scholarly journals Outbreak of Legionnaires' disease at University Hospital, Nottingham. Epidemiology, microbiology and control

1993 ◽  
Vol 110 (1) ◽  
pp. 105-116 ◽  
Author(s):  
A. Colville ◽  
J. Crowley ◽  
D. Dearden ◽  
R. C. B. Slack ◽  
J. V. Lee
Keyword(s):  
Legionella Pneumophila ◽  
Copper Ions ◽  
Virulent Strain ◽  
Water System ◽  
Hot Water ◽  
University Hospital ◽  
Domestic Hot Water ◽  
Large Teaching Hospital ◽  
Legionnaires Disease ◽  
And Control

SUMMARYTwelve patients in a large teaching hospital contracted Legionnaires' disease over a period of 11 months. The source was a domestic hot water system in one of the hospital blocks, which was run at a temperature of 43 °C. Five different subtypes ofLegionella pneumophilaserogroup 1 have been isolated from water in different parts of the hospital, over a period of time. Only one subtype, Benidorm RFLP 14, was implicated in disease. Circumstantial evidence suggested that the outbreak may have been due to recent colonization of the hot water system with a virulent strain ofLegionella pneumophila. The outbreak was controlled by raising the hot water temperature to 60 °C, but careful surveillance uncovered two further cases in the following 30 months. Persistent low numbers ofLegionella pneumophilawere isolated from the domestic hot water of wards where Legionnaires' disease had been contracted, until an electrolytic unit was installed releasing silver and copper ions into this supply.

scholarly journals Environmental Surveillance of Legionellosis within an Italian University Hospital—Results of 15 Years of Analysis

2019 ◽  
Vol 16 (7) ◽  
pp. 1103 ◽  
Author(s):  
Pasqualina Laganà ◽  
Alessio Facciolà ◽  
Roberta Palermo ◽  
Santi Delia
Keyword(s):  
Potential Risk ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Continuous Monitoring ◽  
Water System ◽  
Hot Water ◽  
University Hospital ◽  
Environmental Surveillance ◽  
Standard Procedures ◽  
Legionnaires Disease

Legionnaires’ disease is normally acquired by inhalation of legionellae from a contaminated environmental source. Water systems of large and old buildings, such as hospitals, can be contaminated with legionellae and therefore represent a potential risk for the hospital population. In this study, we demonstrated the constant presence of Legionella in water samples from the water system of a large university hospital in Messina (Sicily, Italy) consisting of 11 separate pavilions during a period of 15 years (2004–2018). In total, 1346 hot water samples were collected between January 2004 and December 2018. During this period, to recover Legionella spp. from water samples, the standard procedures reported by the 2000 Italian Guidelines were adopted; from May 2015 to 2018 Italian Guidelines revised in 2015 (ISS, 2015) were used. Most water samples (72%) were positive to L. pneumophila serogroups 2–14, whereas L. pneumophila serogroup 1 accounted for 18% and non-Legionella pneumophila spp. Accounted for 15%. Most of the positive samples were found in the buildings where the following critical wards are situated: (Intensive Care Unit) ICU, Neurosurgery, Surgeries, Pneumology, and Neonatal Intensive Unit Care. This study highlights the importance of the continuous monitoring of hospital water samples to prevent the potential risk of nosocomial legionellosis.

Nosocomial Legionellosis Traced to a Contaminated Ice Machine

1997 ◽  
Vol 18 (09) ◽  
pp. 637-640 ◽  
Author(s):  
Paul S. Graman ◽  
Gail A. Quinlan ◽  
June A. Rank
Keyword(s):  
Sodium Hypochlorite ◽  
Legionella Pneumophila ◽  
Cold Water ◽  
Water System ◽  
Hot Water ◽  
University Teaching ◽  
Mouth Care ◽  
Colony Forming Units ◽  
And Control

Abstract Objective: To investigate a case of nosocomial legionellosis, identify pathways of transmission, and effect control of the environmental source. Design: Case investigation and environmental culture surveillance. Setting: A 720-bed university teaching hospital. Case Patient: A ventilator-dependent 66-year-old male developed nosocomial pneumonia due to Legionella pneumophila serogroup 6 after 3 months in an intensive-care unit (ICU). The patient had no intake of potable water except for ice chips from an ice machine in the ICU. Results: Cultures revealed L pneumophila serogroup 6 in the ice (4.3 colony-forming units/mL) and ice machine cold water (too numerous to count). Cultures from adjacent hot and cold taps, plus taps located near the patient, all were negative; ice machines and cold water on seven other patient units also were negative. Only sterile water had been used for tube feedings, mouth care, suctioning, and ventilator humidification. Hospital hot water previously had been colonized with L pneumophila serogroup 6, but all surveillance water cultures had been negative since chlorination of the hot-water system began the previous year; cold-water cultures had never before grown Legionella. The ice machine was disinfected with a 2-hour flush of 2.625% sodium hypochlorite. The supply line to the ice machine was replaced, and the cold-water pipe from the floor below was treated with 83 ppm sodium hypochlorite for 48 hours. All follow-up surveillance cultures of the ice machine remained negative through mid-1996. No additional cases of nosocomial legionellosis occurred. Conclusions: Ice machines may be reservoirs of L pneumophila in hospitals. Both ice and water dispensed from these machines may be contaminated, and nosocomial transmission may occur. Successful long-term decontamination and control can be accomplished with shock chlorination.

