Your Garden Hose: A Potential Health Risk Due to <i>Legionella</i> spp. Growth Facilitated by Free-Living Amoebae

Thomas, Jacqueline; Thomas, Torsten; Stuetz, Richard M.; Ashbolt, Nicholas J.

doi:10.1021/es502652n

Cited by 35 publications

(35 citation statements)

References 77 publications

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“…The strong biofilm formation on pPVC, which is caused by the release of biodegradable plasticizers, mostly phthalate esters (62), makes the material unsuited for application in plumbing systems. The use of pPVC-based garden hoses may lead to exposure to elevated numbers of legionellae (63). The CFU/ ATP ratios of the indigenous L. pneumophila non-SG1 and L. pneumophila ST1, ST47, and ST62 strains in the biofilm on pPVC at 38°C (Table 3) show that these organisms attained similar levels of growth in the biofilm at this temperature.…”

Section: Growth Of L Pneumophila Sts In Byeb and Biofilms At Differementioning

confidence: 98%

Multiplication of Legionella pneumophila Sequence Types 1, 47, and 62 in Buffered Yeast Extract Broth and Biofilms Exposed to Flowing Tap Water at Temperatures of 38°C to 42°C

Kooij

Brouwer-Hanzens

Veenendaal

et al. 2016

Appl Environ Microbiol

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Legionella pneumophila proliferates in freshwater environments at temperatures ranging from 25 to 45°C. To investigate the preference of different sequence types (ST) for a specific temperature range, growth of L. pneumophila serogroup 1 (SG1) ST1 (environmental strains), ST47, and ST62 (disease-associated strains) was measured in buffered yeast extract broth (BYEB) and biofilms grown on plasticized polyvinyl chloride in flowing heated drinking water originating from a groundwater supply. The optimum growth temperatures in BYEB were approximately 37°C (ST1), 39°C (ST47), and 41°C (ST62), with maximum growth temperatures of 42°C (ST1) and 43°C (ST47 and ST62). In the biofilm at 38°C, the ST47 and ST62 strains multiplied equally well compared to growth of the environmental ST1 strain and an indigenous L. pneumophila non-SG1 strain, all attaining a concentration of approximately 10 7 CFU/cm ؊2 . Raising the temperature to 41°C did not impact these levels within 4 weeks, but the colony counts of all strains tested declined (at a specific decline rate of 0.14 to 0.41 day ؊1 ) when the temperature was raised to 42°C. At this temperature, the concentration of Vermamoeba vermiformis in the biofilm, determined with quantitative PCR (qPCR), was about 2 log units lower than the concentration at 38°C. In columns operated at a constant temperature, ranging from 38 to 41°C, none of the tested strains multiplied in the biofilm at 41°C, in which also V. vermiformis was not detected. These observations suggest that strains of ST47 and ST62 did not multiply in the biofilm at a temperature of >41°C because of the absence of a thermotolerant host. IMPORTANCEGrowth of Legionella pneumophila in tap water installations is a serious public health concern. The organism includes more than 2,100 varieties (sequence types). More than 50% of the reported cases of Legionnaires' disease are caused by a few sequence types which are very rarely detected in the environment. Strains of selected virulent sequence types proliferated in biofilms on surfaces exposed to warm (38°C) tap water to the same level as environmental varieties and multiplied well as pure culture in a nutrient-rich medium at temperatures of 42 and 43°C. However, these organisms did not grow in the biofilms at temperatures of >41°C. Typical host amoebae also did not multiply at these temperatures. Apparently, proliferation of thermotolerant host amoebae is needed to enable multiplication of the virulent L. pneumophila strains in the environment at elevated temperatures. The detection of these amoebae in water installations therefore is a scientific challenge with practical implications. T he genus Legionella currently includes ca. 63 (sub)species (https://www.dsmz.de), at least 20 of which have been implicated in legionellosis (1). Legionella pneumophila is responsible for more than 90% of the reported cases of Legionnaires' disease (LD) in Europe (2), the United States (3), Canada (4), and Japan (5). This species includes 15 polyclonal serogroups (SGs). Most of the cli...

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Section: Growth Of L Pneumophila Sts In Byeb and Biofilms At Differementioning

confidence: 98%

Multiplication of Legionella pneumophila Sequence Types 1, 47, and 62 in Buffered Yeast Extract Broth and Biofilms Exposed to Flowing Tap Water at Temperatures of 38°C to 42°C

Kooij

Brouwer-Hanzens

Veenendaal

et al. 2016

Appl Environ Microbiol

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“…Underreporting the VBNC cells of P. aeruginosa in water distribution systems by standard culture-based methods may therefore pose serious risks to the public health, especially as free-living amoebae are common in such environments and could resuscitate these bacteria into an active, virulent form (16). In our study, we found that incubation times as low as 2 h lead to resuscitation of VBNC P. aeruginosa, indicating that VBNC P. aeruginosa could rapidly resuscitate in piped water (healthcare) environments colonized with amoebae.…”

