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Dörrie B, Nogueira R. Lessons learned from a one-year study of Legionella spp. cultivation from activated sludge samples. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 369:122266. [PMID: 39216355 DOI: 10.1016/j.jenvman.2024.122266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 08/09/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024]
Abstract
Risk assessment and management of Legionella spp. contamination in activated sludge in wastewater treatment plants is carried out using the culture method. Underestimation of Legionella spp. is frequently reported in the literature, but a comprehensive long-term study of the performance of the method under comparable conditions is still lacking. The aim of this study is to evaluate the recovery rate and limit of detection of the culture method for Legionella spp. from activated sludge samples collected during the different seasons of the year. Activated sludge samples spiked with Legionella pneumophila subsp. pneumophila strain Philadelphia-1 (mean concentration 5.2 ± 0.35 logCFU/mL) were analysed monthly for one year using the culture method. Three different sample pre-treatments were compared, namely filtration, acid treatment and thermal treatment, and the recovery rate and limit of detection were assessed for each. The recovery rate of the culture method for Legionella spp. depended on the type of sample pre-treatment and the season of activated sludge sampling, while the limit of detection depended only on the sample pre-treatment. The best performance of the culture method, defined as the combination of the highest recovery rate and lowest limit of detection, was obtained for the filtered acid pre-treated samples (recovery rate: 89 ± 4 %; limit of detection: 1.3 logCFU/mL in 83 % of the samples). The lowest limit of detection was observed for the filtered thermally pre-treated samples (1.0 logCFU/mL in 93 % of the samples). Simultaneously, both thermally pre-treated samples showed up to a third lower recovery rates than the other pre-treatments in winter, while untreated and acid pre-treated samples showed consistently high recovery rates (>80%, logCFU/mL). The recovery rates of the unfiltered and filtered thermally pre-treated samples showed significant weak to strong positive correlations with the organic and phosphorus load in the influent as well as with the water and atmospheric temperatures, indicating that the recovery rate depends on the seasonal variation of the wastewater composition. This study presents new insights into the detection and quantification of Legionella spp. in activated sludge samples and considers seasonal dependencies in analytical results.
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Affiliation(s)
- Beatriz Dörrie
- Institute of Sanitary Engineering and Waste Management, Leibniz University Hannover, Welfengarten 1, D-30167, Hannover, Germany.
| | - Regina Nogueira
- Institute of Sanitary Engineering and Waste Management, Leibniz University Hannover, Welfengarten 1, D-30167, Hannover, Germany.
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Bolufer Cruañes C, Ouradou A, Pineault S, Boivin MC, Huot C, Bédard E. Uncovering wastewater treatment plants as possible sources of legionellosis clusters through spatial statistics approach and environmental analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:45234-45245. [PMID: 38961023 DOI: 10.1007/s11356-024-34019-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 06/13/2024] [Indexed: 07/05/2024]
Abstract
Wastewater treatment plants (WWTPs) are suspected reservoirs of Legionella pneumophila (Lp). The required aeration and mixing steps lead to the emission and dispersion of bioaerosols potentially harboring Lp. The aim of the project is to evaluate municipal WWTPs as a possible source of legionellosis through the statistical analysis of case clusters. A space-time scanning statistical method was implemented in SaTScan software to identify and analyze WWTPs located within and close to spatiotemporal clusters of legionellosis detected in Quebec between 2016 and 2020. In parallel, WWTPs were ranked according to their pollutant load, flow rate and treatment type. These parameters were used to evaluate the WWTP susceptibility to generate and disperse bioaerosols. Results show that 37 of the 874 WWTPs are located inside a legionellosis cluster study zone, including six of the 40 WWTPs ranked most susceptible. In addition, two susceptible WWTPs located within an extended area of 2.5 km from the study zone (2.5-km buffer) were included, for a total of 39 WWTPs. The selected 39 WWTPs were further studied to document proximity of population, dominant wind direction, and surrounding water quality. Samples collected from the influent and the effluent of six selected WWTPs revealed the presence of Legionella spp. in 92.3% of the samples. Lp and Lp serogroupg 1 (Lp sg1) were detected below the limit of quantification in 69% and 46% of the samples, respectively. The presence of Legionella in wastewater and the novel statistical approach presented here provides information to the public health authorities regarding the investigation of WWTPs as a possible source of Legionella exposure, sporadic cases, and clusters of legionellosis.