scholarly journals Factors Influencing Legionella Contamination of Domestic Household Showers

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 27 ◽  
Author(s):  
Deanna Hayes-Phillips ◽  
Richard Bentham ◽  
Kirstin Ross ◽  
Harriet Whiley
Keyword(s):  
Risk Factors ◽  
Water Temperature ◽  
Legionella Pneumophila ◽  
Public Awareness ◽  
Water System ◽  
South Australia ◽  
Hot Water ◽  
Factors Associated ◽  
Potential Source ◽  
Legionnaires Disease

Legionnaires’ disease is a potentially fatal pneumonia like infection caused by inhalation or aspiration of water particles contaminated with pathogenic Legionella spp. Household showers have been identified as a potential source of sporadic, community-acquired Legionnaires’ disease. This study used qPCR to enumerate Legionella spp. and Legionella pneumophila in water samples collected from domestic showers across metropolitan Adelaide, South Australia. A survey was used to identify risk factors associated with contamination and to examine awareness of Legionella control in the home. The hot water temperature was also measured. A total of 74.6% (50/68) and 64.2% (43/68) showers were positive for Legionella spp. and L. pneumophila, respectively. Statistically significant associations were found between Legionella spp. concentration and maximum hot water temperature (p = 0.000), frequency of shower use (p = 0.000) and age of house (p = 0.037). Lower Legionella spp. concentrations were associated with higher hot water temperatures, showers used at least every week and houses less than 5 years old. However, examination of risk factors associated with L. pneumophila found that there were no statistically significant associations (p > 0.05) with L. pneumophila concentrations and temperature, type of hot water system, age of system, age of house or frequency of use. This study demonstrated that domestic showers were frequently colonized by Legionella spp. and L. pneumophila and should be considered a potential source of sporadic Legionnaires’ disease. Increasing hot water temperature and running showers every week to enable water sitting in pipes to be replenished by the municipal water supply were identified as strategies to reduce the risk of Legionella in showers. The lack of public awareness in this study identified the need for public health campaigns to inform vulnerable populations of the steps they can take to reduce the risk of Legionella contamination and exposure.

Nosocomial Outbreak of Legionnaires' Disease: Molecular Epidemiology and Disease Control Measures

1987 ◽  
Vol 8 (2) ◽  
pp. 53-58 ◽  
Author(s):  
Jeffrey M. Johnston ◽  
Robert H. Latham ◽  
Frederick A. Meier ◽  
Jon A. Green ◽  
Rebecca Boshard ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Potable Water ◽  
Cooling Tower ◽  
Water System ◽  
Hot Water ◽  
Control Measures ◽  
Laboratory Techniques ◽  
Legionnaires Disease ◽  
Water Holding ◽  
Methods Of Control

AbstractMolecular laboratory techniques were used to study the epidemiology of an outbreak of nosocomial Legionnaires' disease. All patient isolates were Legionella pneumophila serogroup 1 and showed identical plasmid profiles and reactions with serogroup-specific monoclonal antibodies. L pneumophila was also cultured from four of five cooling tower water samples; however, the isolate from only one tower was serogroup 1 of the same sub-type as patient isolates. Since the cases were temporally clustered and epidemiologically associated with exposure to cooling tower aerosols, the single cooling tower implicated by molecular analysis was the most likely source of the outbreak. Chlorination of cooling tower ponds has eradicated the epidemic strain. Since potable water also harbored the infecting organism and was the probable source for cooling tower contamination, decontamination of the hospital water system was also undertaken. Superchlorination of hot water holding tanks to 17 ppm on a weekly basis has effectively eradicated L pneumophila from the potable water system and appears to be a reasonable, simple, and relatively inexpensive alternative to previously described methods of control.

scholarly journals Incrimination of an environmental source of a case of Legionnaires' disease by pyrolysis mass spectrometry

1991 ◽  
Vol 107 (1) ◽  
pp. 127-132 ◽  
Author(s):  
P. R. Sisson ◽  
R. Freeman ◽  
N. F. Lightfoot ◽  
I. R. Richardson
Keyword(s):  
Mass Spectrometry ◽  
Legionella Pneumophila ◽  
Water System ◽  
Hot Water ◽  
Pyrolysis Mass Spectrometry ◽  
Environmental Isolates ◽  
Relevant Reference ◽  
Cheap Method ◽  
Legionnaires Disease ◽  
Reference Strains

