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Grimard-Conea M, Bédard E, Prévost M. Can free chlorine residuals entering building plumbing systems really be maintained to prevent microbial growth? THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 939:173651. [PMID: 38821274 DOI: 10.1016/j.scitotenv.2024.173651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/22/2024] [Accepted: 05/28/2024] [Indexed: 06/02/2024]
Abstract
Secondary disinfection aims to prevent microbial regrowth during distribution by maintaining disinfectant residuals in water systems. However, multi-factorial interactions contribute to free chlorine decay in distribution systems, and even more so in building plumbing. Assembling 1737 samples from nine large institutional buildings, a meta-analysis was conducted to determine whether building managers can actively rely on incoming free chlorine residuals to prevent in-building microbial amplification. Findings showed that free chlorine concentrations in first draws met the 0.2 mg/L common guide level in respectively 26 %, 6 % and 2 % of cold, tepid and hot water samples, whereas flushing for 2-60 min only significantly increased this ratio in cold water (83 %), without reaching background levels found in service lines. Free chlorine was significantly but weakly (R≤ 0.2) correlated to adenosine triphosphate, heterotrophic plate count and total and intact cell counts, thus evidencing that residuals contributed to decreased culturable and viable biomass. Detection of culturable Legionella pneumophila spanning over a 4-log distribution solely occurred when free chlorine levels were below 0.2 mg/L, but no such trend could be distinguished clearly for culturable Pseudomonas aeruginosa. Water temperatures below 20 °C and >60 °C also completely prevented L. pneumophila detection. Overall, the majority of elevated microbial counts were measured in distal sites and in tepid and hot water, where free chlorine is less likely to be present due to stagnation and increased temperature. Therefore, building managers cannot solely rely on this chemical barrier to mitigate bacterial growth in bulk water.
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Affiliation(s)
| | - Emilie Bédard
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada.
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2
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Xi H, Ross KE, Hinds J, Molino PJ, Whiley H. Efficacy of chlorine-based disinfectants to control Legionella within premise plumbing systems. WATER RESEARCH 2024; 259:121794. [PMID: 38824796 DOI: 10.1016/j.watres.2024.121794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 06/04/2024]
Abstract
Legionella is an opportunistic waterborne pathogen that causes Legionnaires' disease. It poses a significant public health risk, especially to vulnerable populations in health care facilities. It is ubiquitous in manufactured water systems and is transmitted via inhalation or aspiration of aerosols/water droplets generated from water fixtures (e.g., showers and hand basins). As such, the effective management of premise plumbing systems (building water systems) in health care facilities is essential for reducing the risk of Legionnaires' disease. Chemical disinfection is a commonly used control method and chlorine-based disinfectants, including chlorine, chloramine, and chlorine dioxide, have been used for over a century. However, the effectiveness of these disinfectants in premise plumbing systems is affected by various interconnected factors that can make it challenging to maintain effective disinfection. This systematic literature review identifies all studies that have examined the factors impacting the efficacy and decay of chlorine-based disinfectant within premise plumbing systems. A total of 117 field and laboratory-based studies were identified and included in this review. A total of 20 studies directly compared the effectiveness of the different chlorine-based disinfectants. The findings from these studies ranked the typical effectiveness as follows: chloramine > chlorine dioxide > chlorine. A total of 26 factors were identified across 117 studies as influencing the efficacy and decay of disinfectants in premise plumbing systems. These factors were sorted into categories of operational factors that are changed by the operation of water devices and fixtures (such as stagnation, temperature, water velocity), evolving factors which are changed in-directly (such as disinfectant concentration, Legionella disinfectant resistance, Legionella growth, season, biofilm and microbe, protozoa, nitrification, total organic carbon(TOC), pH, dissolved oxygen(DO), hardness, ammonia, and sediment and pipe deposit) and stable factors that are not often changed(such as disinfectant type, pipe material, pipe size, pipe age, water recirculating, softener, corrosion inhibitor, automatic sensor tap, building floor, and construction activity). A factor-effect map of each of these factors and whether they have a positive or negative association with disinfection efficacy against Legionella in premise plumbing systems is presented. It was also found that evaluating the effectiveness of chlorine disinfection as a water risk management strategy is further complicated by varying disinfection resistance of Legionella species and the form of Legionella (culturable/viable but non culturable, free living/biofilm associated, intracellular replication within amoeba hosts). Future research is needed that utilises sensors and other approaches to measure these key factors (such as pH, temperature, stagnation, water age and disinfection residual) in real time throughout premise plumbing systems. This information will support the development of improved models to predict disinfection within premise plumbing systems. The findings from this study will inform the use of chlorine-based disinfection within premise plumbing systems to reduce the risk of Legionnaires disease.
