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Grimard-Conea M, Prévost M. Controlling Legionella pneumophila in Showerheads: Combination of Remedial Intervention and Preventative Flushing. Microorganisms 2023; 11:1361. [PMID: 37374862 DOI: 10.3390/microorganisms11061361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/17/2023] [Accepted: 05/20/2023] [Indexed: 06/29/2023] Open
Abstract
Shock chlorination and remedial flushing are suggested to address Legionella pneumophila (Lp) contamination in buildings or during their (re)commissioning. However, data on general microbial measurements (adenosine tri-phosphate [ATP], total cell counts [TCC]), and the abundance of Lp are lacking to support their temporary implementation with variable water demands. In this study, the weekly short-term (3-week) impact of shock chlorination (20-25 mg/L free chlorine, 16 h) or remedial flushing (5-min flush) combined with distinct flushing regimes (daily, weekly, stagnant) was investigated in duplicates of showerheads in two shower systems. Results showed that the combination of stagnation and shock chlorination prompted biomass regrowth, with ATP and TCC in the first draws reaching large regrowth factors of 4.31-7.07-fold and 3.51-5.68-fold, respectively, from baseline values. Contrastingly, remedial flushing followed by stagnation generally resulted in complete or larger regrowth in Lp culturability and gene copies (gc). Irrespective of the intervention, daily flushed showerheads resulted in significantly (p < 0.05) lower ATP and TCC, as well as lower Lp concentrations than weekly flushes, in general. Nonetheless, Lp persisted at concentrations ranging from 11 to 223 as the most probable number per liter (MPN/L) and in the same order of magnitude (103-104 gc/L) than baseline values after remedial flushing, despite daily/weekly flushing, unlike shock chlorination which suppressed Lp culturability (down 3-log) for two weeks and gene copies by 1-log. This study provides insights on the most optimal short-term combination of remedial and preventative strategies that can be considered pending the implementation of suitable engineering controls or building-wide treatment.
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Affiliation(s)
- Marianne Grimard-Conea
- Industrial Chair in Drinking Water, Department of Civil, Mining and Geological Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada
| | - Michèle Prévost
- Industrial Chair in Drinking Water, Department of Civil, Mining and Geological Engineering, Polytechnique Montreal, Montreal, QC H3C 3A7, Canada
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Mazzotta M, Salaris S, Pascale MR, Girolamini L, Cristino S. Occurrence of Legionella spp. in Man-Made Water Sources: Isolates Distribution and Phylogenetic Characterization in the Emilia-Romagna Region. Pathogens 2021; 10:552. [PMID: 34063633 PMCID: PMC8147600 DOI: 10.3390/pathogens10050552] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 11/16/2022] Open
Abstract
Legionella species distribution in the Emilia-Romagna region, involving hospital (H) and community (C) environments, was conducted. Legionella culture, agglutination test, and mip-gene sequencing were applied on 240 isolates. The analysis showed a higher prevalence of non-Legionellapneumophila (n-Lp) species (84.1%) compared with L. pneumophila (Lp) (15.9%), with a higher frequency of n-Lp with respect to Lp species in both environments (77.6% and 96.4%, in H and C, respectively). The Shannon index showed a significant difference in Legionella distribution (p = 0.00017), with a significant abundance of Lp in the H compared with C environment (p = 0.00028). The continuous disinfection treatment in H could contribute to adaptive survival of the Lp species. Phylogenetic analysis revealed a conservative clade distribution between H and C: L. feeleii clade with three subclades in C and the Lp clade with five subclades in H and two in C, respectively. Our findings suggest the importance of Legionella surveillance both in H and C, with a focus on n-Lp species less connected to human disease. The Legionella prevalence and diversity found here indicate that geographical and temporal isolate evolution should be considered during surveillance, particularly in the light of global warming and changes in population risk factors.
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Affiliation(s)
| | | | | | | | - Sandra Cristino
- Department of Biological, Geological, and Environmental Sciences, University of Bologna, via San Giacomo 12, 40126 Bologna, Italy; (M.M.); (S.S.); (M.R.P.); (L.G.)
