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LeChevallier MW, Prosser T, Stevens M. Opportunistic Pathogens in Drinking Water Distribution Systems-A Review. Microorganisms 2024; 12:916. [PMID: 38792751 PMCID: PMC11124194 DOI: 10.3390/microorganisms12050916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 04/24/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024] Open
Abstract
In contrast to "frank" pathogens, like Salmonella entrocolitica, Shigella dysenteriae, and Vibrio cholerae, that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a host with a weakened immune system and rarely in a healthy host. Historically, drinking water treatment has focused on control of frank pathogens, particularly those from human or animal sources (like Giardia lamblia, Cryptosporidium parvum, or Hepatitis A virus), but in recent years outbreaks from drinking water have increasingly been due to opportunistic pathogens. Characteristics of opportunistic pathogens that make them problematic for water treatment include: (1) they are normally present in aquatic environments, (2) they grow in biofilms that protect the bacteria from disinfectants, and (3) under appropriate conditions in drinking water systems (e.g., warm water, stagnation, low disinfectant levels, etc.), these bacteria can amplify to levels that can pose a public health risk. The three most common opportunistic pathogens in drinking water systems are Legionella pneumophila, Mycobacterium avium, and Pseudomonas aeruginosa. This report focuses on these organisms to provide information on their public health risk, occurrence in drinking water systems, susceptibility to various disinfectants, and other operational practices (like flushing and cleaning of pipes and storage tanks). In addition, information is provided on a group of nine other opportunistic pathogens that are less commonly found in drinking water systems, including Aeromonas hydrophila, Klebsiella pneumoniae, Serratia marcescens, Burkholderia pseudomallei, Acinetobacter baumannii, Stenotrophomonas maltophilia, Arcobacter butzleri, and several free-living amoebae including Naegleria fowleri and species of Acanthamoeba. The public health risk for these microbes in drinking water is still unclear, but in most cases, efforts to manage Legionella, mycobacteria, and Pseudomonas risks will also be effective for these other opportunistic pathogens. The approach to managing opportunistic pathogens in drinking water supplies focuses on controlling the growth of these organisms. Many of these microbes are normal inhabitants in biofilms in water, so the attention is less on eliminating these organisms from entering the system and more on managing their occurrence and concentrations in the pipe network. With anticipated warming trends associated with climate change, the factors that drive the growth of opportunistic pathogens in drinking water systems will likely increase. It is important, therefore, to evaluate treatment barriers and management activities for control of opportunistic pathogen risks. Controls for primary treatment, particularly for turbidity management and disinfection, should be reviewed to ensure adequacy for opportunistic pathogen control. However, the major focus for the utility's opportunistic pathogen risk reduction plan is the management of biological activity and biofilms in the distribution system. Factors that influence the growth of microbes (primarily in biofilms) in the distribution system include, temperature, disinfectant type and concentration, nutrient levels (measured as AOC or BDOC), stagnation, flushing of pipes and cleaning of storage tank sediments, and corrosion control. Pressure management and distribution system integrity are also important to the microbial quality of water but are related more to the intrusion of contaminants into the distribution system rather than directly related to microbial growth. Summarizing the identified risk from drinking water, the availability and quality of disinfection data for treatment, and guidelines or standards for control showed that adequate information is best available for management of L. pneumophila. For L. pneumophila, the risk for this organism has been clearly established from drinking water, cases have increased worldwide, and it is one of the most identified causes of drinking water outbreaks. Water management best practices (e.g., maintenance of a disinfectant residual throughout the distribution system, flushing and cleaning of sediments in pipelines and storage tanks, among others) have been shown to be effective for control of L. pneumophila in water supplies. In addition, there are well documented management guidelines available for the control of the organism in drinking water distribution systems. By comparison, management of risks for Mycobacteria from water are less clear than for L. pneumophila. Treatment of M. avium is difficult due to its resistance to disinfection, the tendency to form clumps, and attachment to surfaces in biofilms. Additionally, there are no guidelines for management of M. avium in drinking water, and one risk assessment study suggested a low risk of infection. The role of tap water in the transmission of the other opportunistic pathogens is less clear and, in many cases, actions to manage L. pneumophila (e.g., maintenance of a disinfectant residual, flushing, cleaning of storage tanks, etc.) will also be beneficial in helping to manage these organisms as well.