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Affiliation(s)
- Hao Xi
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia; Enware Pty Ltd, Caringbah, NSW, Australia.
| | - Kirstin E Ross
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Jason Hinds
- ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, Australia; Enware Pty Ltd, Caringbah, NSW, Australia
| | | | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia; ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, Australia
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3
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Zhang C, Sienkiewicz N, Struewing I, Mistry JH, Buse H, Hu Z, Lu J. Reconsider the burn: The transient effect of a chlorine burn on controlling opportunistic pathogens in a full-scale chloraminated engineered water system. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 933:172690. [PMID: 38670361 DOI: 10.1016/j.scitotenv.2024.172690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 04/20/2024] [Accepted: 04/20/2024] [Indexed: 04/28/2024]
Abstract
Nitrification is a serious water-quality issue in chloraminated engineered water systems (EWSs). Nitrification is often remediated by a chlorine burn (i.e., a free‑chlorine conversion), a short-term switch from chloramination to chlorination in EWSs. Opportunistic pathogens (OPs) are the dominant infectious agents in EWSs. However, the responses of OPs to a chlorine burn are unknown. This study for the first time assessed how a chlorine burn affected OPs in a full-scale EWS. We determined the impact of a 1.5-month chlorine burn on four dominant OPs (Legionella, Mycobacterium, Pseudomonas, and Vermamoeba vermiformis) in a representative full-scale chloraminated EWS in the United States. Legionella and Mycobacterium were the most abundant OPs. In the water main, the summed concentration of the four OPs during the chlorine burn [3.27 ± 1.58 log10(GCN·L-1); GCN: genome or gene copy number] was lower (p ≤ 0.001) than before the burn [4.83 ± 0.50 log10(GCN·L-1)]. After the burn, the summed concentration increased to 4.27 ± 0.68 log10(GCN·L-1), comparable to before the burn (p > 0.05), indicating a transient effect of the chlorine burn in the water main. At the residential sites, the summed concentrations of the four OPs were comparable (p > 0.05) at 5.50 ± 0.84, 5.27 ± 1.44, and 5.08 ± 0.71 log10(GCN·L-1) before, during, and after the chlorine burn, respectively. Therefore, the chlorine burn was less effective in suppressing OP (re)growth in the premise plumbing. The low effectiveness might be due to more significant water stagnation and disinfectant residual decay in the premise plumbing. Indeed, for the entire sampling period, the total chlorine residual concentration in the premise plumbing (1.8 mg Cl2·L-1) was lower than in the water main (2.4 mg Cl2·L-1). Consequently, for the entire sampling period, the summed concentration of the four OPs in the premise plumbing [5.26 ± 1.08 log10(GCN·L-1)] was significantly higher (p < 0.001) than in the water main [4.04 ± 1.25 log10(GCN·L-1)]. In addition, the chlorine burn substantially increased the levels of disinfection by-products (DBPs) in the water main. Altogether, a chlorine burn is transient or even ineffective in suppressing OP (re)growth but raises DBP concentrations in chloraminated EWSs. Therefore, the practice of chlorine burns to control nitrification should be optimized, reconsidered, or even replaced.
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Affiliation(s)
- Chiqian Zhang
- Civil Engineering Program, College of Engineering & Computer Science, Arkansas State University, AR 72467, United States
| | - Nathan Sienkiewicz
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Ian Struewing
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Jatin H Mistry
- United States Environmental Protection Agency, Region 6, Dallas, TX 75270, United States
| | - Helen Buse
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States
| | - Zhiqiang Hu
- Department of Civil & Environmental Engineering, University of Missouri, Columbia, MO 65211, United States
| | - Jingrang Lu
- Office of Research and Development, United States Environmental Protection Agency, Cincinnati, OH 45268, United States.
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Auld DB, Has P, Mermel LA. Seasonality of healthcare-associated Stenotrophomonas maltophilia. Infect Control Hosp Epidemiol 2023; 44:1500-1501. [PMID: 36416200 PMCID: PMC10507498 DOI: 10.1017/ice.2022.280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/26/2022] [Accepted: 10/27/2022] [Indexed: 11/24/2022]
Abstract
From April 1, 2016, through March 31, 2022, growth of Stenotrophomonas maltophilia from clinical specimens at our academic medical center was significantly more likely during July-September than during other calendar quarters.
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Affiliation(s)
- Dianne B. Auld
- Department of Epidemiology and Infection Control, Lifespan Hospital System, Providence, Rhode Island
| | - Phinnara Has
- Biostatistics, Epidemiology and Research Design, Lifespan Hospital System, Providence, Rhode Island
| | - Leonard A. Mermel
- Department of Epidemiology and Infection Control, Lifespan Hospital System, Providence, Rhode Island
- Division of Infectious Diseases, Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island
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Farina C, Cacciabue E, Averara F, Ferri N, Vailati F, Del Castillo G, Serafini A, Fermi B, Doniselli N, Pezzoli F. Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital. Microorganisms 2023; 11:1794. [PMID: 37512966 PMCID: PMC10384652 DOI: 10.3390/microorganisms11071794] [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: 05/24/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Legionella contamination control is crucial in healthcare settings where patients suffer an increased risk of disease and fatal outcome. To ensure an effective management of this health hazard, the accurate application of a hospital-specific Water Safety Plan (WSP), the choice of a suitable water disinfection system and an extensive monitoring program are required. Here, the ten-year experience of an Italian hospital is reported: since its commissioning, Legionellosis risk management has been entrusted to a multi-disciplinary Working Group, applying the principles of the World Health Organization's WSP. The disinfection strategy to prevent Legionella and other waterborne pathogens relies on the treatment of domestic hot water with a system ensuring the in situ production and dosage of monochloramine. An average of 250 samples/year were collected and analyzed to allow an accurate assessment of the microbiological status of water network. With the aim of increasing the monitoring sensitivity, in addition to the standard culture method, an optimized MALDI-ToF MS-based strategy was applied, allowing the identification of Legionella species and other relevant opportunistic pathogens. Data collected so far confirmed the effectiveness of this multidisciplinary approach: the fraction of positive samples never overcame 1% on a yearly basis and Legionnaires' Disease cases never occurred.
