scholarly journals Outbreak of Legionnaires' disease in a nursing home, Slovenia, August 2010: preliminary report

2010 ◽  
Vol 15 (39) ◽  
Author(s):  
A Trop Skaza ◽  
L Beskovnik ◽  
A Storman ◽  
S Ursic ◽  
B Groboljsek ◽  
...  
Keyword(s):  
Nursing Home ◽  
Distribution System ◽  
Preliminary Report ◽  
Water Distribution ◽  
Water Distribution System ◽  
Source Of Infection ◽  
Dead End ◽  
Probable Source ◽  
Legionnaires Disease

We report an outbreak of Legionnaires' disease in a nursing home in Slovenia in August 2010 affecting 15 of 234 residents. To date, Legionnaires' disease has been confirmed in four patients. Further serum analyses and genotyping of isolates are ongoing. The building's water distribution system with dead end sections has been identified as the probable source of infection.

Application of Artificial Neural Network for Reducing of Chlorine Residual Concentration in Water Distribution Network

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
Jayong Koo ◽  
Toyono Inakazu ◽  
Akira Koizumi ◽  
Yasuhiro Arai ◽  
Kyoungpil Kim ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Residual Chlorine ◽  
Trial And Error ◽  
Ann Model ◽  
Residual Concentration ◽  
Dead End

It is difficult to estimate residual chlorine at the dead-end area of the water distribution network because chlorine consumption is influenced by various factors. Therefore, there are many water utilities that control the amounts of chlorine in reservoirs using empirical trial-and-error methods to maintain safe levels of residual chlorine in the distribution system. In this study, an ANN model of residual chlorine concentration is proposed which could be used to reduce in chlorine use in water distribution system. The ANN model with best performance was selected by training and verification. The five scenarios for the reduction in chlorine use were analyzed by setting the input chlorine as low as 0.05~0.25 mg/L compared with the input chlorine observed in the time series. Case 4 is the best to be satisfied with the input condition (0.4 mg/L or more) and output condition (0.34 mg/L or more) at the same time. It is possible to reduce chlorine in use up to 0.2 mg/L in the maximum amount.

Outbreak of Legionnaires' disease associated with a supermarket mist machine

2010 ◽  
Vol 138 (12) ◽  
pp. 1823-1828 ◽  
Author(s):  
I. BARRABEIG ◽  
A. ROVIRA ◽  
M. GARCIA ◽  
J. M. OLIVA ◽  
A. VILAMALA ◽  
...  
Keyword(s):  
Distribution System ◽  
Water Distribution ◽  
Preliminary Investigation ◽  
Molecular Study ◽  
Epidemiological Survey ◽  
Clinical Samples ◽  
Environmental Investigation ◽  
Source Of Infection ◽  
Molecular Pattern ◽  
Legionnaires Disease

SUMMARYAn outbreak of Legionnaires' disease affected 12 customers of a supermarket in a town in Catalonia, Spain, between August and November 2006. An epidemiological and environmental investigation was undertaken. Preliminary investigation showed that all patients had visited the same supermarket in this town where a mist machine was found in the fish section. Water samples were collected from the machine and from the supermarket's water distribution system when high-risk samples were excluded. Environmental samples from the mist machine and clinical samples from two patients tested positive for L. pneumophila serogroup 1 and had the same molecular pattern. The PFGE pattern detected in the clinical and mist-machine isolates had never previously been identified in Catalonia prior to the outbreak and has not been identified since. Four days after turning off the machine, new cases ceased appearing. Molecular study supports the hypothesis that the mist machine from the fish section of the supermarket was the source of infection. We believe it is essential to include exposure to mist machines in any legionellosis epidemiological survey.

Safety and Efficacy of Chlorine Dioxide for Legionella Control in a Hospital Water System

2007 ◽  
Vol 28 (8) ◽  
pp. 1009-1012 ◽  
Author(s):  
Zhe Zhang ◽  
Carole McCann ◽  
Janet E. Stout ◽  
Steve Piesczynski ◽  
Robert Hawks ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
Environmental Protection Agency ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water System ◽  
Hot Water ◽  
Skilled Nursing ◽  
Legionnaires Disease ◽  
Hospital Acquired

In a 30-month prospective study, we evaluated the efficacy of chlorine dioxide to control Legionella organisms in a water distribution system of a hospital with 364 patient beds and 74 skilled nursing beds. The number of hot water specimens positive for Legionella organisms decreased from 12 (60%) of 20 to 2 (10%) of 20. An extended time (18 months) was needed to achieve a significant reduction in the rate of Legionella positivity among hot water specimens. At the time of writing, no cases of hospital-acquired Legionnaires disease have been detected at the hospital since the chlorine dioxide system was installed in January 2003. Use of chlorine dioxide was safe, based on Environmental Protection Agency limits regarding maximum concentrations of chlorine dioxide and chlorite.

Cytopathogenicity and molecular subtyping ofLegionella pneumophilaenvironmental isolates from 17 hospitals

2008 ◽  
Vol 137 (2) ◽  
pp. 188-193 ◽  
Author(s):  
M. GARCIA-NUÑEZ ◽  
M. L. PEDRO-BOTET ◽  
S. RAGULL ◽  
N. SOPENA ◽  
J. MORERA ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Distribution System ◽  
Water Distribution ◽  
Cytopathic Effect ◽  
Water Distribution System ◽  
Water Reservoir ◽  
Pfge Pattern ◽  
Contaminated Water ◽  
Legionnaires Disease ◽  
Hospital Acquired

SUMMARYThe cytopathogenicity of 22Legionella pneumophilaisolates from 17 hospitals was determined by assessing the dose of bacteria necessary to produce 50% cytopathic effect (CPED50) in U937 human-derived macrophages. All isolates were able to infect and grow in macrophage-like cells (range log10CPED50: 2·67–6·73 c.f.u./ml). Five groups were established and related to the serogroup, the number of PFGE patterns coexisting in the same hospital water distribution system, and the possible reporting of hospital-acquired Legionnaires' disease cases.L. pneumophilaserogroup 1 isolates had the highest cytopathogenicity (P=0·003). Moreover, a trend to more cytopathogenic groups (groups 1–3) in hospitals with more than one PFGE pattern ofL. pneumophilain the water distribution system (60%vs. 17%) and in hospitals reporting cases of hospital-acquired Legionnaires' disease (36·3%vs. 16·6%) was observed. We conclude that the cytopathogenicty of environmentalL. pneumophilashould be taken into account in evaluating the risk of a contaminated water reservoir in a hospital and hospital acquisition of Legionnaires' disease.

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