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Yao XH, Shen F, Hao J, Huang L, Keng B. A review of Legionella transmission risk in built environments: sources, regulations, sampling, and detection. Front Public Health 2024; 12:1415157. [PMID: 39131570 PMCID: PMC11309999 DOI: 10.3389/fpubh.2024.1415157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 07/08/2024] [Indexed: 08/13/2024] Open
Abstract
The risk of Legionella transmission in built environments remains a significant concern. Legionella can spread within buildings through aerosol transmission, prompting the exploration of airborne transmission pathways and proposing corresponding prevention and control measures based on building characteristics. To this end, a comprehensive literature review on the transmission risk of Legionella in built environments was performed. Four electronic databases (PubMed, Web of Science, Google Scholar, and CNKI) were searched from inception to March 2024 for publications reporting the risk of Legionella transmission in built environments. Relevant articles and gray literature reports were hand-searched, and 96 studies were finally included. Legionella pollution comes from various sources, mainly originates in a variety of built environments in which human beings remain for extended periods. The sources, outbreaks, national standards, regulations, and monitoring techniques for Legionella in buildings are reviewed, in addition to increases in Legionella transmission risk due to poor maintenance of water systems and long-distance transmission events caused by aerosol characteristics. Air and water sampling using various analytical methods helps identify Legionella in the environment, recognize sources in the built environments, and control outbreaks. By comparing the standard regulations of national organizations globally, the authors further highlight gaps and deficiencies in Legionella surveillance in China. Such advancements offer essential insights and references for understanding and addressing Legionella transmission risk in the built environment, with the potential to contribute to safeguarding public health and building environment safety.
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Affiliation(s)
- Xiao Hui Yao
- Department of Environmental Health, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Fan Shen
- Department of Environmental Health, Beijing Center for Disease Prevention and Control, Beijing, China
| | - Jing Hao
- Department of Environmental Health, Beijing Fengtai District Center for Disease Prevention and Control, Beijing, China
| | - Lu Huang
- Department of Environmental Health, Beijing Dongcheng District Center for Disease Prevention and Control, Beijing, China
| | - Bin Keng
- Department of Environmental Health, Beijing Huairou District Center for Disease Prevention and Control, Beijing, China
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Nisar MA, Ross KE, Brown MH, Bentham R, Best G, Eyre NS, Leterme SC, Whiley H. Increased flushing frequency of a model plumbing system initially promoted the formation of viable but non culturable cells but ultimately reduced the concentration of culturable and total Legionella DNA. Heliyon 2024; 10:e32334. [PMID: 38933949 PMCID: PMC11200333 DOI: 10.1016/j.heliyon.2024.e32334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 05/30/2024] [Accepted: 06/02/2024] [Indexed: 06/28/2024] Open
Abstract
Legionella is the causative agent of Legionnaires' disease, and its prevalence in potable water is a significant public health issue. Water stagnation within buildings increases the risk of Legionella. However, there are limited studies investigating how stagnation arising through intermittent usage affects Legionella proliferation and the studies that are available do not consider viable but non culturable (VBNC) Legionella. This study used a model plumbing system to examine how intermittent water stagnation affects both VBNC and culturable Legionella. The model plumbing system contained a water tank supplying two biofilm reactors. The model was initially left stagnant for ≈5 months (147 days), after which one reactor was flushed daily, and the other weekly. Biofilm coupons, and water samples were collected for analysis at days 0, 14 and 28. These samples were analysed for culturable and VBNC Legionella, free-living amoebae, and heterotrophic bacteria. After 28 days, once-a-day flushing significantly (p < 0.001) reduced the amount of biofilm-associated culturable Legionella (1.5 log10 reduction) compared with weekly flushing. However, higher counts of biofilm-associated VBNC Legionella (1 log10 higher) were recovered from the reactor with once-a-day flushing compared with weekly flushing. Likewise, once-a-day flushing increased the population of biofilm-associated Vermamoeba vermiformis (approximately 3 log10 higher) compared with weekly flushing, which indicated a positive relationship between VBNC Legionella and V. vermiformis. This is the first study to investigate the influence of stagnation on VBNC Legionella under environmental conditions. Overall, this study showed that a reduction in water stagnation decreased culturable Legionella but not VBNC Legionella.
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Affiliation(s)
- Muhammad Atif Nisar
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Kirstin E. Ross
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Melissa H. Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
- ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, 5042, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
| | - Giles Best
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, 5042, Australia
- Flow Cytometry Facility, Flinders University, Bedford Park, SA, 5042, Australia
| | - Nicholas S. Eyre
- College of Medicine and Public Health, Flinders University, Bedford Park, SA, 5042, Australia
| | - Sophie C. Leterme
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
- ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, 5042, Australia
- Institute for Nanoscience and Technology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford Park, SA, 5042, Australia
- ARC Training Centre for Biofilm Research and Innovation, Flinders University, Bedford Park, SA, 5042, Australia
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Fang Z, Zhou X, Liao H, Xu H. A meta-analysis of Legionella pneumophila contamination in hospital water systems. Am J Infect Control 2023; 51:1250-1262. [PMID: 37054892 DOI: 10.1016/j.ajic.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/31/2023] [Accepted: 04/01/2023] [Indexed: 04/15/2023]
Abstract
BACKGROUND Legionella pneumophila is a common cause of community-acquired pneumonia. We aimed to determine the pooled rates of L pneumophila contamination in the water environment of the hospital. METHODS We searched PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure, WangFang and Science Direct, The Cochrane Library, and Science Finder, for relevant studies published until December 2022. Stata 16.0 software was used to determine pooled contamination rates, publication bias, and subgroup analysis. RESULTS Forty-eight eligible articles with a total of 23,640 samples of water were evaluated, and the prevalence of L pneumophila was 41.6%. The results of the subgroup analysis showed that the pollution rate of L pneumophila in hot water (47.6%) was higher than that in other water bodies. The rates of L pneumophila contamination were higher in developed countries (45.2%), culture methods (42.3%), published between 1985 and 2015 (42.9%), and studies with a sample size of less than 100 (53.0%). CONCLUSIONS L pneumophila contamination in medical institutions is still very serious and should be paid attention to, especially in developed countries and hot water tanks.
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Affiliation(s)
- Zisi Fang
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Xiaocong Zhou
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Hui Liao
- School of Public Health, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Hong Xu
- Department of Environmental Health, Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
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Bertolino G, Marras L, Coroneo V. The Detection Limits of Legionella According to the EU Directive 2020/2184. Could That Be Too Permissive? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023. [PMID: 37777698 DOI: 10.1007/5584_2023_790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/02/2023]
Abstract
INTRODUCTION The problem of detecting legionella after a case of legionellosis from the source of environmental contamination has been known since a long time ago. Legionella is a bacterium present in various natural and artificial habitats and especially in surface fresh waters. It is found in greater concentration in warm waters, at temperatures between 20 °C and 42 °C. The greatest risk factor for humans is represented by the presence of Legionella in water distribution systems in hospitals, medical equipment (e.g. respirators, dialyzers, inhalers, humidifiers, water, massage equipment used in balneotherapy) and turbines used in dental practices, especially for hospitalized individuals. In the EU directive 2020/2184, issued by the European parliament on 16/12/2020, the concentration of Legionella was added to the parameters to be determined in assessing the quality of drinking water intended for human consumption. The objectives were to improve the quality standard of drinking water, reduce the consumption of bottled water and consequently reduce plastic waste. The WHO notes that Legionella causes the greatest burden from a health point of view and it is included among the parameters that require careful monitoring with a limit of less than 1000 CFU/L. The aim of this report was to evaluate the new EU directive 2020/2184 on the light of our laboratory experience. MATERIALS AND METHODS A total of 459 samples were processed at our Hygiene of food Laboratory - Department of Medical Sciences and Public Health. All statistical analyses were conducted using the SPSS statistical package (version 23 for Windows. SPSS, Inc. Chicago, Ill). RESULTS AND DISCUSSION Of the 67 structures examined where the cases occurred, 35 showed samples with at least one over-threshold value considering the reference value of 100 CFU/L, whereas using the new limit of 1000 CFU/L, only 25 structures resulted as having at least one sample above the threshold. In our experience as a regional reference laboratory for Legionella research, the increase from 100 CFU/L to 1,000 CFU/L could lead to a lower alert level. In fact, in the period between October 2017 and October 2021, the median value of CFU/L in presence of a case was 0 (0-100). Despite the large amount of studies on Legionella only a few relate the withdrawals and the consequent CFU/L with the confirmed cases of legionellosis, as in our analysis. The 75° percentile values of the Legionella concentration equal to 100 CFU/L in all samples associated with cases and clusters leads us to hypothesize that the limit equal to 1000 CFU/L that will be introduced for environmental monitoring as per recent European regulations may not be sufficiently protective for minimizing risk in the population, especially in healthcare facilities where fragile patients are assisted.