SUMMARYFollowing a case of Legionnaires' diseaseLegionella pneumophilaof the same serogroup was isolated from the hot water system of the hotel which had been epidemiologically implicated as the source of the infection. Pyrolysis mass spectrometry (PyMS) was used to compare 11 isolates from the hotel water sample with the patient's strain. Epidemiologically unrelated isolates, both clinical and environmental, of the same serogroup and monoclonal antibody type ofL. pneumophilawere included in the same analysis, together with relevant reference strains. The patient strain was shown to be indistinguishable from seven of the hotel water isolates, but clearly different from other unrelated clinical isolates, the reference strains and some of the other environmental isolates. PyMS is a rapid and cheap method for inter-strain comparison forL. pneumophila.

scholarly journals Optimizing production efficiencies of hot water units using building energy simulations - Trade-off between Legionella pneumophila contamination risk and energy efficiency

2019 ◽  
Vol 111 ◽  
pp. 04053
Author(s):  
Elisa Van Kenhove ◽  
Lien De Backer ◽  
Jelle Laverge
Keyword(s):  
Simulation Model ◽  
Legionella Pneumophila ◽  
Energy Demand ◽  
Energy Use ◽  
Tap Water ◽  
Water System ◽  
High Energy ◽  
Hot Water ◽  
Domestic Hot Water ◽  
Production Efficiencies

The energy needed for domestic hot water represents an important share in the total energy use of well-insulated and airtight buildings. One of the main reasons for this high energy demand is that hot water is produced at temperatures above 60°C to mitigate the risk of contaminating the hot water system with Legionella pneumophila. However, this elevated temperature is not necessary for most domestic hot water applications, and has a negative effect on the efficiency of hot water production units. A simulation model has been developed which proposes an alternative to this constant 60°C by predicting the Legionella pneumophila concentration dynamically throughout the hot water system. Based on this knowledge, a hot water controller is added to the simulation model that sets a lower hot water comfort temperature in combination with heat shocks. In this paper, the simulation model is used to estimate the energy saving potential in a case study building, at the level of the heat production system by reaching higher production efficiencies. Three different production units, namely an electric boiler, heat pump and solar collector have been investigated. The controller is expected to become an alternative for the current, energy intensive, high temperature tap water heating systems.

Sporadic Legionnaires' disease: the role of domestic electric hot-water tanks

2011 ◽  
Vol 140 (1) ◽  
pp. 172-181 ◽  
Author(s):  
S. F. DUFRESNE ◽  
M. C. LOCAS ◽  
A. DUCHESNE ◽  
C. RESTIERI ◽  
J. ISMAÏL ◽  
...  
Keyword(s):  
Potable Water ◽  
Water System ◽  
Water Systems ◽  
Pulsed Field Gel Electrophoresis ◽  
Hot Water ◽  
Clinical Isolates ◽  
Domestic Hot Water ◽  
Legionnaires Disease ◽  
Water Tanks

SUMMARYSporadic community-acquired legionellosis (SCAL) can be acquired through contaminated aerosols from residential potable water. Electricity-dependent hot-water tanks are widely used in the province of Quebec (Canada) and have been shown to be frequently contaminated withLegionellaspp. We prospectively investigated the homes of culture-proven SCAL patients from Quebec in order to establish the proportion of patients whose domestic potable hot-water system was contaminated with the sameLegionellaisolate that caused their pneumonia. Water samples were collected in each patient's home. Environmental and clinical isolates were compared using pulsed-field gel electrophoresis. Thirty-six patients were enrolled into the study.Legionellawas recovered in 12/36 (33%) homes. The residential and clinical isolates were found to be microbiologically related in 5/36 (14%) patients. Contaminated electricity-heated domestic hot-water systems contribute to the acquisition of SCAL. The proportion is similar to previous reports, but may be underestimated.

scholarly journals A field study of the survival ofLegionella pneumophilain a hospital hot–water system

1990 ◽  
Vol 104 (3) ◽  
pp. 381-387 ◽  
Author(s):  
I. D. Farrell ◽  
J. E. Barker ◽  
E. P. Miles ◽  
J. G. P. Hutchison
Keyword(s):  
Water Supply ◽  
Legionella Pneumophila ◽  
Water Samples ◽  
Cold Water ◽  
Water System ◽  
Hot Water ◽  
Undetectable Level ◽  
Drain Water ◽  
Water Feed ◽  
And Control

SUMMARYThe colonization, survival and control ofLegionella pneumophilain a hospital hot–water system was examined. The organism was consistently isolated from calorifier drain–water samples at temperatures of 50°C or below, despite previous chlorination of the system. When the temperature of one of two linked calorifiers was raised to 60°C, by closing off the cold–water feed, the legionella count decreased from c. 104c.f.u./l to an undetectable level. However, 10 min after turning on the cold–water feed which produced a fall in calorifier temperature, the count in the calorifier drain water returned to its original level. Investigations revealed that the cold–water supply was continually feeding the calorifiers withL. pneumophila. Simple modifications in the design of the system were made so that the cold–water feed no longer exceeds 20°C; these measures have considerably reduced the number ofL. pneumophilareaching the calorifiers.

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