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3
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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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Water as a Source of Antimicrobial Resistance and Healthcare-Associated Infections. Pathogens 2020; 9:pathogens9080667. [PMID: 32824770 PMCID: PMC7459458 DOI: 10.3390/pathogens9080667] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 12/13/2022] Open
Abstract
Healthcare-associated infections (HAIs) are one of the most common patient complications, affecting 7% of patients in developed countries each year. The rise of antimicrobial resistant (AMR) bacteria has been identified as one of the biggest global health challenges, resulting in an estimated 23,000 deaths in the US annually. Environmental reservoirs for AMR bacteria such as bed rails, light switches and doorknobs have been identified in the past and addressed with infection prevention guidelines. However, water and water-related devices are often overlooked as potential sources of HAI outbreaks. This systematic review examines the role of water and water-related devices in the transmission of AMR bacteria responsible for HAIs, discussing common waterborne devices, pathogens, and surveillance strategies. AMR strains of previously described waterborne pathogens including Pseudomonas aeruginosa, Mycobacterium spp., and Legionella spp. were commonly isolated. However, methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae that are not typically associated with water were also isolated. Biofilms were identified as a hot spot for the dissemination of genes responsible for survival functions. A limitation identified was a lack of consistency between environmental screening scope, isolation methodology, and antimicrobial resistance characterization. Broad universal environmental surveillance guidelines must be developed and adopted to monitor AMR pathogens, allowing prediction of future threats before waterborne infection outbreaks occur.
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Pieper KJ, Rhoads WJ, Saucier L, Katner A, Barrett JR, Edwards M. Improving state-level emergency well disinfection strategies in the United States. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 720:137451. [PMID: 32325565 DOI: 10.1016/j.scitotenv.2020.137451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 06/11/2023]
Abstract
After flooding events, well users are encouraged to disinfect their private wells. However, well disinfection strategies are not consistently applied or proven effective. This study examines the science-based evidence that disinfection procedures reduce microbial loading in well water; reviews inclusion of disinfection principles in state-level emergency protocols; and explores research gaps potentially hindering disinfection efficacy. Emergency well disinfection protocols from 34 states were reviewed based on instructions for creating chlorine solutions; circulating chlorine solutions throughout the distribution system; achieving effective CT disinfection (chlorine dose*contact time); and post-disinfection guidance. Many protocols were missing key information about fundamentals of disinfection. Only two protocols instructed well users to verify chlorine residuals and three protocols instructed users to measure water pH. Most protocols recommended that high chlorine doses be introduced into the well, circulated throughout the system, and stagnated for several hours. A CT value estimated to inactivate at least 99.9% (3-log removal) of Cryptosporidium (255 mg-hr/L) was predicted to be achieved by 72.7% of protocols, and estimated CT values ranged from 35 to 16,327 mg-hr/L. Two research gaps identified were determining whether chlorine doses should differ based on well water chemistries and evaluating the appropriate chlorine dose that should be recommended for inactivating pathogens. This effort underscores a need for consistent, evidence-based messaging in emergency well disinfection protocols.
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Affiliation(s)
- Kelsey J Pieper
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA, United States of America.
| | - William J Rhoads
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, United States of America
| | - Leslie Saucier
- Environmental and Occupational Health Sciences Program, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Adrienne Katner
- Environmental and Occupational Health Sciences Program, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Jason R Barrett
- Extension Center for Government and Community Development, Mississippi State University, Starkville, MS, United States of America
| | - Marc Edwards
- Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA, United States of America
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6
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Chatfield CH, Zaia J, Sauer C. Legionella pneumophila Attachment to Biofilms of an Acidovorax Isolate from a Drinking Water-Consortium Requires the Lcl-Adhesin Protein. Int Microbiol 2020; 23:597-605. [PMID: 32451737 DOI: 10.1007/s10123-020-00126-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 03/02/2020] [Accepted: 04/07/2020] [Indexed: 12/17/2022]
Abstract
Human infection by Legionella pneumophila (Lpn) only occurs via contaminated water from man-made sources, and eradication of these bacteria from man-made water systems is complicated by biofilm colonization. Using a continuously fed biofilm reactor model, we grew a biofilm consortium from potable water that was able to prolong recovery of Lpn CFU from biofilms. This effect was recreated using a subset of those species in a simplified consortium composed of eight bacterial isolates from the first biofilm reactor. In the reactor with the eight-species consortium, Lpn biofilm CFU was relatively stable over a 12-day trial. An isolate of Acidovorax from the consortium was, as a single species biofilm, able to promote Lpn surface attachment. Other isolates from the Pelomonas genus grew as equally robust biofilms alone, but did not promote surface attachment of Lpn. This attachment was disrupted by cationic polysaccharides and loss of the Lpn Lcl collagen-like adhesin protein. This work demonstrates that, while Lpn was fairly incompetent at attachment to surfaces to form a biofilm alone, pre-existing biofilms allowed attachment of Lpn as secondary colonizers. In addition, we demonstrate that initial attachment of Lpn to Acidovorax biofilms is likely via the Lcl-adhesin protein.