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Affiliation(s)
- G Bertolino
- Department of Pharmacy, Azienda Ospedaliero-Universitaria di Cagliari, Cagliari, Italy
| | - L Marras
- Department of Pharmacy, Azienda Ospedaliero-Universitaria di Cagliari, Cagliari, Italy
- Clinical Laboratory, Cagliari, Italy
| | - V Coroneo
- Department of Pharmacy, Azienda Ospedaliero-Universitaria di Cagliari, Cagliari, Italy
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italia
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Nakade J, Nakamura Y, Katayama Y, Obata H, Takahashi Y, Zaimoku Y, Fujii Y, Iwata Y. Systematic active environmental surveillance successfully identified and controlled the Legionella contamination in the hospital. J Infect Chemother 2022; 29:43-47. [PMID: 36162645 DOI: 10.1016/j.jiac.2022.09.010] [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: 06/20/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Legionella disease can manifest as severe respiratory tract infection with a high mortality rate and is sometimes associated with a hospital outbreak by a contaminated water supply. A patient with breast cancer admitted about a month before. High fever was observed 18 days after admission and the Legionella antigen test showed the positive result. METHODS Due to the incidence of Legionella infection, we demonstrated the active surveillance of Legionella contamination in the entire hospital. RESULTS Cultures of her environmental samples revealed that hot water in two bathrooms were contaminated with Legionella. In our hospital, the hot water is heated and pumped up on the roof and distributed to each room. The contaminated bathrooms were related to the same plumbing. Therefore, we further collected samples throughout the hot water system. Legionella was not detected in the central part of the system. However, we detected Legionella in the hot water sampled from other five rooms, which were also associated with the same plumbing of the two bathrooms. The temperature and chlorine concentration of the hot water were not high enough to inactivate Legionella at the end of the plumbing. After the adjustment of the water temperature and chlorine concentration, Legionella became undetectable. Our prompt and active surveillance successfully identified the plumbing of the hot water system as the source of Legionella contamination and took precautions against future outbreaks. CONCLUSIONS Monitoring of water temperature and chloride concentration at the end of the hot water circulation is important to prevent nosocomial Legionella disease.
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Affiliation(s)
- Junya Nakade
- Department of Infection Control and Prevention, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan; Department of Hospital Pharmacy, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoko Nakamura
- Department of Infection Control and Prevention, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan; Division of Nursing, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yusuke Katayama
- Division of Nursing, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Hiroyuki Obata
- Facilities Department, Takara-machi Facility Support Office, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoshinori Takahashi
- Department of Infection Control and Prevention, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan; Department of Rheumatology, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yoshitaka Zaimoku
- Department of Infection Control and Prevention, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan; Department of Hematology, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yumi Fujii
- Department of Breast Surgery, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Yasunori Iwata
- Department of Infection Control and Prevention, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan; Department of Nephrology and Laboratory Medicine, University Hospital, Kanazawa University, Kanazawa, Ishikawa, Japan.
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Werner KA, Schneider D, Poehlein A, Diederich N, Feyen L, Axtmann K, Hübner T, Brüggemann N, Prost K, Daniel R, Grohmann E. Metagenomic Insights Into the Changes of Antibiotic Resistance and Pathogenicity Factor Pools Upon Thermophilic Composting of Human Excreta. Front Microbiol 2022; 13:826071. [PMID: 35432262 PMCID: PMC9009411 DOI: 10.3389/fmicb.2022.826071] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/17/2022] [Indexed: 01/12/2023] Open
Abstract
In times of climate change, practicing a form of sustainable, climate-resilient and productive agriculture is of primordial importance. Compost could be one form of sustainable fertilizer, which is increasing humus, water holding capacity, and nutrient contents of soils. It could thereby strengthen agriculture toward the adverse effects of climate change, especially when additionally combined with biochar. To get access to sufficient amounts of suitable materials for composting, resources, which are currently treated as waste, such as human excreta, could be a promising option. However, the safety of the produced compost regarding human pathogens, pharmaceuticals (like antibiotics) and related resistance genes must be considered. In this context, we have investigated the effect of 140- and 154-days of thermophilic composting on the hygienization of human excreta and saw dust from dry toilets together with straw and green cuttings with and without addition of biochar. Compost samples were taken at the beginning and end of the composting process and metagenomic analysis was conducted to assess the fate of antibiotic resistance genes (ARGs) and pathogenicity factors of the microbial community over composting. Potential ARGs conferring resistance to major classes of antibiotics, such as beta-lactam antibiotics, vancomycin, the MLSB group, aminoglycosides, tetracyclines and quinolones were detected in all samples. However, relative abundance of ARGs decreased from the beginning to the end of composting. This trend was also found for genes encoding type III, type IV, and type VI secretion systems, that are involved in pathogenicity, protein effector transport into eukaryotic cells and horizontal gene transfer between bacteria, respectively. The results suggest that the occurrence of potentially pathogenic microorganisms harboring ARGs declines during thermophilic composting. Nevertheless, ARG levels did not decline below the detection limit of quantitative PCR (qPCR). Thresholds for the usage of compost regarding acceptable resistance gene levels are yet to be evaluated and defined.
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Affiliation(s)
- Katharina A. Werner
- Department of Microbiology, Faculty of Life Sciences and Technology, Berliner Hochschule für Technik, Berlin, Germany
| | - Dominik Schneider
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, Göttingen, Germany
| | - Nina Diederich
- Department of Microbiology, Faculty of Life Sciences and Technology, Berliner Hochschule für Technik, Berlin, Germany
| | - Lara Feyen
- Department of Microbiology, Faculty of Life Sciences and Technology, Berliner Hochschule für Technik, Berlin, Germany
| | - Katharina Axtmann
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Tobias Hübner
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH—Umweltforschungszentrum Leipzig (UFZ), Leipzig, Germany
| | - Nicolas Brüggemann
- Institute of Bio- and Geosciences—Agrosphere (IBG-3), Forschungszentrum Jülich, Jülich, Germany
| | - Katharina Prost
- Institute of Bio- and Geosciences—Agrosphere (IBG-3), Forschungszentrum Jülich, Jülich, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, Göttingen, Germany
| | - Elisabeth Grohmann
- Department of Microbiology, Faculty of Life Sciences and Technology, Berliner Hochschule für Technik, Berlin, Germany
- *Correspondence: Elisabeth Grohmann,
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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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Causes, Factors, and Control Measures of Opportunistic Premise Plumbing Pathogens—A Critical Review. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review critically analyses the chemical and physical parameters that influence the occurrence of opportunistic pathogens in the drinking water distribution system, specifically in premise plumbing. A comprehensive literature review reveals significant impacts of water age, disinfectant residual (type and concentration), temperature, pH, and pipe materials. Evidence suggests that there is substantial interplay between these parameters; however, the dynamics of such relationships is yet to be elucidated. There is a correlation between premise plumbing system characteristics, including those featuring water and energy conservation measures, and increased water quality issues and public health concerns. Other interconnected issues exacerbated by high water age, such as disinfectant decay and reduced corrosion control efficiency, deserve closer attention. Some common features and trends in the occurrence of opportunistic pathogens have been identified through a thorough analysis of the available literature. It is proposed that the efforts to reduce or eliminate their incidence might best focus on these common features.
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Papagianeli SD, Aspridou Z, Didos S, Chochlakis D, Psaroulaki A, Koutsoumanis K. Dynamic modelling of Legionella pneumophila thermal inactivation in water. WATER RESEARCH 2021; 190:116743. [PMID: 33352528 DOI: 10.1016/j.watres.2020.116743] [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: 08/03/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
A predictive mathematical model describing the effect of temperature on the inactivation of Legionella pneumophila in water was developed. Thermal inactivation of L. pneumophila was monitored under isothermal conditions (51 - 61°C). A primary log-linear model was fitted to the inactivation data and the estimated D values ranged from 0.23 to 25.31 min for water temperatures from 61 to 51°C, respectively. The effect of temperature on L. pneumophila inactivation was described using a secondary model, and the model parameters z value and Dref (D-value at 55°C) were estimated at 5.54°C and 3.47 min, respectively. The developed model was further validated under dynamic temperature conditions mimicking various conditions of water thermal disinfection in plumbing systems. The results indicated that the model can satisfactorily predict thermal inactivation of the pathogen at dynamic temperature environments and effectively translate water temperature profiles to cell number reduction. The application of the model in combination with effective temperature monitoring could provide the basis of an integrated preventive approach for the effective control of L. pneumophila in plumbing systems.
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Affiliation(s)
- Styliani Dimitra Papagianeli
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Zafeiro Aspridou
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Spyros Didos
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Dimosthenis Chochlakis
- Laboratory of Clinical Microbiology and Microbial Pathogenesis, Unit of Water, Food and Environmental Microbiology, School of Medicine, University of Crete, Heraklion, 71110, Greece
| | - Anna Psaroulaki
- Laboratory of Clinical Microbiology and Microbial Pathogenesis, Unit of Water, Food and Environmental Microbiology, School of Medicine, University of Crete, Heraklion, 71110, Greece
| | - Konstantinos Koutsoumanis
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
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Ghomimaghsad N, Yaslianifard S, Mohammadzadeh M, Dadashi M, Noorisepehr M. Contamination of Water Sources of Karaj Hospitals with Legionella pneumophila and Campylobacter jejuni. INTERNATIONAL JOURNAL OF ENTERIC PATHOGENS 2020. [DOI: 10.34172/ijep.2020.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: One of the most common routes of infection development in humans is contaminated water. Legionella pneumophila and Campylobacter jejuni are the important causes of community- and hospital-acquired pneumonia and gastroenteritis that are transmitted to humans via the inhalation of contaminated water droplets and consumption of contaminated water, respectively. Thus, continuous monitoring of the water supply systems for these pathogens has great importance in public health. Objective: This study aimed to evaluate the water contamination of Karaj hospitals with these two bacterial species. Materials and Methods: In this study, 62 water samples were obtained from different parts of the hospitals of Karaj from April to September 2019, including air conditioning systems, dialysis equipment, ventilation tanks, and different wards of a hospital such as infectious diseases, pediatrics, gastroenterology, dialysis, and intensive and neonatal intensive care units. The samples were collected in sterile containers and immediately transferred to the laboratory for further analysis. The culture on specific media, staining, and biochemical tests were performed to identify the L. pneumophila and C. jejuni. Results: Out of 62 water samples, 25.8% (16 samples) were positive for L. pneumophila; 68.75% were observed in hot water samples, and 31.25% were attributed to cold water samples. Among 62 samples, 4.84% (3 samples) were positive for C. jejuni, which were all detected in hot water samples. Conclusion: Considering that the methods of water refinery of municipal water have no high efficiency, the quality improvement of the water sources of hospitals seems to be necessary.
