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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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Cullom A, Spencer MS, Williams MD, Falkinham JO, Pruden A, Edwards MA. Influence of pipe materials on in-building disinfection of P. aeruginosa and A. baumannii in simulated hot water plumbing. WATER RESEARCH X 2023; 21:100189. [PMID: 38098877 PMCID: PMC10719577 DOI: 10.1016/j.wroa.2023.100189] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 04/20/2023] [Accepted: 06/12/2023] [Indexed: 12/17/2023]
Abstract
A framework is needed to account for interactive effects of plumbing materials and disinfectants on opportunistic pathogens (OPs) in building water systems. Here we evaluated free chlorine, monochloramine, chlorine dioxide, and copper-silver ionization (CSI) for controlling Pseudomonas aeruginosa and Acinetobacter baumannii as two representative OPs that colonize hot water plumbing, in tests using polyvinylchloride (PVC), copper-PVC, and iron-PVC convectively-mixed pipe reactors (CMPRs). Pipe materials vulnerable to corrosion (i.e., iron and copper) altered the pH, dissolved oxygen, and disinfectant levels in a manner that influenced growth trends of the two OPs and total bacteria. P. aeruginosa grew well in PVC CMPRs, poorly in iron-PVC CMPRs, and was best controlled by CSI disinfection, whereas A. baumannii showed the opposite trend for pipe material and was better controlled by chlorine and chlorine dioxide. Various scenarios were identified in which pipe material and disinfectant can interact to either hinder or accelerate growth of OPs, illustrating the difficulties of controlling OPs in portions of plumbing systems experiencing warm, stagnant water.
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Affiliation(s)
- Abraham Cullom
- Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 418 Durham Hall, Blacksburg, VA, 24061
| | - Mattheu Storme Spencer
- Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 418 Durham Hall, Blacksburg, VA, 24061
| | - Myra D. Williams
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Joseph O. Falkinham
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Amy Pruden
- Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 418 Durham Hall, Blacksburg, VA, 24061
| | - Marc A. Edwards
- Civil and Environmental Engineering, Virginia Tech, 1145 Perry St., 418 Durham Hall, Blacksburg, VA, 24061
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Gu Q, Lin T, Wei X, Zhang Y, Wu S, Yang X, Zhao H, Wang C, Wang J, Ding Y, Zhang J, Wu Q. Prevalence of antimicrobial resistance in a full-scale drinking water treatment plant. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 344:118396. [PMID: 37331316 DOI: 10.1016/j.jenvman.2023.118396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/27/2023] [Accepted: 06/12/2023] [Indexed: 06/20/2023]
Abstract
Antibiotic resistance in drinking water has received increasing attention in recent years. In this study, the occurrence and abundance of antibiotic resistance genes (ARGs) in a drinking water treatment plant (DWTP) was comprehensively investigated using metagenomics. Bioinformatics analysis showed that 381 ARG subtypes belonging to 15 ARG types were detected, and bacitracin had the highest abundance (from 0.26 × 10-2 to 0.86 copies/cell), followed by multidrug (from 0.57 × 10-1 to 0.47 copies/cell) and sulfonamide (from 0.83 × 10-2 to 0.35 copies/cell). Additionally, 933 ARG-carrying contigs (ACCs) were obtained from the metagenomic data, among which 153 contigs were annotated as pathogens. The most abundant putative ARG host was Staphylococcus (7.9%), which most frequently carried multidrug ARGs (43.2%). Additionally, 38 high-quality metagenome-assembled genomes (MAGs) were recovered, one of which was identified as Staphylococcus aureus (Bin.624) and harboured the largest number of ARGs (n = 16). Using the cultivation technique, 60 isolates were obtained from DWTP samples, and Staphylococcus spp. (n = 11) were found to be dominant in all isolates, followed by Bacillus spp. (n = 17). Antimicrobial susceptibility testing showed that most Staphylococcus spp. were multidrug resistant (MDR). These results deepen our understanding of the distribution profiles of ARGs and antibiotic resistant bacteria (ARB) in DWTPs for potential health risk evaluation. Our study also highlights the need for new and efficient water purification technologies that can be introduced and applied in DWTPs.
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Affiliation(s)
- Qihui Gu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Tao Lin
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China; School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, Guangdong, PR China
| | - Xianhu Wei
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Youxiong Zhang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Shi Wu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Xiaojuan Yang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Hui Zhao
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Chufang Wang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Juan Wang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Yu Ding
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China; Department of Food Science and Engineering, Institute of Food Safety and Nutrition, College of Science and Engineering, College of Life Science and Technology, Jinan University, Guangzhou 510632, China
| | - Jumei Zhang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, 510070, PR China.