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Affiliation(s)
| | - Toby Prosser
- Melbourne Water, Melbourne, VIC 3001, Australia; (T.P.); (M.S.)
| | - Melita Stevens
- Melbourne Water, Melbourne, VIC 3001, Australia; (T.P.); (M.S.)
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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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Buchholz U, Jahn HJ, Brodhun B, Lehfeld AS, Lewandowsky MM, Reber F, Adler K, Bochmann J, Förster C, Koch M, Schreiner Y, Stemmler F, Gagell C, Harbich E, Bärwolff S, Beyer A, Geuß-Fosu U, Hänel M, Larscheid P, Murajda L, Morawski K, Peters U, Pitzing R, von Welczeck A, Widders G, Wischnewski N, Abdelgawad I, Hinzmann A, Hedeler D, Schilling B, Schmidt S, Schumacher J, Zuschneid I, Atmowihardjo I, Arastéh K, Behrens S, Creutz P, Elias J, Gregor M, Kahl S, Kahnert H, Kimmel V, Lehmke J, Migaud P, Mikolajewska A, Moos V, Naumann MB, Pankow W, Scherübl H, Schmidt B, Schneider T, Stocker H, Suttorp N, Thiemig D, Gollnisch C, Mannschatz U, Haas W, Schaefer B, Lück C. Source attribution of community-acquired cases of Legionnaires' disease-results from the German LeTriWa study; Berlin, 2016-2019. PLoS One 2020; 15:e0241724. [PMID: 33237924 PMCID: PMC7688155 DOI: 10.1371/journal.pone.0241724] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 10/20/2020] [Indexed: 01/08/2023] Open
Abstract
INTRODUCTION Sources of infection of most cases of community-acquired Legionnaires' disease (CALD) are unknown. OBJECTIVE Identification of sources of infection of CALD. SETTING Berlin; December 2016-May 2019. PARTICIPANTS Adult cases of CALD reported to district health authorities and consenting to the study; age and hospital matched controls. MAIN OUTCOME MEASURE Percentage of cases of CALD with attributed source of infection. METHODS Analysis of secondary patient samples for monoclonal antibody (MAb) type (and sequence type); questionnaire-based interviews, analysis of standard household water samples for Legionella concentration followed by MAb (and sequence) typing of Legionella pneumophila serogroup 1 (Lp1) isolates; among cases taking of additional water samples to identify the infectious source as appropriate; recruitment of control persons for comparison of exposure history and Legionella in standard household water samples. For each case an appraisal matrix was filled in to attribute any of three source types (external (non-residence) source, residential non-drinking water (RnDW) source (not directly from drinking water outlet), residential drinking water (RDW) as source) using three evidence types (microbiological results, cluster evidence, analytical-comparative evidence (using added information from controls)). RESULTS Inclusion of 111 study cases and 202 controls. Median age of cases was 67 years (range 25-93 years), 74 (67%) were male. Among 65 patients with urine typable for MAb type we found a MAb 3/1-positive strain in all of them. Compared to controls being a case was not associated with a higher Legionella concentration in standard household water samples, however, the presence of a MAb 3/1-positive strain was significantly associated (odds ratio (OR) = 4.9, 95% confidence interval (CI) 1.7 to 11). Thus, a source was attributed by microbiological evidence if it contained a MAb 3/1-positive strain. A source was attributed by cluster evidence if at least two cases were exposed to the same source. Statistically significant general source types were attributed by calculating the population attributable risk (analytical-comparative evidence). We identified an external source in 16 (14%) cases, and RDW as source in 28 (25%). Wearing inadequately disinfected dentures was the only RnDW source significantly associated with cases (OR = 3.2, 95% CI 1.3 to 7.8) and led to an additional 8% of cases with source attribution, for a total of 48% of cases attributed. CONCLUSION Using the appraisal matrix we attributed almost half of all cases of CALD to an infectious source, predominantly RDW. Risk for LD seems to be conferred primarily by the type of Legionella rather than the amount. Dentures as a new infectious source needs further, in particular, integrated microbiological, molecular and epidemiological confirmation.