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Affiliation(s)
| | - Somayeh Yaslianifard
- Department of Microbiology, School of Medicine, Dietary Supplements and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Mohammad Mohammadzadeh
- Department of Microbiology, School of Medicine, Dietary Supplements and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Masoud Dadashi
- Department of Microbiology, School of Medicine, Dietary Supplements and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran
| | - Mohammad Noorisepehr
- Department of Environmental Health Engineering, Faculty of Health, Alborz University of Medical Sciences, Karaj, Iran
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Abstract
Energy usage in buildings is coming increasingly under the spotlight as carbon policy focus shifts towards the utilization of thermal energy. In the UK, heating and hot water accounts for around 40% of energy consumption and 20% of greenhouse gas emissions. Heating is typically produced onsite, making widescale carbon or energetic improvements challenging. District heating networks (DHNs) can offer significant carbon reduction for many users but can only be implemented if the end user buildings have good thermal energy efficiency. This greatly limits the ability to implement advancing 4th and 5th generation DHNs, which are the most advanced systems available. We elucidate the current state of thermal efficiency in buildings in the UK and provide recommendations for necessary building requirements and modifications in order to accommodate 4th and 5th generation district heating. We conclude that key sectors must be addressed including creating a skilled workforce, producing relevant metrics and benchmarks, and providing financial support for early stage design exploration.
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Paduano S, Marchesi I, Casali ME, Valeriani F, Frezza G, Vecchi E, Sircana L, Romano Spica V, Borella P, Bargellini A. Characterisation of Microbial Community Associated with Different Disinfection Treatments in Hospital hot Water Networks. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E2158. [PMID: 32213901 PMCID: PMC7143765 DOI: 10.3390/ijerph17062158] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/20/2020] [Accepted: 03/22/2020] [Indexed: 12/16/2022]
Abstract
Many disinfection treatments can be adopted for controlling opportunistic pathogens in hospital water networks in order to reduce infection risk for immunocompromised patients. Each method has limits and strengths and it could determine modifications on bacterial community. The aim of our investigation was to study under real-life conditions the microbial community associated with different chemical (monochloramine, hydrogen peroxide, chlorine dioxide) and non-chemical (hyperthermia) treatments, continuously applied since many years in four hot water networks of the same hospital. Municipal cold water, untreated secondary, and treated hot water were analysed for microbiome characterization by 16S amplicon sequencing. Cold waters had a common microbial profile at genera level. The hot water bacterial profiles differed according to treatment. Our results confirm the effectiveness of disinfection strategies in our hospital for controlling potential pathogens such as Legionella, as the investigated genera containing opportunistic pathogens were absent or had relative abundances ≤1%, except for non-tuberculous mycobacteria, Sphingomonas, Ochrobactrum and Brevundimonas. Monitoring the microbial complexity of healthcare water networks through 16S amplicon sequencing is an innovative and effective approach useful for Public Health purpose in order to verify possible modifications of microbiota associated with disinfection treatments.
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Affiliation(s)
- Stefania Paduano
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Isabella Marchesi
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Maria Elisabetta Casali
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Federica Valeriani
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Rome ‘Foro Italico’, 00135 Rome, Italy; (F.V.); (V.R.S.)
| | - Giuseppina Frezza
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Elena Vecchi
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Luca Sircana
- University Hospital Policlinico of Modena, 41124 Modena, Italy; (E.V.); (L.S.)
| | - Vincenzo Romano Spica
- Department of Movement, Human and Health Sciences, Public Health Unit, University of Rome ‘Foro Italico’, 00135 Rome, Italy; (F.V.); (V.R.S.)
| | - Paola Borella
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
| | - Annalisa Bargellini
- Department of Biomedical, Metabolic and Neural Sciences, Section of Public Health, University of Modena and Reggio Emilia, 41125 Modena, Italy; (S.P.); (I.M.); (M.E.C.); (G.F.); (P.B.)
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Bertolino G, Marras L, Sanna C, Carrucciu G, Schintu M, Coroneo V. Ten-Year Retrospective Analysis of Legionella Diffusion in Hospital Water Systems and Its Serogroup Seasonal Variation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1282:93-103. [PMID: 32030638 DOI: 10.1007/5584_2020_484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Legionella spp. are ubiquitous aquatic organisms found to be associated with community-acquired pneumoniae (CAP) as well as hospital-acquired pneumonia (HAP). Direct inhalation of aerosols from environmental colonisation is typically the source of infection. The aim of this study was to determine the level of colonisation in hospital water supply systems in order to assess the criticality of the water distribution network and strengthen preventive measures. METHODS From 2009 to 2018, 769 water samples were collected and then analysed according to the standard methods indicated in ISO11731-2:2004 and ISO11731:2017 for Legionella detection. RESULTS The samples were positive in 37.1% cases (n. 285) and negative in 62.9% cases (n. 484). The threshold of 10,000 CFU/L was exceeded in 15.1% cases and led to decolonisation as indicated by Italian and European ECDC guidelines. In the autumn-winter period SG1 showed a positivity of 41.2% (n. 40) with a decrease in the spring-summer period with 9.6% (n. 18) of positivity. In contrast, SG2-15 showed a positivity of 30.9% (n. 30) in autumn-winter, which tends to increase to 56.9% (n. 112) in spring-summer (p < 0.001). CONCLUSION Surprisingly, besides showing a seasonal trend already described previously in the literature, the positivity of our sample was not balanced even for serogroups in the two periods. This could be due to genetic differences and ecological niches to be further investigated that could also have links with the greater pathogenicity of SG1. Environmental microbiological surveillance and risk assessment should be performed more frequently and disinfection must be carried out, especially in health facilities where people are more susceptible to infections.
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Affiliation(s)
- Giacomo Bertolino
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy. .,Pharmaceutical Department, ATS Sardegna, ASSL Cagliari, Cagliari, Italy.
| | - Luisa Marras
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Clara Sanna
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Gerolamo Carrucciu
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Marco Schintu
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
| | - Valentina Coroneo
- Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy
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14
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Mapili K, Pieper KJ, Dai D, Pruden A, Edwards MA, Tang M, Rhoads WJ. Legionella pneumophila
occurrence in drinking water supplied by private wells. Lett Appl Microbiol 2020; 70:232-240. [DOI: 10.1111/lam.13273] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/12/2019] [Accepted: 12/23/2019] [Indexed: 11/30/2022]
Affiliation(s)
- K. Mapili
- Virginia Tech, Civil and Environmental Engineering Blacksburg VA USA
| | - K. J. Pieper
- Northeastern University, Civil and Environmental Engineering Snell Engineering Center Boston MA USA
| | - D. Dai
- Virginia Tech, Civil and Environmental Engineering Blacksburg VA USA
| | - A. Pruden
- Virginia Tech, Civil and Environmental Engineering Blacksburg VA USA
| | - M. A. Edwards
- Virginia Tech, Civil and Environmental Engineering Blacksburg VA USA
| | - M. Tang
- Oak Ridge Institute for Science and Education (ORISE) at Environmental Protection Agency Cincinnati OH USA
| | - W. J. Rhoads
- Virginia Tech, Civil and Environmental Engineering Blacksburg VA USA
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Cloutman-Green E, Barbosa VL, Jimenez D, Wong D, Dunn H, Needham B, Ciric L, Hartley JC. Controlling Legionella pneumophila in water systems at reduced hot water temperatures with copper and silver ionization. Am J Infect Control 2019; 47:761-766. [PMID: 30661910 DOI: 10.1016/j.ajic.2018.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND Hospital-acquired Legionnaires' disease is associated with the presence of Legionella pneumophila in hospital water systems. In the United Kingdom, the Department of Health recommends maintaining hot water temperatures >55°C and cold water temperatures <20°C at the point of delivery to prevent proliferation of L pneumophila in water systems. In this study, we evaluated the efficacy of copper and silver ionization to control L pneumophila at deliberately reduced hot water temperatures (43°C) within a newly installed water system in a new building linked to a large health care facility in the United Kingdom. METHODS One thousand, five hundred ninety-eight water samples were collected between September 2011 and June 2017. Samples were tested using accredited methods for L pneumophila, copper and silver ion levels, and total viable counts. Energy consumption and water usage data were also collected to permit carbon emission calculations. RESULTS The results of 1,598 routine samples from September 2011 to June 2017, and the recordings of temperatures at outlets in this facility, demonstrated effective (100%) L pneumophila control throughout the study period with an average hot water temperature of 42°C. The energy savings and reduction of carbon emissions were calculated to amount to 33% and 24%, respectively, compared to an equivalent temperature-controlled system. Water system management interventions were required to achieve consistently adequate levels of copper and silver across outlets. CONCLUSIONS This study demonstrated that it is possible to control L pneumophila independent of temperature when copper and silver ionization is introduced into a new building in conjunction with an appropriately managed water system.
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Laganà P, Facciolà A, Palermo R, Delia S. Environmental Surveillance of Legionellosis within an Italian University Hospital-Results of 15 Years of Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E1103. [PMID: 30925660 PMCID: PMC6480113 DOI: 10.3390/ijerph16071103] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 11/16/2022]
Abstract
Legionnaires' disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large and old buildings, such as hospitals, can be contaminated with legionellae and therefore represent a potential risk for the hospital population. In this study, we demonstrated the constant presence of Legionella in water samples from the water system of a large university hospital in Messina (Sicily, Italy) consisting of 11 separate pavilions during a period of 15 years (2004⁻2018). In total, 1346 hot water samples were collected between January 2004 and December 2018. During this period, to recover Legionella spp. from water samples, the standard procedures reported by the 2000 Italian Guidelines were adopted; from May 2015 to 2018 Italian Guidelines revised in 2015 (ISS, 2015) were used. Most water samples (72%) were positive to L. pneumophila serogroups 2⁻14, whereas L. pneumophila serogroup 1 accounted for 18% and non-Legionellapneumophila spp. Accounted for 15%. Most of the positive samples were found in the buildings where the following critical wards are situated: (Intensive Care Unit) ICU, Neurosurgery, Surgeries, Pneumology, and Neonatal Intensive Unit Care. This study highlights the importance of the continuous monitoring of hospital water samples to prevent the potential risk of nosocomial legionellosis.