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Affiliation(s)
| | - Jenna Zaia
- Department of Biological Sciences, SUNY Cortland, Cortland, New York, USA
| | - Cassidy Sauer
- Department of Biological Sciences, SUNY Cortland, Cortland, New York, USA
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Julien R, Dreelin E, Whelton AJ, Lee J, Aw TG, Dean K, Mitchell J. Knowledge gaps and risks associated with premise plumbing drinking water quality. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/aws2.1177] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ryan Julien
- Department of Biosystems and Agricultural EngineeringMichigan State University East Lansing Michigan
| | - Erin Dreelin
- Department of Fisheries and WildlifeMichigan State University East Lansing Michigan
| | - Andrew J. Whelton
- Lyles School of Civil Engineering and Environmental and Ecological EngineeringPurdue University West Lafayette Indiana
| | - Juneseok Lee
- Department of Civil and Environmental EngineeringManhattan College Riverdale New York
| | - Tiong Gim Aw
- Department of Environmental Health Sciences, School of Public Health and Tropical MedicineTulane University New Orleans Louisiana
| | - Kara Dean
- Department of Biosystems and Agricultural EngineeringMichigan State University East Lansing Michigan
| | - Jade Mitchell
- Department of Biosystems and Agricultural EngineeringMichigan State University East Lansing Michigan
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8
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Inglis TJJ, Spittle C, Carmichael H, Downes J, Chiari M, McQueen-Mason A, Merritt AJ, Hodge M, Murray RJ, Dowse GK. Legionnaires' Disease Outbreak on a Merchant Vessel, Indian Ocean, Australia, 2015. Emerg Infect Dis 2019; 24:1345-1348. [PMID: 29912714 PMCID: PMC6038751 DOI: 10.3201/eid2407.171978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Two cases of Legionnaires' disease and 1 of Pontiac fever occurred among the crew of a merchant ship operating off the shores of Australia. PCR assays identified potential sources in the ship's cabins. Modification of maritime regulations for Legionnaires' disease prevention in commercial vessels is needed for nonpassenger merchant ships.
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9
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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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10
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Peterson CP, Sauer C, Chatfield CH. The Extracellular Polymeric Substances of Legionella pneumophila Biofilms Contain Amyloid Structures. Curr Microbiol 2018; 75:736-744. [PMID: 29468303 DOI: 10.1007/s00284-018-1440-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/16/2018] [Indexed: 12/25/2022]
Abstract
Human infection by bacteria of the genus Legionella most often result in the pneumonia known as Legionnaires Disease. Legionella is found as a resident of adherent biofilms in man-made water systems. Disinfection efforts to prevent Legionella infections require a better understanding of the structures that promote Legionella surface attachment and biofilm colonization. Various enzymatic treatments, including multiple carbohydrate-targeting mixtures, failed to disrupt Legionella biofilms, despite the presence of carbohydrates in the biofilms as shown by biochemical methods and concanavalin-A lectin staining. Moreover, Legionella biofilms contained amyloids as detected by three microscopic staining methods (congo red, thioflavin T, and the amyloid-specific antibody WO2). Amyloid structures were seen in biofilms of both L. pneumophila and L. longbeachae, the two Legionella species most associated with human infection. Inhibition of amyloid assembly by congo red and thioflavin T limited both self-aggregation and surface attachment of L. pneumophila, indicating that functional amyloid structures have a key role in initial biofilm formation by these pathogenic bacteria.