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Affiliation(s)
- Carmen Bolufer Cruañes
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada
- University Polytechnic Valencia (UPV), Valencia, Spain
| | - Arthur Ouradou
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Simon Pineault
- Ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs, Québec, QC, Canada
| | | | - Caroline Huot
- Institut National de Santé Publique du Québec, Québec, QC, Canada
| | - Emilie Bédard
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada.
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Pijnacker R, Brandsema P, Euser S, Vahidnia A, Kuiter A, Limaheluw J, Schout C, Haj Mohammad G, Raven S. An outbreak of Legionnaires' disease linked to a municipal and industrial wastewater treatment plant, The Netherlands, September-October 2022. Euro Surveill 2024; 29:2300506. [PMID: 38757288 PMCID: PMC11100293 DOI: 10.2807/1560-7917.es.2024.29.20.2300506] [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: 09/19/2023] [Accepted: 02/19/2024] [Indexed: 05/18/2024] Open
Abstract
Wastewater treatment plants (WWTPs) are increasingly identified as Legionnaires' disease (LD) sources. An outbreak investigation was initiated following five LD cases reported in September 2022 in Houten, the Netherlands. Case identification was based on the European LD case definition, with symptom onset from 1 September 2022, residence in or within 5 km of Houten, or visit to Houten within the incubation period, without other likely sources. We sampled potential sources and genotyped environmental and clinical isolates. We identified 15 LD cases with onset between 13 September and 23 October 2022. A spatial source identification and wind direction model suggested an industrial (iWWTP) and a municipal WWTP (mWWTP) as potential sources, with the first discharging water into the latter. Both tested positive for Legionella pneumophila serogroups 1 and 6 with multiple sequence types (ST). We detected L. pneumophila sg1 ST42 in the mWWTP, matching with one of three available clinical isolates. Following control measures at the WWTPs, no further cases were observed. This outbreak underlines that municipal and industrial WWTPs can play an important role in community LD cases and outbreaks, especially those with favourable conditions for Legionella growth and dissemination, or even non-favourable conditions for growth but with the influx of contaminated water.
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Affiliation(s)
- Roan Pijnacker
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
- Department of Infectious Diseases, Public Health Service region Utrecht (GGD), Zeist, the Netherlands
| | - Petra Brandsema
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Sjoerd Euser
- Regional Public Health Laboratory Kennemerland, Haarlem, the Netherlands
| | - Ali Vahidnia
- Regional Public Health Laboratory Kennemerland, Haarlem, the Netherlands
| | - Arnold Kuiter
- Environmental Services Regarding Authorization and Enforcement (RUD Utrecht), Utrecht, the Netherlands
| | - Jesse Limaheluw
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands
| | - Christine Schout
- Department of Infectious Diseases, Public Health Service region Utrecht (GGD), Zeist, the Netherlands
| | - Gaaled Haj Mohammad
- Department of Infectious Diseases, Public Health Service region Utrecht (GGD), Zeist, the Netherlands
| | - Stijn Raven
- Department of Infectious Diseases, Public Health Service region Utrecht (GGD), Zeist, the Netherlands
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van den Berg H, Lodder W, Bartels A, Brandsema P, Vermeulen L, Lynch G, Euser S, de Roda Husman AM. Legionella detection in wastewater treatment plants with increased risk for Legionella growth and emission. JOURNAL OF WATER AND HEALTH 2023; 21:1291-1302. [PMID: 37756196 PMCID: wh_2023_164 DOI: 10.2166/wh.2023.164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Legionnaires' disease (LD) is a severe pneumonia mainly caused by the bacterium Legionella pneumophila. Although many environmental sources of LD have been described, the sources of the majority of non-outbreak LD cases have not been identified. In several outbreaks in the Netherlands, wastewater treatment plants (WWTPs) were identified as the most likely source of infection. In this study, four criteria for Legionella growth and emission to air and surface waters were selected based on the literature and a risk matrix was drafted. An inventory was made of all WWTPs and their characteristics in the Netherlands. The risk matrix was applied to identify WWTPs at risk for Legionella growth and emission. Wastewater was collected at WWTPs with moderate to high risk for Legionella growth and emission. In 18% of the sampled WWTPs, Legionella spp. was detected using culture methods. The presented risk matrix can be used to assess the risks of Legionella growth and emission for WWTPs and support surveillance by prioritizing WWTPs. When Legionella is detected in the wastewater, it is recommended to take action to prevent emission to air or discharge on surface waters and, if possible, reduce the Legionella concentration.