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Affiliation(s)
- Pasqualina Laganà
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Branch of Messina, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Torre Biologica 3p, AOU 'G. Martino, Via C. Valeria, s.n.c., 98125 Messina, Italy.
| | - Alessio Facciolà
- Department of Clinical and Experimental Medicine, University of Messina, 98125 Messina, Italy.
| | - Roberta Palermo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, 98125 Messina, Italy.
| | - Santi Delia
- Regional Reference Laboratory of Clinical and Environmental Surveillance of Legionellosis, Branch of Messina, Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Torre Biologica 3p, AOU 'G. Martino, Via C. Valeria, s.n.c., 98125 Messina, Italy.
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17
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Gavaldà L, Garcia-Nuñez M, Quero S, Gutierrez-Milla C, Sabrià M. Role of hot water temperature and water system use on Legionella control in a tertiary hospital: An 8-year longitudinal study. WATER RESEARCH 2019; 149:460-466. [PMID: 30472548 DOI: 10.1016/j.watres.2018.11.032] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/24/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Although measures to minimize Legionella colonization in sanitary hot water installations are well established, there is little evidence of their long-term effectiveness in hospital buildings. During an 8-year period, hot water in a large hospital building was sampled monthly in areas with suitable dimensioning and recirculation and in areas with dead legs and low-use taps. In the former areas, the percentage of Legionella-negative samples was 83.2% when the temperature was ≥55%, 64.9% when between 50.1 °C and 54.0 °C, and 51.6% when ≤50 °C (p for trend <0.001). In the highest temperature group, no samples with ≥103 cfu/L were observed. In poorly designed areas, only 44.7% of samples were negative, and 28.9% presented ≥103 cfu/L although reaching 55 °C. In these areas, multivariate analysis showed that if hot water supplies were not used daily, the risk of Legionella colonization was greater than two-fold (odds ratio: 2.84; 95% confidence interval: 1.26-6.41), and the risk of finding Legionella concentrations ≥103 cfu/L was more than three-fold (odds ratio: 3.18; 95% confidence interval: 1.36-7.46), regardless the temperature. These findings indicate that the effectiveness of maintaining sanitary hot water at a minimum temperature of 55 °C is significantly better than that at 50 °C for the environmental control of Legionella but only in installations with suitable dimensioning and recirculation. In installations that do not meet these conditions, high temperatures alone result in insufficient control.
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Affiliation(s)
- Laura Gavaldà
- Department of Preventive Medicine-Hospital Hygiene. Hospital Universitari de Bellvitge-IDIBELL, Feixa Llarga, s/n. 08907 L'Hospitalet de Llobregat, Barcelona, Spain.
| | - Marian Garcia-Nuñez
- Infectious diseases Unit, Fundació Institut d'Investigació Germans Trias I Pujol, Hospital Universitari Germans Trias i Pujol, Carretera de Canyet, s/n, 08916, Badalona, Barcelona, Spain; CIBER de Enfermedades Respiratorias, CIBERES, Av. de Monforte de Lemos, 3-5, 28029 Madrid, Spain; Department of Respiratory Medicine, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí, I3PT, Parc Taulí, 1, 08208, Sabadell, Barcelona, Spain.
| | - Sara Quero
- Infectious diseases Unit, Fundació Institut d'Investigació Germans Trias I Pujol, Hospital Universitari Germans Trias i Pujol, Carretera de Canyet, s/n, 08916, Badalona, Barcelona, Spain.
| | - Carmen Gutierrez-Milla
- Department of Preventive Medicine-Hospital Hygiene. Hospital Universitari de Bellvitge-IDIBELL, Feixa Llarga, s/n. 08907 L'Hospitalet de Llobregat, Barcelona, Spain.
| | - Miquel Sabrià
- Infectious diseases Unit, Fundació Institut d'Investigació Germans Trias I Pujol, Hospital Universitari Germans Trias i Pujol, Carretera de Canyet, s/n, 08916, Badalona, Barcelona, Spain; CIBER de Enfermedades Respiratorias, CIBERES, Av. de Monforte de Lemos, 3-5, 28029 Madrid, Spain; Department of Medicine, Universitat Autònoma de Barcelona (UAB), Av. de Can Domènech, 737, 08193, Cerdanyola del Vallès, Barcelona, Spain.
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18
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Tracing and Preventing Infections. PREVENTION AND CONTROL OF INFECTIONS IN HOSPITALS 2019. [PMCID: PMC7122663 DOI: 10.1007/978-3-319-99921-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A total of 10–20% of somatic patients experience hospital infections during/after hospitalization. Pneumonia, sepsis, surgical site infections and urinary tract infections are most often associated with patient-related use of medical devices for approximately 65% of cases, while nontechnical equipment may be linked to 35% of cases. It is resource-intensive to detect the cause of infection outbreaks and even more expensive not to take action. Unexplained causes of outbreaks may lead to uncertainty and reduced activity at the hospital. To trace and prevent hospital outbreaks, joint efforts from hospital management, microbiology and infection control are needed. This chapter is focused on practical measures to trace and prevent hospital outbreaks.
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19
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Lecointe D, Beauvais R, Breton N, Cailleret R, Pangon B. Control of legionellae in a new healthcare facility following implementation of a thermal control strategy. Infect Dis (Lond) 2018; 51:102-112. [DOI: 10.1080/23744235.2018.1518582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Affiliation(s)
- Didier Lecointe
- Unité Fonctionnelle d’Hygiène Hospitalière et de Lutte contre les Infections Nosocomiales, Centre Hospitalier Sud Francilien, Corbeil-Essonnes, France
| | - Raphaëlle Beauvais
- Unité Fonctionnelle d’Hygiène Hospitalière et de Lutte contre les Infections Nosocomiales, Centre Hospitalier Sud Francilien, Corbeil-Essonnes, France
| | - Nelly Breton
- Service de Biologie, Unité de Microbiologie-Hygiène, Le Chesnay, France
| | | | - Béatrice Pangon
- Service de Biologie, Unité de Microbiologie-Hygiène, Le Chesnay, France
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20
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Ji P, Rhoads WJ, Edwards MA, Pruden A. Effect of heat shock on hot water plumbing microbiota and Legionella pneumophila control. MICROBIOME 2018; 6:30. [PMID: 29426363 PMCID: PMC5807837 DOI: 10.1186/s40168-018-0406-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 01/18/2018] [Indexed: 05/25/2023]
Abstract
BACKGROUND Heat shock is a potential control strategy for Legionella pneumophila in hot water plumbing systems. However, it is not consistently effective, with little understanding of its influence on the broader plumbing microbiome. Here, we employed a lab-scale recirculating hot water plumbing rig to compare the pre- and post-"heat shock" (i.e., 40 → 60 → 40 °C) microbiota at distal taps. In addition, we used a second plumbing rig to represent a well-managed system at 60 °C and conducted a "control" sampling at 60 °C, subsequently reducing the temperature to 40 °C to observe the effects on Legionella and the microbiota under a simulated "thermal disruption" scenario. RESULTS According to 16S rRNA gene amplicon sequencing, in the heat shock scenario, there was no significant difference or statistically significant, but small, difference in the microbial community composition at the distal taps pre- versus post-heat shock (both biofilm and water; weighted and unweighted UniFrac distance matrices). While heat shock did lead to decreased total bacteria numbers at distal taps, it did not measurably alter the richness or evenness of the microbiota. Quantitative PCR measurements demonstrated that L. pneumophila relative abundance at distal taps also was not significantly different at 2-month post-heat shock relative to the pre-heat shock condition, while relative abundance of Vermamoeba vermiformis, a known Legionella host, did increase. In the thermal disruption scenario, relative abundance of planktonic L. pneumophila (quantitative PCR data) increased to levels comparable to those observed in the heat shock scenario within 2 months of switching long-term operation at 60 to 40 °C. Overall, water use frequency and water heater temperature set point exhibited a stronger effect than one-time heat shock on the microbial composition and Legionella levels at distal taps. CONCLUSIONS While heat shock may be effective for instantaneous Legionella control and reduction in total bacteria numbers, water heater temperature set point and water use frequency are more promising factors for long-term Legionella and microbial community control, illustrating the importance of maintaining consistent elevated temperatures in the system relative to short-term heat shock.
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Affiliation(s)
- Pan Ji
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - William J Rhoads
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Marc A Edwards
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
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21
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Prussin AJ, Schwake DO, Marr LC. Ten Questions Concerning the Aerosolization and Transmission of Legionella in the Built Environment. BUILDING AND ENVIRONMENT 2017; 123:684-695. [PMID: 29104349 PMCID: PMC5665586 DOI: 10.1016/j.buildenv.2017.06.024] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Legionella is a genus of pathogenic Gram-negative bacteria responsible for a serious disease known as legionellosis, which is transmitted via inhalation of this pathogen in aerosol form. There are two forms of legionellosis: Legionnaires' disease, which causes pneumonia-like symptoms, and Pontiac fever, which causes influenza-like symptoms. Legionella can be aerosolized from various water sources in the built environment including showers, faucets, hot tubs/swimming pools, cooling towers, and fountains. Incidence of the disease is higher in the summertime, possibly because of increased use of cooling towers for air conditioning systems and differences in water chemistry when outdoor temperatures are higher. Although there have been decades of research related to Legionella transmission, many knowledge gaps remain. While conventional wisdom suggests that showering is an important source of exposure in buildings, existing measurements do not provide strong support for this idea. There has been limited research on the potential for Legionella transmission through heating, ventilation, and air conditioning (HVAC) systems. Epidemiological data suggest a large proportion of legionellosis cases go unreported, as most people who are infected do not seek medical attention. Additionally, controlled laboratory studies examining water-to-air transfer and source tracking are still needed. Herein, we discuss ten questions that spotlight current knowledge about Legionella transmission in the built environment, engineering controls that might prevent future disease outbreaks, and future research that is needed to advance understanding of transmission and control of legionellosis.
