Concentration and Diversity of Uncultured
            <i>Legionella</i>
            spp. in Two Unchlorinated Drinking Water Supplies with Different Concentrations of Natural Organic Matter

Wullings, Bart; Bakker, Geo; Kooij, D. van der

doi:10.1128/aem.01215-10

Cited by 75 publications

(67 citation statements)

References 37 publications

(47 reference statements)

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“…These results suggest that the AOC levels in drinking water relate to the presence of L. pneumophila. Our results are consistent with results from a previous study where L. pneumophila was detected in a distribution system that was fed with drinking water with a high concentration of natural organic matter (NOM) but not in a distribution system that was fed with drinking water having a low NOM concentration (50). P. aeruginosa and S. maltophilia were also sporadically observed in drinking water, but these organisms were present in drinking water with high or low concentrations of AOC and TOC.…”

Section: Discussionsupporting

confidence: 82%

“…However, L. pneumophila could not be cultivated from drinking water samples that were positive for the mip gene of L. pneumophila. Similar results were reported for unchlorinated drinking water sampled from the distribution systems of two groundwater treatment plants in the Netherlands (50). However, in contrast to our findings, the mip gene copy numbers observed in that study were below the detection level of the culture method, which could explain the observed differences between qPCR and cultivation results.…”

Section: Discussioncontrasting

confidence: 57%

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Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

Wielen

Kooij

2013

Appl Environ Microbiol

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120

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aThe multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereas Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Aspergillus fumigatus were sporadically observed. Mycobacterium avium complex and Acanthamoeba spp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM and S. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or on P. aeruginosa-and S. maltophilia-positive samples. However, L. pneumophila was detected more often in water with AOC concentrations above 10 g C liter ؊1 than in water with AOC levels below 5 g C liter ؊1 . Finally, samples that contained L. pneumophila, P. aeruginosa, or S. maltophilia were more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.

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Section: Discussionsupporting

confidence: 82%

Section: Discussioncontrasting

confidence: 57%

Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

Wielen

Kooij

2013

Appl Environ Microbiol

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120

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“…Consequently, cultivation-based methods provide a limited view of NTM diversity in drinking water. The observation that most NTM in unchlorinated drinking water have not yet been cultivated, and may not be cultivable, is consistent with observations made for other microorganisms in unchlorinated drinking water such as Legionella (29), protozoa (46), and fungi (37).…”

Section: Discussionsupporting

confidence: 72%

“…Subsequently, the filter was added to phosphate and MT buffer of a FastDNA Spin kit for soil (Qbiogene) and a DNA fragment of an internal control was included before the buffer with filter was stored at Ϫ20°C. The internal control was used to determine the recovery efficiency of DNA isolation and PCR analysis (28,29). DNA was isolated using a FastDNA Spin kit for soil according to the supplier's protocol and eluted in 200 l elution buffer.…”

Section: Methodsmentioning

confidence: 99%

Pyrosequence Analysis of the hsp65 Genes of Nontuberculous Mycobacterium Communities in Unchlorinated Drinking Water in the Netherlands