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Affiliation(s)
- Claudio Farina
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Eleonora Cacciabue
- Health Care Coordination Offices, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Franca Averara
- Department of Health Care Professions, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Nadia Ferri
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Francesca Vailati
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | | | | | - Beatrice Fermi
- Sanipur S.p.A., 25020 Flero, Italy
- ESCMID Study Group for Legionella Infections (ESGLI), 4001 Basel, Switzerland
| | - Nicola Doniselli
- Sanipur S.p.A., 25020 Flero, Italy
- ESCMID Study Group for Legionella Infections (ESGLI), 4001 Basel, Switzerland
| | - Fabio Pezzoli
- Health Care Coordination Offices, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
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Heterotrophic Plate Count Can Predict the Presence of Legionella spp. in Cooling Towers. Pathogens 2023; 12:pathogens12030466. [PMID: 36986388 PMCID: PMC10059076 DOI: 10.3390/pathogens12030466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Legionella pneumophila (Lp) colonizes aquatic environments and is a potential pathogen to humans, causing outbreaks of Legionnaire’s disease. It is mainly associated with contaminated cooling towers (CTs). Several regulations, including Spanish legislation (Sl), have introduced the analysis of heterotrophic plate count (HPC) bacteria and Legionella spp. (Lsp) in management plans to prevent and control Legionella outbreaks from CTs. The 2003 Sl for CTs (RD 865/2003) considered that concentrations of HPC bacteria ≤10,000 cfu/mL and of Lsp ≤100 cfu/L are safe; therefore, no action is required, whereas management actions should be implemented above these standards. We have investigated to what extent the proposed standard for HPC bacteria is useful to predict the presence of Lsp in cooling waters. For this, we analyzed Lsp and HPC concentrations, water temperature, and the levels of chlorine in 1376 water samples from 17 CTs. The results showed that in the 1138 water samples negative for Legionella spp. (LN), the HPC geometric mean was significantly lower (83 cfu/mL, p < 0.05) than in the positive Lsp. samples (135 cfu/mL). Of the 238 (17.3%) LP samples, 88.4% (210/238) were associated with values of HPC ≤10,000 cfu/mL and most of them showed HPC concentrations ≤100 (53.7%). In addition, a relatively low percentage of LP (28/238, 11.6%) samples were associated with HPC bacteria concentrations >10,000 cfu/mL, indicating that this standard does not predict the colonization risk for Legionella in the CTs studied. The present study has demonstrated that a threshold concentration ≤100 cfu/mL of HPC bacteria could better predict the higher concentration of Legionella in CTs, which will aid in preventing possible outbreaks.
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Proctor C, Garner E, Hamilton KA, Ashbolt NJ, Caverly LJ, Falkinham JO, Haas CN, Prevost M, Prevots DR, Pruden A, Raskin L, Stout J, Haig SJ. Tenets of a holistic approach to drinking water-associated pathogen research, management, and communication. WATER RESEARCH 2022; 211:117997. [PMID: 34999316 PMCID: PMC8821414 DOI: 10.1016/j.watres.2021.117997] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 12/13/2021] [Accepted: 12/19/2021] [Indexed: 05/10/2023]
Abstract
In recent years, drinking water-associated pathogens that can cause infections in immunocompromised or otherwise susceptible individuals (henceforth referred to as DWPI), sometimes referred to as opportunistic pathogens or opportunistic premise plumbing pathogens, have received considerable attention. DWPI research has largely been conducted by experts focusing on specific microorganisms or within silos of expertise. The resulting mitigation approaches optimized for a single microorganism may have unintended consequences and trade-offs for other DWPI or other interests (e.g., energy costs and conservation). For example, the ecological and epidemiological issues characteristic of Legionella pneumophila diverge from those relevant for Mycobacterium avium and other nontuberculous mycobacteria. Recent advances in understanding DWPI as part of a complex microbial ecosystem inhabiting drinking water systems continues to reveal additional challenges: namely, how can all microorganisms of concern be managed simultaneously? In order to protect public health, we must take a more holistic approach in all aspects of the field, including basic research, monitoring methods, risk-based mitigation techniques, and policy. A holistic approach will (i) target multiple microorganisms simultaneously, (ii) involve experts across several disciplines, and (iii) communicate results across disciplines and more broadly, proactively addressing source water-to-customer system management.
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Affiliation(s)
- Caitlin Proctor
- Department of Agricultural and Biological Engineering, Division of Environmental and Ecological Engineering, Purdue University, West Lafayette, IN, USA
| | - Emily Garner
- Wadsworth Department of Civil & Environmental Engineering, West Virginia University, Morgantown, WV, USA
| | - Kerry A Hamilton
- School of Sustainable Engineering and the Built Environment and The Biodesign Centre for Environmental Health Engineering, Arizona State University, Tempe, AZ, USA
| | - Nicholas J Ashbolt
- Faculty of Science and Engineering, Southern Cross University, Gold Coast. Queensland, Australia
| | - Lindsay J Caverly
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, MI, USA
| | | | - Charles N Haas
- Department of Civil, Architectural & Environmental Engineering, Drexel University, Philadelphia, PA, USA
| | - Michele Prevost
- Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, Quebec, Canada
| | - D Rebecca Prevots
- Epidemiology Unit, Laboratory of Clinical Immunology and Microbiology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Amy Pruden
- Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA USA
| | - Lutgarde Raskin
- Department of Civil & Environmental Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Janet Stout
- Department of Civil & Environmental Engineering, University of Pittsburgh, and Special Pathogens Laboratory, Pittsburgh, PA, USA
| | - Sarah-Jane Haig
- Department of Civil & Environmental Engineering, and Department of Environmental & Occupational Health, University of Pittsburgh, Pittsburgh, PA, USA.