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Affiliation(s)
- Harold van den Berg
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Center for Zoonoses and Environmental Microbiology, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands E-mail:
| | - Willemijn Lodder
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Center for Zoonoses and Environmental Microbiology, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Alvin Bartels
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, National Coordination Centre for Communicable Disease Control, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Petra Brandsema
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Centre for Infectious Diseases, Epidemiology and Surveillance, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Lucie Vermeulen
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Center for Zoonoses and Environmental Microbiology, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Gretta Lynch
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Center for Zoonoses and Environmental Microbiology, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
| | - Sjoerd Euser
- Regional Public Health Laboratory Kennemerland, Boerhaavelaan 26, 2035 RC, Haarlem, The Netherlands
| | - Ana Maria de Roda Husman
- National Institute for Public Health and The Environment (RIVM), Centre for Infectious Disease Control, Center for Zoonoses and Environmental Microbiology, P.O. Box 1, 3720 BA, Bilthoven, The Netherlands
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Ouradou A, Veillette M, Bélanger Cayouette A, Corbin S, Boulanger C, Dorner S, Duchaine C, Bédard E. Effect of odor treatment systems on bioaerosol microbial concentration and diversity from wastewater treatment plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 874:162419. [PMID: 36858219 DOI: 10.1016/j.scitotenv.2023.162419] [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: 12/06/2022] [Revised: 01/30/2023] [Accepted: 02/19/2023] [Indexed: 06/18/2023]
Abstract
Biofiltration, activated carbon and chemical scrubbing are technologies used for odor control in wastewater treatment plants. These systems may also influence the airborne microbial load in treated air. The study objectives were to 1) evaluate the capacity of three odor control system technologies to reduce the airborne concentration of total bacteria, Legionella, L. pneumophila, non-tuberculous mycobacteria (NTM) and Cladosporium in winter and summer seasons and 2) to describe the microbial ecology of the biofiltration system and evaluate its impact on treated air microbial diversity. A reduction of the total bacterial concentration up to 25 times was observed after odor treatment. Quantification by qPCR revealed the presence of Legionella spp. in all air samples ranging between 26 and 1140 GC/m3, while L. pneumophila was not detected except for three samples below the limit of quantification. A significant increase of up to 25-fold of Legionella spp. was noticed at the outlet of two of the three treatment systems. NTM were ubiquitously detected before air treatment (up to 2500 GC/m3) and were significantly reduced by all 3 systems (up to 13-fold). Cladosporium was measured at low concentrations for each system (< 190 GC/m3), with 68 % of the air samples below the limit of detection. Biodiversity results revealed that biofiltration system is an active process that adapts to air pollutants over time. Legionella spp. were detected in significant abundance in the air once treated in winter (up to 27 %). Nevertheless, the abundance of protozoan hosts is low and does not explain the multiplication of Legionella spp. The season remains the most influential factor shaping biodiversity. In summer only, air biofiltration caused a significant enrichment of the biodiversity. Although odor control technologies are not designed for bacterial mitigation, findings from this study suggest their potential to reduce the abundance of some genera harboring pathogenic species.
