, Leederville, Western Australia 6007, Australia
| | - Geoffrey J Puzon
- CSIRO Land and Water, Private Bag No.5, Wembley, Western Australia 6913, Australia.
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Mendis N, McBride P, Faucher SP. Short-Term and Long-Term Survival and Virulence of Legionella pneumophila in the Defined Freshwater Medium Fraquil. PLoS One 2015; 10:e0139277. [PMID: 26406895 PMCID: PMC4583229 DOI: 10.1371/journal.pone.0139277] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/09/2015] [Indexed: 12/03/2022] Open
Abstract
Legionella pneumophila (Lp) is the etiological agent responsible for Legionnaires’ disease, a potentially fatal pulmonary infection. Lp lives and multiplies inside protozoa in a variety of natural and man-made water systems prior to human infection. Fraquil, a defined freshwater medium, was used as a highly reproducible medium to study the behaviour of Lp in water. Adopting a reductionist approach, Fraquil was used to study the impact of temperature, pH and trace metal levels on the survival and subsequent intracellular multiplication of Lp in Acanthamoeba castellanii, a freshwater protozoan and a natural host of Legionella. We show that temperature has a significant impact on the short- and long-term survival of Lp, but that the bacterium retains intracellular multiplication potential for over six months in Fraquil. Moreover, incubation in Fraquil at pH 4.0 resulted in a rapid decline in colony forming units, but was not detrimental to intracellular multiplication. In contrast, variations in trace metal concentrations had no impact on either survival or intracellular multiplication in amoeba. Our data show that Lp is a resilient bacterium in the water environment, remaining infectious to host cells after six months under the nutrient-deprived conditions of Fraquil.
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Affiliation(s)
- Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Peter McBride
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Sébastien P. Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
- * E-mail:
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24
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Cervero-Aragó S, Rodríguez-Martínez S, Puertas-Bennasar A, Araujo RM. Effect of Common Drinking Water Disinfectants, Chlorine and Heat, on Free Legionella and Amoebae-Associated Legionella. PLoS One 2015; 10:e0134726. [PMID: 26241039 PMCID: PMC4524690 DOI: 10.1371/journal.pone.0134726] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/13/2015] [Indexed: 12/12/2022] Open
Abstract
Chlorine and thermal treatments are the most commonly used procedures to control and prevent Legionella proliferation in drinking water systems of large buildings. However, cases of legionellosis still occur in facilities with treated water. The purpose of this work was to model the effect of temperature and free chlorine applied in similar exposure conditions as in drinking water systems on five Legionella spp. strains and two amoebal strains of the genera Acanthamoeba. Inactivation models obtained were used to determine the effectiveness of the treatments applied which resulted more effective against Legionella than Acanthamoeba, especially those in cystic stages. Furthermore, to determine the influence of the relationship between L. pneumophila and Acanthamoeba spp. on the treatment effectiveness, inactivation models of the bacteria-associated amoeba were also constructed and compared to the models obtained for the free living bacteria state. The Legionella-amoeba association did not change the inactivation models, but it reduced the effectiveness of the treatments applied. Remarkably, at the lowest free chlorine concentration, 0.5 mg L-1, as well as at the lowest temperatures, 50°C and 55°C, the influence of the Legionella-amoeba associate state was the strongest in reducing the effectiveness of the treatments compared to the free Legionella state. Therefore, the association established between L. pneumophila and amoebae in the water systems indicate an increased health risk in proximal areas of the system (close to the tap) where lower free chlorine concentrations and lower temperatures are commonly observed.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Water Hygiene, Institute for Hygiene and Applied Immunology, Medical University of Vienna, Kinderspitalgasse 15, A-1090, Vienna, Austria
| | - Sarah Rodríguez-Martínez
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, 36006, Tivon, Israel
| | - Antoni Puertas-Bennasar
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - Rosa M. Araujo
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
- * E-mail:
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McCoy WF, Rosenblatt AA. HACCP-Based Programs for Preventing Disease and Injury from Premise Plumbing: A Building Consensus. Pathogens 2015; 4:513-28. [PMID: 26184325 PMCID: PMC4584270 DOI: 10.3390/pathogens4030513] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/04/2015] [Accepted: 07/06/2015] [Indexed: 12/22/2022] Open
Abstract
Thousands of preventable injuries and deaths are annually caused by microbial, chemical and physical hazards from building water systems. Water is processed in buildings before use; this can degrade the quality of the water. Processing steps undertaken on-site in buildings often include conditioning, filtering, storing, heating, cooling, pressure regulation and distribution through fixtures that restrict flow and temperature. Therefore, prevention of disease and injury requires process management. A process management framework for buildings is the hazard analysis and critical control point (HACCP) adaptation of failure mode effects analysis (FMEA). It has been proven effective for building water system management. Validation is proof that hazards have been controlled under operating conditions and may include many kinds of evidence including cultures of building water samples to detect and enumerate potentially pathogenic microorganisms. However, results from culture tests are often inappropriately used because the accuracy and precision are not sufficient to support specifications for control limit or action triggers. A reliable negative screen is based on genus-level Polymerase Chain Reaction (PCR) for Legionella in building water systems; however, building water samples with positive results from this test require further analysis by culture methods.
