Computational framework for evaluating risk trade-offs in costs associated with Legionnaires’ Disease risk, energy, and scalding risk for hospital hot water systems

2021 ◽  
Author(s):  
Ashley Heida ◽  
Alexis Mraz ◽  
Mark Hamilton ◽  
Mark Weir ◽  
Kerry A Hamilton
Keyword(s):  
Legionella Pneumophila ◽  
Disease Risk ◽  
Disease Outbreaks ◽  
Febrile Illness ◽  
Water Systems ◽  
Hot Water ◽  
Computational Framework ◽  
Trade Offs ◽  
Pontiac Fever ◽  
Legionnaires Disease

Legionella pneumophila are bacteria that when inhaled cause Legionnaires’ Disease (LD) and febrile illness Pontiac Fever. As of 2014, LD is the most frequent cause of waterborne disease outbreaks due...

scholarly journals Evaluation of Legionella spp. Colonization in Residential Buildings Having Solar Thermal System for Hot Water Production

2020 ◽  
Vol 17 (19) ◽  
pp. 7050
Author(s):  
Michele Totaro ◽  
Anna Laura Costa ◽  
Lorenzo Frendo ◽  
Sara Profeti ◽  
Beatrice Casini ◽  
...  
Keyword(s):  
Cold Water ◽  
Disease Risk ◽  
Residential Buildings ◽  
Water Systems ◽  
Hot Water ◽  
Solar Thermal ◽  
Water Production ◽  
Systems Maintenance ◽  
Legionnaires Disease ◽  
Cold Water Temperature

Despite an increase of literature data on Legionella spp. presence in private water systems, epidemiological reports assert a continuing high incidence of Legionnaires’ disease infection in Italy. In this study, we report a survey on Legionella spp. colonization in 58 buildings with solar thermal systems for hot water production (TB). In all buildings, Legionella spp. presence was enumerated in hot and cold water samples. Microbiological potability standards of cold water were also evaluated. Legionella spp. was detected in 40% of the buildings. Moreover, we detected correlations between the count of Legionella spp. and the presence of the optimal temperature for the microorganism growth (less than 40 °C). Our results showed that cold water was free from microbiological hazards, but Legionella spp., was detected when the mean cold water temperature was 19.1 ± 2.2 °C. This may considered close to the suboptimal value for the Legionella growth (more then 20 °C). In conclusion, we observed the presence of a Legionnaires’ disease risk and the need of some strategies aimed to reduce it, such as the application of training programs for all the workers involved in water systems maintenance.

scholarly journals Legionella Contamination in Hot Water of Italian Hotels

2005 ◽  
Vol 71 (10) ◽  
pp. 5805-5813 ◽  
Author(s):  
Paola Borella ◽  
Maria Teresa Montagna ◽  
Serena Stampi ◽  
Giovanna Stancanelli ◽  
Vincenzo Romano-Spica ◽  
...  
Keyword(s):  
Risk Factors ◽  
Legionella Pneumophila ◽  
Water Systems ◽  
Hot Water ◽  
Cross Sectional ◽  
Multicenter Survey ◽  
Multivariate Logistic Model ◽  
Legionnaires Disease ◽  
Building Characteristics

ABSTRACT A cross-sectional multicenter survey of Italian hotels was conducted to investigate Legionella spp. contamination of hot water. Chemical parameters (hardness, free chlorine concentration, and trace element concentrations), water systems, and building characteristics were evaluated to study risk factors for colonization. The hot water systems of Italian hotels were strongly colonized by Legionella; 75% of the buildings examined and 60% of the water samples were contaminated, mainly at levels of ≥103 CFU liter−1, and Legionella pneumophila was the most frequently isolated species (87%). L. pneumophila serogroup 1 was isolated from 45.8% of the contaminated sites and from 32.5% of the hotels examined. When a multivariate logistic model was used, only hotel age was associated with contamination, but the risk factors differed depending on the contaminating species and serogroup. Soft water with higher chlorine levels and higher temperatures were associated with L. pneumophila serogroup 1 colonization, whereas the opposite was observed for serogroups 2 to 14. In conclusion, Italian hotels, particularly those located in old buildings, represent a major source of risk for Legionnaires' disease due to the high frequency of Legionella contamination, high germ concentration, and major L. pneumophila serogroup 1 colonization. The possible role of chlorine in favoring the survival of Legionella species is discussed.

scholarly journals Legionella spp. Colonization in Water Systems of Hotels Linked with Travel-Associated Legionnaires’ Disease

