The Hospital Tap Water System as a Source of Nosocomial Infections for Staff Members and Patients in the West Banks' Hospitals

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
Azhar Shareef ◽  
Ziad Mimi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Legionella Pneumophila ◽  
Nosocomial Infections ◽  
Distribution Systems ◽  
Water System ◽  
Hot Water ◽  
The West ◽  
Staff Members ◽  
Microbiological Methods ◽  
Thermal Disinfection

The number of nosocomial infections due to Legionella pneumophila and Pseudomonas aeruginosa is probably underestimated in many countries. This paper discusses the risk of legionellosis due to Legionella and Pseudomonas aeruginosa for patients and hospitals staff members from the water system in different Palestinian hospitals. A total of 134 water samples were collected in 2005 from six governmental hospitals located in the West Bank. Legionella pneumophila serogroup 2-14 was isolated from 33 of 53 samples and Pseudomonas aeruginosa was isolated from 17 of 81 before thermal disinfection. Thermal disinfection at 80°C and progressively flushing the hot water outlets around the system was successfully efficient to eliminate Legionella and Pseudomonas aeruginosa pathogens in water distribution systems. The current study is an example on how microbiological methods along with site history could be used to successfully track the source of bacterial water contamination and subsequently remediate it. Thorough contaminant characterization and forensic source identification is important for designing of appropriate management strategies

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.

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.

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 Effects of Disinfection on Legionella spp., Eukarya, and Biofilms in a Hot Water System

2012 ◽  
Vol 78 (19) ◽  
pp. 6850-6858 ◽  
Author(s):  
Maha Farhat ◽  
Marina Moletta-Denat ◽  
Jacques Frère ◽  
Séverine Onillon ◽  
Marie-Cécile Trouilhé ◽  
...  
Keyword(s):  
Community Structure ◽  
Heat Shock ◽  
Legionella Pneumophila ◽  
Water System ◽  
Single Strand Conformation Polymorphism ◽  
Pilot Scale ◽  
Small Subunit ◽  
Hot Water ◽  
Content Type ◽  
Chemical Treatments

ABSTRACTLegionellaspecies are frequently detected in hot water systems, attached to the surface as a biofilm. In this work, the dynamics ofLegionellaspp. and diverse bacteria and eukarya associated together in the biofilm, coming from a pilot scale 1 system simulating a real hot water system, were investigated throughout 6 months after two successive heat shock treatments followed by three successive chemical treatments. Community structure was assessed by a fingerprint technique, single-strand conformation polymorphism (SSCP). In addition, the diversity and dynamics ofLegionellaand eukarya were investigated by small-subunit (SSU) ribosomal cloning and sequencing. Our results showed that pathogenicLegionellaspecies remained after the heat shock and chemical treatments (Legionella pneumophilaandLegionella anisa, respectively). The biofilm was not removed, and the bacterial community structure was transitorily affected by the treatments. Moreover, several amoebae had been detected in the biofilm before treatments (Thecamoebaesp.,Vannellasp., andHartmanella vermiformis) and after the first heat shock treatment, but onlyH. vermiformisremained. However, another protozoan affiliated with Alveolata, which is known as a host cell forLegionella, dominated the eukaryal species after the second heat shock and chemical treatment tests. Therefore, effectiveLegionelladisinfection may be dependent on the elimination of these important microbial components. We suggest that eradicatingLegionellain hot water networks requires better study of bacterial and eukaryal species associated withLegionellain biofilms.

scholarly journals Integrated Real-Time PCR for Detection and Monitoring of Legionella pneumophila in Water Systems

2006 ◽  
Vol 73 (5) ◽  
pp. 1452-1456 ◽  
Author(s):  
Diaraf Farba Yaradou ◽  
Sylvie Hallier-Soulier ◽  
Sophie Moreau ◽  
Florence Poty ◽  
Yves Hillion ◽  
...  
Keyword(s):  
Real Time ◽  
Legionella Pneumophila ◽  
Cooling Tower ◽  
Water System ◽  
Culture Method ◽  
Hot Water ◽  
Pcr Assay ◽  
Standard Culture ◽  
Serial Samples ◽  
Over Time

ABSTRACT We evaluated a ready-to-use real-time quantitative Legionella pneumophila PCR assay system by testing 136 hot-water-system samples collected from 55 sites as well as 49 cooling tower samples collected from 20 different sites, in parallel with the standard culture method. The PCR assay was reproducible and suitable for routine quantification of L. pneumophila. An acceptable correlation between PCR and culture results was obtained for sanitary hot-water samples but not for cooling tower samples. We also monitored the same L. pneumophila-contaminated cooling tower for 13 months by analyzing 104 serial samples. The culture and PCR results were extremely variable over time, but the curves were similar. The differences between the PCR and culture results did not change over time and were not affected by regular biocide treatment. This ready-to-use PCR assay for L. pneumophila quantification could permit more timely disinfection of cooling towers.

Disconnecting central hot water and using electric showers to avoid colonization of the water system by Legionella pneumophila: an 11-year study

2007 ◽  
Vol 66 (4) ◽  
pp. 327-331 ◽  
Author(s):  
M.S. Oliveira ◽  
F.R. Maximino ◽  
R.D. Lobo ◽  
S. Gobara ◽  
S.I. Sinto ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Water System ◽  
Hot Water

scholarly journals Quantitative Real-Time Legionella PCR for Environmental Water Samples: Data Interpretation

2006 ◽  
Vol 72 (4) ◽  
pp. 2801-2808 ◽  
Author(s):  
Philippe Joly ◽  
Pierre-Alain Falconnet ◽  
Janine André ◽  
Nicole Weill ◽  
Monique Reyrolle ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Legionella Pneumophila ◽  
Cooling Tower ◽  
Water System ◽  
Data Interpretation ◽  
Environmental Water ◽  
Hot Water ◽  
Rrna Gene ◽  
Conventional Culture

ABSTRACT Quantitative Legionella PCRs targeting the 16S rRNA gene (specific for the genus Legionella) and the mip gene (specific for the species Legionella pneumophila) were applied to a total of 223 hot water system samples (131 in one laboratory and 92 in another laboratory) and 37 cooling tower samples (all in the same laboratory). The PCR results were compared with those of conventional culture. 16S rRNA gene PCR results were nonquantifiable for 2.8% of cooling tower samples and up to 39.1% of hot water system samples, and this was highly predictive of Legionella CFU counts below 250/liter. PCR cutoff values for identifying hot water system samples containing >103 CFU/liter legionellae were determined separately in each laboratory. The cutoffs differed widely between the laboratories and had sensitivities from 87.7 to 92.9% and specificities from 77.3 to 96.5%. The best specificity was obtained with mip PCR. PCR cutoffs could not be determined for cooling tower samples, as the results were highly variable and often high for culture-negative samples. Thus, quantitative Legionella PCR appears to be applicable to samples from hot water systems, but the positivity cutoff has to be determined in each laboratory.

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.

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