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Affiliation(s)
- William F McCoy
- Phigenics, LLC, 1701 Quincy Ave., Suite 32, Naperville, IL 60540, USA.
| | - Aaron A Rosenblatt
- Gordon & Rosenblatt, LLC, 45 Rockefeller Plaza, 20th Floor, New York, NY 10111, USA.
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Fouque E, Héchard Y, Hartemann P, Humeau P, Trouilhé MC. Sensitivity of Vermamoeba (Hartmannella) vermiformis cysts to conventional disinfectants and protease. JOURNAL OF WATER AND HEALTH 2015; 13:302-310. [PMID: 26042964 DOI: 10.2166/wh.2014.154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Vermamoeba vermiformis is a free-living amoeba (FLA) widely distributed in the environment, known to colonize hot water networks and to be the reservoir of pathogenic bacteria such as Legionella pneumophila. FLA are partly resistant to biocides, especially in their cyst form. The control of V. vermiformis in hot water networks represents an important health issue, but there are very few data on their resistance to disinfection treatments. The sensitivity of cysts of two strains of V. vermiformis to three disinfectants frequently used in hot water networks (chlorine, heat shock, peracetic acid (PAA) mixed with hydrogen peroxide (H2O2)) was investigated. In vitro, several concentrations of biocides, temperatures and exposure times according to the French regulation were tested. Cysts were fully inactivated by the following conditions: 15 mg/L of chlorine for 10 min; 60 °C for 30 min; and 0.5 g/L equivalent H2O2 of PAA mixed with H2O2 for 30 min. For the first time, the strong efficacy of subtilisin (0.625 U/mL for 24 h), a protease, to inactivate the V. vermiformis cysts has been demonstrated. It suggests that novel approaches may be efficient for disinfection processes. Finally, V. vermifomis cysts were sensitive to all the tested treatments and appeared to be more sensitive than Acanthamoeba cysts.
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Affiliation(s)
- Emilie Fouque
- Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail: ; Université de Poitiers, CNRS UMR 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, 1 rue Georges Bonnet, BP 633, 86073 Poitiers Cedex 9, France
| | - Yann Héchard
- Université de Poitiers, CNRS UMR 7267, Laboratoire Ecologie et Biologie des Interactions, Equipe Microbiologie de l'Eau, 1 rue Georges Bonnet, BP 633, 86073 Poitiers Cedex 9, France
| | - Philippe Hartemann
- Faculty of Medicine, INSERM INGRES EA 7298, Department of Environment and Public Health, 9 avenue de la Forêt de Haye, BP 184, 59505 Vandœuvre-lès-Nancy Cedex, France
| | - Philippe Humeau
- Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail:
| | - Marie-Cécile Trouilhé
- Scientific and Technical Center for Building, AQUASIM, 11 rue Henri Picherit, BP 82341, 44323 Nantes Cedex 3, France E-mail:
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Demirjian A, Lucas CE, Garrison LE, Kozak-Muiznieks NA, States S, Brown EW, Wortham JM, Beaudoin A, Casey ML, Marriott C, Ludwig AM, Sonel AF, Muder RR, Hicks LA. The Importance of Clinical Surveillance in Detecting Legionnaires' Disease Outbreaks: A Large Outbreak in a Hospital With a Legionella Disinfection System—Pennsylvania, 2011–2012. Clin Infect Dis 2015; 60:1596-602. [DOI: 10.1093/cid/civ153] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/15/2015] [Indexed: 11/13/2022] Open
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Hsu CS, Lu MC, Huang DJ. Disinfection of indoor air microorganisms in stack room of university library using gaseous chlorine dioxide. ENVIRONMENTAL MONITORING AND ASSESSMENT 2015; 187:17. [PMID: 25626564 DOI: 10.1007/s10661-014-4235-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/12/2014] [Indexed: 05/26/2023]
Abstract
