scholarly journals Evaluation of Legionella pneumophila Decrease in Hot Water Network of Four Hospital Buildings after Installation of Electron Time Flow Taps

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 210 ◽  
Author(s):  
Michele Totaro ◽  
Tommaso Mariotti ◽  
Costanza Bisordi ◽  
Erica De Vita ◽  
Paola Valentini ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Cold Water ◽  
Control Measure ◽  
Critical Issue ◽  
Hot Water ◽  
Low Flow ◽  
Water Networks ◽  
Water Network ◽  
Time Flow ◽  
Chemical Disinfection

Legionella spp. control is a critical issue in hospital with old water networks. Chemical disinfection methods are applied as a control measure over prolonged time periods, but Legionella may be resistant to chemical agents in pipeworks with low flow and frequent water stagnation. We evaluated Legionella spp. colonization in the hot water network of Italian hospitals after the installation of time flow taps (TFTs). In the period between 2017 and 2019, TFTs were installed in four hospital water networks. They were programmed in order to obtain a hot water flow of 192 L/day from each TFTs. A continuous chlorination system (chlorine dioxide) and a cold water pre-filtration device were applied in all the buildings. Before and after TFT installation, Legionella spp. was investigated at scheduled times. Before TFT installation, Legionella pneumophila was detected in all the hospitals with counts ranging from 2 × 102 to 1.4 × 105 CFU/L. After TFT installation, a loss in Legionella pneumophila culturability was always achieved in the period between 24 h and 15 days. Total chlorine concentration (Cl2) was detected in the range between 0.23 and 0.36 mg/L while temperature values were from 44.8 to 53.2 °C. TFTs together with chemical disinfection represent a method which improve water quality and disinfectant efficacy, reducing Legionella colonization in dead-end sections.

Rate of Legionella pneumophila colonization in hospital hot water network after time flow taps installation

2018 ◽  
Vol 98 (1) ◽  
pp. 60-63 ◽  
Author(s):  
M. Totaro ◽  
P. Valentini ◽  
A.L. Costa ◽  
S. Giorgi ◽  
B. Casini ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Hot Water ◽  
Water Network ◽  
Time Flow

scholarly journals Presence of Legionella spp. in Hot Water Networks of Different Italian Residential Buildings: A Three-Year Survey

2017 ◽  
Author(s):  
Michele Totaro ◽  
Paola Valentini ◽  
Anna Laura Costa ◽  
Lorenzo Frendo ◽  
Alessia Cappello ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water Samples ◽  
Cold Water ◽  
Residential Buildings ◽  
Hot Water ◽  
Water Production ◽  
Water Networks ◽  
Legionella Species ◽  
Solar Thermal System ◽  
And Control

Although the European reports highlight an increase in community-acquired Legionnaires’ disease cases, the risk of Legionella spp. in private houses is underestimated. In Pisa (Italy) we performed a three-year survey on Legionella presence in 121 buildings with an independent hot water production (IB); 64 buildings with a central hot water production (CB); and 35 buildings with a solar thermal system for hot water production (TB). From all the 220 buildings Legionella spp. was researched in two hot water samples collected either at the recirculation point or at on the first floor and on the last floor, while the potable water quality was analyzed in three cold water samples collected at the inlet from the aqueduct network, at the exit from the autoclave, and at the most remove remote? tap. Legionella pneumophila sg1, Legionella pneumophila sg2-16 and not-pneumophila Legionella species were detected in 26% of the hot water networks, mostly in CB and TB. In these buildings we detected correlations between the presence of Legionella and the total chlorine concentration decrease or/and the increase of the temperature. Cold water resulted free from microbiological hazards, with the exception of Serratia liquefaciens and Enterobacter cloacae isolated at the exit from two different autoclaves. We observed an increase in total microbial counts at 22 and 37°C between the samples collected at the most remote taps compared to the ones collected at the inlet from the aqueduct. The study highlights a condition of potential risk for susceptible categories of population and supports the need for measures of risk assessment and control.