Section: Discussionmentioning

confidence: 99%

Interactions of Pseudomonas aeruginosa with Acanthamoeba polyphaga Observed by Imaging Flow Cytometry

et al. 2019

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Pseudomonas aeruginosa is a Gram‐negative bacterium that is abundant in the environment and water systems, with strains that cause serious infections, especially in patients with compromised immune systems. In times of stress or as part of its natural life cycle, P. aeruginosa can adopt a viable but not culturable (VBNC) state, which renders it undetectable by current conventional food and water testing methods and makes it highly resistant to antibiotic treatment. Specific conditions can resuscitate these coccoid VBNC P. aeruginosa cells, which returns them to their active, virulent rod‐shaped form. Underreporting the VBNC cells of P. aeruginosa by standard culture‐based methods in water distribution systems may therefore pose serious risks to public health. As such, being able to accurately detect and quantify the presence of VBNC P. aeruginosa, especially in a hospital setting, is of critical importance. Herein, we describe a method to analyze VBNC P. aeruginosa using imaging flow cytometry. With this technique, we can accurately distinguish between active and VBNC forms. We also show here that association of VBNC P. aeruginosa with Acanthamoeba polyphaga results in resuscitation of P. aeruginosa to an active form within 2 h. Our approach could provide an alternative, reliable detection method of VBNC P. aeruginosa when coupled with species‐specific staining. Most importantly, our experiments demonstrate that the coculture with amoebae can lead to a resuscitation of P. aeruginosa of culturable morphology after only 2 h, indicating that VBNC P. aeruginosa could potentially resuscitate in piped water (healthcare) environments colonized with amoebae. © 2019 International Society for Advancement of Cytometry

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“…With regard to NTM and amoebae, for which there is no surveillance guideline for their monitoring in premise plumbing, recent studies generally followed standard methods for microbiological tests or sampling guidelines. Taps and showers were the frequent targets (Falkinham, 2011; Feazel et al, 2009; Ichijo et al, 2014; Kilvington et al, 2004; Thomas et al, 2006), with cisterns, filters, garden hoses and ice machines also sampled in some cases (Covert et al, 1999; Falkinham, 2010, 2011; Thomas et al, 2014). In an epidemiological and environmental investigation of a PAM death, a garden hose, service line hose bib, and toilet tank were also included in household samples, all of which were positive for Naegleria fowleri (Cope et al, 2015).…”

Section: Sampling Premise Plumbing and Sample Handlingmentioning

confidence: 99%

“…In premise plumbing, biofilm samples are often collected from faucets, shower heads, drains, hoses and water filters (Charron et al, 2015; Falkinham, 2010; Liu et al, 2012; Proctor et al, 2016; Thomas et al, 2014; Wang et al, 2012). Anti-splash or spray nozzles are recommended to be removed from faucets and shower heads and disassembled prior to biofilm sampling in order to access the inner area and obtain representative biofilm (U.K.…”

Section: Sampling Premise Plumbing and Sample Handlingmentioning

confidence: 99%

Methodological approaches for monitoring opportunistic pathogens in premise plumbing: A review

et al. 2017

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Opportunistic pathogens inhabiting premise (i.e., building) plumbing (OPPPs, e.g., L. pneumophila, M. avium complex, P. aeruginosa, Acanthamoeba, and N. fowleri) are a significant and growing source of disease. Because OPPPs establish and grow as part of the native drinking water microbiota, they do not correspond to fecal indicators, presenting a significant challenge to common and effective monitoring strategies. Further, different OPPPs present distinct requirements for sampling, preservation, and analysis, creating a significant impediment to their parallel detection. The aim of this critical review is to synthesize the state of the science of monitoring OPPPs and to identify a path forward for their simultaneous detection and quantification in a manner commensurate with the need for reliable data to inform risk assessment and mitigation. Water and biofilm sampling procedures, as well as factors influencing sample representativeness and detection sensitivity, are critically evaluated with respect to the five representative bacterial and amoebal OPPPs noted above. Available culturing and molecular approaches are discussed in terms of their advantages, limitations, and applicability. Knowledge gaps and research needs are identified.

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Your Garden Hose: A Potential Health Risk Due to Legionella spp. Growth Facilitated by Free-Living Amoebae

Cited by 35 publications

References 77 publications

Multiplication of Legionella pneumophila Sequence Types 1, 47, and 62 in Buffered Yeast Extract Broth and Biofilms Exposed to Flowing Tap Water at Temperatures of 38°C to 42°C

Multiplication of Legionella pneumophila Sequence Types 1, 47, and 62 in Buffered Yeast Extract Broth and Biofilms Exposed to Flowing Tap Water at Temperatures of 38°C to 42°C

Interactions of Pseudomonas aeruginosa with Acanthamoeba polyphaga Observed by Imaging Flow Cytometry

Methodological approaches for monitoring opportunistic pathogens in premise plumbing: A review

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