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Affiliation(s)
- A Ouradou
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada.
| | - M Veillette
- Research Center of the University Institute of Cardiology and Pneumology of Quebec-University Laval, Québec, QC, Canada.
| | - A Bélanger Cayouette
- Research Center of the University Institute of Cardiology and Pneumology of Quebec-University Laval, Québec, QC, Canada; Department of Biochemistry, Microbiology and Bioinformatics, Faculty of Science and Engineering, University Laval, Québec, QC, Canada.
| | - S Corbin
- City of Repentigny, Repentigny, QC, Canada.
| | | | - S Dorner
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada.
| | - C Duchaine
- Research Center of the University Institute of Cardiology and Pneumology of Quebec-University Laval, Québec, QC, Canada; Department of Biochemistry, Microbiology and Bioinformatics, Faculty of Science and Engineering, University Laval, Québec, QC, Canada; Canada Research Chair on Bioaerosols, University Laval, Québec, QC, Canada.
| | - E Bédard
- Department of Civil, Geological and Mining Engineering, Polytechnique Montréal, Montréal, QC, Canada.
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Selak L, Marković T, Pjevac P, Orlić S. Microbial marker for seawater intrusion in a coastal Mediterranean shallow Lake, Lake Vrana, Croatia. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 849:157859. [PMID: 35940271 DOI: 10.1016/j.scitotenv.2022.157859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/24/2022] [Accepted: 08/02/2022] [Indexed: 05/13/2023]
Abstract
Climate change-induced rising sea levels and prolonged dry periods impose a global threat to the freshwater scarcity on the coastline: salinization. Lake Vrana is the largest surface freshwater resource in mid-Dalmatia, while the local springs are heavily used in agriculture. The karstified carbonate ridge that separates this shallow lake from the Adriatic Sea enables seawater intrusion if the lakes' precipitation-evaporation balance is disturbed. In this study, the impact of anthropogenic activities and drought exuberated salinization on microbial communities was tracked in Lake Vrana and its inlets, using 16S rRNA gene sequencing. The lack of precipitation and high water temperatures in summer months introduced an imbalance in the water regime of the lake, allowing for seawater intrusion, mainly via the karst conduit Jugovir. The determined microbial community spatial differences in the lake itself and the main drainage canals were driven by salinity, drought, and nutrient loading. Particle-associated and free-living microorganisms both strongly responded to the ecosystem perturbations, and their co-occurrence was driven by the salinization event. Notably, a bloom of halotolerant taxa, predominant the sulfur-oxidizing genus Sulfurovum, emerged with increased salinity and sulfate concentrations, having the potential to be used as an indicator for salinization of shallow coastal lakes. Following summer salinization, lake water column homogenization took from a couple of weeks up to a few months, while the entire system displayed increased salinity despite increased precipitation. This study represents a valuable contribution to understanding the impact of the Freshwater Salinization Syndrome on Mediterranean lakes' microbial communities and the ecosystem resilience.
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Affiliation(s)
- Lorena Selak
- Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Tamara Marković
- Croatian Geological Survey, Milan Sachs 2 Street, 10000 Zagreb, Croatia
| | - Petra Pjevac
- Joint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria; University of Vienna, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, Djerassiplatz 1, 1030 Vienna, Austria
| | - Sandi Orlić
- Division of Materials Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia; Center of Excellence for Science and Technology-Integration of Mediterranean Region (STIM), Split, Croatia.