Determinants of Legionella pneumophila Contamination of Water Distribution Systems: 15-Hospital Prospective Study

1987 ◽  
Vol 8 (9) ◽  
pp. 357-363 ◽  
Author(s):  
Richard M. Vickers ◽  
Victor L. Yu ◽  
S. Sue Hanna ◽  
Paul Muraca ◽  
Warren Diven ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Cold Water ◽  
Physicochemical Characteristics ◽  
Hot Water ◽  
Environmental Study ◽  
Water Tank ◽  
One Year

AbstractWe conducted a prospective environmental study for Legionella pneumophila in 15 hospitals in Pennsylvania. Hot water tanks, cold water sites, faucets, and show-erheads were surveyed four times over a one-year period. Sixty percent (9/15) of hospitals surveyed were contaminated with L pneumophila. Although contamination could not be linked to a specific municipal water supplier, most of the contaminated supplies came from rivers. Parameters found to be significantly associated with contamination included elevated hot water temperature, vertical configuration of the hot water tank, older tanks, and elevated calcium and magnesium concentrations of the water (P < 0.05). This study suggests that L pneumophila contamination could be predicted based on design of the distribution system, as well as physicochemical characteristics of the water.

Molecular typing of the Legionella pneumophila population isolated from several locations in a contaminated water network

2004 ◽  
Vol 50 (1) ◽  
pp. 281-285 ◽  
Author(s):  
A.-S. Lepeuple ◽  
M. Jovic ◽  
M.-R. de Roubin
Keyword(s):  
Legionella Pneumophila ◽  
Molecular Typing ◽  
Random Amplified Polymorphic Dna ◽  
Hot Water ◽  
Water Network ◽  
Rapd Pattern ◽  
Different Populations ◽  
Definition Of ◽  
Different Strains ◽  
Key Steps

The RAPD (random amplified polymorphic DNA) technique has been developed for the molecular typing of Legionella in order to characterise the populations of hot water systems. During this study, 22 primers were tested and the four most informative ones were selected. The optimisation of the PCR conditions allowed the setting up of a powerful discriminative genotyping method. Moreover, the definition of a quality management method allowed definition of the key steps and the number of replicates to ensure reproducibility of the RAPD pattern. The RAPD was used to study the hot water network of a building. Legionella colonies (91) were isolated from seven locations and genotyped. The diversity of the population in one sample could vary from one to seven different strains. The study of the traceability showed that, in most of the cases, different populations could be present at different locations of the same network.

scholarly journals Sensitivity of Vermamoeba (Hartmannella) vermiformis cysts to conventional disinfectants and protease

2014 ◽  
Vol 13 (2) ◽  
pp. 302-310 ◽  
Author(s):  
Emilie Fouque ◽  
Yann Héchard ◽  
Philippe Hartemann ◽  
Philippe Humeau ◽  
Marie-Cécile Trouilhé
Keyword(s):  
Legionella Pneumophila ◽  
Pathogenic Bacteria ◽  
Hot Water ◽  
Water Networks ◽  
Important Health ◽  
Hartmannella Vermiformis ◽  
Important Health Issue ◽  
Few Data ◽  
First Time

Vermamoeba vermiformis is a free-living amoeba (FLA) widely distributed in the environment, known to colonize hot water networks and to be the reservoir of pathogenic bacteria such as Legionella pneumophila. FLA are partly resistant to biocides, especially in their cyst form. The control of V. vermiformis in hot water networks represents an important health issue, but there are very few data on their resistance to disinfection treatments. The sensitivity of cysts of two strains of V. vermiformis to three disinfectants frequently used in hot water networks (chlorine, heat shock, peracetic acid (PAA) mixed with hydrogen peroxide (H2O2)) was investigated. In vitro, several concentrations of biocides, temperatures and exposure times according to the French regulation were tested. Cysts were fully inactivated by the following conditions: 15 mg/L of chlorine for 10 min; 60 °C for 30 min; and 0.5 g/L equivalent H2O2 of PAA mixed with H2O2 for 30 min. For the first time, the strong efficacy of subtilisin (0.625 U/mL for 24 h), a protease, to inactivate the V. vermiformis cysts has been demonstrated. It suggests that novel approaches may be efficient for disinfection processes. Finally, V. vermifomis cysts were sensitive to all the tested treatments and appeared to be more sensitive than Acanthamoeba cysts.