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Affiliation(s)
- Casey P Peterson
- Department of Biological Sciences, SUNY Cortland, Cortland, NY, USA
| | - Cassidy Sauer
- Department of Biological Sciences, SUNY Cortland, Cortland, NY, USA
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11
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Boamah DK, Zhou G, Ensminger AW, O'Connor TJ. From Many Hosts, One Accidental Pathogen: The Diverse Protozoan Hosts of Legionella. Front Cell Infect Microbiol 2017; 7:477. [PMID: 29250488 PMCID: PMC5714891 DOI: 10.3389/fcimb.2017.00477] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/31/2017] [Indexed: 01/03/2023] Open
Abstract
The 1976 outbreak of Legionnaires' disease led to the discovery of the intracellular bacterial pathogen Legionella pneumophila. Given their impact on human health, Legionella species and the mechanisms responsible for their replication within host cells are often studied in alveolar macrophages, the primary human cell type associated with disease. Despite the potential severity of individual cases of disease, Legionella are not spread from person-to-person. Thus, from the pathogen's perspective, interactions with human cells are accidents of time and space—evolutionary dead ends with no impact on Legionella's long-term survival or pathogenic trajectory. To understand Legionella as a pathogen is to understand its interaction with its natural hosts: the polyphyletic protozoa, a group of unicellular eukaryotes with a staggering amount of evolutionary diversity. While much remains to be understood about these enigmatic hosts, we summarize the current state of knowledge concerning Legionella's natural host range, the diversity of Legionella-protozoa interactions, the factors influencing these interactions, the importance of avoiding the generalization of protozoan-bacterial interactions based on a limited number of model hosts and the central role of protozoa to the biology, evolution, and persistence of Legionella in the environment.
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Affiliation(s)
- David K Boamah
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Guangqi Zhou
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Alexander W Ensminger
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.,Public Health Ontario, Toronto, ON, Canada
| | - Tamara J O'Connor
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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12
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Mercante JW, Winchell JM. Current and emerging Legionella diagnostics for laboratory and outbreak investigations. Clin Microbiol Rev 2015; 28:95-133. [PMID: 25567224 PMCID: PMC4284297 DOI: 10.1128/cmr.00029-14] [Citation(s) in RCA: 214] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Legionnaires' disease (LD) is an often severe and potentially fatal form of bacterial pneumonia caused by an extensive list of Legionella species. These ubiquitous freshwater and soil inhabitants cause human respiratory disease when amplified in man-made water or cooling systems and their aerosols expose a susceptible population. Treatment of sporadic cases and rapid control of LD outbreaks benefit from swift diagnosis in concert with discriminatory bacterial typing for immediate epidemiological responses. Traditional culture and serology were instrumental in describing disease incidence early in its history; currently, diagnosis of LD relies almost solely on the urinary antigen test, which captures only the dominant species and serogroup, Legionella pneumophila serogroup 1 (Lp1). This has created a diagnostic "blind spot" for LD caused by non-Lp1 strains. This review focuses on historic, current, and emerging technologies that hold promise for increasing LD diagnostic efficiency and detection rates as part of a coherent testing regimen. The importance of cooperation between epidemiologists and laboratorians for a rapid outbreak response is also illustrated in field investigations conducted by the CDC with state and local authorities. Finally, challenges facing health care professionals, building managers, and the public health community in combating LD are highlighted, and potential solutions are discussed.
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Affiliation(s)
- Jeffrey W Mercante
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Jonas M Winchell
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Denham ME, Kasali A, Steinberg JP, Cowan DZ, Zimring C, Jacob JT. The Role of Water in the Transmission of Healthcare-Associated Infections: Opportunities for Intervention through the Environment. HERD-HEALTH ENVIRONMENTS RESEARCH & DESIGN JOURNAL 2013. [DOI: 10.1177/193758671300701s08] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE: To assess and synthesize available evidence in the infection control and healthcare design literature on strategies using the built environment to reduce the transmission of pathogens in water that cause healthcare-associated infections (HAIs). BACKGROUND: Water can serve as a reservoir or source for pathogens, which can lead to the transmission of healthcare-associated infections (HAIs). Water systems harboring pathogens, such as Legionella and Pseudomonas spp., can also foster the growth of persistent biofilms, presenting a great health risk. TOPICAL HEADINGS: Strategies for interrupting the chain of transmission through the built environment can be proactive or reactive, and include three primary approaches: safe plumbing practices (maintaining optimal water temperature and pressure; eliminating dead ends), decontamination of water sources (inactivating or killing pathogens to prevent contamination), and selecting appropriate design elements (fixtures and materials that minimize the potential for contamination). CONCLUSIONS: Current evidence clearly identifying the environment's role in the chain of infection is limited by the variance in surveillance strategies and in the methods used to assess impact of these strategies. In order to optimize the built environment to serve as a tool for mitigating infection risk from waterborne pathogens—from selecting appropriate water features to maintaining the water system—multidisciplinary collaboration and planning is essential.