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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
- Correspondence: Jingrang Lu,
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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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Chambers ST, Slow S, Scott-Thomas A, Murdoch DR. Legionellosis Caused by Non- Legionella pneumophila Species, with a Focus on Legionella longbeachae. Microorganisms 2021; 9:291. [PMID: 33572638 PMCID: PMC7910863 DOI: 10.3390/microorganisms9020291] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/23/2021] [Accepted: 01/26/2021] [Indexed: 12/13/2022] Open
Abstract
Although known as causes of community-acquired pneumonia and Pontiac fever, the global burden of infection caused by Legionella species other than Legionella pneumophila is under-recognised. Non-L. pneumophila legionellae have a worldwide distribution, although common testing strategies for legionellosis favour detection of L. pneumophila over other Legionella species, leading to an inherent diagnostic bias and under-detection of cases. When systematically tested for in Australia and New Zealand, L. longbeachae was shown to be a leading cause of community-acquired pneumonia. Exposure to potting soils and compost is a particular risk for infection from L. longbeachae, and L. longbeachae may be better adapted to soil and composting plant material than other Legionella species. It is possible that the high rate of L. longbeachae reported in Australia and New Zealand is related to the composition of commercial potting soils which, unlike European products, contain pine bark and sawdust. Genetic studies have demonstrated that the Legionella genomes are highly plastic, with areas of the chromosome showing high levels of recombination as well as horizontal gene transfer both within and between species via plasmids. This, combined with various secretion systems and extensive effector repertoires that enable the bacterium to hijack host cell functions and resources, is instrumental in shaping its pathogenesis, survival and growth. Prevention of legionellosis is hampered by surveillance systems that are compromised by ascertainment bias, which limits commitment to an effective public health response. Current prevention strategies in Australia and New Zealand are directed at individual gardeners who use potting soils and compost. This consists of advice to avoid aerosols generated by the use of potting soils and use masks and gloves, but there is little evidence that this is effective. There is a need to better understand the epidemiology of L. longbeachae and other Legionella species in order to develop effective treatment and preventative strategies globally.
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Affiliation(s)
- Stephen T. Chambers
- Department of Pathology and Biomedical Science, University of Otago, Christchurch 8011, New Zealand; (S.S.); (A.S.-T.); (D.R.M.)
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Marchesi I, Paduano S, Frezza G, Sircana L, Vecchi E, Zuccarello P, Oliveri Conti G, Ferrante M, Borella P, Bargellini A. Safety and Effectiveness of Monochloramine Treatment for Disinfecting Hospital Water Networks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17176116. [PMID: 32842654 PMCID: PMC7503937 DOI: 10.3390/ijerph17176116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/12/2020] [Accepted: 08/20/2020] [Indexed: 11/16/2022]
Abstract
The formation of potentially carcinogenic N-nitrosamines, associated with monochloramine, requires further research due to the growing interest in using this biocide for the secondary disinfection of water in public and private buildings. The aim of our study was to evaluate the possible formation of N-nitrosamines and other toxic disinfection by-products (DBPs) in hospital hot water networks treated with monochloramine. The effectiveness of this biocide in controlling Legionella spp. contamination was also verified. For this purpose, four different monochloramine-treated networks, in terms of the duration of treatment and method of biocide injection, were investigated. Untreated hot water, municipal cold water and, limited to N-nitrosamines analysis, hot water treated with chlorine dioxide were analyzed for comparison. Legionella spp. contamination was successfully controlled without any formation of N-nitrosamines. No nitrification or formation of the regulated DBPs, such as chlorites and trihalomethanes, occurred in monochloramine-treated water networks. However, a stable formulation of hypochlorite, its frequent replacement with a fresh product, and the routine monitoring of free ammonia are recommended to ensure a proper disinfection. Our study confirms that monochloramine may be proposed as an effective and safe strategy for the continuous disinfection of building plumbing systems, preventing vulnerable individuals from being exposed to legionellae and dangerous DBPs.
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Affiliation(s)
- Isabella Marchesi
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (S.P.); (G.F.); (P.B.); (A.B.)