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.

scholarly journals Safety and Effectiveness of Monochloramine Treatment for Disinfecting Hospital Water Networks

2020 ◽  
Vol 17 (17) ◽  
pp. 6116 ◽  
Author(s):  
Isabella Marchesi ◽  
Stefania Paduano ◽  
Giuseppina Frezza ◽  
Luca Sircana ◽  
Elena Vecchi ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
Cold Water ◽  
Hot Water ◽  
Water Networks ◽  
Duration Of Treatment ◽  
Public And Private ◽  
Routine Monitoring ◽  
Safe Strategy ◽  
Plumbing Systems ◽  
By Products

The formation of potentially carcinogenic N-nitrosamines, associated with monochloramine, requires further research due to the growing interest in using this biocide for the secondary disinfection of water in public and private buildings. The aim of our study was to evaluate the possible formation of N-nitrosamines and other toxic disinfection by-products (DBPs) in hospital hot water networks treated with monochloramine. The effectiveness of this biocide in controlling Legionella spp. contamination was also verified. For this purpose, four different monochloramine-treated networks, in terms of the duration of treatment and method of biocide injection, were investigated. Untreated hot water, municipal cold water and, limited to N-nitrosamines analysis, hot water treated with chlorine dioxide were analyzed for comparison. Legionella spp. contamination was successfully controlled without any formation of N-nitrosamines. No nitrification or formation of the regulated DBPs, such as chlorites and trihalomethanes, occurred in monochloramine-treated water networks. However, a stable formulation of hypochlorite, its frequent replacement with a fresh product, and the routine monitoring of free ammonia are recommended to ensure a proper disinfection. Our study confirms that monochloramine may be proposed as an effective and safe strategy for the continuous disinfection of building plumbing systems, preventing vulnerable individuals from being exposed to legionellae and dangerous DBPs.

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

2021 ◽  
Author(s):  
Antonios Papadakis ◽  
Maria Keramarou ◽  
Dimosthenis Chochlakis ◽  
Vassilios Sandalakis ◽  
Varvara Mouchtouri ◽  
...  
Keyword(s):  
Water Supply ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Water Systems ◽  
Hot Water ◽  
Water Supply Systems ◽  
Water Safety ◽  
Surveillance Network ◽  
Hot Water Supply ◽  
Supply Systems

Hotel water systems colonized with Legionella spp. have been the source of travel-associated Legionnaires&rsquo; disease and cases, clusters or outbreaks continue to be reported worldwide each year. A total of 132 hotels linked with travel-associated Legionnaires&rsquo; disease, as reported through the European Legionnaires&rsquo; Disease Surveillance Network, were inspected and tested for Legionella spp. during 2000&ndash;2019 by the public health authorities of the island of Crete (Greece). A total of 3,311 samples were collected: 1,885 (56.93%) from cold water supply systems, 1,387 (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 (&ge; 50CFU/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.) &gt; 1 (p &lt; 0.0001) was calculated for hot water temperature &lt;55 &deg;C (R.R.: 4.43), chlorine concentrations &lt;0.2 mg/L (R.R.: 2.69), star rating &lt;4 (R.R.: 1.73) and absence of Water Safety Plan implementation (R.R.: 1.57).

scholarly journals The Effect of Hydrogen Peroxide on Reducing the Colonization of Legionella spp. in a Hospital Water Network

2017 ◽  
Author(s):  
Beatrice Casini ◽  
Francesco Aquino ◽  
Michele Totaro ◽  
Mario Miccoli ◽  
Irio Galli ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
General Hospital ◽  
Legionella Pneumophila ◽  
Hot Water ◽  
Water Network ◽  
Progressive Reduction ◽  
Complete Control ◽  
Food Grade ◽  
Legionella Species ◽  
The Mean

Objectives: To evaluate the effectiveness of hydrogen peroxide (HP) use in the hospital water network disinfection to control Legionella spp. colonization. Methods: Following the detection of high levels of Legionella contamination in a 136-bed general hospital water network, an HP treatment of the hot water (25 mg/L) was adopted. During a period of 34 months, the effectiveness of HP on Legionella colonization was assessed. Legionella was isolated in accordance with ISO-11731 and identification was carried out by sequencing of the mip gene. Results: Before HP treatment L.pneumophila sg 2-15 was isolated in all sites with a mean count of 9950&plusmn;8279 CFU/L. After one month of HP-treatment, we observed the disappearance of L. pneumophila 2-15, however other Legionella species never cultured before appeared; Legionella pneumophila 1 was isolated in 1 out of 4 sampling sites (2,000 CFU/L) and other non-pneumophila species in all sites (mean load 3,000 &plusmn;2887 CFU/L). Starting from September 2013, HP-treatment was modified adding food-grade polyphosphates and in the following months we observed a progressive reduction of the mean load of all species (p&lt;0.05), until to a substantial disappearing of Legionella colonization. Conclusion: Hydrogen peroxide demonstrated a good efficacy in controlling Legionella. Although in the initial phases of treatment it seemed unable to eliminate all the species, by keeping HP levels to 25 mg/L and adding food-grade polyphosphates, a progressive and complete control of colonisation was obtained.

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