scholarly journals How Molecular Typing Can Support Legionella Environmental Surveillance in Hot Water Distribution Systems: A Hospital Experience

2020 ◽  
Vol 17 (22) ◽  
pp. 8662
Author(s):  
Luna Girolamini ◽  
Silvano Salaris ◽  
Jessica Lizzadro ◽  
Marta Mazzotta ◽  
Maria Rosaria Pascale ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Molecular Typing ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Gene Sequencing ◽  
Culture Technique ◽  
Hot Water ◽  
Environmental Surveillance ◽  
Risk Map

In this study, we aimed to associate the molecular typing of Legionella isolates with a culture technique during routine Legionella hospital environmental surveillance in hot water distribution systems (HWDSs) to develop a risk map able to be used to prevent nosocomial infections and formulate appropriate preventive measures. Hot water samples were cultured according to ISO 11731:2017. The isolates were serotyped using an agglutination test and genotyped by sequence-based typing (SBT) for Legionella pneumophila or macrophage infectivity potentiator (mip) gene sequencing for non-pneumophila Legionella species. The isolates’ relationship was phylogenetically analyzed. The Legionella distribution and level of contamination were studied in relation to temperature and disinfectant residues. The culture technique detected 62.21% of Legionella positive samples, characterized by L. pneumophila serogroup 1, Legionella non-pneumophila, or both simultaneously. The SBT assigned two sequence types (STs): ST1, the most prevalent in Italy, and ST104, which had never been isolated before. The mip gene sequencing detected L. anisa and L. rubrilucens. The phylogenetic analysis showed distinct clusters for each species. The distribution of Legionella isolates showed significant differences between buildings, with a negative correlation between the measured level of contamination, disinfectant, and temperature. The Legionella molecular approach introduced in HWDSs environmental surveillance permits (i) a risk map to be outlined that can help formulate appropriate disinfection strategies and (ii) rapid epidemiological investigations to quickly identify the source of Legionella infections.

scholarly journals Environmental Surveillance of Legionella spp. in an Italian University Hospital Results of 10 Years of Analysis

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2304
Author(s):  
Giovanna Deiana ◽  
Antonella Arghittu ◽  
Marco Dettori ◽  
Maria Dolores Masia ◽  
Maria Grazia Deriu ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Linear Trend ◽  
Water Distribution Systems ◽  
University Hospital ◽  
Environmental Surveillance ◽  
National Guidelines ◽  
Increased Risk ◽  
Definitive Method

The occurrence of Legionella spp. in the water distribution systems of large hospitals and other healthcare facilities is considered particularly dangerous, due to the critical nature of the hospitalized patients. The aim of this study is to present a pluri-annual environmental surveillance in a large university hospital assessing the prevalence of Legionella spp. and underlining its variability over the years. The samples of water were collected in accordance with the Italian National Guidelines and the sampling sites considered in this study were selected favoring wards with very high-risk patients and with patients at increased risk. The laboratory analyzed a total of 305 water samples deriving from 24 different sampling points. Legionella spp. were detected in 39.4% of samples, the majority of which were contaminated by Legionella pneumophila serogroups 2–14 (68.7%). Statistically significant differences were found among different seasons with a linear trend in positive proportion from summer to spring. Several experimental interventions to prevent and reduce Legionella colonization were attempted, but there is no a definitive method for the complete eradication of this microorganism. The permanent monitoring of hospital water distribution systems is fundamental to preventing the potential risk of nosocomial Legionellosis and to implementing procedures to minimize the risk of Legionella spp. colonization.

scholarly journals Temperature diagnostic to identify high risk areas and optimize Legionella pneumophila surveillance in hot water distribution systems

2015 ◽  
Vol 71 ◽  
pp. 244-256 ◽  
Author(s):  
Emilie Bédard ◽  
Stéphanie Fey ◽  
Dominique Charron ◽  
Cindy Lalancette ◽  
Philippe Cantin ◽  
...  
Keyword(s):  
High Risk ◽  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Hot Water ◽  
Risk Areas ◽  
Temperature Diagnostic

scholarly journals Prevalence of Legionella spp. in hot water samples from Polish hospitals in 2009-2013