Wielen

Heijnen

Kooij

2013

Appl Environ Microbiol

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Studies have shown that certain opportunistic pathogenic species of nontuberculous mycobacteria (NTM) can be present in distributed drinking water. However, detailed information about NTM population composition in drinking water is lacking. Therefore, NTM communities in unchlorinated drinking water from the distribution system of five treatment plants in the Netherlands were characterized using 454 pyrosequencing of the hsp65 gene. Results showed high diversities in unchlorinated drinking water, with up to 28 different NTM operational taxonomic units (OTUs) in a single sample. Each drinking water sample had a unique NTM community, and most (81.1%) OTUs were observed only once. One OTU was observed in 14 of 16 drinking water samples, indicating that this NTM species is well adapted to unchlorinated drinking water conditions. A clear influence of season, source type (groundwater, surface water), easily assimilable organic carbon (AOC) concentration, biofilm formation rate, and active biomass in treated water on the establishment of an NTM community in drinking water was not observed. Apparently, local conditions are more important for the development of a specific NTM community in the drinking water distribution system. A low (4.2%) number of hsp65 gene sequences showed more than 97% similarity to sequences of the opportunistic pathogens M. avium, M. genavense, and M. gordonae. However, most (95.8%) NTM hsp65 gene sequences were related to notyet-described NTM species that have not been linked to disease, indicating that most NTM species in unchlorinated drinking water from distribution systems in the Netherlands have a low public health significance. Several species of the genus Mycobacterium are described as nontuberculous mycobacteria (NTM), and these NTM species can be opportunistic pathogens, causing disease in immunocompromised humans (1). The drinking water environment provides niches for certain NTM species, since some species are capable of multiplying in biofilms, protozoa that graze on biofilms, and sediments (2-7). As a result, studies using cultivation methods have identified different NTM species isolated from drinking water (8-11). Moreover, several studies have suggested that NTM isolates from drinking water and from patients have the same genotype (12-17). Thus, drinking water can be a route of transmission of opportunistic pathogenic NTM species to immunocompromised humans.A large proportion of the NTM species in drinking water cannot be cultivated with the currently used culture methods (18). Consequently, cultivation-based studies provide a limited view of NTM communities in drinking water. A more complete characterization of the NTM populations in drinking water can be achieved by employing molecular methods such as PCR and sequencing, but such studies are still scarce (19,20). As a result, the NTM diversity in drinking water is still largely unexplored. A possible reason for this is that the generally used 16S rRNA gene sequence analysis is not suitable to investigate NTM populations, because...

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“…An extensive collection of case studies and research articles dating back Ͼ30 years demonstrates the adaptability and potential of legionellae to colonize man-made aquatic environments ( Fig. 1), from the initial point of water treatment (69)(70)(71)(72)(73) to private homes (74)(75)(76)(77)(78), hospitals (79)(80)(81)(82)(83), restaurants (84,85), bath houses (86)(87)(88)(89), hotels (90)(91)(92), and, eventually, wastewater facilities (93,94). These studies underscore the resiliency and persistence of legionellae.…”

Section: Physiology and Ecologymentioning

confidence: 99%

Current and Emerging Legionella Diagnostics for Laboratory and Outbreak Investigations

2015

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SUMMARY Legionnaires' disease (LD) is an often severe and potentially fatal form of bacterial pneumonia caused by an extensive list of Legionella species. These ubiquitous freshwater and soil inhabitants cause human respiratory disease when amplified in man-made water or cooling systems and their aerosols expose a susceptible population. Treatment of sporadic cases and rapid control of LD outbreaks benefit from swift diagnosis in concert with discriminatory bacterial typing for immediate epidemiological responses. Traditional culture and serology were instrumental in describing disease incidence early in its history; currently, diagnosis of LD relies almost solely on the urinary antigen test, which captures only the dominant species and serogroup, Legionella pneumophila serogroup 1 (Lp1). This has created a diagnostic “blind spot” for LD caused by non-Lp1 strains. This review focuses on historic, current, and emerging technologies that hold promise for increasing LD diagnostic efficiency and detection rates as part of a coherent testing regimen. The importance of cooperation between epidemiologists and laboratorians for a rapid outbreak response is also illustrated in field investigations conducted by the CDC with state and local authorities. Finally, challenges facing health care professionals, building managers, and the public health community in combating LD are highlighted, and potential solutions are discussed.

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Concentration and Diversity of Uncultured Legionella spp. in Two Unchlorinated Drinking Water Supplies with Different Concentrations of Natural Organic Matter

Cited by 75 publications

References 37 publications

Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

Nontuberculous Mycobacteria, Fungi, and Opportunistic Pathogens in Unchlorinated Drinking Water in the Netherlands

Pyrosequence Analysis of the hsp65 Genes of Nontuberculous Mycobacterium Communities in Unchlorinated Drinking Water in the Netherlands

Current and Emerging Legionella Diagnostics for Laboratory and Outbreak Investigations

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