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Affiliation(s)
- Aaron J. Prussin
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
- Corresponding Author:
| | - David Otto Schwake
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Linsey C. Marr
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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Whiley H, Bentham R, Brown MH. Legionella Persistence in Manufactured Water Systems: Pasteurization Potentially Selecting for Thermal Tolerance. Front Microbiol 2017; 8:1330. [PMID: 28769899 PMCID: PMC5515819 DOI: 10.3389/fmicb.2017.01330] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 06/30/2017] [Indexed: 01/13/2023] Open
Abstract
Legionella is an opportunistic waterborne pathogen of increasing public health significance. Pasteurization, otherwise known as super-heat and flush (increasing water temperature to above 70°C and flushing all outlets), has been identified as an important mechanism for the disinfection of Legionella in manufactured water systems. However, several studies have reported that this procedure was ineffective at remediating water distribution systems as Legionella was able to maintain long term persistent contamination. Up to 25% of L. pneumophila cells survived heat treatment of 70°C, but all of these were in a viable but non-culturable state. This demonstrates the limitations of the culture method of Legionella detection currently used to evaluate disinfection protocols. In addition, it has been demonstrated that pasteurization and nutrient starvation can select for thermal tolerant strains, where L. pneumophila was consistently identified as having greater thermal tolerance compared to other Legionella species. This review demonstrates that further research is needed to investigate the effectiveness of pasteurization as a disinfection method. In particular, it focuses on the potential for pasteurization to select for thermal tolerant L. pneumophila strains which, as the primary causative agent of Legionnaires disease, have greater public health significance compared to other Legionella species.
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Affiliation(s)
- Harriet Whiley
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
| | - Richard Bentham
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
| | - Melissa H Brown
- College of Science and Engineering, Flinders University, Bedford ParkSA, Australia
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23
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Impact of water heater temperature setting and water use frequency on the building plumbing microbiome. ISME JOURNAL 2017; 11:1318-1330. [PMID: 28282040 PMCID: PMC5437349 DOI: 10.1038/ismej.2017.14] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 11/28/2016] [Accepted: 01/22/2017] [Indexed: 01/06/2023]
Abstract
Hot water plumbing is an important conduit of microbes into the indoor environment and can increase risk of opportunistic pathogens (for example, Legionella pneumophila). We examined the combined effects of water heater temperature (39, 42, 48, 51 and 58 °C), pipe orientation (upward/downward), and water use frequency (21, 3 and 1 flush per week) on the microbial composition at the tap using a pilot-scale pipe rig. 16S rRNA gene amplicon sequencing indicated that bulk water and corresponding biofilm typically had distinct taxonomic compositions (R2Adonis=0.246, PAdonis=0.001), yet similar predicted functions based on PICRUSt analysis (R2Adonis=0.087, PAdonis=0.001). Although a prior study had identified 51 °C under low water use frequency to enrich Legionella at the tap, here we reveal that 51 °C is also a threshold above which there are marked effects of the combined influences of temperature, pipe orientation, and use frequency on taxonomic and functional composition. A positive association was noted between relative abundances of Legionella and mitochondrial DNA of Vermamoeba, a genus of amoebae that can enhance virulence and facilitate replication of some pathogens. This study takes a step towards intentional control of the plumbing microbiome and highlights the importance of microbial ecology in governing pathogen proliferation.
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Li L, Faucher SP. The Membrane Protein LasM Promotes the Culturability of Legionella pneumophila in Water. Front Cell Infect Microbiol 2016; 6:113. [PMID: 27734007 PMCID: PMC5039212 DOI: 10.3389/fcimb.2016.00113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/12/2016] [Indexed: 11/13/2022] Open
Abstract
The water-borne pathogen Legionella pneumophila (Lp) strongly expresses the lpg1659 gene in water. This gene encodes a hypothetical protein predicted to be a membrane protein using in silico analysis. While no conserved domains were identified in Lpg1659, similar proteins are found in many Legionella species and other aquatic bacteria. RT-qPCR showed that lpg1659 is positively regulated by the alternative sigma factor RpoS, which is essential for Lp to survive in water. These observations suggest an important role of this novel protein in the survival of Lp in water. Deletion of lpg1659 did not affect cell morphology, membrane integrity or tolerance to high temperature. Moreover, lpg1659 was dispensable for growth of Lp in rich medium, and during infection of the amoeba Acanthamoeba castellanii and of THP-1 human macrophages. However, deletion of lpg1659 resulted in an early loss of culturability in water, while over-expression of this gene promoted the culturability of Lp. Therefore, these results suggest that lpg1659 is required for Lp to maintain culturability, and possibly long-term survival, in water. Since the loss of culturability observed in the absence of Lpg1659 was complemented by the addition of trace metals into water, this membrane protein is likely a transporter for acquiring essential trace metal for maintaining culturability in water and potentially in other metal-deprived conditions. Given its role in the survival of Lp in water, Lpg1659 was named LasM for Legionella aquatic survival membrane protein.
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Affiliation(s)
- Laam Li
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Montreal, QC, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Montreal, QC, Canada
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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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Combination of Heat Shock and Enhanced Thermal Regime to Control the Growth of a Persistent Legionella pneumophila Strain. Pathogens 2016; 5:pathogens5020035. [PMID: 27092528 PMCID: PMC4931386 DOI: 10.3390/pathogens5020035] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 04/04/2016] [Accepted: 04/11/2016] [Indexed: 11/16/2022] Open
Abstract
Following nosocomial cases of Legionella pneumophila, the investigation of a hot water system revealed that 81.5% of sampled taps were positive for L. pneumophila, despite the presence of protective levels of copper in the water. A significant reduction of L. pneumophila counts was observed by culture after heat shock disinfection. The following corrective measures were implemented to control L. pneumophila: increasing the hot water temperature (55 to 60 °C), flushing taps weekly with hot water, removing excess lengths of piping and maintaining a water temperature of 55 °C throughout the system. A gradual reduction in L. pneumophila counts was observed using the culture method and qPCR in the 18 months after implementation of the corrective measures. However, low level contamination was retained in areas with hydraulic deficiencies, highlighting the importance of maintaining a good thermal regime at all points within the system to control the population of L. pneumophila.
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Rhoads WJ, Pruden A, Edwards MA. Convective Mixing in Distal Pipes Exacerbates Legionella pneumophila Growth in Hot Water Plumbing. Pathogens 2016; 5:E29. [PMID: 26985908 PMCID: PMC4810150 DOI: 10.3390/pathogens5010029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/15/2016] [Accepted: 03/01/2016] [Indexed: 11/17/2022] Open
Abstract
Legionella pneumophila is known to proliferate in hot water plumbing systems, but little is known about the specific physicochemical factors that contribute to its regrowth. Here, L. pneumophila trends were examined in controlled, replicated pilot-scale hot water systems with continuous recirculation lines subject to two water heater settings (40 °C and 58 °C) and three distal tap water use frequencies (high, medium, and low) with two pipe configurations (oriented upward to promote convective mixing with the recirculating line and downward to prevent it). Water heater temperature setting determined where L. pneumophila regrowth occurred in each system, with an increase of up to 4.4 log gene copies/mL in the 40 °C system tank and recirculating line relative to influent water compared to only 2.5 log gene copies/mL regrowth in the 58 °C system. Distal pipes without convective mixing cooled to room temperature (23-24 °C) during periods of no water use, but pipes with convective mixing equilibrated to 30.5 °C in the 40 °C system and 38.8 °C in the 58 °C system. Corresponding with known temperature effects on L. pneumophila growth and enhanced delivery of nutrients, distal pipes with convective mixing had on average 0.2 log more gene copies/mL in the 40 °C system and 0.8 log more gene copies/mL in the 58 °C system. Importantly, this work demonstrated the potential for thermal control strategies to be undermined by distal taps in general, and convective mixing in particular.
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Affiliation(s)
- William J Rhoads
- Via Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 401 Durham Hall, Blacksburg, VA 24061, USA.
| | - Amy Pruden
- Via Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 401 Durham Hall, Blacksburg, VA 24061, USA.
| | - Marc A Edwards
- Via Department of Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 401 Durham Hall, Blacksburg, VA 24061, USA.
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Rhoads WJ, Ji P, Pruden A, Edwards MA. Water heater temperature set point and water use patterns influence Legionella pneumophila and associated microorganisms at the tap. MICROBIOME 2015; 3:67. [PMID: 26627188 PMCID: PMC4666224 DOI: 10.1186/s40168-015-0134-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/17/2015] [Indexed: 05/22/2023]
Abstract
BACKGROUND Lowering water heater temperature set points and using less drinking water are common approaches to conserving water and energy; yet, there are discrepancies in past literature regarding the effects of water heater temperature and water use patterns on the occurrence of opportunistic pathogens, in particular Legionella pneumophila. Our objective was to conduct a controlled, replicated pilot-scale investigation to address this knowledge gap using continuously recirculating water heaters to examine five water heater set points (39-58 °C) under three water use conditions. We hypothesized that L. pneumophila levels at the tap depend on the collective influence of water heater temperature, flow frequency, and the resident plumbing ecology. RESULTS We confirmed temperature setting to be a critical factor in suppressing L. pneumophila growth both in continuously recirculating hot water lines and at distal taps. For example, at 51 °C, planktonic L. pneumophila in recirculating lines was reduced by a factor of 28.7 compared to 39 °C and was prevented from re-colonizing biofilm. However, L. pneumophila still persisted up to 58 °C, with evidence that it was growing under the conditions of this study. Further, exposure to 51 °C water in a low-use tap appeared to optimally select for L. pneumophila (e.g., 125 times greater numbers than in high-use taps). We subsequently explored relationships among L. pneumophila and other ecologically relevant microbes, noting that elevated temperature did not have a general disinfecting effect in terms of total bacterial numbers. We documented the relationship between L. pneumophila and Legionella spp., and noted several instances of correlations with Vermamoeba vermiformis, and generally found that there is a dynamic relationship with this amoeba host over the range of temperatures and water use frequencies examined. CONCLUSIONS Our study provides a new window of understanding into the microbial ecology of potable hot water systems and helps to resolve past discrepancies in the literature regarding the influence of water temperature and stagnation on L. pneumophila, which is the cause of a growing number of outbreaks. This work is especially timely, given society's movement towards "green" buildings and the need to reconcile innovations in building design with public health.