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Lynch VD, Shaman J. The effect of seasonal and extreme floods on hospitalizations for Legionnaires' disease in the United States, 2000-2011. BMC Infect Dis 2022; 22:550. [PMID: 35705915 PMCID: PMC9202215 DOI: 10.1186/s12879-022-07489-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/24/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND An increasing severity of extreme storms and more intense seasonal flooding are projected consequences of climate change in the United States. In addition to the immediate destruction caused by storm surges and catastrophic flooding, these events may also increase the risk of infectious disease transmission. We aimed to determine the association between extreme and seasonal floods and hospitalizations for Legionnaires' disease in 25 US states during 2000-2011. METHODS We used a nonparametric bootstrap approach to examine the association between Legionnaires' disease hospitalizations and extreme floods, defined by multiple hydrometeorological variables. We also assessed the effect of extreme flooding associated with named cyclonic storms on hospitalizations in a generalized linear mixed model (GLMM) framework. To quantify the effect of seasonal floods, we used multi-model inference to identify the most highly weighted flood-indicator variables and evaluated their effects on hospitalizations in a GLMM. RESULTS We found a 32% increase in monthly hospitalizations at sites that experienced cyclonic storms, compared to sites in months without storms. Hospitalizations in months with extreme precipitation were in the 89th percentile of the bootstrapped distribution of monthly hospitalizations. Soil moisture and precipitation were the most highly weighted variables identified by multi-model inference and were included in the final model. A 1-standard deviation (SD) increase in average monthly soil moisture was associated with a 49% increase in hospitalizations; in the same model, a 1-SD increase in precipitation was associated with a 26% increase in hospitalizations. CONCLUSIONS This analysis is the first to examine the effects of flooding on hospitalizations for Legionnaires' disease in the United States using a range of flood-indicator variables and flood definitions. We found evidence that extreme and seasonal flooding is associated with increased hospitalizations; further research is required to mechanistically establish whether floodwaters contaminated with Legionella bacteria drive transmission.
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Affiliation(s)
- Victoria D Lynch
- Department of Environmental Health Sciences, Columbia Mailman School of Public Health, Columbia University, 722 W. 168th St, New York, NY, 10032, USA.
| | - Jeffrey Shaman
- Department of Environmental Health Sciences, Columbia Mailman School of Public Health, Columbia University, 722 W. 168th St, New York, NY, 10032, USA
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Probabilistic Analysis of a French Legionellosis Outbreak Shows Potential Role of Wastewater Basin. Microorganisms 2022; 10:microorganisms10020422. [PMID: 35208875 PMCID: PMC8875701 DOI: 10.3390/microorganisms10020422] [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: 12/17/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/17/2022] Open
Abstract
Based on the data from a French outbreak of legionellosis, a probabilistic approach was developed to analyze and assess the potential role of several suspected sources of contamination. Potential dates of exposure of all cases were determined using back-calculation, using two probability distribution functions to model incubation period. A probabilistic analysis and risk assessment were then used to determine the most probable sources of contamination for each wave of the outbreak. The risk assessment was based on parameters representing emission and dispersion of Legionella: level and duration of emission; aerosol dispersion capacity; and probability of potential exposure for each patient. Four types of facilities containing the Legionella epidemic strain were analyzed: cooling towers, aerated wastewater basins, high pressure water cleaners, and car wash stations. The results highlighted the potential role of an aerated wastewater basin in the outbreak in addition to cooling towers. The role of high-pressure water cleaners and car wash stations appeared to be non-significant. This study also reveals the lack of knowledge on facility parameters that can be useful for microbial risk assessments. This type of probabilistic analysis can be used to quantitatively assess the risk for various facilities in order to manage a legionellosis outbreak.
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Jalili M, Ehrampoush MH, Zandi H, Ebrahimi AA, Mokhtari M, Samaei MR, Abbasi F. Risk assessment and disease burden of legionella presence in cooling towers of Iran's central hospitals. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:65945-65951. [PMID: 34327641 DOI: 10.1007/s11356-021-14791-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 07/27/2020] [Indexed: 06/13/2023]
Abstract
Regular monitoring and measurement of Legionella in tower water and preventive measures against contamination are particularly important in hospitals. This study aimed at risk assessment and disease burden because of legionella presence in cooling towers of Iran's central hospitals. Then its correlation with temperature, pH, turbidity, residual chlorine, and EC was investigated by the Pearson test. The health risk and burden of diseases caused by Legionella exposure were determined using QMRA and DALY models. Statistical analysis and modeling were performed in MATLAB2018. Of the total samples, 30-43% was infected with Legionella. The mean concentrations in hospital A and B were 5-102.5 ± 10 and 5-89.7 ± 0.7 CFU/L, respectively. Among environmental factors, turbidity and pH were the most effective factors in increasing and decreasing Legionella concentration, respectively. According to the QMRA model, the risks of Legionella infections and annual mortality in both hospitals were 0.2-0.3, 0-0.19, 2-2.9 × 10-5, and 0-0.7 × 10-5, respectively, which was higher than the acceptable risk range for Legionella (10-4-10-7). However, the trend of its change was negatively correlated with time (RB = - 0.77). According to the results, the concentration of Legionella and the exposure risk in both hospitals were higher than the permissible range, which is necessary to decrease to 0.1 current concentrations.