As with all indoor public spaces in Taiwan, the stack rooms in public libraries should meet the air quality guidelines laid down by the Taiwan Environmental Protection Administration. Accordingly, utilizing a university library in Taiwan for experimental purposes, this study investigates the efficiency of gaseous chlorine dioxide (ClO2) as a disinfection agent when applied using three different treatment modes, namely a single-daily disinfection mode (SIM), a twice-daily disinfection mode (TWM), and a triple-daily disinfection mode (TRM). For each treatment mode, the ClO2 is applied using an ultrasonic aerosol device and is performed both under natural lighting conditions and under artificial lighting conditions. The indoor air quality is evaluated before and after each treatment session by measuring the bioaerosol levels of bacteria and fungi. The results show that for all three disinfection modes, the application of ClO2 reduces the indoor bacteria and fungi concentrations to levels lower than those specified by the Taiwan EPA (i.e., bacteria <1500 CFU/m(3), fungi <1000 CFU/m(3)), irrespective of the lighting conditions under which the disinfection process is performed. For each disinfection mode, a better disinfection efficiency is obtained under natural lighting conditions since ClO2 readily decomposes under strong luminance levels. Among the three treatment modes, the disinfection efficiencies of the TWM and TRM modes are very similar under natural lighting conditions and are significantly better than that of the SIM mode. Thus, overall, the results suggest that the TWM treatment protocol represents the most cost-effective and efficient method for meeting the indoor air quality requirements of the Taiwan EPA.
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Affiliation(s)
- Ching-Shan Hsu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan,
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Hinenoya A, Awasthi SP, Yasuda N, Shima A, Morino H, Koizumi T, Fukuda T, Miura T, Shibata T, Yamasaki S. Chlorine Dioxide is a Better Disinfectant than Sodium Hypochlorite against Multi-Drug Resistant Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. Jpn J Infect Dis 2015; 68:276-9. [DOI: 10.7883/yoken.jjid.2014.294] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Atsushi Hinenoya
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | | | - Noritomo Yasuda
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | - Ayaka Shima
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
| | | | | | | | | | | | - Shinji Yamasaki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University
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Cervero-Aragó S, Sommer R, Araujo RM. Effect of UV irradiation (253.7 nm) on free Legionella and Legionella associated with its amoebae hosts. WATER RESEARCH 2014; 67:299-309. [PMID: 25306486 DOI: 10.1016/j.watres.2014.09.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 09/15/2014] [Accepted: 09/22/2014] [Indexed: 06/04/2023]
Abstract
Water systems are the primary reservoir for Legionella spp., where the bacteria live in association with other microorganisms, such as free-living amoebae. A wide range of disinfection treatments have been studied to control and prevent Legionella colonization but few of them were performed considering its relation with protozoa. In this study, the effectiveness of UV irradiation (253.7 nm) using low-pressure lamps was investigated as a disinfection method for Legionella and amoebae under controlled laboratory conditions. UV treatments were applied to 5 strains of Legionella spp., 4 strains of free-living amoeba of the genera Acanthamoeba and Vermamoeba, treating separately trophozoites and cysts, and to two different co-cultures of Legionella pneumophila with the Acanthamoeba strains. No significant differences in the UV inactivation behavior were observed among Legionella strains tested which were 3 logs reduced for fluences around 45 J/m(2). UV irradiation was less effective against free-living amoebae; which in some cases required up to 990 J/m(2) to obtain the same population reduction. UV treatment was more effective against trophozoites compared to cysts; moreover, inactivation patterns were clearly different between the genus Acanthamoeba and Vermamoeba. For the first time data about Vermamoeba vermiformis UV inactivation has been reported in a study. Finally, the results showed that the association of L. pneumophila with free-living amoebae decreases the effectiveness of UV irradiation against the bacteria in a range of 1.5-2 fold. That fact demonstrates that the relations established between different microorganisms in the water systems can modify the effectiveness of the UV treatments applied.