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Affiliation(s)
- William J Rhoads
- Charles E. Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA.
| | - Pan Ji
- Charles E. Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amy Pruden
- Charles E. Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Marc A Edwards
- Charles E. Via Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, 24061, USA
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Falkinham JO, Hilborn ED, Arduino MJ, Pruden A, Edwards MA. Epidemiology and Ecology of Opportunistic Premise Plumbing Pathogens: Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. ENVIRONMENTAL HEALTH PERSPECTIVES 2015; 123:749-58. [PMID: 25793551 PMCID: PMC4529011 DOI: 10.1289/ehp.1408692] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 03/17/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa are opportunistic premise plumbing pathogens (OPPPs) that persist and grow in household plumbing, habitats they share with humans. Infections caused by these OPPPs involve individuals with preexisting risk factors and frequently require hospitalization. OBJECTIVES The objectives of this report are to alert professionals of the impact of OPPPs, the fact that 30% of the population may be exposed to OPPPs, and the need to develop means to reduce OPPP exposure. We herein present a review of the epidemiology and ecology of these three bacterial OPPPs, specifically to identify common and unique features. METHODS A Water Research Foundation-sponsored workshop gathered experts from across the United States to review the characteristics of OPPPs, identify problems, and develop a list of research priorities to address critical knowledge gaps with respect to increasing OPPP-associated disease. DISCUSSION OPPPs share the common characteristics of disinfectant resistance and growth in biofilms in water distribution systems or premise plumbing. Thus, they share a number of habitats with humans (e.g., showers) that can lead to exposure and infection. The frequency of OPPP-infected individuals is rising and will likely continue to rise as the number of at-risk individuals is increasing. Improved reporting of OPPP disease and increased understanding of the genetic, physiologic, and structural characteristics governing the persistence and growth of OPPPs in drinking water distribution systems and premise plumbing is needed. CONCLUSIONS Because broadly effective community-level engineering interventions for the control of OPPPs have yet to be identified, and because the number of at-risk individuals will continue to rise, it is likely that OPPP-related infections will continue to increase. However, it is possible that individuals can take measures (e.g., raise hot water heater temperatures and filter water) to reduce home exposures.
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Affiliation(s)
- Joseph O Falkinham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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Bédard E, Fey S, Charron D, Lalancette C, Cantin P, Dolcé P, Laferrière C, Déziel E, Prévost M. Temperature diagnostic to identify high risk areas and optimize Legionella pneumophila surveillance in hot water distribution systems. WATER RESEARCH 2015; 71:244-56. [PMID: 25622002 DOI: 10.1016/j.watres.2015.01.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Revised: 12/22/2014] [Accepted: 01/05/2015] [Indexed: 05/08/2023]
Abstract
Legionella pneumophila is frequently detected in hot water distribution systems and thermal control is a common measure implemented by health care facilities. A risk assessment based on water temperature profiling and temperature distribution within the network is proposed, to guide effective monitoring strategies and allow the identification of high risk areas. Temperature and heat loss at control points (water heater, recirculation, representative points-of-use) were monitored in various sections of five health care facilities hot water distribution systems and results used to develop a temperature-based risk assessment tool. Detailed investigations show that defective return valves in faucets can cause widespread temperature losses because of hot and cold water mixing. Systems in which water temperature coming out of the water heaters was kept consistently above 60 °C and maintained above 55 °C across the network were negative for Legionella by culture or qPCR. For systems not meeting these temperature criteria, risk areas for L. pneumophila were identified using temperature profiling and system's characterization; higher risk was confirmed by more frequent microbiological detection by culture and qPCR. Results confirmed that maintaining sufficiently high temperatures within hot water distribution systems suppressed L. pneumophila culturability. However, the risk remains as shown by the persistence of L. pneumophila by qPCR.
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Affiliation(s)
- Emilie Bédard
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada; INRS-Institut Armand-Frappier, Laval, QC, Canada.
| | - Stéphanie Fey
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | - Dominique Charron
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada
| | | | - Philippe Cantin
- Centre d'expertise en analyse environnementale du Québec, Québec, QC, Canada
| | - Patrick Dolcé
- Department of Medical Microbiology and Infectious Diseases, Centre Hospitalier Régional de Rimouski, Rimouski, QC, Canada
| | - Céline Laferrière
- Department of Microbiology and Immunology (Infection Control), CHU Ste-Justine, Université de Montréal, Montréal, QC, Canada
| | - Eric Déziel
- INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Michèle Prévost
- Department of Civil Engineering, Polytechnique Montréal, Montréal, QC, Canada
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Necessity and effect of combating Legionella pneumophila in municipal shower systems. PLoS One 2014; 9:e114331. [PMID: 25490721 PMCID: PMC4260836 DOI: 10.1371/journal.pone.0114331] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 11/06/2014] [Indexed: 11/19/2022] Open
Abstract
The objective was to obtain research-based, holistic knowledge about necessity and effect of practiced measures against L. pneumophila in municipal shower systems in Stavanger, Norway. The effects of hot water treatment and membrane-filtering were investigated and compared to no intervention at all. The studies were done under real-world conditions. Additionally, a surveillance pilot study of municipal showers in Stavanger was performed. The validity of high total plate count (TPC) as an indication of L. pneumophila was evaluated. A simplified method, named "dripping method", for detection and quantification of L. pneumophila was developed. The sensitivity of the dripping method is 5 colony-forming units of L. pneumophila/ml. The transference of L. pneumophila from shower water to aerosols was studied. Interviews and observational studies among the stakeholders were done in order to identify patterns of communication and behavior in a Legionella risk perspective. No substantial effects of the measures against L. pneumophila were demonstrated, except for a distally placed membrane filter. No significant positive correlation between TPC and L. pneumophila concentrations were found. L. pneumophila serogroup 2-14 was demonstrated in 21% of the 29 buildings tested in the surveillance pilot. Relatively few cells of L. pneumophila were transferred from shower water to aerosols. Anxiety appeared as the major driving force in the risk governance of Legionella. In conclusion, the risk of acquiring Legionnaires' disease from municipal shower systems is evaluated as low and uncertain. By eliminating ineffective approaches, targeted Legionella risk governance can be practiced. Risk management by surveillance is evaluated as appropriate.
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Pierre D, Stout JE, Yu VL. Editorial commentary: risk assessment and prediction for health care-associated Legionnaires' disease: percent distal site positivity as a cut-point. Am J Infect Control 2014; 42:1248-50. [PMID: 25444274 DOI: 10.1016/j.ajic.2014.06.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/07/2014] [Accepted: 06/23/2014] [Indexed: 11/27/2022]
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Wang S, Huang J, Yang Y, Hui Y, Ge Y, Larssen T, Yu G, Deng S, Wang B, Harman C. First report of a Chinese PFOS alternative overlooked for 30 years: its toxicity, persistence, and presence in the environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:10117-28. [PMID: 23952109 DOI: 10.1021/es402455r] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This is the first report on the environmental occurrence of a chlorinated polyfluorinated ether sulfonate (locally called F-53B, C8ClF16O4SK). It has been widely applied as a mist suppressant by the chrome plating industry in China for decades but has evaded the attention of environmental research and regulation. In this study, F-53B was found in high concentrations (43-78 and 65-112 μg/L for the effluent and influent, respectively) in wastewater from the chrome plating industry in the city of Wenzhou, China. F-53B was not successfully removed by the wastewater treatments in place. Consequently, it was detected in surface water that receives the treated wastewater at similar levels to PFOS (ca. 10-50 ng/L) and the concentration decreased with the increasing distance from the wastewater discharge point along the river. Initial data presented here suggest that F-53B is moderately toxic (Zebrafish LC50-96 h 15.5 mg/L) and is as resistant to degradation as PFOS. While current usage is limited to the chrome plating industry, the increasing demand for PFOS alternatives in other sectors may result in expanded usage. Collectively, the results of this work call for future assessments on the effects of this overlooked contaminant and its presence and fate in the environment.
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Affiliation(s)
- Siwen Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control (SKJLESPC), School of Environment, POPs Research Centre, Tsinghua University , Beijing 100084, P.R. China
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Serrano-Suárez A, Dellundé J, Salvadó H, Cervero-Aragó S, Méndez J, Canals O, Blanco S, Arcas A, Araujo R. Microbial and physicochemical parameters associated with Legionella contamination in hot water recirculation systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2013; 20:5534-44. [PMID: 23436060 DOI: 10.1007/s11356-013-1557-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 02/05/2013] [Indexed: 05/07/2023]
Abstract
Hot water recirculation systems (HWRS) in hotels and nursing homes, which are common in countries such as Spain, have been related to outbreaks of legionellosis. To establish the relationships of microbial and physicochemical parameters, especially protozoa, with the occurrence of Legionella in HWRS, 231 samples from hotels and nursing homes were analysed for Legionella, protozoa, heterotrophic plate counts (HPC) at 22 and 37 °C, Pseudomonas, metals, temperature and others. Legionella pneumophila was the dominant species isolated, and 22 % were sg. 1. The sampling method became particularly important in order to define which factors were involved on the occurrence of Legionella. Results showed that the bacteria and the accompanying microbiota were more abundant in the first flush water whose temperature was lower. The bacteria occurred in those samples with high HPC and were inversely correlated with high temperatures. Multivariate regression showed that a concentration above 1 × 10(5) CFU/100 mL of HPC at 37 °C, Fe above 0.095 ppm and the presence of protozoa increased significantly the risk of Legionella colonization, while univariant regression showed that the presence of Cu above 0.76 ppm and temperature above 55 °C diminished it. Therefore, to reduce the risk associated with Legionella occurrence in HWRS these parameters should be taken into consideration.