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Affiliation(s)
- Mahrokh Jalili
- Department of Environmental Health Engineering, Genetic and Environmental Adventures Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Student Research Committee, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Department of Environmental Health Engineering, Environmental Science and Technology Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Hassan Ehrampoush
- Department of Environmental Health Engineering, Genetic and Environmental Adventures Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Hengameh Zandi
- Department of Microbiology, School of Public Health, Research Center for Food Hygiene and Safety, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Ali Asghar Ebrahimi
- Department of Environmental Health Engineering, Genetic and Environmental Adventures Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mehdi Mokhtari
- Department of Environmental Health Engineering, Genetic and Environmental Adventures Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Reza Samaei
- Department of Environmental Health Engineering, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fariba Abbasi
- Department of Environmental Health Engineering, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran.
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10
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Atmospheric dispersion and transmission of Legionella from wastewater treatment plants: A 6-year case-control study. Int J Hyg Environ Health 2021; 237:113811. [PMID: 34311418 DOI: 10.1016/j.ijheh.2021.113811] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/17/2021] [Accepted: 07/13/2021] [Indexed: 01/25/2023]
Abstract
Legionnaires Disease incidence has risen in the Netherlands in recent years. For the majority of the cases, the source of infection is never identified. Two Dutch wastewater treatment plants (WWTPs) have previously been identified as source of outbreaks of Legionnaires Disease (LD) among local residents. The objective of this study is to examine if LD patients in the Netherlands are more exposed to aerosols originating from WWTPs than controls. METHODS An atmospheric dispersion model was used to generate nationwide exposure maps of aerosols from 776 WWTPs in the Netherlands. Municipal sewage treatment plants and industrial WWTPs were both included. Exposure of LD cases and controls at the residential address was compared, in a matched case-control design using a conditional logistic regression. Cases were notified LD cases with onset of disease in the period 2013-2018 in the Netherlands (n = 1604). RESULTS Aerosols dispersed over a large part of the Netherlands, but modelled concentrations are estimated to be elevated in close proximity to WWTPs. A statistically significant association was found between LD and the calculated annual average aerosol concentrations originating from WWTPs (odds-ratio: 1.32 (1.06-1.63)). This association remained significant when the two outbreak-related WWTPs were removed from the analysis (odds-ratio: 1.28 (1.03-1.58)). CONCLUSION LD cases were more exposed to aerosols from WWTPs than controls. This indicates that exposure to aerosols dispersed from WWTPs caused Legionnaires Disease in residents living near WWTPs in the period 2013-2018. In order to investigate which characteristics of WWTPs are associated with an increased LD risk, the WWTP database should be updated and more data is needed on the presence and survival of aerosolized Legionella bacteria to improve the Legionella dispersion modelling. Furthermore, it is recommended to further investigate how aerosol dispersion of WWTPs can effectively be reduced in order to reduce the potential health risk.
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11
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Mori J, Uprety S, Mao Y, Koloutsou-Vakakis S, Nguyen TH, Smith RL. Quantification and Comparison of Risks Associated with Wastewater Use in Spray Irrigation. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2021; 41:745-760. [PMID: 33084120 DOI: 10.1111/risa.13607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 09/12/2020] [Accepted: 09/22/2020] [Indexed: 06/11/2023]
Abstract
In the U.S., spray irrigation is the most common method used in agriculture and supplementing with animal wastewater has the potential to reduce water demands. However, this could expose individuals to respiratory pathogens such as Legionella pneumophila and nontuberculosis Mycobacteria (NTM). Disinfection with methods like anaerobic digestion is an option but can increase concentrations of cytotoxic ammonia (personal communication). Our study aimed to model the annual risks of infection from these bacterial pathogens and the air concentrations of ammonia and determine if anaerobically digesting this wastewater is a safe option. Air dispersion modeling, conducted in AERMOD, generated air concentrations of water during the irrigation season (May-September) for the years 2013-2018. These values fed into the quantitative microbial risk assessments for the bacteria and allowed calculation of ammonia air concentrations. The outputs of these models were compared to the safety thresholds of 10-4 infections/year and 0.5 mg/m3 , respectively, to determine their potential for negative health outcomes. It was determined that infection from NTM was not a concern for individuals near active spray irrigators, but that infection with L. pneumophila could be a concern, with a maximum predicted annual risk of infection of 3.5 × 10-3 infections/year and 25.2% of parameter combinations exceeding the established threshold. Ammonia posed a minor risk, with 1.5% of parameter combinations surpassing the risk threshold of 0.5 mg/m3 . These findings suggest that animal wastewater should be anaerobically digested prior to use in irrigation to remove harmful pathogens.