- Correspondence: ; Tel.: +39-059-2055460
| | - Stefania Paduano
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (S.P.); (G.F.); (P.B.); (A.B.)
| | - Giuseppina Frezza
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (S.P.); (G.F.); (P.B.); (A.B.)
| | - Luca Sircana
- University Hospital Policlinico of Modena, Largo del Pozzo 71, 41124 Modena, Italy; (L.S.); (E.V.)
| | - Elena Vecchi
- University Hospital Policlinico of Modena, Largo del Pozzo 71, 41124 Modena, Italy; (L.S.); (E.V.)
| | - Pietro Zuccarello
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95123 Catania, Italy; (P.Z.); (G.O.C.); (M.F.)
| | - Gea Oliveri Conti
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95123 Catania, Italy; (P.Z.); (G.O.C.); (M.F.)
| | - Margherita Ferrante
- Environmental and Food Hygiene Laboratory (LIAA), Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University of Catania, 95123 Catania, Italy; (P.Z.); (G.O.C.); (M.F.)
| | - Paola Borella
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (S.P.); (G.F.); (P.B.); (A.B.)
| | - Annalisa Bargellini
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, Via Campi 287, 41125 Modena, Italy; (S.P.); (G.F.); (P.B.); (A.B.)
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12
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Buse HY, Morris BJ, Gomez-Alvarez V, Szabo JG, Hall JS. Legionella Diversity and Spatiotemporal Variation in The Occurrence of Opportunistic Pathogens within a Large Building Water System. Pathogens 2020; 9:E567. [PMID: 32668779 PMCID: PMC7400177 DOI: 10.3390/pathogens9070567] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 01/22/2023] Open
Abstract
Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occurrence within a BWS over 18-28 months at six locations differing in plumbing material and potable water age, quality, and usage. A total of 114 bulk water and 57 biofilm samples were analyzed. Legionella culturability fluctuated seasonally with most culture-positive samples being collected during the winter compared to the spring, summer, and fall months. Positive and negative correlations between Legionella and L. pneumophila occurrence and other physiochemical and microbial water quality parameters varied between location and sample types. Whole genome sequencing of 19 presumptive Legionella isolates, from four locations across three time points, identified nine isolates as L. pneumophila serogroup (sg) 1 sequence-type (ST) 1; three as L. pneumophila sg5 ST1950 and ST2037; six as L. feeleii; and one as Ochrobactrum. Results showed the presence of a diverse Legionella population with consistent and sporadic occurrence at four and two locations, respectively. Viewed collectively with similar studies, this information will enable a better understanding of the engineering, operational, and water quality parameters supporting Legionella growth within BWSs.
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Affiliation(s)
- Helen Y. Buse
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - Brian J. Morris
- Pegasus Technical Services, Inc c/o US EPA, Cincinnati, OH 45268, USA;
| | - Vicente Gomez-Alvarez
- Water Infrastructure Division, Center for Environmental Solutions & Emergency Response (CESER), US Environmental Protection Agency (USEPA), Office of Research and Development (ORD), Cincinnati, OH 45268, USA;
| | - Jeffrey G. Szabo
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
| | - John S. Hall
- Homeland Security and Materials Management Division, Center for Environmental Solutions & Emergency Response (CESER), Office of Research and Development (ORD), US Environmental Protection Agency (USEPA), Cincinnati, OH 45268, USA; (J.G.S.); (J.S.H.)
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13
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Advances in Legionella Control by a New Formulation of Hydrogen Peroxide and Silver Salts in a Hospital Hot Water Network. Pathogens 2019; 8:pathogens8040209. [PMID: 31671765 PMCID: PMC6963979 DOI: 10.3390/pathogens8040209] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 01/22/2023] Open
Abstract
Legionella surveillance is an important issue in public health, linked to the severity of disease and the difficulty associated with eradicating this bacterium from the water environment. Different treatments are suggested to reduce Legionella risk, however long-term studies of their efficiency are lacking. This study focused on the activity of a new formulation of hydrogen peroxide and silver salts, WTP828, in the hospital hot water network (HWN) to contain Legionella contamination during two years of treatment. The effectiveness of WTP828 was tested measuring physical-chemical and microbiological parameters such as Legionella, Pseudomonas aeruginosa (P. aeruginosa), and a heterotopic plate count (HPC) at 36 °C. Legionella isolates were identified by serotyping and genotyping. WTP 828 induced a reduction in Legionella–positive sites (60% to 36%) and contamination levels (2.12 to 1.7 log10 CFU/L), with isolates belonging to L. pneumophila SG1 (ST1 and ST104), L. anisa and L. rubrilucens widely distributed in HWN. No relevant contamination was found for other parameters tested. The long-term effect of WTP828 on Legionella containment suggest the easy and safe application of this disinfectant, that combined with knowledge of building characteristics, an adequate environmental monitoring and risk assessment plan, become the key elements in preventing Legionella contamination and exposure.
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14
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Coniglio MA, Ferrante M, Yassin MH. Preventing Healthcare-Associated Legionellosis: Results after 3 Years of Continuous Disinfection of Hot Water with Monochloramine and an Effective Water Safety Plan. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15081594. [PMID: 30060459 PMCID: PMC6121960 DOI: 10.3390/ijerph15081594] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/22/2018] [Accepted: 07/26/2018] [Indexed: 12/13/2022]
Abstract
The purpose of this study is to report the experience of the implementation and application of a 3-year Water Safety Plan (WSP) together with the secondary disinfection of water by monochloramine to control and prevent healthcare-associated legionellosis in an Italian hospital strongly colonized by Legionella. Risk assessment was carried out by the WSP team. The main critical control points focused on in developing the WSP for the control of Legionella was the water distribution system. A sampling plan for the detection of Legionella was implemented. A widespread contamination of the hot water distribution system by L. pneumophila sg5 was found. Results after 3 years of the continuous disinfection of hot water with monochloramine indicate the eradication of Legionella. The implementation and application of a WSP in a hospital, together with the disinfection of the water distribution system with monochloramine, can be effective in controlling the growth of Legionella and in preventing nosocomial legionellosis.
