Molecular evidence for the ubiquitous presence of Legionella species in Dutch tap water installations

Diederen, Bram M. W.; Jong, Caroline M. A. de; Aarts, Ingrid; Peeters, Marcel; Zee, Anneke van der

doi:10.2166/wh.2007.033

Cited by 32 publications

(32 citation statements)

References 22 publications

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“…Gold standard method for detection of Legionella species is based on cultivation (Den et al, 2004). This method allows the isolation and the quantification of cultivable Legionella species from environmental and clinic samples (Diederen et al, 2007). Isolating Legionella strains from environmental water samples is of great importance for epidemiological study (Den et al, 2004;Diederen et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…Isolating Legionella strains from environmental water samples is of great importance for epidemiological study (Den et al, 2004;Diederen et al, 2008). Routine environmental cultures for Legionella in the water distribution system are recommended for risk assessments and transmission tracing that even if the hospital had not previously recognized cases of hospital-acquired Legionnaires' disease (Hoge et al, 1991).The cultivation procedure currently used to isolate Legionella genus from environmental water samples is complex and time consuming and the effect sometimes is pending (Diederen et al, 2007). There has been many other means to detect Legionella in water samples such as PCR and Qpcr Dusserre et al, 2008), with potential to detect infections caused by any Legionella species and serogroups, in addition to detect non-culturable Legionella and allow the manipulation of a large number of samples (Diederen et al, 2008;Jarraud et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

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Comparative study on sampling methods for monitoring Legionella species in environmental water

Zhan¹,

Hu²,

Zhu³

2014

Afr. J. Microbiol. Res.

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Infections caused by Legionella spp. are considered an emerging public health problem and are linked to high rates of mortality and morbidity, if not properly treated. This study analyzes 76 samples of water in Guangzhou with the aim of obtaining a more efficient means based on culture to isolate the genus Legionella. A comparative assessment of techniques recommended was performed on monitoring Legionella spp. in environmental water samples. Fourteen (14) sampling methods included in four categories based on concentration (filtration or centrifugation), acid buffer treatment (no acid treatment, treatment for 10 min), thermal treatment (no thermal treatment or treated for 30 min in 50°C) and heat enrich the samples in 37°C for 72 h were tested to identify their sensitivity. The four categories methodologies were assembled by different procedures and 14 methods were obtained to compare the efficiency for isolating Legionella in 76 water samples and in which Legionella were isolated from 42 water samples through these 14 methods. Merit and demerit of each single method was evaluated. Results suggest that a single category methodology for water sampling was insufficient to isolate Legionella spp. from water samples. Some Legionella positive water samples were missed through a single category methodology which made the results mistranslation. PSF category methods in this study were recommended methods and they could isolate Legionella species from 78.6% Legionella positive water samples; and if time was enough, PSF category methods combined with ERCT category methods to isolate Legionella from water samples are strongly recommended. Legionella were isolated from 41 water samples through these two category methods, it only missed 2.4% positive water sample. The results obtained, highlighted the importance of improving culture method for the identification of Legionella in water samples.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Comparative study on sampling methods for monitoring Legionella species in environmental water

Zhan¹,

Hu²,

Zhu³

2014

Afr. J. Microbiol. Res.

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show abstract

Section: Discussionmentioning

confidence: 99%

“…This method allows the isolation and the quantification of cultivable Legionella species from environmental and clinic samples but it does have limitations [13,59]. The cultivation method has also the disadvantage of being a very time-consuming technique, requiring selective media and several days of incubation (7 to 10 days) to obtain results [25,59]. In addition, although there is an international consensus standard for culture detection and enumeration of Legionella in water (ISO 11731:1998), the overgrowth of other accompanying bacteria, the presence of viable but non-culturable (VBNC) cells, loss of viability of bacteria after collection and during the sample treatment (concentration stage followed by decontamination with heat or acid), reduced recoveries by the use of antibiotics in the medium and low concentration of legionellae in the samples limit the use of this method [16,24,52,59,60].…”

Section: Discussionmentioning

confidence: 99%

“…Amplification of Legionella DNA by PCR can provide results within a short time. It also has the potential to detect infections caused by any Le-gionella species and serogroups, in addition to detect non-culturable legionella and allow the manipulation of a large number of samples [3,9,59,64]. The detection of other species besides L. pneumophila is relevant to the diagnosis of Legionnaires' disease, since this disease can be caused by other species, such as L. longbeachae and L. bozemanii.…”

Section: Discussionmentioning

confidence: 99%

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Detection of <i>Legionella</i> spp. in Natural and Man-made Water Systems Using Standard Guidelines