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Jakubek D, Guillaume C, Binet M, Leblon G, DuBow M, Le Brun M. Susceptibility of Legionella strains to the chlorinated biocide, monochloramine. Microbes Environ 2013; 28:336-45. [PMID: 24005820 PMCID: PMC4070956 DOI: 10.1264/jsme2.me12205] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Members of the Legionella genus find suitable conditions for their growth and survival in nuclear power plant cooling circuits. To limit the proliferation of Legionella pathogenic bacteria in nuclear power plant cooling circuits, and ensure that levels remain below regulatory thresholds, monochloramine treatment can be used. Although the treatment is highly effective, i.e. it reduces Legionella numbers by over 99%, Legionella bacteria can still be detected at low concentrations and rapid re-colonisation of circuits can occur after the treatment has ceased. The aim of this study was to develop an in vitro methodology for determining the intrinsic susceptibility of L. pneumophila strains, collected from various nuclear power plant cooling circuits subjected to different treatment conditions. The methodology was developed by using an original approach based on response surface methodology (RSM) combined with a multifactorial experimental design. The susceptibility was evaluated by the Ct factor. The susceptibility of environmental strains varies widely and is, for some strains, greater than that of known tolerant species; however, strain susceptibility was not related to treatment conditions. Selection pressure induced by monochloramine use did not result in the selection of more tolerant Legionella strains and did not explain the detection of Legionella during treatment or the rapid re-colonisation of cooling circuits after disinfection has ceased.
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15
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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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16
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17
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Jakubek D, Le Brun M, Leblon G, DuBow M, Binet M. The impact of monochloramine on the diversity and dynamics ofLegionella pneumophilasubpopulations in a nuclear power plant cooling circuit. FEMS Microbiol Ecol 2013; 85:302-12. [DOI: 10.1111/1574-6941.12121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 11/28/2022] Open
Affiliation(s)
| | | | - Gerard Leblon
- Institut de Génétique et de Microbiologie; CNRS UMR 8621; Univ Paris-Sud; Orsay Cedex; France
| | - Michael DuBow
- Institut de Génétique et de Microbiologie; CNRS UMR 8621; Univ Paris-Sud; Orsay Cedex; France
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18
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Williams MM, Armbruster CR, Arduino MJ. Plumbing of hospital premises is a reservoir for opportunistically pathogenic microorganisms: a review. BIOFOULING 2013; 29:147-62. [PMID: 23327332 PMCID: PMC9326810 DOI: 10.1080/08927014.2012.757308] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Several bacterial species that are natural inhabitants of potable water distribution system biofilms are opportunistic pathogens important to sensitive patients in healthcare facilities. Waterborne healthcare-associated infections (HAI) may occur during the many uses of potable water in the healthcare environment. Prevention of infection is made more challenging by lack of data on infection rate and gaps in understanding of the ecology, virulence, and infectious dose of these opportunistic pathogens. Some healthcare facilities have been successful in reducing infections by following current water safety guidelines. This review describes several infections, and remediation steps that have been implemented to reduce waterborne HAIs.