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Affiliation(s)
- Maria Anna Coniglio
- Legionella Reference Laboratory, Department of Medical, Surgical Sciences and Advanced Technologies "G.F. Ingrassia", University of Catania, via Santa Sofia 87, 95123 Catania, Italy.
- Hygiene Complex Operative Unit, A.O.U. Policlinico-Vittorio Emanuele, via S. Sofia 87, 95123 Catania, Italy.
| | - Margherita Ferrante
- Hygiene Complex Operative Unit, A.O.U. Policlinico-Vittorio Emanuele, via S. Sofia 87, 95123 Catania, Italy.
| | - Mohamed H Yassin
- Infection Control Department, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA 15213, USA.
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15
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Casini B, Baggiani A, Totaro M, Mansi A, Costa AL, Aquino F, Miccoli M, Valentini P, Bruschi F, Lopalco PL, Privitera G. Detection of viable but non-culturable legionella in hospital water network following monochloramine disinfection. J Hosp Infect 2017; 98:46-52. [PMID: 28917570 DOI: 10.1016/j.jhin.2017.09.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/04/2017] [Accepted: 09/07/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Prevention of legionellosis remains a critical issue in healthcare settings where monochloramine (MC) disinfection was recently introduced as an alternative to chlorine dioxide in controlling Legionella spp. contamination of the hospital water network. Continuous treatments with low MC doses in some instances have induced a viable but non-culturable state (VBNC) of Legionella spp. AIM To investigate the occurrence of such dormant cells during a long period of continuous MC treatment. METHODS Between November 2010 and April 2015, 162 water and biofilm samples were collected and Legionella spp. isolated in accordance with standard procedures. In sampling sites where MC was <1.5mg/L, VBNC cells were investigated by ethidium monoazide bromide (EMA)-real-time polymerase chain reaction (qPCR) and 'resuscitation' test into Acanthamoeba polyphaga CCAP 1501/18. According to the Health Protection Agency protocol, free-living protozoa were researched in 60 five-litre water samples. FINDINGS In all, 136 out of 156 (87.2%) of the samples taken from sites previously positive for L. pneumophila ST269 were negative by culture, but only 47 (34.5%) negative by qPCR. Although no positive results were obtained by EMA-qPCR, four out of 22 samples associated with MC concentration of 1.3 ± 0.5mg/L showed VBNC legionella resuscitation. The presence of the amoeba A. polyphaga in the hospital water network was demonstrated. CONCLUSION Our study is the first report evidencing the emergence of VNBC legionella during a long period of continuous MC treatment of a hospital water network, highlighting the importance of keeping an appropriate and uninterrupted MC dosage to ensure the control of legionella colonization in hospital water supplies.
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Affiliation(s)
- B Casini
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy.
| | - A Baggiani
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - M Totaro
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - A Mansi
- INAIL, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, Monte Porzio Catone (Roma), Roma, Italy
| | - A L Costa
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - F Aquino
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - M Miccoli
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - P Valentini
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - F Bruschi
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - P L Lopalco
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
| | - G Privitera
- Department of Translational Research, N.T.M.S., University of Pisa, Pisa, Italy
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16
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Ma X, Bibby K. Free chlorine and monochloramine inactivation kinetics of Aspergillus and Penicillium in drinking water. WATER RESEARCH 2017; 120:265-271. [PMID: 28501787 DOI: 10.1016/j.watres.2017.04.064] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 04/17/2017] [Accepted: 04/26/2017] [Indexed: 06/07/2023]
Abstract
Fungi are near-ubiquitous in potable water distribution systems, but the disinfection kinetics of commonly identified fungi are poorly studied. In the present study, laboratory scale experiments were conducted to evaluate the inactivation kinetics of Aspergillus fumigatus, Aspergillus versicolor, and Penicillium purpurogenum by free chlorine and monochloramine. The observed inactivation data were then fit to a delayed Chick-Watson model. Based on the model parameter estimation, the Ct values (integrated product of disinfectant concentration C and contact time t over defined time intervals) for 99.9% inactivation of the tested fungal strains ranged from 48.99 mg min/L to 194.7 mg min/L for free chlorine and from 90.33 mg min/L to 531.3 mg min/L for monochloramine. Fungal isolates from a drinking water system (Aspergillus versicolor and Penicillium purpurogenum) were more disinfection resistant than Aspergillus fumigatus type and clinical isolates. The required 99.9% inactivation Ct values for the tested fungal strains are higher than E. coli, a commonly monitored indicator bacteria, and within a similar range for bacteria commonly identified within water distribution systems, such as Mycobacterium spp. and Legionella spp.
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Affiliation(s)
- Xiao Ma
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Kyle Bibby
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261, USA.