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Affiliation(s)
- Udo Buchholz
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Heiko Juergen Jahn
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Bonita Brodhun
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Ann-Sophie Lehfeld
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Marina M. Lewandowsky
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Franziska Reber
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Kristin Adler
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Jacqueline Bochmann
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Christina Förster
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Madlen Koch
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Yvonne Schreiner
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Fabian Stemmler
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Corinna Gagell
- Faculty of Medicine Carl Gustav Carus, Institute of Medical Microbiology and Hygiene/Institute of Virology, National Consulting Laboratory for Legionella, TU Dresden, Dresden, Germany
| | - Edith Harbich
- Faculty of Medicine Carl Gustav Carus, Institute of Medical Microbiology and Hygiene/Institute of Virology, National Consulting Laboratory for Legionella, TU Dresden, Dresden, Germany
| | - Sina Bärwolff
- Health Department, DHA Tempelhof-Schöneberg, Berlin, Germany
| | - Andreas Beyer
- Health Department, DHA Steglitz-Zehlendorf, Berlin, Germany
| | | | - Martina Hänel
- Health Department, DHA Marzahn-Hellersdorf, Berlin, Germany
| | | | | | | | - Uwe Peters
- Health Department, DHA Pankow, Berlin, Germany
| | - Raimund Pitzing
- Health Department, DHA Friedrichshain-Kreuzberg, Berlin, Germany
| | | | | | | | | | | | - Denis Hedeler
- Health Department, DHA Treptow-Köpenick, Berlin, Germany
| | - Birte Schilling
- Health Department, DHA Tempelhof-Schöneberg, Berlin, Germany
| | - Silvia Schmidt
- Health Department, DHA Steglitz-Zehlendorf, Berlin, Germany
| | | | - Irina Zuschneid
- Health Department, DHA Charlottenburg-Wilmersdorf, Berlin, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Uwe Mannschatz
- Hygiene Inspection for Drinking Water Systems, Berlin, Germany
| | - Walter Haas
- Department of Infectious Disease Epidemiology, Unit 36: Respiratory Infections, Robert Koch Institute, Berlin, Germany
| | - Benedikt Schaefer
- Section II 3.5 Microbiology of Drinking Water and Swimming Pool Water, German Environment Agency, Bad Elster, Germany
| | - Christian Lück
- Faculty of Medicine Carl Gustav Carus, Institute of Medical Microbiology and Hygiene/Institute of Virology, National Consulting Laboratory for Legionella, TU Dresden, Dresden, Germany
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Rasheduzzaman M, Singh R, Haas CN, Gurian PL. Required water temperature in hotel plumbing to control Legionella growth. WATER RESEARCH 2020; 182:115943. [PMID: 32590203 DOI: 10.1016/j.watres.2020.115943] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 05/07/2023]
Abstract
Legionella spp. occurring in hotel hot water systems, in particular Legionella pneumophila, are causing serious pneumonic infections, and water temperature is a key factor to control their occurrence in plumbing systems. We performed a systematic review and meta-analyses of the available evidence on the association between water temperature and Legionella colonization to identify the water temperature in hotel hot water systems required for control of Legionella. Qualitative synthesis and quantitative analysis were performed on 13 studies that met our inclusion criteria to identify the effect of temperature. The Receiver Operating Characteristic (ROC) curve identified 55 °C as a cutoff point for hotel hot water temperature with an Area Under the Curve (AUC) value of 0.914. The odds ratios (OR) for detecting Legionella at temperatures >55 °C compared to lower temperatures from a meta-analysis of three studies was 0.17 [95% CI: 0.11, 0.25], which indicates a strong negative association between temperature and Legionella colonization. A logistic regression on results from multiple studies using both molecular and culture methods found a temperature of 59 °C associated with an 8% probability of detectable Legionella. Only two studies reported sufficiently detailed data to allow a model of concentration vs. temperature to be fit, and this model was not statistically significant. Additional research or more detailed reporting of existing datasets is required to assess if Legionella growth can be limited below particular concentration targets at different temperatures.
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Affiliation(s)
- Md Rasheduzzaman
- Department of Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA.
| | - Rajveer Singh
- Department of Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA
| | - Charles N Haas
- Department of Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA
| | - Patrick L Gurian
- Department of Civil, Architectural and Environmental Engineering, Drexel University, 3141 Chestnut Street, Philadelphia, PA, 19104, USA
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