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Affiliation(s)
- Sílvia Cervero-Aragó
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - Regina Sommer
- Medical University Vienna, Institute for Hygiene and Applied Immunology, Water Hygiene, Kinderspitalgasse 15, A-1090 Vienna, Austria
| | - Rosa M Araujo
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain.
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Necessity and effect of combating Legionella pneumophila in municipal shower systems. PLoS One 2014; 9:e114331. [PMID: 25490721 PMCID: PMC4260836 DOI: 10.1371/journal.pone.0114331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 11/06/2014] [Indexed: 11/19/2022] Open
Abstract
The objective was to obtain research-based, holistic knowledge about necessity and effect of practiced measures against L. pneumophila in municipal shower systems in Stavanger, Norway. The effects of hot water treatment and membrane-filtering were investigated and compared to no intervention at all. The studies were done under real-world conditions. Additionally, a surveillance pilot study of municipal showers in Stavanger was performed. The validity of high total plate count (TPC) as an indication of L. pneumophila was evaluated. A simplified method, named "dripping method", for detection and quantification of L. pneumophila was developed. The sensitivity of the dripping method is 5 colony-forming units of L. pneumophila/ml. The transference of L. pneumophila from shower water to aerosols was studied. Interviews and observational studies among the stakeholders were done in order to identify patterns of communication and behavior in a Legionella risk perspective. No substantial effects of the measures against L. pneumophila were demonstrated, except for a distally placed membrane filter. No significant positive correlation between TPC and L. pneumophila concentrations were found. L. pneumophila serogroup 2-14 was demonstrated in 21% of the 29 buildings tested in the surveillance pilot. Relatively few cells of L. pneumophila were transferred from shower water to aerosols. Anxiety appeared as the major driving force in the risk governance of Legionella. In conclusion, the risk of acquiring Legionnaires' disease from municipal shower systems is evaluated as low and uncertain. By eliminating ineffective approaches, targeted Legionella risk governance can be practiced. Risk management by surveillance is evaluated as appropriate.
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Community outbreak of legionellosis and an environmental investigation into a community water system. Epidemiol Infect 2014; 143:1322-31. [PMID: 25083716 DOI: 10.1017/s0950268814001964] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
During two legionellosis outbreak investigations, one at a geriatric centre and the other in high-rise housing for seniors, it was observed that additional cases of legionellosis occurred in nearby smaller residential settings. This apparent geographical cluster of legionellosis occurred in the same general area of a community water storage tank. No potential airborne sources in or near the area could be identified, but a community water system storage tank that was centrally located among case residences spurred an investigation of water-quality factors in the identified investigation area. Conditions conducive for Legionella growth, particularly low chlorine residuals, were found. The rate of legionellosis among residents aged ⩾50 years in the investigation areas (61·0 and 64·1/100 000) was eight times higher than in the rest of the service area (9·0/100 000) and almost 20 times higher than the statewide annual average incidence rate (3·2/100 000). A water mains flushing programme in the area was launched by the water utility, and water samples taken before and during flushing found L. pneumophila.
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Hsu CS, Huang DJ. Evaluation and improvement of air quality in school public elevator. ENVIRONMENTAL MONITORING AND ASSESSMENT 2014; 186:2941-2948. [PMID: 24374804 DOI: 10.1007/s10661-013-3591-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 12/12/2013] [Indexed: 06/03/2023]
Abstract
Public elevators are an essential requirement in modern high-rise buildings. However, the confined, crowded interior of an elevator provides an ideal breeding ground for all manners of biological aerosols. Consequently, when using an elevator at a university in Taiwan as the research target, this study performs an experimental investigation into the effectiveness of hand-sprayed gaseous chlorine dioxide as a disinfection agent. The air quality before and after disinfection is evaluated by measuring the bioaerosol concentrations of bacteria and fungi, respectively. The average background levels of bacteria and fungi before disinfection are found to be 635.7 ± 469.6 and 1296.8 ± 966.6 colony-forming unit (CFU)/m(3), respectively. Following disinfection, the bacteria and fungi concentrations reduced by an average of 35 and 25 %, respectively. The multivariate analysis of variance (MANOVA) results showed that the residual bacteria and fungi concentration levels were determined primarily by the number of individuals within the elevator and the elapsed time following disinfection. In general, the present results show that given a maximum of five individuals within the elevator, a disinfection schedule of once every 40 min is sufficient to reduce the bioaerosol concentrations of bacteria and fungi to the levels specified by the Taiwan Environmental Protection Agency (EPA).