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17
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Control of Legionella Contamination and Risk of Corrosion in Hospital Water Networks following Various Disinfection Procedures. Appl Environ Microbiol 2016; 82:2959-2965. [PMID: 26969696 DOI: 10.1128/aem.03873-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022] Open
Abstract
Physical and chemical disinfection methods have been proposed with the aim of controlling Legionella water contamination. To date, the most effective procedures for reducing bacterial contamination have not yet been defined. The aim of this study was to assess the long-term effectiveness of various disinfection procedures in order to reduce both culturable and nonculturable (NC) legionellae in different hospital water networks treated with heat, chlorine dioxide, monochloramine, and hydrogen peroxide. The temperature levels and biocide concentrations that proved to give reliable results were analyzed. In order to study the possible effects on the water pipes, we verified the extent of corrosion on experimental coupons after applying each method for 6 months. The percentage of positive points was at its lowest after treatment with monochloramine, followed by chlorine dioxide, hydrogen peroxide, and hyperthermia. Different selections of Legionella spp. were observed, as networks treated with chlorine-based disinfectants were contaminated mainly by Legionella pneumophila serogroup 1, hyperthermia was associated with serogroups 2 to 14, and hydrogen peroxide treatment was associated mainly with non-pneumophila species. NC cells were detected only in heat-treated waters, and also when the temperature was approximately 60°C. The corrosion rates of the coupons were within a satisfactory limit for water networks, but the morphologies differed. We confirm here that chemical disinfection controls Legionella colonization more effectively than hyperthermia does. Monochloramine was the most effective treatment, while hydrogen peroxide may be a promising alternative to chlorine-based disinfectants due to its ability to select for other, less virulent or nonpathogenic species.
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18
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Jjemba PK, Johnson W, Bukhari Z, LeChevallier MW. Occurrence and Control of Legionella in Recycled Water Systems. Pathogens 2015; 4:470-502. [PMID: 26140674 PMCID: PMC4584268 DOI: 10.3390/pathogens4030470] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Accepted: 06/24/2015] [Indexed: 01/11/2023] Open
Abstract
Legionella pneumophila is on the United States Environmental Protection Agency (USEPA) Candidate Contaminant list (CCL) as an important pathogen. It is commonly encountered in recycled water and is typically associated with amoeba, notably Naegleria fowleri (also on the CCL) and Acanthamoeba sp. No legionellosis outbreak has been linked to recycled water and it is important for the industry to proactively keep things that way. A review was conducted examine the occurrence of Legionella and its protozoa symbionts in recycled water with the aim of developing a risk management strategy. The review considered the intricate ecological relationships between Legionella and protozoa, methods for detecting both symbionts, and the efficacy of various disinfectants.
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Affiliation(s)
- Patrick K Jjemba
- American Water Research Laboratory, 213 Carriage Lane, Delran, NJ 08075, USA.
| | - William Johnson
- American Water Research Laboratory, 213 Carriage Lane, Delran, NJ 08075, USA.
| | - Zia Bukhari
- American Water, 1025 Laurel Oak Road, Voorhees, NJ 08043, USA.
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19
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Mancini B, Scurti M, Dormi A, Grottola A, Zanotti A, Cristino S. Effect of monochloramine treatment on colonization of a hospital water distribution system by Legionella spp.: a 1 year experience study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:4551-4558. [PMID: 25723867 DOI: 10.1021/es506118e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Contamination of hot water distribution systems by Legionella represents a great challenge due to difficulties associated with inactivating microorganisms, preserving the water characteristics. The aim of this study was to examine over the course of 1 year in 11 fixed sites, the impact of monochloramine disinfection on Legionella, heterotrophic bacteria (36 °C), Pseudomonas aeruginosa contamination, and chemical parameters of a plumbing system in an Italian hospital. Three days after installation (T0), in the presence of monochloramine concentration between 1.5 and 2 mg/L, 10/11 sites (91%) were contaminated by L. pneumophila serogroups 3 and 10. After these results, the disinfectant dosage was increased to between 6 and 10 mg/L, reducing the level of Legionella by three logarithmic unit by 2 months postinstallation (T2) until 6 months later (T3). One year later (T4), there was a significant reduction (p = 0.0002) at 8/11 (73%) sites. Our data showed also a significant reduction of heterotrophic bacteria (36 °C) in 6/11 (55%) sites at T4 (p = 0.0004), by contrast the contamination of P. aeruginosa found at T0 in two sites persisted up until T4. The results of the present study show that monochloramine is a promising disinfectant that can prevent Legionella contamination of hospital water supplies.
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Affiliation(s)
| | | | | | - Antonella Grottola
- §Regional Reference Laboratory for Clinical Diagnosis of Legionellosis, Unit of Microbiology and Virology, Modena University Hospital, via del Pozzo 71, 41124, Modena, Italy
| | - Andrea Zanotti
- ⊥ITACA srl ITACA s.r.l., via Remigia, 19, 40068, San Lazzaro di Savena (BO), Italy
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20
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Baron JL, Harris JK, Holinger EP, Duda S, Stevens MJ, Robertson CE, Ross KA, Pace NR, Stout JE. Effect of monochloramine treatment on the microbial ecology of Legionella and associated bacterial populations in a hospital hot water system. Syst Appl Microbiol 2015; 38:198-205. [PMID: 25840824 DOI: 10.1016/j.syapm.2015.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 12/22/2022]
Abstract
Opportunistic pathogens, including Legionella spp. and non-tuberculous mycobacteria, can thrive in building hot water systems despite municipal and traditional on-site chlorine disinfection. Monochloramine is a relatively new approach to on-site disinfection, but the microbiological impact of on-site chloramine use has not been well studied. We hypothesized that comparison of the microbial ecology associated with monochloramine treatment versus no on-site treatment would yield highly dissimilar bacterial communities. Hot water samples were collected monthly from 7 locations for three months from two buildings in a Pennsylvania hospital complex supplied with common municipal water: (1) a hospital administrative building (no on-site treatment) and (2) an adjacent acute-care hospital treated on-site with monochloramine to control Legionella spp. Water samples were subjected to DNA extraction, rRNA PCR, and 454 pyrosequencing. Stark differences in the microbiome of the chloraminated water and the control were observed. Bacteria in the treated samples were primarily Sphingomonadales and Limnohabitans, whereas Flexibacter and Planctomycetaceae predominated in untreated control samples. Serendipitously, one sampling month coincided with dysfunction of the on-site disinfection system that resulted in a Legionella bloom detected by sequencing and culture. This study also demonstrates the potential utility of high-throughput DNA sequencing to monitor microbial ecology in water systems.
