Prevalence Of Legionella Research Articles

Forebygging av legionærsykdom i sykehus

The first instance of Legionella infection in a Norwegian hospital was confirmed in 2005. We describe the best-known methods of eradicating Legionella in hospitals. The article is based on the authors' experience of measures to prevent Legionnaires' disease in hospitals and on a non-systematic search in PubMed. There are several methods of combating Legionella in hospitals. These include chlorination, heat treatment, and the use of filters. However, recontamination easily re-occurs after eradication. The silver and copper ionisation treatment of water is a well-documented method for the systematic and long-term eradication of Legionella in water. The disadvantages of this method are that it is expensive, that there is a risk of discolouring the water, and that there is a possibility of developing resistance in environmental bacteria. This resistance mechanism can theoretically be transferred to bacteria that cause illness. We recommend the silver and copper ionisation treatment of water as a method of preventing nosocomial Legionnaires' disease when standard methods fail and there is a high prevalence of Legionella in the water. The discolouration of operation instruments that occurs as a result of high silver concentrations can be avoided by using a separate water supply for operation units.

LEGIONELLA INFECTION

Respiratory system is most commonly affected during Hajj season. Objectives: (1) to determine the prevalence of Legionella in drinking water, cooling sprinklers and other sources of water consumed in pilgrimage area of the holy city, Makkah; (2) to study the prevalence of pneumonia caused by Legionella species from clinically suspected cases; and (3) to determine whether there is any relationship diseaseincidence and water supply system. Material & methods: The clinical samples were received from in-patients of the following five Ministry of Health (MOH) Hospitals; Hera General Hospital, Al-Noor Specialist Hospital, King Faisal Hospital, King Abdul-Aziz Hospital, and Ajyad Hospital during Hajj 2003. The patients included in the study were those who fulfilled the following criteria; clinically diagnosed as pneumonia, negativeon routine cultures and found negative for acid fast bacilli (AFB) from sputum/bronchial aspirate (BAL). Serological tests was done by Enzyme linked Immunosorbent assay (ELISA) for Legionella antibodies Total IgG and IgM. Results: Out of total 133 patients suspected for Legionella, 83 (62.4%) were male and 50 (37.6%) female. The male versus female ratio was 1:0.6. The major age group affected was between 50-70 years(63.2%). There were 4 (3.0%) cases of Legionella species isolated from Microbiological cultures. The overall seropositive rate among clinically suspected cases was 4.51%. A total of 560 water samples were collected from Arafat, Muzdalifa, Mena, and areas around the Holy Mosque and found negative for Legionella species. Conclusion: Pneumonia was one of the most common illnesses among pilgrims. The water supplied toall areas of the pilgrimage was free from the Legionella and no link has been established among the patients with water supply systems. Both clinicians’ awareness and availability of specialized laboratory tests for atypical pneumonia such as Legionella is necessary. Although, all water samples found negative for Legionella but it is recommended to screen all water reservoirs for Legionella annually before Hajj season.

Water quality parameters associated with prevalence of Legionella in hot spring facility water bodies

Some species of Legionella are recognized as opportunistic potential human pathogens, such as Legionella pneumophila, which causes legionnaires disease. Indeed, outbreaks of legionellosis are frequently reported in areas in which the organism has been spread via aerosols from contaminated institutional water systems. Contamination in hot tubs, spas and public baths are also possible. As a result, in this study, we investigated the distribution of Legionella at six hot spring recreation areas throughout Taiwan. Legionella were detected in all six hot spring recreation areas, as well as in 20 of the 72 samples that were collected (27.8%). Seven species of Legionella identified from samples by the direct DNA extraction method were unidentified Legionella spp., Legionella anisa, L. pneumophila, Legionella erythra, Legionella lytica, Legionella gresilensis and Legionella rubrilucen. Three species of Legionella identified in the samples using the culture method were L. pneumophila, unidentified Legionella spp. and L. erythra. Legionella species were found in water with temperatures ranging from 22.7 °C to 48.6 °C. The optimal pH appeared to range from 5.0 to 8.0. Taken together, the results of this survey confirmed the ubiquity of Legionella in Taiwan spring recreational areas. Therefore, a long-term investigation of the health of workers at hot spring recreational areas and the occurrence of Legionella in hot spring recreational areas throughout Taiwan are needed.