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Affiliation(s)
- Ching-Shan Hsu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan, 71710, Taiwan,
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34
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Goudot S, Herbelin P, Mathieu L, Soreau S, Banas S, Jorand F. Biocidal efficacy of monochloramine against planktonic and biofilm-associated Naegleria fowleri
cells. J Appl Microbiol 2014; 116:1055-65. [DOI: 10.1111/jam.12429] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/17/2013] [Accepted: 12/30/2013] [Indexed: 11/30/2022]
Affiliation(s)
- S. Goudot
- EDF Recherche et Développement; Laboratoire National d'Hydraulique et Environnement; Chatou Cedex France
- Université de Lorraine; LCPME; UMR 7564 CNRS - UL; Institut Jean Barriol; Villers-lès-Nancy France
- CNRS; LCPME; UMR 7564 CNRS - UL; Villers-lès-Nancy France
| | - P. Herbelin
- EDF Recherche et Développement; Laboratoire National d'Hydraulique et Environnement; Chatou Cedex France
| | - L. Mathieu
- CNRS; LCPME; UMR 7564 CNRS - UL; Villers-lès-Nancy France
- Ecole Pratique des Hautes Etudes (EPHE); LCPME; UMR 7564 CNRS-UL; Vandoeuvre-lès-Nancy France
| | - S. Soreau
- EDF Recherche et Développement; Laboratoire National d'Hydraulique et Environnement; Chatou Cedex France
| | - S. Banas
- Université de Lorraine; LCPME; UMR 7564 CNRS - UL; Institut Jean Barriol; Villers-lès-Nancy France
- CNRS; LCPME; UMR 7564 CNRS - UL; Villers-lès-Nancy France
| | - F.P.A. Jorand
- Université de Lorraine; LCPME; UMR 7564 CNRS - UL; Institut Jean Barriol; Villers-lès-Nancy France
- CNRS; LCPME; UMR 7564 CNRS - UL; Villers-lès-Nancy France
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35
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Hsu CS, Huang DJ. Disinfection efficiency of chlorine dioxide gas in student cafeterias in Taiwan. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2013; 63:796-805. [PMID: 23926849 DOI: 10.1080/10962247.2012.735212] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
UNLABELLED In Taiwan, the food and drink requirements of students and faculty members are met by student cafeterias. The air quality within these cafeterias should satisfy the guidelines laid down by the Taiwan Environmental Protection Agency (Taiwan EPA). Accordingly, this study performed an experimental investigation into the efficiency of two different gaseous chlorine dioxide (ClO2) treatments in disinfecting a local student cafeteria, namely a single, one-off application and a twice-daily application. In both cases, the ClO2 was applied using strategically placed aerosol devices. The air quality before and after disinfection was evaluated by measuring the bioaerosol levels of bacteria and fungi. Moreover, a stepwise discriminant analysis method was applied for predicting the residual concentrations of bacteria and fungi, as a function of the environmental parameters and the ClO2 concentration. The experimental results showed that the average background levels of bacteria and fungi prior to ClO2 disinfection were 972.5 +/- 623.6 and 1534.1 +/- 631.8 colony-forming units (CFU)/m3, respectively. A single ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 65% and 30%, respectively. By contrast, a twice-daily ClO2 application was found to reduce the bacterial and fungal concentration levels by as much as 74% and 38%, respectively. The statistical analysis results showed that the residual bacterial concentration level was determined primarily by the number of individuals present in the cafeteria, the temperature, and the ClO2 concentration, whereas the residual fungal concentration level was determined mainly by the temperature, the total number of suspended particles, and the ClO2 concentration. Thus, the integrated results suggest that the air quality guidelines prescribed by the Taiwan EPA for student cafeteria can best be achieved by applying ClO2 twice daily using an appropriate deployment of aerosol devices. IMPLICATIONS ClO2 gas can destroy all manner of microorganisms, including bacteria, spores, fungi, viruses, and even protozoans, in indoor environments. Moreover, it is popularly known that bioaerosols are able to grow and propagate on a wide variety of building materials and indoor surfaces. Thus, through optimal ClO2 disinfection methodology, the indoor microbial contaminants can be decreased and the residual concentrations of bacteria and fungi as a function of the environmental parameters and the ClO2 concentration can be predicted via some statistical techniques.