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Affiliation(s)
- Jameson Mori
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Sital Uprety
- Department of Civil & Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Yuqing Mao
- Department of Civil & Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Sotiria Koloutsou-Vakakis
- Department of Civil & Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Thanh H Nguyen
- Department of Civil & Environmental Engineering, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign
| | - Rebecca L Smith
- Department of Pathobiology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign
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12
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Allegra S, Riffard S, Leclerc L, Girardot F, Stauffert M, Forest V, Pourchez J. A valuable experimental setup to model exposure to Legionella's aerosols generated by shower-like systems. WATER RESEARCH 2020; 172:115496. [PMID: 31972415 DOI: 10.1016/j.watres.2020.115496] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
The mechanism underlying Legionella aerosolization and entry into the respiratory tract remains poorly documented. In previous studies, we characterized the aerodynamic behaviour of Legionella aerosols and assessed their regional deposition within the respiratory tract using a human-like anatomical model. The aim of this study was to assess whether this experimental setup could mimic the exposure to bioaerosols generated by showers. To achieve this objective we performed experiments to measure the mass median aerodynamic diameter (MMAD) as well as the emitted dose and the physiological state of the airborne bacteria generated by a shower and two nebulizers (vibrating-mesh and jet nebulizers). The MMADs of the dispersed bioaerosols were characterized using a 12-stage cascade low-pressure impactor. The amount of dispersed airborne bacteria from a shower was quantified using a Coriolis® Delta air sampler and compared to the airborne bacteria reaching the thoracic region in the experimental setup. The physiological state and concentration of airborne Legionella were assessed by qPCR for total cells, culture for viable and cultivable Legionella (VC), and flow cytometry for viable but non-cultivable Legionella (VBNC). In summary, the experimental setup developed appears to mimic the bioaerosol emission of a shower in terms of aerodynamic size distribution. Compared to the specific case of a shower used as a reference in this study, the experimental setup developed underestimates by 2 times (when the jet nebulizer is used) or overestimates by 43 times (when the vibrating-mesh nebulizer is used) the total emitted dose of airborne bacteria. To our knowledge, this report is the first showing that an experimental model mimics so closely an exposure to Legionella aerosols produced by showers to assess human lung deposition and infection in well-controlled and safe conditions.
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Affiliation(s)
- Séverine Allegra
- University of Lyon, University Jean Monnet of Saint-Etienne, CNRS, EVS-ISTHME UMR 5600, F-42023, Saint-Etienne, France.