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2243
Author(s):  
Antonios Papadakis ◽  
Maria Keramarou ◽  
Dimosthenis Chochlakis ◽  
Vassilios Sandalakis ◽  
Varvara A. Mouchtouri ◽  
...  
Keyword(s):  
Water Supply ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Water Systems ◽  
Hot Water ◽  
Water Supply Systems ◽  
Surveillance Network ◽  
Legionnaires Disease ◽  
Hot Water Supply ◽  
Supply Systems

Hotel water systems colonized with Legionella spp. have been the source of travel-associated Legionnaires’ disease, and cases, clusters and outbreaks continue to be reported worldwide each year. A total of 132 hotels linked with travel-associated Legionnaires’ disease, as reported through the European Legionnaires’ Disease Surveillance Network, were inspected and tested for Legionella spp. during 2000–2019 by the public health authorities of the island of Crete (Greece). A total of 3311 samples were collected: 1885 (56.93%) from cold water supply systems, 1387 (41.89%) from hot water supply systems, 37 (1.12%) were swab samples and two (0.06%) were soil. Of those, 685 (20.69%), were collected from 83 (62.89%) hotels, testing positive (≥50 CFU/L) for Legionella pneumophila) serogroups 1–10, 12–14 and non-pneumophila species (L. anisa, L. erythra, L. tusconensis, L. taurinensis, L. birminghamensis, L. rubrilucens, L. londiniesis, L. oakridgensis, L. santicrusis, L. brunensis, L. maceacherii). The most frequently isolated L. pneumophila serogroups were 1 (27.92%) and 3 (17.08%). Significantly higher isolation rates were obtained from hot water supply systems (25.96%) versus cold water systems (16.98%) and swab samples (13.51%). A Relative Risk (R.R.) > 1 (p < 0.0001) was calculated for hot water temperature <55 °C (R.R.: 4.43), chlorine concentrations <0.2 mg/L (R.R.: 2.69), star ratings <4 (R.R.: 1.73) and absence of Water Safety Plan implementation (R.R.: 1.57).

scholarly journals Highlighting the Potency of Biosurfactants Produced by Pseudomonas Strains as Anti-Legionella Agents

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Clémence Loiseau ◽  
Emilie Portier ◽  
Marie-Hélène Corre ◽  
Margot Schlusselhuber ◽  
Ségolène Depayras ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Close Association ◽  
Water Systems ◽  
Antagonistic Activity ◽  
Reverse Phase Hplc ◽  
Reverse Phase ◽  
Free Living ◽  
Legionnaires Disease ◽  
Culture Supernatants ◽  
Multispecies Biofilms

Legionella pneumophila, the causative agent of Legionnaires’ disease, is a waterborne bacterium mainly found in man-made water systems in close association with free-living amoebae and multispecies biofilms. Pseudomonas strains, originating from various environments including freshwater systems or isolated from hospitalized patients, were tested for their antagonistic activity towards L. pneumophila. A high amount of tested strains was thus found to be active. This antibacterial activity was correlated to the presence of tensioactive agents in culture supernatants. As Pseudomonas strains were known to produce biosurfactants, these compounds were specifically extracted and purified from active strains and further characterized using reverse-phase HPLC and mass spectrometry methods. Finally, all biosurfactants tested (lipopeptides and rhamnolipids) were found active and this activity was shown to be higher towards Legionella strains compared to various other bacteria. Therefore, described biosurfactants are potent anti-Legionella agents that could be used in the water treatment industry although tests are needed to evaluate how effective they would be under field conditions.

Effect of heat flushing on the concentrations of Legionella pneumophila and other heterotrophic microbes in hot water systems of apartment buildings

1996 ◽  
Vol 42 (8) ◽  
pp. 811-818 ◽  
Author(s):  
Outi M. Zacheus ◽  
Pertti J. Martikainen
Keyword(s):  
Water Temperature ◽  
Legionella Pneumophila ◽  
Heterotrophic Bacteria ◽  
Water System ◽  
Water Systems ◽  
Hot Water ◽  
Circulating Water ◽  
Heterotrophic Microbes ◽  
Before And After ◽  
Circulating Water System

The decontamination of Legionella pneumophila and other heterotrophic microbes by heat flushing in four legionellae-positive hot water systems was studied. Before the decontamination procedure, the concentration of legionellae varied from 3.0 × 10−3 to 3.5 × 10−5 cfu/L and the hot water temperature from 43.6 to 51.5 °C. During the contamination the temperature was raised to 60–70 °C. All taps and showers were cleaned from sediments and flushed with hot water twice a day for several minutes. The decontamination lasted for 2–4 weeks. In a few weeks the heat-flushing method reduced the concentration of legionellae below the detection limit (50 cfu/L) in the hot circulating water system just before and after the heat exchanger. The high hot water temperature also decreased the viable counts of heterotrophic bacteria, fungi, and total microbial cells determined by the epifluorescent microscopy. However, the eradication of legionellae failed in a water system where the water temperature remained below 60 °C in some parts of the system. After the decontamination, the temperature of hot water was lowered to 55 °C. Thereafter, all the studied hot water systems were recolonized by legionellae within a few months, showing that the decontamination by heat flushing was temporary. Also, the contamination of other bacteria increased in a few months to the level before decontamination.Key words: legionellae, hot water system, decontamination, water temperature, heterotrophic bacteria.