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Affiliation(s)
- Margaret M Williams
- Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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19
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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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Rauwel G, Leclercq L, Criquelion J, Aubry JM, Nardello-Rataj V. Aqueous mixtures of di-n-decyldimethylammonium chloride/polyoxyethylene alkyl ether: dramatic influence of tail/tail and head/head interactions on co-micellization and biocidal activity. J Colloid Interface Sci 2012; 374:176-86. [PMID: 22402182 DOI: 10.1016/j.jcis.2012.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/02/2012] [Accepted: 02/04/2012] [Indexed: 11/30/2022]
Abstract
Mixed aggregate formation and synergistic interactions of binary surfactant mixtures of di-n-decyldimethylammonium chloride, [DiC(10)][Cl], with polyoxyethylene alkyl ethers, C(i)E(j) (i=10, 12, j=4, 6, 8), have been investigated for various [DiC(10)][Cl]/C(i)E(j) ratios. The critical aggregation concentration of the binary mixtures has been determined by tensiometry, and the aggregate characteristics (i.e., size and composition, free ammonium concentration) have been estimated using the pulsed field gradient NMR spectroscopy and a [DiC(10)]-selective electrode. Diffusion coefficient measurements of micelles confirmed the synergistic interaction between the surfactants. It is thus shown that the formation of surface monolayers and mixed aggregates from [DiC(10)][Cl]/C(10)E(j) mixtures is driven by both tail/tail and head/head interactions, whereas [DiC(10)][Cl]/C(12)E(j) co-aggregation is mainly driven by tail/tail interactions. As a consequence, the co-aggregation phenomenon notably influences the biocidal activity of [DiC(10)][Cl] on the Candida albicans fungi. In the presence of C(12)E(j), the biocidal activity of the ammonium salt is inhibited due to the trapping of the cationic surfactants in the mixed aggregates, whereas in the presence of C(10)E(j), the biocidal activity of the surfactant mixture is maintained. The mode of action is also confirmed by a faster increase in the zeta potential of a C. albicans suspension in the presence of [DiC(10)][Cl]/C(10)E(8) than in the presence of [DiC(10)][Cl]/C(12)E(8). Therefore, a judicious adjustment of the alkyl (i) and polyoxyethylene (j) chain lengths of C(i)E(j) avoids its antagonistic effect on the biocidal activity of [DiC(10)][Cl].
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Affiliation(s)
- Gaétan Rauwel
- Laboratoires Anios, Pavé du Moulin, F-59260 Hellemmes Lille, France
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Lin YE, Stout JE, Yu VL. Controlling Legionella in hospital drinking water: an evidence-based review of disinfection methods. Infect Control Hosp Epidemiol 2011; 32:166-73. [PMID: 21460472 DOI: 10.1086/657934] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hospital-acquired Legionnaires' disease is directly linked to the presence of Legionella in hospital drinking water. Disinfecting the drinking water system is an effective preventive measure. The efficacy of any disinfection measures should be validated in a stepwise fashion from laboratory assessment to a controlled multiple-hospital evaluation over a prolonged period of time. In this review, we evaluate systemic disinfection methods (copper-silver ionization, chlorine dioxide, monochloramine, ultraviolet light, and hyperchlorination), a focal disinfection method (point-of-use filtration), and short-term disinfection methods in outbreak situations (superheat-and-flush with or without hyperchlorination). The infection control practitioner should take the lead in selection of the disinfection system and the vendor. Formal appraisals by other hospitals with experience of the system under consideration is indicated. Routine performance of surveillance cultures of drinking water to detect Legionella and monitoring of disinfectant concentrations are necessary to ensure long-term efficacy.
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Affiliation(s)
- Yusen E Lin
- National Kaohsiung Normal University, Kaohsiung, Taiwan
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Marchesi I, Marchegiano P, Bargellini A, Cencetti S, Frezza G, Miselli M, Borella P. Effectiveness of different methods to control legionella in the water supply: ten-year experience in an Italian university hospital. J Hosp Infect 2011; 77:47-51. [DOI: 10.1016/j.jhin.2010.09.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 09/02/2010] [Indexed: 10/18/2022]
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Identification of protozoa in dairy lagoon wastewater that consume Escherichia coli O157:H7 preferentially. PLoS One 2010; 5:e15671. [PMID: 21187934 PMCID: PMC3004959 DOI: 10.1371/journal.pone.0015671] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 11/20/2010] [Indexed: 11/30/2022] Open
Abstract
Escherichia coli O157:H7 (EcO157), an agent of life threatening hemolytic-uremic syndrome, resides in ruminants and is released in feces at numbers as high as 10 million cells/gram. EcO157 could survive in manure for as long as 21 months, but we observed a 90% decrease in cells of an outbreak strain of EcO157 within half a day in wastewater from dairy lagoons. Although chemical, environmental and biological factors may be responsible for this decrease, we observed an 11-fold increase in native protozoa when wastewater was re-inoculated with 2×107 cells of EcO157/mL. These protozoa engulfed the green fluorescent protein labeled EcO157 within 2 hours after inoculation, but expelled vacuoles filled with live EcO157 cells within 3 days into surrounding wastewater, whereas other protozoa retained the EcO157-filled vacuoles for 7 days. EcO157 was not detected by confocal microscopy either inside or outside protozoa after 7 days. Mixed cultures of protozoa enriched from wastewater consumed EcO157 preferentially as compared to native aerobic bacteria, but failed to eliminate them when EcO157 cells declined to 104/mL. We isolated three protozoa from mixed cultures and typed them by 18S sequencing as Vorticella microstoma, Platyophyra sp. and Colpoda aspera. While all three protozoa internalized EcO157, only Platyophyra and Colpoda acted as predators. Similar to mixed cultures, these protozoa failed to eliminate EcO157 from PBS containing no other supplemental nutrients or prey. However, spiking PBS with cereal grass medium as nutrients induced predation of EcO157 by Platyophyra sp. after 3 days or enhanced predation by Colpoda after 5 days. Therefore, attempts to enrich protozoa to decrease EcO157 from dairy lagoons, may correspond to an increase in protozoa similar to Vorticella and possibly facilitate transport of bacterial pathogens to food crops grown in proximity.