| | - Serge Riffard
- University of Lyon, University Jean Monnet of Saint-Etienne, CNRS, EVS-ISTHME UMR 5600, F-42023, Saint-Etienne, France
| | - Lara Leclerc
- Mines Saint-Etienne, University of Lyon, University Jean Monnet of Saint-Etienne, INSERM, U 1059 Sainbiose, Centre CIS, F-42023, Saint-Etienne, France
| | - Françoise Girardot
- University of Lyon, University Jean Monnet of Saint-Etienne, CNRS, EVS-ISTHME UMR 5600, F-42023, Saint-Etienne, France
| | - Magalie Stauffert
- University of Lyon, University Jean Monnet of Saint-Etienne, CNRS, EVS-ISTHME UMR 5600, F-42023, Saint-Etienne, France
| | - Valérie Forest
- Mines Saint-Etienne, University of Lyon, University Jean Monnet of Saint-Etienne, INSERM, U 1059 Sainbiose, Centre CIS, F-42023, Saint-Etienne, France
| | - Jérémie Pourchez
- Mines Saint-Etienne, University of Lyon, University Jean Monnet of Saint-Etienne, INSERM, U 1059 Sainbiose, Centre CIS, F-42023, Saint-Etienne, France
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13
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Smith AF, Huss A, Dorevitch S, Heijnen L, Arntzen VH, Davies M, Robert-Du Ry van Beest Holle M, Fujita Y, Verschoor AM, Raterman B, Oesterholt F, Heederik D, Medema G. Multiple Sources of the Outbreak of Legionnaires' Disease in Genesee County, Michigan, in 2014 and 2015. ENVIRONMENTAL HEALTH PERSPECTIVES 2019; 127:127001. [PMID: 31799878 PMCID: PMC6957290 DOI: 10.1289/ehp5663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
BACKGROUND A community-wide outbreak of Legionnaires' disease (LD) occurred in Genesee County, Michigan, in 2014 and 2015. Previous reports about the outbreak are conflicting and have associated the outbreak with a change of water source in the city of Flint and, alternatively, to a Flint hospital. OBJECTIVE The objective of this investigation was to independently identify relevant sources of Legionella pneumophila that likely resulted in the outbreak. METHODS An independent, retrospective investigation of the outbreak was conducted, making use of public health, health care, and environmental data and whole-genome multilocus sequence typing (wgMLST) of clinical and environmental isolates. RESULTS Strong evidence was found for a hospital-associated outbreak in both 2014 and 2015: a) 49% of cases had prior exposure to Flint hospital A, significantly higher than expected from Medicare admissions; b) hospital plumbing contained high levels of L. pneumophila; c) Legionella control measures in hospital plumbing aligned with subsidence of hospital A-associated cases; and d) wgMLST showed Legionella isolates from cases exposed to hospital A and from hospital plumbing to be highly similar. Multivariate analysis showed an increased risk of LD in 2014 for people residing in a home that received Flint water or was located in proximity to several Flint cooling towers. DISCUSSION This is the first LD outbreak in the United States with evidence for three sources (in 2014): a) exposure to hospital A, b) receiving Flint water at home, and c) residential proximity to cooling towers; however, for 2015, evidence points to hospital A only. Each source could be associated with only a proportion of cases. A focus on a single source may have delayed recognition and remediation of other significant sources of L. pneumophila. https://doi.org/10.1289/EHP5663.
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Affiliation(s)
- Anya F. Smith
- KWR Water Research Institute, Nieuwegein, Netherlands
| | - Anke Huss
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
| | - Samuel Dorevitch
- School of Public Health, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Leo Heijnen
- KWR Water Research Institute, Nieuwegein, Netherlands
| | | | - Megan Davies
- Davies Public Health Consulting, LLC, Raleigh, North Carolina, USA
| | | | - Yuki Fujita
- KWR Water Research Institute, Nieuwegein, Netherlands
| | | | | | | | - Dick Heederik
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
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14
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Caicedo C, Rosenwinkel KH, Exner M, Verstraete W, Suchenwirth R, Hartemann P, Nogueira R. Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review. WATER RESEARCH 2019; 149:21-34. [PMID: 30445393 DOI: 10.1016/j.watres.2018.10.080] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.
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Affiliation(s)
- C Caicedo
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
| | - K-H Rosenwinkel
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany
| | - M Exner
- University of Bonn, Institute for Hygiene and Public Health, Bonn, Germany
| | - W Verstraete
- Ghent University, CMET, Ghent, and Avecom, Wondelgem, Belgium
| | - R Suchenwirth
- Public Health Office of Lower Saxony, Hannover, Germany
| | - P Hartemann
- Faculty of Medicine, Department of Environment and Public Health, Nancy University-CHU Nancy, Vandoeuvre Les Nancy, France
| | - R Nogueira
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
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