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Affiliation(s)
- Ching-Shan Hsu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan 71710, Taiwan, Republic of China.
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36
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Ngwenya N, Ncube EJ, Parsons J. Recent advances in drinking water disinfection: successes and challenges. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 222:111-70. [PMID: 22990947 DOI: 10.1007/978-1-4614-4717-7_4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Drinking water is the most important single source of human exposure to gastroenteric diseases, mainly as a result of the ingestion of microbial contaminated water. Waterborne microbial agents that pose a health risk to humans include enteropathogenic bacteria, viruses, and protozoa. Therefore, properly assessing whether these hazardous agents enter drinking water supplies, and if they do, whether they are disinfected adequately, are undoubtedly aspects critical to protecting public health. As new pathogens emerge, monitoring for relevant indicator microorganisms (e.g., process microbial indicators, fecal indicators, and index and model organisms) is crucial to ensuring drinking water safety. Another crucially important step to maintaining public health is implementing Water Safety Plans (WSPs), as is recommended by the current WHO Guidelines for Drinking Water Quality. Good WSPs include creating health-based targets that aim to reduce microbial risks and adverse health effects to which a population is exposed through drinking water. The use of disinfectants to inactivate microbial pathogens in drinking water has played a central role in reducing the incidence of waterborne diseases and is considered to be among the most successful interventions for preserving and promoting public health. Chlorine-based disinfectants are the most commonly used disinfectants and are cheap and easy to use. Free chlorine is an effective disinfectant for bacteria and viruses; however, it is not always effective against C. parvum and G. lamblia. Another limitation of using chlorination is that it produces disinfection by-products (DBPs), which pose potential health risks of their own. Currently, most drinking water regulations aggressively address DBP problems in public water distribution systems. The DBPs of most concern include the trihalomethanes (THMs), the haloacetic acids (HAAs), bromate, and chlorite. However, in the latest edition of the WHO Guidelines for Drinking Water Quality, it is recommended that water disinfection should never be compromised by attempting to control DBPs. The reason for this is that the risks of human illness and death from pathogens in drinking water are much greater than the risks from exposure to disinfectants and disinfection by-products. Nevertheless, if DBP levels exceed regulatory limits, strategies should focus on eliminating organic impurities that foster their formation, without compromising disinfection. As alternatives to chlorine, disinfectants such as chloramines, ozone, chlorine dioxide, and UV disinfection are gaining popularity. Chlorine and each of these disinfectants have individual advantage and disadvantage in terms of cost, efficacy-stability, ease of application, and nature of disinfectant by-products (DBPs). Based on efficiency, ozone is the most efficient disinfectant for inactivating bacteria, viruses, and protozoa. In contrast, chloramines are the least efficient and are not recommended for use as primary disinfectants. Chloramines are favored for secondary water disinfection, because they react more slowly than chlorine and are more persistent in distribution systems. In addition, chloramines produce lower DBP levels than does chlorine, although microbial activity in the distribution system may produce nitrate from monochloramine, when it is used as a residual disinfectant, Achieving the required levels of water quality, particularly microbial inactivation levels, while minimizing DBP formation requires the application of proper risk and disinfection management protocols. In addition, the failure of conventional treatment processes to eliminate critical waterborne pathogens in drinking water demand that improved and/or new disinfection technologies be developed. Recent research has disclosed that nanotechnology may offer solutions in this area, through the use of nanosorbents, nanocatalysts, bioactive nanoparticles, nanostructured catalytic membranes, and nanoparticle-enhanced filtration.
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Affiliation(s)
- Nonhlanhla Ngwenya
- Scientific Services Division, Rand Water, Johannesburg, 1170 2000 South Africa.
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Vaerewijck MJM, Sabbe K, Baré J, Spengler HP, Favoreel HW, Houf K. Assessment of the efficacy of benzalkonium chloride and sodium hypochlorite against Acanthamoeba polyphaga and Tetrahymena spp. J Food Prot 2012; 75:541-6. [PMID: 22410229 DOI: 10.4315/0362-028x.jfp-11-359] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The efficacy of benzalkonium chloride and sodium hypochlorite against Acanthamoeba polyphaga and two Tetrahymena spp. was determined based on the European Standard EN 1276:2009 suspension test. Trophozoite viability was assessed by determination of the membrane integrity using flow cytometry as a fast screening technique. Bovine serum albumin was added to simulate clean (0.3 g/liter) and dirty (3 g/liter) conditions. Benzalkonium chloride caused cell lysis at concentrations above 50 mg/liter under clean and dirty conditions. A concentration of 50 mg of free chlorine per liter had a strong biocidal effect on acanthamoebae and tetrahymenae after 15 min under clean and dirty conditions. Our results suggest that benzalkonium chloride and sodium hypochlorite were effective against the three microorganisms at concentrations commonly applied in the food industry.