Legionella prevalence in wastewater treatment plants of Taiwan

Legionella is a bacterium that is ubiquitous in natural and artificial aquatic environments. Some species of Legionella are recognized as opportunistic potential human pathogens. We investigated the distribution of Legionella at seventeen WWTPs throughout Taiwan. Legionella were detected in 10 of the 17 WWTPs (58.8%) and 25 of 41 samples (61.0%). In the integrated, hospital, industrial and domestic wastewater systems were 13/18 (72.2%), 7/12 (58.3%), 2/7 (28.6%) and 3/4 (75.0%) of the samples were positive for Legionella, respectively. The most frequently encountered species were L. donaldsonii and uncultured L. spp., which were both found in 10 samples (24.4% of all samples), then followed by L. lytica (4.9%) and L. pneumophila (4.9%). L. anisa was detected in one sample (2.4%). The results of this survey confirm that Legionella are ubiquitous in WWTPs in Taiwan. Therefore, long-term investigations should be conducted to evaluate the overall occurrence of Legionella in WWTPs in Taiwan.

Characteristics of Cooling Towers and Evaporative Condensers and Presence of Legionella in Water

P-721 Introduction: Cooling towers and evaporative condensers are elements associated with cooling and refrigeration systems. Many legionella outbreaks have been linked to this type of installations. To minimise the risk of legionella transmission, the Spanish Ministry of Health and Consumption published Royal Decree 865/2003, which establishes the preventive design and surveillance system to be fulfilled by these installations. With the aim of assessing the degree of fulfilment (infrastructure, maintenance, cleaning, disinfection) of the mentioned installations in Gipuzkoa (the Basque Country, Spain), they were characterised and the water in the cooling circuits was checked for legionella. Methods: Over the period 2002–2004, 297 cooling circuits were visited and characterised. A survey gathered information on three variables: infrastructure, maintenance of circuits and water quality control. The sampling and analysis of the water was carried out in two points of the cooling circuit (the tray and the bleeder valve). The Legionella analysis was conducted according to the ISO 11734 standard. Results: 260 (87.5%) of installations carried out maintenance operations; 243 (81.8%) had a continuous treatment of the water in the circuits and 270 (90.9%) cleaned and disinfected the circuits periodically. Out of the 200 samples taken, 72 (36%) were positive (detection limit 100 u.f.c/l) for Legionella spp and 56 (28%) were positive for L. pneumophila. The cooling towers which did not incorporate a stop mode proved to be more risky for Legionella spp. (O.R: 4.89; IC: 1.17–20.38) and for L. pneumophila (O.R: 3.56; IC: 0.86–14.85)than those which incorporated this mode. Four factors were identified as protective against Legionella spp.: collecting the water from the municipal network (O.R: 0.46; IC: 0.24–0.86); having circuits which are accessible for cleaning (O.R: 0.32; IC: 0.10–0.94); conducting periodical cleaning and shock disinfections in the circuits (O.R: 0.17; IC: 0.04–0.64), and carrying out a continuous treatment of the water by using a disinfectant with residual power (O.R: 0.40; IC:0.15–0.83). In the case of L. pneumophila, two protective factors were identified: collecting the water from the municipal network (O.R: 0.35; IC: 0.18–0.68), and carrying out a continuous treatment of the water by using a disinfectant with residual power (O.R: 0.25; IC:0.08–0.0.83) Discussion and Conclusions: Designing the installations properly, using water coming from the municipal net work, periodically cleaning and disinfecting the circuits and treating the water they contain by means of disinfectant products with residual power reduces the prevalence of Legionella in water.

Legionella prevalence in hot spring recreation areas of Taiwan

Legionella is a bacterium ubiquitous to aquatic environments. Within the genus a few species are recognized as opportunistic potential human pathogens, especially the species Legionella pneumophila, which causes pneumonia legionellosis. Outbreaks of legionellosis are frequently reported by hotel guests and hospital patients, and are spread through inhaled aerosols of contaminated institutional water systems. Contaminations in hot tubs, spas and public baths are also possible. As a result, in this study, we investigated the distribution of Legionella at seven hot spring recreational areas throughout Taiwan. We gathered data on factors potentially associated with the pathogen's distribution, including environment, facility operation, and physical and microbiological water quality parameters. Spring water was collected from 91 sites and Legionella was detected in 21 (23%). The most frequently detected was L. pneumophila, followed by uncultured Legionella species, Legionella-like amoebal pathogen. Five species, L. bozemanii, L. dumoffi, L. feelei, L. lyticum and L. oakridgenesis, were all detected once. Legionella species were found in water temperatures ranging from 22 to 50 °C. Optimal pH appeared to be between 5.0 and 9.0. The prevalence of Legionella also coincided with the prevalence of indicator microorganisms. Legionella detection was not proportional to the frequency of cleaning. Results of this survey confirm the ubiquity of Legionella in Taiwan spring recreation areas. L. pneumophila, the organism responsible for the majority of legionellosis outbreaks, should be considered a potential public health threat in spa areas of Taiwan.

Prevalence of legionella waterline contamination and Legionella pneumophila antibodies in general dental practitioners in London and rural Northern Ireland.