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Affiliation(s)
- Julianne L Baron
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15261, USA; Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - J Kirk Harris
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eric P Holinger
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Scott Duda
- Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - Mark J Stevens
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Charles E Robertson
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Kimberly A Ross
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Norman R Pace
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Janet E Stout
- Special Pathogens Laboratory, Pittsburgh, PA 15219, USA; Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, PA 15261, USA.
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21
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Ma X, Baron JL, Vikram A, Stout JE, Bibby K. Fungal diversity and presence of potentially pathogenic fungi in a hospital hot water system treated with on-site monochloramine. WATER RESEARCH 2015; 71:197-206. [PMID: 25618520 DOI: 10.1016/j.watres.2014.12.052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/09/2014] [Accepted: 12/30/2014] [Indexed: 06/04/2023]
Abstract
Currently, our knowledge of fungal ecology in engineered drinking water systems is limited, despite the potential for these systems to serve as a reservoir for opportunistic pathogens. In this study, hot water samples were collected both prior to and following the addition of monochloramine as an on-site disinfectant in a hospital hot water system. Fungal ecology was then analyzed by high throughput sequencing of the fungal ITS1 region. The results demonstrate that the genera Penicillium, Aspergillus, Peniophora, Cladosporium and Rhodosporidium comprised the core fungal biome of the hospital hot water system. Penicillium dominated the fungal community with an average relative abundance of 88.89% (±6.37%). ITS1 sequences of fungal genera containing potential pathogens such as Aspergillus, Candida, and Fusarium were also detected in this study. No significant change in fungal community structure was observed before and after the initiation of on-site monochloramine water treatment. This work represents the first report of the effects of on-site secondary water disinfection on fungal ecology in premise plumbing system, and demonstrates the necessity of considering opportunistic fungal pathogens during the evaluation of secondary premise plumbing disinfection systems.
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Affiliation(s)
- Xiao Ma
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Julianne L Baron
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA 15261, USA; Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - Amit Vikram
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Janet E Stout
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Special Pathogens Laboratory, Pittsburgh, PA 15219, USA
| | - Kyle Bibby
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261, USA.
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22
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Baron JL, Vikram A, Duda S, Stout JE, Bibby K. Shift in the microbial ecology of a hospital hot water system following the introduction of an on-site monochloramine disinfection system. PLoS One 2014; 9:e102679. [PMID: 25033448 PMCID: PMC4102543 DOI: 10.1371/journal.pone.0102679] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 06/22/2014] [Indexed: 01/14/2023] Open
Abstract
Drinking water distribution systems, including premise plumbing, contain a diverse microbiological community that may include opportunistic pathogens. On-site supplemental disinfection systems have been proposed as a control method for opportunistic pathogens in premise plumbing. The majority of on-site disinfection systems to date have been installed in hospitals due to the high concentration of opportunistic pathogen susceptible occupants. The installation of on-site supplemental disinfection systems in hospitals allows for evaluation of the impact of on-site disinfection systems on drinking water system microbial ecology prior to widespread application. This study evaluated the impact of supplemental monochloramine on the microbial ecology of a hospital's hot water system. Samples were taken three months and immediately prior to monochloramine treatment and monthly for the first six months of treatment, and all samples were subjected to high throughput Illumina 16S rRNA region sequencing. The microbial community composition of monochloramine treated samples was dramatically different than the baseline months. There was an immediate shift towards decreased relative abundance of Betaproteobacteria, and increased relative abundance of Firmicutes, Alphaproteobacteria, Gammaproteobacteria, Cyanobacteria and Actinobacteria. Following treatment, microbial populations grouped by sampling location rather than sampling time. Over the course of treatment the relative abundance of certain genera containing opportunistic pathogens and genera containing denitrifying bacteria increased. The results demonstrate the driving influence of supplemental disinfection on premise plumbing microbial ecology and suggest the value of further investigation into the overall effects of premise plumbing disinfection strategies on microbial ecology and not solely specific target microorganisms.
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Affiliation(s)
- Julianne L. Baron
- Department of Infectious Diseases and Microbiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania, United States of America
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
| | - Amit Vikram
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
| | - Scott Duda
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
| | - Janet E. Stout
- Special Pathogens Laboratory, Pittsburgh, Pennsylvania, United States of America
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
| | - Kyle Bibby
- Department of Civil and Environmental Engineering, University of Pittsburgh, Swanson School of Engineering, Pittsburgh, Pennsylvania, United States of America
- Department of Computational and Systems Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, United States of America
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