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Affiliation(s)
- Alejandra Serrano-Suárez
- Departament de Microbiologia, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal 643, 08028, Barcelona, Spain
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Allen JG, Myatt TA, MacIntosh DL, Ludwig JF, Minegishi T, Stewart JH, Connors BF, Grant MP, McCarthy JF. Assessing risk of health care-acquired Legionnaires' disease from environmental sampling: the limits of using a strict percent positivity approach. Am J Infect Control 2012; 40:917-21. [PMID: 22633439 DOI: 10.1016/j.ajic.2012.01.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 01/12/2012] [Accepted: 01/12/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Elevated percent positivity (≥30%) of Legionella in hospital domestic water systems has been suggested as a metric for assessing the risk of health care-acquired Legionnaires' disease (LD). METHODS We examined the validity of this metric by analyzing data from peer-reviewed studies containing reports of Legionella prevalence in hospital water (ie, percent positivity) and temporally matched reports of patients with health care-acquired LD. RESULTS Our literature review identified 31 peer-reviewed publications reporting matched data. We abstracted a total of 206 data points, representing 119 hospitals, from these articles. We determined that the proposed 30% positivity metric has 59% sensitivity and 74% specificity (ie, a 41% false-negative rate and a 26% false-positive rate). These notable error rates could have significant implications, given that we identified 16 peer-reviewed articles and 6 government guidance documents that referenced the 30% positivity metric as a risk assessment tool. CONCLUSIONS Environmental sampling of hospital water distribution systems for Legionella can be an important component of risk management for LD. However, the possible consequence of using a percent positivity metric with low sensitivity and specificity is that many hospitals might fail to mitigate when a true risk is present, or might unnecessarily allocate limited resources to deal with a negligible risk.
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Retrofitting Domestic Hot Water Heaters for Solar Water Heating Systems in Single-Family Houses in a Cold Climate: A Theoretical Analysis. ENERGIES 2012. [DOI: 10.3390/en5104110] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Völker S, Schreiber C, Kistemann T. Drinking water quality in household supply infrastructure--A survey of the current situation in Germany. Int J Hyg Environ Health 2010; 213:204-9. [PMID: 20471912 DOI: 10.1016/j.ijheh.2010.04.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 03/25/2010] [Accepted: 04/16/2010] [Indexed: 11/27/2022]
Abstract
As a result of the amendment to the German Drinking Water Ordinance in 2001, local public health authorities are obliged to monitor the water supply in installations providing water for public use (Section 18 German Drinking Water Ordinance). With a systematic and nationwide survey of locally available data relating to hygienic drinking water quality and the existing drinking water infrastructure in buildings, the extent of microbial contamination of in-building distribution systems in Germany is intended to be assessed. To gain an overview of the microbial contamination of drinking water in public buildings all 419 local public health authorities in Germany were contacted in 2007. In a detailed study with a representative cooperation level of 5% of these local public health authorities, the available data relating to microbiological, chemical, physical and technical parameters gained from in-building distribution systems were collected. Drinking water parameters were combined with regard to the total number of analyses and the absolute number as well as the percentage of limit compliance failures (n=108,288). Limits exceeded were classified as the failure to comply with the German Drinking Water Ordinance, DVGW technical regulations and Federal Environment Agency recommended limits. The highest rates of samples exceeding these limits were found for the parameter Legionella sp. which contaminated 12.8% of all samples (n=22,786; limit: 100 CFU/100ml), followed by heterotrophic plate count at 36 degrees C (3.5%, n=10,928; limit: 100 CFU/1 ml) and Pseudomonas sp. (2.9%, n=3468; limit: 0 CFU/100ml). Legionella sp. and Pseudomonas sp. pose a direct health risk to immunosuppressed users. Additionally, for some chemical parameters, such as nickel, iron and lead, a potential risk for the health of consumers was detected. Further data analysis may reveal whether this contamination is related to stagnation where there is only sporadic use or whether other factors are involved in the process of microbial growth in installation systems.
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Affiliation(s)
- Sebastian Völker
- Institute for Hygiene and Public Health, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
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Darelid J, Bernander S, Jacobson K, Löfgren S. The Presence of a Specific Genotype of Legionella pneumophila Serogroup 1 in a Hospital and Municipal Water Distribution System over a 12-year Period. ACTA ACUST UNITED AC 2009; 36:417-23. [PMID: 15307560 DOI: 10.1080/00365540410020749] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The genotypic distribution of Legionella pneumophila serogroup 1 was investigated in the water distribution system of a 450-bed Swedish hospital and the surrounding community. A single genotype identified by amplified fragment length polymorphism (AFLP) analysis, was found in all 34 hospital isolates and in 18 out of 20 community isolates over a 12-y surveillance period. All isolates were either monoclonal antibody subtypes Benidorm or Bellingham. In a geographical comparison, the hospital genotype was also identified in 2 out of 6 Swedish hospitals, both located within 100 km of the studied community. In all, 70 isolates originating from 7 Swedish communities clustered in 4 groups, each also containing 1 AFLP type as defined by the European Working Group on Legionella Infections (EWGLI). It was concluded that a single Legionella pneumophila serogroup 1 genotype may colonize a large water distribution system over a long period of time, and that certain clones seem to be widely spread in the environment. Results from molecular typing of isolates originating from a limited geographical area must, therefore, be interpreted cautiously in epidemiological investigations of Legionnaires' disease.
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Affiliation(s)
- Johan Darelid
- Department of Infectious Diseases, Ryhov Hospital, S-55185 Jönköping, Sweden.
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García M, Baladrón B, Gil V, Tarancon M, Vilasau A, Ibañez A, Elola C, Pelaz C. Persistence of chlorine-sensitiveLegionella pneumophilain hyperchlorinated installations. J Appl Microbiol 2008; 105:837-47. [DOI: 10.1111/j.1365-2672.2008.03804.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mavridou A, Smeti E, Mandilara G, Pappa O, Plakadonaki S, Grispou E, Polemis M. Prevalence study of Legionella spp. contamination in Greek hospitals. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2008; 18:295-304. [PMID: 18668417 DOI: 10.1080/09603120801966035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Water and swab samples were collected from 13 hospitals and analyzed for Legionella counts. Legionella was detected in eight out of 13 hospitals and in 22 of 130 water and swab-collected samples. A total of 72.7% of the strains were L. pneumophila ser. 1, 22.7% were L. pneumophila ser. 2-14, and 4.5% did not belong to any of these groups. AFLP typing of the L. pneumophila ser. 1 strains generated two distinguishable AFLP types. There was no significant correlation to the sample type with Legionella recovery. Legionella isolation was more likely to occur in the cooling towers than the water system. Water temperatures of 30-40 degrees C seem to favor Legionella growth. Of the 265 serum samples taken from the medical and technical staff for the control of IgG titre, 89.4% were negative, 7.2% were positive, and for 3.4% the result was doubtful. No association between IgG titre and maximum observed level of Legionella occurrence was detected.
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Affiliation(s)
- Athena Mavridou
- Technological Educational Institution of Athens Athens, Greece.
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Mathys W, Stanke J, Harmuth M, Junge-Mathys E. Occurrence of Legionella in hot water systems of single-family residences in suburbs of two German cities with special reference to solar and district heating. Int J Hyg Environ Health 2008; 211:179-85. [PMID: 17409022 DOI: 10.1016/j.ijheh.2007.02.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 11/23/2006] [Accepted: 02/06/2007] [Indexed: 11/17/2022]
Abstract
A total of 452 samples from hot water systems of randomly selected single family residences in the suburbs of two German cities were analysed for the occurrence of Legionella. Technical data were documented using a standardized questionnaire to evaluate possible factors promoting the growth of the bacterium in these small plumbing systems. All houses were supplied with treated groundwater from public water works. Drinking water quality was within the limits specified in the German regulations for drinking water and the water was not chlorinated. The results showed that plumbing systems in private houses that provided hot water from instantaneous water heaters were free of Legionella compared with a prevalence of 12% in houses with storage tanks and recirculating hot water where maximum counts of Legionella reached 100,000 CFU/100ml. The presence of L. pneumophila accounted for 93.9% of all Legionella positive specimens of which 71.8% belonged to serogroup 1. The volume of the storage tank, interrupting circulation for several hours daily and intermittently raising hot water temperatures to >60 degrees C had no influence on Legionella counts. Plumbing systems with copper pipes were more frequently contaminated than those made of synthetic materials or galvanized steel. An inhibitory effect due to copper was not present. Newly constructed systems (<2 years) were not colonized. The type of hot water preparation had a marked influence. More than 50% of all houses using district heating systems were colonized by Legionella. Their significantly lower hot water temperature is thought to be the key factor leading to intensified growth of Legionella. Although hot water systems using solar energy to supplement conventional hot water supplies operate at temperatures 3 degrees C lower than conventional systems, this technique does not seem to promote proliferation of the bacterium. Our data show convincingly that the temperature of the hot water is probably the most important or perhaps the only determinant factor for multiplication of Legionella. Water with a temperature below 46 degrees C was most frequently colonized and contained the highest concentrations of legionellae. It is evident that the same factors affecting colonization by Legionella in large buildings also exist in small residential water systems. If temperatures are low there is no difference between large and small systems and Legionella counts are high in both. Since private residences are an important source of community-acquired legionellosis, these findings emphasize the need for preventive control measures in small residential buildings. In some situations it may be necessary to install filtration devices at the point-of-use.
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Affiliation(s)
- Werner Mathys
- Institute for Hygiene, University of Muenster, Robert-Koch-Str. 41, 48129 Muenster, Germany.