scholarly journals Legionella pneumophila and Protozoan Hosts: Implications for the Control of Hospital and Potable Water Systems

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 286 ◽  
Author(s):  
Muhammad Atif Nisar ◽  
Kirstin E. Ross ◽  
Melissa H. Brown ◽  
Richard Bentham ◽  
Harriet Whiley
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Water Systems ◽  
Water Disinfection ◽  
Health Concern ◽  
Waterborne Pathogen ◽  
Microbial Biofilms ◽  
Pontiac Fever

Legionella pneumophila is an opportunistic waterborne pathogen of public health concern. It is the causative agent of Legionnaires’ disease (LD) and Pontiac fever and is ubiquitous in manufactured water systems, where protozoan hosts and complex microbial communities provide protection from disinfection procedures. This review collates the literature describing interactions between L. pneumophila and protozoan hosts in hospital and municipal potable water distribution systems. The effectiveness of currently available water disinfection protocols to control L. pneumophila and its protozoan hosts is explored. The studies identified in this systematic literature review demonstrated the failure of common disinfection procedures to achieve long term elimination of L. pneumophila and protozoan hosts from potable water. It has been demonstrated that protozoan hosts facilitate the intracellular replication and packaging of viable L. pneumophila in infectious vesicles; whereas, cyst-forming protozoans provide protection from prolonged environmental stress. Disinfection procedures and protozoan hosts also facilitate biogenesis of viable but non-culturable (VBNC) L. pneumophila which have been shown to be highly resistant to many water disinfection protocols. In conclusion, a better understanding of L. pneumophila-protozoan interactions and the structure of complex microbial biofilms is required for the improved management of L. pneumophila and the prevention of LD.

scholarly journals Is a Proactive Approach to Controlling Legionella in the Environment Justified?

2021 ◽  
Vol 59 (3) ◽  
Author(s):  
Daniela Glažar Ivče ◽  
Dobrica Rončević ◽  
Marina Šantić ◽  
Arijana Cenov ◽  
Dijana Tomić Linšak ◽  
...  
Keyword(s):  
Drinking Water ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Aged Care ◽  
Water Systems ◽  
Hot Water ◽  
Plate Count ◽  
Surveillance Program ◽  
Adequate Treatment ◽  
Proactive Approach

Research background. Legionella are Gram-negative bacteria that are ubiquitous in the natural environment. Contaminated water in manmade water systems is a potential source of transmission of Legionnaires’ disease (LD). The aim of this study was to explore the prevalence of Legionella pneumophila (L. pneumophila) in the drinking water distribution system (DWDS) of Primorje-Gorski Kotar County (PGK County), Croatia, for the period 2013-2019, coupled with the incidence of LD. A number of L. pneumophila-positive samples (>100 CFU/L), serogroup distribution, and the degree of contamination of specific facilities (health & aged care, tourism, sports) were assessed. Based on the results obtained, the reasoning for the implementation of a mandatory Legionella environmental surveillance program was assessed. Experimental approach. Sample testing for Legionella was carried out according to ISO 1173. A Heterotrophic Plate Count (HPC) and P. aeruginosa were analysed along with the basic physico-chemical indicators of drinking water quality. The research period was divided into two parts, namely, the 2013-2018 period (before implementation of the prevention program, after the outbreak of LD), and year 2019 (proactive approach, no LD cases recorded). Results and conclusion. During the 7-year observation period in PGK County, an increase in the number of samples tested for Legionella was found. An increase in Legionella-positive samples (particularly pronounced during the warmer part of the year) was recorded, along with a growing trend in the number of reported LD cases. In addition to hot water systems, the risk of Legionella colonization also applies to cold water systems. Health & aged care facilities appear to be at highest risk. In addition to the higher proportion of positive samples and a higher degree of microbiological load at these facilities, the highest proportion of L. pneumophila SGs 2-14 was identified. Due to the diagnostic limitations of the applied tests, the number of LD cases is underdiagnosed. Novelty and scientific contribution. The introduction of a mandatory preventive approach to monitoring Legionella in DWDS water samples, along with the definition of national criteria for the interpretation of results, will create the preconditions for diagnosis and adequate treatment of larger numbers of LD cases.

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