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Farina C, Cacciabue E, Averara F, Ferri N, Vailati F, Del Castillo G, Serafini A, Fermi B, Doniselli N, Pezzoli F. Water Safety Plan, Monochloramine Disinfection and Extensive Environmental Sampling Effectively Control Legionella and Other Waterborne Pathogens in Nosocomial Settings: The Ten-Year Experience of an Italian Hospital. Microorganisms 2023; 11:1794. [PMID: 37512966 PMCID: PMC10384652 DOI: 10.3390/microorganisms11071794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/10/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023] Open
Abstract
Legionella contamination control is crucial in healthcare settings where patients suffer an increased risk of disease and fatal outcome. To ensure an effective management of this health hazard, the accurate application of a hospital-specific Water Safety Plan (WSP), the choice of a suitable water disinfection system and an extensive monitoring program are required. Here, the ten-year experience of an Italian hospital is reported: since its commissioning, Legionellosis risk management has been entrusted to a multi-disciplinary Working Group, applying the principles of the World Health Organization's WSP. The disinfection strategy to prevent Legionella and other waterborne pathogens relies on the treatment of domestic hot water with a system ensuring the in situ production and dosage of monochloramine. An average of 250 samples/year were collected and analyzed to allow an accurate assessment of the microbiological status of water network. With the aim of increasing the monitoring sensitivity, in addition to the standard culture method, an optimized MALDI-ToF MS-based strategy was applied, allowing the identification of Legionella species and other relevant opportunistic pathogens. Data collected so far confirmed the effectiveness of this multidisciplinary approach: the fraction of positive samples never overcame 1% on a yearly basis and Legionnaires' Disease cases never occurred.
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Affiliation(s)
- Claudio Farina
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Eleonora Cacciabue
- Health Care Coordination Offices, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Franca Averara
- Department of Health Care Professions, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Nadia Ferri
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | - Francesca Vailati
- Microbiology and Virology Laboratory, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
| | | | | | - Beatrice Fermi
- Sanipur S.p.A., 25020 Flero, Italy
- ESCMID Study Group for Legionella Infections (ESGLI), 4001 Basel, Switzerland
| | - Nicola Doniselli
- Sanipur S.p.A., 25020 Flero, Italy
- ESCMID Study Group for Legionella Infections (ESGLI), 4001 Basel, Switzerland
| | - Fabio Pezzoli
- Health Care Coordination Offices, ASST "Papa Giovanni XXIII", 24127 Bergamo, Italy
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Mercaldo RA, Marshall JE, Cangelosi GA, Donohue M, Falkinham JO, Fierer N, French JP, Gebert MJ, Honda JR, Lipner EM, Marras TK, Morimoto K, Salfinger M, Stout J, Thomson R, Prevots DR. Environmental risk of nontuberculous mycobacterial infection: Strategies for advancing methodology. Tuberculosis (Edinb) 2023; 139:102305. [PMID: 36706504 PMCID: PMC10023322 DOI: 10.1016/j.tube.2023.102305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/27/2022] [Accepted: 01/04/2023] [Indexed: 01/11/2023]
Abstract
The National Institute of Allergy and Infectious Diseases organized a symposium in June 2022, to facilitate discussion of the environmental risks for nontuberculous mycobacteria exposure and disease. The expert researchers presented recent studies and identified numerous research gaps. This report summarizes the discussion and identifies six major areas of future research related to culture-based and culture independent laboratory methods, alternate culture media and culturing conditions, frameworks for standardized laboratory methods, improved environmental sampling strategies, validation of exposure measures, and availability of high-quality spatiotemporal data.
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Affiliation(s)
- Rachel A Mercaldo
- Division of Intramural Research, Epidemiology and Population Studies Unit, NIAID, NIH, Rockville, MD, USA.
| | - Julia E Marshall
- Division of Intramural Research, Epidemiology and Population Studies Unit, NIAID, NIH, Rockville, MD, USA.
| | - Gerard A Cangelosi
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.
| | - Maura Donohue
- United States Environmental Protection Agency, Center for Environmental Solutions and Emergency Response, Cincinnati, OH, USA.
| | | | - Noah Fierer
- Department of Ecology and Evolutionary Biology, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.
| | - Joshua P French
- Department of Mathematical and Statistical Sciences, University of Colorado Denver, Denver, CO, USA.
| | - Matthew J Gebert
- Department of Ecology and Evolutionary Biology, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA.
| | - Jennifer R Honda
- Center for Genes, Environment, and Health, National Jewish Health, Denver, CO, USA.
| | - Ettie M Lipner
- Division of Intramural Research, Epidemiology and Population Studies Unit, NIAID, NIH, Rockville, MD, USA.
| | - Theodore K Marras
- Department of Medicine, University of Toronto and University Health Network, Toronto, Canada.
| | - Kozo Morimoto
- Division of Clinical Research, Fukujuji Hospital, Japan Anti-Tuberculosis Association, Tokyo, Japan.
| | - Max Salfinger
- College of Public Health & Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
| | - Janet Stout
- Special Pathogens Laboratory, Pittsburgh, PA, USA; Department of Civil and Environmental Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Rachel Thomson
- Gallipoli Medical Research Institute & Greenslopes Clinical School, The University of Queensland, Brisbane, Australia.
| | - D Rebecca Prevots
- Division of Intramural Research, Epidemiology and Population Studies Unit, NIAID, NIH, Rockville, MD, USA.
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