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 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.

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 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 pneumophila in water distribution systems in hospitals and public buildings of the Lublin region of eastern Poland

2015 ◽  
Vol 22 (2) ◽  
pp. 195-201 ◽  
Author(s):  
Agnieszka Sikora ◽  
Małgorzata Wójtowicz-Bobin ◽  
Maria Kozioł-Montewka ◽  
Agnieszka Magryś ◽  
Iwona Gładysz
Keyword(s):  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Public Buildings

scholarly journals Role of biofilms in the survival of Legionella pneumophila to sodium chloride treatment

2021 ◽  
Author(s):  
Abdelwahid Assaidi ◽  
Mostafa Ellouali ◽  
Hassan Latrache ◽  
Hafida Zahir ◽  
El Mostafa Mliji
Keyword(s):  
Sodium Chloride ◽  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Chloride Concentration ◽  
Health Concern ◽  
Bacterial Strains ◽  
Planktonic Cells

Background and Objectives: Legionnaires’ disease continues to be a public health concern. Colonized water distribution systems are often implicated in Legionella transmission, despite the use of various disinfection strategies, the bacterium is capable to persist and survive in water systems. The aim of this study was to investigate the persistence of Legionella pneumophila to sodium chloride over time at different temperatures and analysing the role of biofilms in the survival of this bacteria. Materials and Methods: L. pneumophila serogroup 1 and L. pneumophila serogroup 2-15 were used to study the effect of sodium chloride on planktonic and sessile cells. The tested concentrations were: 0.5%, 1%, 2%, 3%, 4%, 6% and 8% (W/V) NaCl. Biofilms were grown on 24-well microplates. Results: At 20°C, L. pneumophila planktonic cells were able to survive in sodium chloride concentrations up to 2%. How- ever, at 37°C, a sodium chloride concentration over 1.5%, reduced systematically the numbers of bacterial cells. Biofilms were grown for 20 days in the absence and presence of sodium chloride. The results show that bacterial strains were able to survive and regrow after the sodium chloride shock (2-3%). Moreover, it seems that this effect is less expressed with the age of the biofilm; old biofilms were more persistent than the young ones. Conclusion: Results from this study demonstrate that the sodium chloride disinfection strategy was effective on Legionella pneumophila planktonic cells but not on biofilms, which demonstrate the role of biofilms in the persistence and recoloniza- tion of L. pneumophila in water distribution systems.

scholarly journals Survival of Mycobacterium avium, Legionella pneumophila, Escherichia coli, and Caliciviruses in Drinking Water-Associated Biofilms Grown under High-Shear Turbulent Flow

2007 ◽  
Vol 73 (9) ◽  
pp. 2854-2859 ◽  
Author(s):  
Markku J. Lehtola ◽  
Eila Torvinen ◽  
Jaana Kusnetsov ◽  
Tarja Pitkänen ◽  
Leena Maunula ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Drinking Water ◽  
Turbulent Flow ◽  
Mycobacterium Avium ◽  
Legionella Pneumophila ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
High Shear ◽  
Culture Methods

ABSTRACT Most of the bacteria in drinking water distribution systems are associated with biofilms. In biofilms, their nutrient supply is better than in water, and biofilms can provide shelter against disinfection. We used a Propella biofilm reactor for studying the survival of Mycobacterium avium, Legionella pneumophila, Escherichia coli, and canine calicivirus (CaCV) (as a surrogate for human norovirus) in drinking water biofilms grown under high-shear turbulent-flow conditions. The numbers of M. avium and L. pneumophila were analyzed with both culture methods and with peptide nucleic acid fluorescence in situ hybridization (FISH) methods. Even though the numbers of pathogens in biofilms decreased during the experiments, M. avium and L. pneumophila survived in biofilms for more than 2 to 4 weeks in culturable forms. CaCV was detectable with a reverse transcription-PCR method in biofilms for more than 3 weeks. E. coli was detectable by culture for only 4 days in biofilms and 8 days in water, suggesting that it is a poor indicator of the presence of certain waterborne pathogens. With L. pneumophila and M. avium, culture methods underestimated the numbers of bacteria present compared to the FISH results. This study clearly proved that pathogenic bacteria entering water distribution systems can survive in biofilms for at least several weeks, even under conditions of high-shear turbulent flow, and may be a risk to water consumers. Also, considering the low number of virus particles needed to result in an infection, their extended survival in biofilms must be taken into account as a risk for the consumer.

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.

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