Borges¹,

Simes²,

Martínez‐Murcia³

et al. 2012

MICROBIOLOGY

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Infections caused by Legionella spp. are considered at the present time, an emerging public health problem and are linked to high rates of mortality and morbidity, if not properly treated. In this study were analyzed 54 samples of water from 8 counties at Northern Portugal, with the aim of obtaining a collection of strains of the genus Legionella and to characterize them genetically and phenotypically. Another objective of this study was to evaluate the effectiveness of the technique of cultivation, a standard method according to International Organization for Standardization ISO 11731:1998, for detection and enumeration of species of Legionella. For laboratory processing, after the filtration of samples (1 L), the filtrate was resuspended in sterile distilled water (5 ml). Heat treatment for selective inhibition of non-Legionella bacteria was performed. Subsequently, 100 μl of the suspension was spread in GVPC selective agar medium, and incubated (7 to 10 days) at 37 ℃. Colonies that were morphologically characteristic of the genus were sub-cultured onto BCYE agar and blood agar for verification. According to the procedure recommended by the standard method, only the colonies which grew in BCYE agar and not on blood agar were considered as suspected Legionella strains. The identification of these initially selected colonies was performed by sequencing the 16S rRNA gene, which revealed that none of the isolates were identified as belonging to the genus Legionella. However, through the ISO 11731:1998 they were interpreted as positive, corresponding therefore to "false-positive" results. The methods used in this study allowed the isolation of a number of isolates (40), which form an independent group of all genus of the family Chitinophagaceae outlined so far, and that by their phylogenetic distance might be a genus not yet described and therefore a new species. The results obtained, highlighted the importance of using culture and genetic methods in parallel for the proper identification of microorganisms.

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Rapid and quantitative detection of Legionella pneumophila applying immunomagnetic separation and flow cytometry

et al. 2010

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Legionella is a pathogenic bacterium that establishes and proliferates well in water storage and distribution systems. Worldwide it is responsible for numerous outbreaks of legionellosis, which can be fatal. Despite recent advances in molecular and immunological methods, the official, internationally accepted detection method for Legionella spp. in water samples (ISO 11371) is still based on cultivation. This method has major disadvantages such as a long assay time of 10 days and the detection of cultivable cells only. Therefore, we developed a cultivation-independent, quantitative, and fast detection method for Legionella pneumophila in water samples. It consists of four steps, starting with (1) a concentrating step, in which cells present in one litre of water are concentrated into 5 ml by filtration (pore size 0.45 lm), (2) then cells are resuspended with sterile filtered buffer and double-stained with FITC-and Alexa-conjugated Legionellaspecific antibodies, (3) subsequently, the cells are immunomagnetically caught, and (4) finally, fluorescently labeled Legionella cells were flow cytometrically detected and quantified. The efficiency of each step was tested separately. The whole method allows detection of L. pneumophila in 180 min with a detection limit of around 500 cells/l and a recovery of Legionella cells of 52.1 % out of spiked tap water. Fluorescence microscopy and flow cytometric cell-counting correlated well. ' 2010 International Society for Advancement of Cytometry Key terms drinking water; flow cytometry; immunomagnetic separation; immunodetection; Legionella spp.; microbeads LEGIONELLA pneumophila is responsible for numerous outbreaks and isolated cases of legionellosis worldwide. Legionnaires' disease is caused by inhalation of contaminated water aerosols and is lethal in 5-40% of the cases (1). Legionella spp. are found especially in aquatic biofilms, not only in nature but also in warm water plumbing systems, air conditioners, or cooling towers. Because of the negative impact on the human health, a tolerance limit for L. pneumophila in tap water was set in different countries, including Switzerland (2), to 1000 colony-forming units (CFU)/l. The official, internationally accepted detection method for Legionella spp. in water samples (ISO 11371) is based on cultivation. Specific shortcomings of this detection method are the long assay time of 10 days, the detection of colony-forming cells only and that it is highly labor-intensive. In practice, this delay is unacceptably long, and a specific and sensitive fast screening method is of much interest. A fast screening method would be of particular interest for quickly testing water installation systems in public buildings such as hospitals, nursing homes, or hotels before closing them to prevent an outbreak of legionellosis. Several attempts were made to develop alternative fast detection methods. The most frequently used approach for fast detection is based on the polymerase chain reaction (PCR). However, the presence of PCR-inhibitory compo...

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Molecular evidence for the ubiquitous presence of Legionella species in Dutch tap water installations

Abstract: ABSTRACT

Cited by 32 publications

References 22 publications

Comparative study on sampling methods for monitoring Legionella species in environmental water

Comparative study on sampling methods for monitoring Legionella species in environmental water

Detection of <i>Legionella</i> spp. in Natural and Man-made Water Systems Using Standard Guidelines

Rapid and quantitative detection of Legionella pneumophila applying immunomagnetic separation and flow cytometry

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