2019 ◽  
Vol 73 ◽  
pp. 47-52
Author(s):  
Iwona Gładysz ◽  
Maria Kozioł-Montewka ◽  
Agnieszka Sikora ◽  
Małgorzata Wójtowicz-Bobin ◽  
Jan Karczewski
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Microbiological Quality ◽  
The State ◽  
Hot Water ◽  
Epidemiological Surveillance ◽  
Bacterial Counts ◽  
Microbiological Analyses

Background: Microbiological threat from Legionella spp. is associated with the current widespread use of air-condition systems and frequent colonization of hot water distribution systems in public facilities (hospitals, hotels, nursing homes). This poses a particularly high risk in hospitalized patients, as many of them are immunocompromised. More than 50 species and 72 serogroups of Legionella spp. have been described thus far, including more than 20 species being pathogenic to humans. Material/Methods: Microbiological threat posed by Legionella spp. was assessed based on a retrospective analysis of microbiological quality of water from hot water distribution systems in Polish hospitals, determined in 2009-2013 at certified laboratories of the Sanitary-Epidemiological Surveillance. The results were kindly provided by the hospitals’ administration upon request, for which the authors would like to express their deepest gratitude. The study material included samples of hot water from internal distribution systems in 379 Polish hospitals, collected by the State Sanitary Inspectorate. Results: Based on the results of microbiological analyses, we were able to estimate Legionella spp. colonization rates in hospital water distribution systems and to assess the activities undertaken by the State Sanitary Inspectorate to reduce excessive bacterial counts in this reservoir. Microbiological analyses conducted in 2009-2013, i.e. after implementing a statutory obligation to monitor Legionella spp. in hospital hot water distribution systems, showed elevated bacterial counts in 3.92% to 12.7% of the samples. These findings justify further microbiological monitoring of hospital water distribution systems. Discussion: The prevalence of the most pathogenic serotype SG1 in hot water distribution systems of Polish hospitals is relatively low compared to other European countries. To maintain this favorable status, hospital water systems should be monitored not only for the presence of Legionella pneumophila, but also for the prevalence of serogroup 1 L. pneumophila.

scholarly journals Legionella pneumophila’s Tsp is important for surviving thermal stress in water and inside amoeba

2020 ◽  
Author(s):  
Joseph Saoud ◽  
Thangadurai Mani ◽  
Sébastien P. Faucher
Keyword(s):  
Heat Treatment ◽  
Thermal Stress ◽  
Heat Shock ◽  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Exponential Phase ◽  
Hot Water

ABSTRACTLegionella pneumophila (Lp) is an inhabitant of natural and man-made water systems where it replicates within amoebae and ciliates and survives within biofilms. When Lp-contaminated aerosols are breathed in, Lp will enter the lungs and infect human alveolar macrophages, causing a severe pneumonia known as Legionnaires Disease. Lp is often found in hot water distribution systems (HWDS), which are linked to nosocomial outbreaks. Heat treatment is used to disinfect HWDS and reduce the concentration of Lp. However, Lp is often able to recolonize these water systems, indicating an efficient heat-shock response. Tail-specific proteases (Tsp) are typically periplasmic proteases implicated in degrading aberrant proteins in the periplasm and important for surviving thermal stress. In this paper, we show that Tsp, encoded by the lpg0499 gene in Lp Philadelphia-1, is important for surviving thermal stress in water and for optimal infection of amoeba when a shift in temperature occurs during intracellular growth. Tsp is expressed in the post-exponential phase but repressed in the exponential phase. The cis-encoded small regulatory RNA Lpr17 shows opposite expression, suggesting that it represses translation of tsp. In addition, tsp is regulated by CpxR, a major regulator in Lp, in a Lpr17-independent manner. Deletion of CpxR also reduced the ability of Lp to survive heat shock. In conclusion, this study shows that Tsp is an important factor for the survival and growth of Lp in water systems.IMPORTANCELegionella pneumophila (Lp) is a major cause of nosocomial and community-acquired pneumonia. Lp is found in water systems including hot water distribution systems. Heat treatment is a method of disinfection often used to limit Lp’s presence in such systems; however, the benefit is usually short term as Lp is able to quickly recolonize these systems. Presumably, Lp respond efficiently to thermal stress, but so far not much is known about the genes involved. In this paper, we show that the Tail-specific protease (Tsp) and the two-component system CpxRA are required for resistance to thermal stress, when Lp is free in water and when it is inside host cells. Our study identifies critical systems for the survival of Lp in its natural environment under thermal stress.