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Thermal disinfection of hotels, hospitals, and athletic venues hot water distribution systems contaminated by Legionella species. Am J Infect Control 2007; 35:623-7. [PMID: 17980243 DOI: 10.1016/j.ajic.2007.01.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 01/16/2007] [Accepted: 01/17/2007] [Indexed: 11/21/2022]
Abstract
Legionella spp. (> or = 500 cfu liter(-1)) were detected in 92 of 497 water distribution systems (WDS) examined. Thermal disinfection was applied at 33 WDS. After the first and second application of the disinfection procedure, 15 (45.4%) and 3 (9%) positive for remedial actions WDS were found, respectively. Legionella pneumophila was more resistant to thermal disinfection than Legionella non-pneumophila spp. (relative risk [RR]=5.4, 95% confidence intervals [CI]=1-35). WDS of hotels with oil heater were more easily disinfected than those with electrical or solar heater (RR=0.4 95% CI=0.2-0.8). Thermal disinfection seems not to be efficient enough to eliminate legionellae, unless repeatedly applied and in combination with extended heat flushing, and faucets chlorine disinfection.
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Documento de Consenso sobre pneumonia nosocomial11Sociedade Portuguesa de Pneumologia e Sociedade Portuguesa de Cuidados Intensivos / Portuguese Society of Pulmonology and Intensive Care Society,22O presente documento é simultaneamente publicado na Revista Portuguesa de Medicina Intensiva (2007; 14(1):7-30) / This work is published simultaneously in the Portuguese Journal of Intensive Care Medicine (2007; 14(1):7-30). REVISTA PORTUGUESA DE PNEUMOLOGIA 2007. [DOI: 10.1016/s0873-2159(15)30360-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Ragull S, Luisa Pedro-Botet M, García-Núñez M, Esteve M, Sopena N, Rey Joly C, Sabrià M. Choque térmico como medida de control de un brote de legionelosis hospitalaria. Med Clin (Barc) 2006; 127:211-3. [PMID: 16938241 DOI: 10.1157/13091014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND OBJECTIVE Superheat-and-flush is one of the methods of disinfection used against Legionella in hospital water distribution systems. An outbreak of nosocomial legionellosis (NL) was detected in the hospital Germans Trias i Pujol in January 1996. The aim of this study was to evaluate the impact of this disinfection technique at an environmental and clinical level. MATERIAL AND METHOD Water samples were collected daily from central and tap water points 3 days prior to 15 days after superheating and flushing. Clinical surveillance of NL was performed 30 consecutive days following disinfection. RESULTS After superheat-and-flush, the inoculum of Legionella pneumophila decreased in the central points but increased after day 11, achieving maximum values at 15 days. On the other hand, L. pneumophila was not detected in tap water points after 4 days but recolonization was observed after day 7, achieving 66% at day 9. No clinical cases of NL were detected during the study period. CONCLUSIONS Superheat-and-flush is an effective albeit transitory method of rapid disinfection in outbreaks of NL.
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Affiliation(s)
- Sonia Ragull
- Unidad de Enfermedades Infecciosas, Servicio de Medicina Interna, Hospital Universitari Germans Trias i Pujol, Badalona, Barcelona
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Young M, Smith H, Gray B, Huang B, Barten J, Towner C, Plowman S, Blair B, Savill J, McCall B. Authors stand by recommendation on water heating. Aust N Z J Public Health 2006. [DOI: 10.1111/j.1467-842x.2006.tb00877.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Andriesse GI, Verhoef J. Nosocomial pneumonia : rationalizing the approach to empirical therapy. TREATMENTS IN RESPIRATORY MEDICINE 2006; 5:11-30. [PMID: 16409013 PMCID: PMC7100095 DOI: 10.2165/00151829-200605010-00002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Nosocomial pneumonia or hospital-acquired pneumonia (HAP) causes considerable morbidity and mortality. It is the second most common nosocomial infection and the leading cause of death from hospital-acquired infections. In 1996 the American Thoracic Society (ATS) published guidelines for empirical therapy of HAP. This review focuses on the literature that has appeared since the ATS statement. Early diagnosis of HAP and its etiology is crucial in guiding empirical therapy. Since 1996, it has become clear that differentiating mere colonization from etiologic pathogens infecting the lower respiratory tract is best achieved by employing bronchoalveolar lavage (BAL) or protected specimen brush (PSB) in combination with quantitative culture and detection of intracellular microorganisms. Endotracheal aspirate and non-bronchoscopic BAL/PSB in combination with quantitative culture provide a good alternative in patients suspected of ventilator-associated pneumonia. Since culture results take 2-3 days, initial therapy of HAP is by definition empirical. Epidemiologic studies have identified the most frequently involved pathogens: Enterobacteriaceae, Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus ('core pathogens'). Empirical therapy covering only the 'core pathogens' will suffice in patients without risk factors for resistant microorganisms. Studies that have appeared since the ATS statement issued in 1996, demonstrate several new risk factors for HAP with multiresistant pathogens. In patients with risk factors, empirical therapy should consist of antibacterials with a broader spectrum. The most important risk factors for resistant microorganisms are late onset of HAP (>/=5 days after admission), recent use of antibacterial therapy, and mechanical ventilation. Multiresistant bacteria of specific interest are methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter calcoaceticus-baumannii, Stenotrophomonas maltophilia and extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae. Each of these organisms has its specific susceptibility pattern, demanding appropriate antibacterial treatment. To further improve outcomes, specific therapeutic options for multiresistant pathogens and pharmacological factors are discussed. Antibacterials developed since 1996 or antibacterials with renewed interest (linezolid, quinupristin/dalfopristin, teicoplanin, meropenem, new fluoroquinolones, and fourth-generation cephalosporins) are discussed in the light of developing resistance.Since the ATS statement, many reports have shown increasing incidences of resistant microorganisms. Therefore, one of the most important conclusions from this review is that empirical therapy for HAP should not be based on general guidelines alone, but that local epidemiology should be taken into account and used in the formulation of local guidelines.
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Affiliation(s)
- Gunnar I Andriesse
- Eijkman-Winkler Institute for Medical and Clinical Microbiology, University Medical Center Utrecht (UMCU), Utrecht, The Netherlands
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Exner M, Kramer A, Lajoie L, Gebel J, Engelhart S, Hartemann P. Prevention and control of health care-associated waterborne infections in health care facilities. Am J Infect Control 2005; 33:S26-40. [PMID: 15940114 DOI: 10.1016/j.ajic.2005.04.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The current article is a review of the public health risks attributable to waterborne pathogens in health care. The consequences of health care-associated infections (HAIs) are discussed. Not only are Legionella spp involved in HAIs, but also Pseudomonas aeruginosa, other gram-negative microorganisms, fungi, and amoeba-associated bacteria. This is particularly noteworthy among immunocompromised patients. New prevention strategies and control measures brought about through advanced planning, facility remodelling and reconstruction, disinfection, and filtration have resulted in a significant reduction of the incidence of waterborne HAIs. The positive consequences of a comprehensive multibarrier approach including prevention and control programs in health care facilities are discussed. Environmental cultures are now integrated within the infection control program of some European countries. In high-risk areas, the application of disposable sterile point-of-use filters for faucets and shower heads appears to be the practice of choice to efficiently control waterborne pathogens and to prevent infections.
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Affiliation(s)
- M Exner
- Institute for Hygiene and Public Health, University of Bonn, Bonn, Germany.
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O'Neill E, Humphreys H. Surveillance of hospital water and primary prevention of nosocomial legionellosis: what is the evidence? J Hosp Infect 2005; 59:273-9. [PMID: 15749313 DOI: 10.1016/j.jhin.2004.09.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Hospital-acquired Legionnaires' disease may be sporadic or may occur as part of an outbreak. As Legionella spp. are ubiquitous in many water systems, it is not surprising that hospital water may be colonized with Legionella pneumophila and other species. However, there is some controversy about the relationship between the presence of legionella in hospital water systems and nosocomial legionellosis. Primary prevention, i.e. measures to prevent legionella in a hospital or healthcare facility with no previous documented cases of nosocomial legionellosis, includes heightened awareness of hospital-acquired Legionnaires' disease with appropriate laboratory diagnostic facilities, and ensuring that the water system is well designed and maintained in accordance with national standards, e.g. the circulating hot water is maintained above 55 degrees C. Secondary prevention, i.e. preventing further cases occurring when a case has been confirmed, should include an investigation to exclude the hospital water system as a source. However, the necessity to sample hospital water routinely to detect legionella outside of outbreaks, i.e. as a component of primary prevention, is unclear. Some studies demonstrate a clear link but others do not. Differences between the patient populations studied, the methods of laboratory diagnosis of clinical cases, the analysis of hospital water and differences in the design of hospital water systems may partly explain this. Whilst further research, probably in the form of multi-centred prospective trials, is needed to confirm the relationship between environmental legionella and hospital-acquired legionellosis, including establishing the relative importance of L. pneumophila group 1 vs. non-group 1 and other Legionella spp., each hospital should consider the spectrum of patients at particular risk locally. Centres with transplant units or other patients with significant immunosuppression should, in the interim, consider routine sampling for legionella in hospital water in addition to other control measures. Therefore, infection control teams must work closely with hospital engineering and technical services departments and hospital management, as well as ensuring that physicians and others have a heightened awareness of hospital-acquired legionellosis.
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Affiliation(s)
- E O'Neill
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Dublin, Ireland.
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Molmeret M, Horn M, Wagner M, Santic M, Abu Kwaik Y. Amoebae as training grounds for intracellular bacterial pathogens. Appl Environ Microbiol 2005; 71:20-8. [PMID: 15640165 PMCID: PMC544274 DOI: 10.1128/aem.71.1.20-28.2005] [Citation(s) in RCA: 388] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Maëlle Molmeret
- Department of Microbiology and Immunology, University of Louisville, Louisville, KY 40202, USA
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