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Affiliation(s)
- M J M Vaerewijck
- Department of Veterinary Public Health and Food Safety, Ghent University, Merelbeke, Belgium
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Hsu CS, Lu MC, Huang DJ. Application of chlorine dioxide for disinfection of student health centers. ENVIRONMENTAL MONITORING AND ASSESSMENT 2012; 184:741-747. [PMID: 21452077 DOI: 10.1007/s10661-011-1998-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Accepted: 03/10/2011] [Indexed: 05/30/2023]
Abstract
In Taiwan, the immediate health care requirements of students and faculty members are satisfied by on-campus medical service centers. The air quality within these centers should comply with the guidelines laid down by the Taiwan Environmental Protection Agency (EPA). Accordingly, this study performed an experimental investigation into the efficiency of various chlorine dioxide applications in disinfecting a local student health center (SHC). The air quality before and after disinfection were evaluated in terms of the bioaerosol levels of bacteria and fungi. The average background levels of bacteria and fungi before disinfection were found to be 1,142 ± 455.4 CFU/m(3) and 520 ± 442.4 CFU/m(3), respectively. Chlorine dioxide (0.3 mg/m(3)) was applied using three different methods, namely a single, one-off application, multiple applications within a single day, and regular (daily) applications. Among the three disinfection methods, the regular application method was found to yield a high disinfection efficiency for both bacteria and fungi, i.e., 6.5 ± 0.7% and 4.2 ± 0.3%, respectively. The average residual bacteria and fungi levels after regular daily interval disinfection were 318.8 ± 51.5 CFU/m(3) and 254.0 ± 43.8 CFU/m(3), respectively. Therefore, the results suggest that the air quality guidelines prescribed by the Taiwan EPA for SHCs and other healthcare facilities can best be achieved by applying chlorine dioxide at regular (daily) intervals.
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Affiliation(s)
- Ching-Shan Hsu
- Department of Environmental Resource Management, Chia-Nan University of Pharmacy and Science, Tainan 71710, Taiwan.
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39
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Shams A, O’Connell H, Arduino M, Rose L. Chlorine dioxide inactivation of bacterial threat agents. Lett Appl Microbiol 2011; 53:225-30. [DOI: 10.1111/j.1472-765x.2011.03095.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chord F, Fascia P, Mallaval F, Cornillon J, Roesch L, Pozzetto B, Grattard F, Berthelot P. Chlorine dioxide for Legionella spp. disinfection: a danger for cross-linked polyethylene pipes? J Hosp Infect 2011; 78:242-3. [PMID: 21507519 DOI: 10.1016/j.jhin.2011.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 03/03/2011] [Indexed: 10/18/2022]
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Loret JF, Greub G. Free-living amoebae: Biological by-passes in water treatment. Int J Hyg Environ Health 2010; 213:167-75. [PMID: 20418158 DOI: 10.1016/j.ijheh.2010.03.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/24/2010] [Accepted: 03/24/2010] [Indexed: 11/30/2022]
Abstract
Free-living amoebae constitute reservoirs for many bacteria including not only well-known pathogens but also emerging pathogens responsible for respiratory diseases, and contribute to the protection, survival and dissemination of these bacteria in water systems, despite the application of disinfection or thermal treatments. In this article we review the available information on the presence of free-living amoebae and amoebae-resisting bacteria in drinking water systems, on the factors that contribute to their presence in the water and/or the biofilms, on the possible control measures and their effectiveness, and we identify some gaps in current knowledge needing further research.
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Affiliation(s)
- Jean-François Loret
- Suez Environnement, CIRSEE, 38 rue du Président Wilson, 78230 Le Pecq, France.