scholarly journals The Tail-Specific Protease Is Important for Legionella pneumophila To Survive Thermal Stress in Water and inside Amoebae

2021 ◽  
Vol 87 (9) ◽  
Author(s):  
Joseph Saoud ◽  
Thangadurai Mani ◽  
Sébastien P. Faucher
Keyword(s):  
Heat Treatment ◽  
Thermal Stress ◽  
Heat Shock ◽  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Systems ◽  
Hot Water ◽  
Host Cells

ABSTRACT Legionella pneumophila (Lp) is an inhabitant of natural and human-made water systems, where it replicates within amoebae and ciliates and survives within biofilms. When Lp-contaminated aerosols are breathed in, Lp can enter the lungs and may infect human alveolar macrophages, causing severe pneumonia known as Legionnaires’ disease. Lp is often found in hot water distribution systems (HWDS), which are linked to nosocomial outbreaks. Heat treatment is used to disinfect HWDS and reduce the concentration of Lp. However, Lp is often able to recolonize these water systems, indicating an efficient heat shock response. Tail-specific proteases (Tsp) are typically periplasmic proteases implicated in degrading aberrant proteins in the periplasm and important for surviving thermal stress. In Lp Philadelphia-1, Tsp is encoded by the lpg0499 gene. In this paper, we show that Tsp is important for surviving thermal stress in water and for optimal infection of amoeba when a shift in temperature occurs during intracellular growth. We also demonstrate that Tsp is expressed in the postexponential phase but repressed in the exponential phase and that the cis-encoded small regulatory RNA Lpr17 shows the opposite expression, suggesting that it represses translation of tsp. In addition, our results show that tsp is regulated by CpxR, a major regulator in Lp, in an Lpr17-independent manner. Deletion of CpxR also reduced the ability of Lp to survive heat shock. In conclusion, our study shows that Tsp is likely an important factor for the survival and growth of Lp in water systems. IMPORTANCE Lp is a major cause of nosocomial and community-acquired pneumonia. Lp is found in water systems, including hot water distribution systems. Heat treatment is a method of disinfection often used to limit the presence of Lp in such systems; however, the benefit is usually short term, as Lp is able to quickly recolonize these systems. Presumably, Lp responds efficiently to thermal stress, but so far, not much is known about the genes involved. In this paper, we show that the Tsp and the two-component system CpxRA are required for resistance to thermal stress when Lp is free in water and when it is inside host cells. Our study identifies critical systems for the survival of Lp in its natural environment under thermal stress.

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.

Multiple disinfection processes of Legionella pneumophila positive in hotels’ water distribution systems in Jordan

2019 ◽  
Vol 163 ◽  
pp. 7-16
Author(s):  
Motasem N. Saidan ◽  
Ahlam I. Abdalla ◽  
Nivin Al Alami ◽  
Hanan Al-Naimat
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems

Long-Term Effects of Hospital Water Network Disinfection onLegionellaand Other Waterborne Bacteria in an Italian University Hospital

2014 ◽  
Vol 35 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Beatrice Casini ◽  
Andrea Buzzigoli ◽  
Maria Luisa Cristina ◽  
Anna Maria Spagnolo ◽  
Pietro Del Giudice ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Hot Water ◽  
Control Measures ◽  
University Hospital ◽  
Long Term Effects ◽  
Water Safety ◽  
Safety Plan ◽  
Water Safety Plan