To determine the prevalence of legionellae in dental unit waterlines (DUWL) in general dental practices in London and rural Northern Ireland and whether the organism occurs at a high enough frequency and magnitude in DUWL to represent a threat to dentists' health. Two hundred and sixty six (166 London, 100 Northern Ireland) randomly selected dental surgeries were recruited. Standardised 250 ml water samples were taken from the DUWL and 1 litre samples from the surgery cold water tap to measure the prevalence of legionellae. The dentists provided a blood sample for legionella serology. The prevalence of legionellae was very low (0.37%). Legionellae were not isolated from DUWL or surgery basin taps in Northern Ireland. Legionella spp were isolated from the DUWL and surgery basin of one practice in London and from the cold water supply of a further three practices. The prevalence of Legionella pneumophila antibodies was less than that seen in a comparable group of London blood donors. The risk to dentists' health from potential exposure to legionellae in this cohort of dentists was very low and this was confirmed by the very low seroprevalence and antibody titres to legionella detected in the dentists.

Legionella contamination of waterlines?

Objectives To determine the prevalence of legionellae in dental unit waterlines (DUWL) in general dental practices in London and rural Northern Ireland and whether the organism occurs at a high enough frequency and magnitude in DUWL to represent a threat to dentists' health. Materials and method Two hundred and sixty six (166 London, 100 Northern Ireland) randomly selected dental surgeries were recruited. Standardised 250 ml water samples were taken from the DUWL and 1 litre samples from the surgery cold water tap to measure the prevalence of legionellae. The dentists provided a blood sample for legionella serology. Results The prevalence of legionellae was very low (0.37%). Legionellae were not isolated from DUWL or surgery basin taps in Northern Ireland. Legionella spp were isolated from the DUWL and surgery basin of one practice in London and from the cold water supply of a further three practices. The prevalence of Legionella pneumophila antibodies was less than that seen in a comparable group of London blood donors. Conclusion The risk to dentists' health from potential exposure to legionellae in this cohort of dentists was very low and this was confirmed by the very low seroprevalence and antibody titres to legionella detected in the dentists.

Community‐Acquired Pneumonia in Older Patients

To document the prevalence of Legionella sp., Mycoplasma Pneumoniae and Influenza A and B in older patients hospitalized for community-acquired pneumonia (CAP) of nursing-home acquired pneumonia (NHAP) and to determine risk factors associated with fatal outcome or prolonged hospital stay. Prospective clinical and serological study. All patients with CAP of NHAP--confirmed by chest roentgenogram--admitted to a 320-bed acute care geriatric university hospital from May 1, 1988 to August 31, 1989, were included. Serological testing was performed upon admission and after 2 and 4 weeks. Relevant data concerning medical history, clinical examination, and laboratory data were recorded upon admission. Ninety-nine patients (age: 85 +/- 6.3 years, 36 male, 63 female) met inclusion criteria; 20 came from nursing homes, 79 from their homes in the community. Fourteen patients died during the month after admission. An etiological diagnosis could be established in 22 patients. No cases of Legionella pneumonia and one case of M. pneumoniae were detected. Seven patients had evidence of Influenza pneumonia. Nonsurvivors were more likely to have been admitted from a nursing home and to have a temperature less than 37.5 degrees C and elevated urea nitrogen (BUN). Cyanosis, involvement of upper lobes, elevated white blood cell counts, and higher percentage of band forms were associated statistically with longer treatment. This study confirms the low prevalence of Legionella sp. and M. Pneumoniae infection in CAP and NHAP in this age group. Risk factors as to outcome and length of treatment may be used as points to identify high risk patients, with special attention to patients coming from nursing homes, and patients with high BUN.

Legionella pneumophila in cooling water systems. Report of a survey of cooling towers in London and a pilot trial of selected biocides.

Fourteen recirculating cooling water systems were surveyed during the summer, 1981, to see what factors might influence the prevalence of Legionella pneumophila. The effect on the organism of three anti-microbials was studied, each in two systems, by intermittent treatment at two week intervals. L. pneumophila was isolated from six of the 14 cooling systems at the beginning of the trial but by the end was present in ten. An association was found between the presence of the organism and the concentration of dissolved solids, and chlorides and the pH. There also appeared to be associations with exclusion of light and higher water temperatures. Repeated tests on eight untreated systems showed that two were consistently infected, three became and remained infected, one was infected on a single occasion and two were never infected with L. pneumophila. Treatment of a contaminated system, either with a 10 p.p.m mixture of a quaternary ammonium compound and tributyltinoxide or slow release chlorine briquettes (maximum recorded free chlorine level 1.2 p.p.m.), did not eliminated legionellae. Treatment of two infected towers with a chlorinated phenol (100 p.p.m.) eliminated legionellae for at least three days, but after 14 days the organism was again found.