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Costa J, da Costa MS, Veríssimo A. Colonization of a therapeutic spa with Legionella spp: a public health issue. Res Microbiol 2009; 161:18-25. [PMID: 20004717 DOI: 10.1016/j.resmic.2009.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 10/21/2009] [Accepted: 10/23/2009] [Indexed: 10/20/2022]
Abstract
Traditional geothermally heated therapeutic spas, widely distributed in Europe, use water that is not disinfected. The colonization of therapeutic spas by Legionella spp. has been reported and several outbreaks and sporadic cases of legionellosis have been associated with the use of these facilities. We tested the effectiveness of hyperchlorination and the combination of hyperchlorination and ultraviolet light (UV) disinfection against legionellae which were persistently detected in the water used to supply the therapeutic spa. The hyperchlorination of the water distribution system was performed with a free residual chlorine concentration of 50 mg/l for 4h. An initial reduction in the numbers of legionellae was determined, but it rapidly increased to the original values. A UV unit was installed at the entrance to the spa's water distribution system and a new hyperchlorination procedure was performed immediately before UV irradiation (40 mJ/cm(2)), which was in use continuously for a nine-month period. While legionellae were not recovered during the irradiation period, these organisms were detected immediately after deactivation of the UV unit. We demonstrated that UV disinfection provides effective control of Legionella spp., with the advantage of being a method that, unlike chemical disinfectants, does not affect the physicochemical composition of the water. These findings suggest that UV irradiation, applied at key points in therapeutic spas, can be used to control colonization of water distribution systems by Legionella spp.
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Affiliation(s)
- Joana Costa
- Centro de Neurociências e Biologia Celular, 3004-517 Coimbra, Portugal.
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Lecointe D, Fagundez E, Pierron P, Musset JP, Brissé P, Vollereau D, Breton D, Théodora C, Beauvais R, Malbrunot C, Crine L, Fèvre C. [Management of the Legionella-link risk in a multicentre area's hospital: lessons learned of a six-year experience]. ACTA ACUST UNITED AC 2009; 58:131-6. [PMID: 19875245 DOI: 10.1016/j.patbio.2009.07.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 07/27/2009] [Indexed: 10/20/2022]
Abstract
To reduce the Legionella-linked risk in the several sites of Sud-Francilien Hospital, following a hospital-acquired legionellosis case, a multidisciplinary working group performed an action plan monitored through Legionella pneumophila counts in hot water supply. From 2003 to the first half year 2009, positive points for Legionella pneumophila in the main sites of the hospital decreased from 85.71 to 28.00%, representing a significant reduction of 67.33%. Similar results were observed for three of the four establishments, whereas the last did not describe a pronounced reduction of Legionella pneumophila counts and showed constantly serogroup 1 strains. During this period, investigations of additional cases of legionellosis demonstrated a nosocomial transmission in one case in this last site. Multidisciplinary mobilization in management of Legionella-linked risk contributed to these results.
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Affiliation(s)
- D Lecointe
- Unité fonctionnelle d'hygiène hospitalière et de lutte contre les infections nosocomiales, centre hospitalier Sud-Francilien, 59, boulevard Henri-Dunant, Corbeil-Essonnes, France.
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