Objective and Design.Legionellacontrol still remains a critical issue in healthcare settings where the preferred approach to health risk assessment and management is to develop a water safety plan. We report the experience of a university hospital, where a water safety plan has been applied since 2002, and the results obtained with the application of different methods for disinfecting hot water distribution systems in order to provide guidance for the management of water risk.Interventions.The disinfection procedures included continuous chlorination with chlorine dioxide (0.4–0.6 mg/L in recirculation loops) reinforced by endpoint filtration in critical areas and a water treatment based on monochloramine (2-3 mg/L). Real-time polymerase chain reaction and a new immunoseparation and adenosine triphosphate bioluminescence analysis were applied in environmental monitoring.Results.After 9 years, the integrated disinfection-filtration strategy significantly reduced positive sites by 55% and the mean count by 78% (P< .05); however, the high costs and the occurrence of a chlorine-tolerant clone belonging toLegionella pneumophilaST269 prompted us to test a new disinfectant. The shift to monochloramine allowed us to eliminate planktonicLegionellaand did not require additional endpoint filtration; however, nontuberculous mycobacteria were isolated more frequently as long as the monochloramine concentration was 2 mg/L; their cultivability was never regained by increasing the concentration up to 3 mg/L.Conclusions.Any disinfection method needs to be adjusted/fine-tuned in individual hospitals in order to maintain satisfactory results over time, and only a locally adapted evidence-based approach allows assessment of the efficacy and disadvantages of the control measures.

scholarly journals Forensic Engineering Analysis Of The Negative Effect Of Hot Water Distribution Systems On Heater Operation

2002 ◽  
Vol 19 (1) ◽  
Author(s):  
Edward W. Saltzberg
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Hot Water ◽  
Engineering Analysis ◽  
Water Heater ◽  
Water Heaters ◽  
Negative Effect ◽  
Forensic Engineering ◽  
Construction Defects

Our Office Had Two Condominium Litigation Cases That Had A Number Of Construction Defects. One Was A Luxury Complex And One Was A Moderately Priced Project. However, There Were Two Common Allegations In Both Cases. These Allegations Were That The Occupants Complained That They Did Not Have Sufficient Hot Water And That The Water Heater Was Not Able To Provide A Sufficient Quantity Of Hot Water. We Prepared Calculations On Both Of The Water Heater Systems To Determine If They Were Undersized. The Calculations Determined That The Water Heater Assembly Of Both Installations Were Liberally Sized And Should Have Been Able To Maintain Design Temperature All The Time, Even At Peak Use. To Ensure That The Water Heaters Were Both Operating Correctly, We Had The Water Heater Manufacturer Come Out And Service The Heaters On Both Systems. Both Systems Were Operating Properly.

scholarly journals Preventing Healthcare-Associated Legionellosis with Rapid Reduction of High Concentrations of Legionella Using Mechanical Removal of Blind Ends and Intensive Hot Water Flushing

2021 ◽  
Vol 41 (1) ◽  
pp. 3-7
Author(s):  
Alan Medić ◽  
Ljilja Balorda ◽  
Ivanka Matas ◽  
Ines Leto ◽  
Dinko Puntarić ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Hot Water ◽  
Rapid Reduction ◽  
Mechanical Removal ◽  
Two Measures ◽  
High Concentrations ◽  
Healthcare Associated ◽  
Emergency Measures

Background: The aim of this paper was to present the effectiveness of the mechanical removal of blind ends and flushing of hot water systems at outlets as the only possible emergency measures to reduce the concentration of Legionella spp in hot water. Methods: Two measures have been undertaken: mechanical removal of blind ends and intensive hot water flushing when the water has not been used for more than 7 days. Results: We detected Legionella pneumophila serogroup 1 in concentration of 1.000- 55.000 CFU/L at all samples sites. In the control sampling, after three weeks, we found seven sampling sites negative for Legionella and only two sampling sites positive. All nine sampling sites were negative after ten weeks. Conclusion: Establishing good water flow throughout the hospital seems to be the most important measure, in order to make the multiplication of Legionella in the hot water distribution systems unlikely.

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