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James R. DECHLORINATION BY ULTRAVIOLET RADIATION: A SUITABLE ALTERNATIVE TO ACTIVATED CARBON IN DIALYSIS WATER SYSTEMS? J Ren Care 2009; 35:205-10. [DOI: 10.1111/j.1755-6686.2009.00117.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Palmore TN, Stock F, White M, Bordner M, Michelin A, Bennett JE, Murray PR, Henderson DK. A cluster of cases of nosocomial legionnaires disease linked to a contaminated hospital decorative water fountain. Infect Control Hosp Epidemiol 2009; 30:764-8. [PMID: 19580436 DOI: 10.1086/598855] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Nosocomial outbreaks of Legionnaires disease have been linked to contaminated water in hospitals. Immunocompromised patients are particularly vulnerable and, when infected, have a high mortality rate. We report the investigation of a cluster of cases of nosocomial pneumonia attributable to Legionella pneumophila serogroup 1 that occurred among patients on our stem cell transplantation unit. METHODS We conducted a record review to identify common points of potential exposure, followed by environmental and water sampling for Legionella species from those sources. We used an air sampler to in an attempt to detect aerosolized Legionella and pulsed-field gel electrophoresis to compare clinical and environmental isolates. RESULTS The most likely sources identified were the water supply in the patients' rooms and a decorative fountain in the radiation oncology suite. Samples from the patients' rooms did not grow Legionella species. Cultures of the fountain, which had been restarted 4 months earlier after being shut off for 5 months, yielded L. pneumophila serogroup 1. The isolates from both patients and the fountain were identical by pulsed-field gel electrophoresis. Both patients developed pneumonia within 10 days of completing radiation therapy, and each reported having observed the fountain at close range. Both patients' infections were identified early and treated promptly, and both recovered. CONCLUSIONS This cluster was caused by contamination of a decorative fountain despite its being equipped with a filter and ozone generator. Fountains are a potential source of nosocomial Legionnaires disease despite standard maintenance and sanitizing measures. In our opinion, fountains present unacceptable risk in hospitals serving immunocompromised patients.
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Affiliation(s)
- Tara N Palmore
- Warren Grant Magnusen Clinical Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1888, USA.
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A quantitative approach to the effectiveness of ozone against microbiota organisms colonizing toothbrushes. J Dent 2008; 36:600-5. [DOI: 10.1016/j.jdent.2008.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 04/14/2008] [Accepted: 04/14/2008] [Indexed: 11/20/2022] Open
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Ogata N, Shibata T. Protective effect of low-concentration chlorine dioxide gas against influenza A virus infection. J Gen Virol 2008; 89:60-67. [DOI: 10.1099/vir.0.83393-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Influenza virus infection is one of the major causes of human morbidity and mortality. Between humans, this virus spreads mostly via aerosols excreted from the respiratory system. Current means of prevention of influenza virus infection are not entirely satisfactory because of their limited efficacy. Safe and effective preventive measures against pandemic influenza are greatly needed. We demonstrate that infection of mice induced by aerosols of influenza A virus was prevented by chlorine dioxide (ClO2) gas at an extremely low concentration (below the long-term permissible exposure level to humans, namely 0.1 p.p.m.). Mice in semi-closed cages were exposed to aerosols of influenza A virus (1 LD50) and ClO2 gas (0.03 p.p.m.) simultaneously for 15 min. Three days after exposure, pulmonary virus titre (TCID50) was 102.6±1.5 in five mice treated with ClO2, whilst it was 106.7±0.2 in five mice that had not been treated (P=0.003). Cumulative mortality after 16 days was 0/10 mice treated with ClO2 and 7/10 mice that had not been treated (P=0.002). In in vitro experiments, ClO2 denatured viral envelope proteins (haemagglutinin and neuraminidase) that are indispensable for infectivity of the virus, and abolished infectivity. Taken together, we conclude that ClO2 gas is effective at preventing aerosol-induced influenza virus infection in mice by denaturing viral envelope proteins at a concentration well below the permissible exposure level to humans. ClO2 gas could therefore be useful as a preventive means against influenza in places of human activity without necessitating evacuation.
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Affiliation(s)
- Norio Ogata
- Research Institute, Taiko Pharmaceutical Co. Ltd, 3-34-14 Uchihonmachi, Suita, Osaka 564-0032, Japan
| | - Takashi Shibata
- Research Institute, Taiko Pharmaceutical Co. Ltd, 3-34-14 Uchihonmachi, Suita, Osaka 564-0032, Japan
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