Occurrence and Genetic Diversity of Uncultured
            <i>Legionella</i>
            spp. in Drinking Water Treated at Temperatures below 15°C

Wullings, Bart; Kooij, D. van der

doi:10.1128/aem.72.1.157-166.2006

Cited by 106 publications

(96 citation statements)

References 58 publications

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“…Notwithstanding, L. pneumophila was detected in both streams (surface water) and wells (ground water). This study is comparable to a study conducted in Netherlands where PCR technique was used for detection of legionellae in groundwater (well) and surface water (stream); surface water showed a high yield of Legionella organism compared to groundwater water samples (Wullings and van der Kooij, 2006).…”

Section: Discussionsupporting

confidence: 63%

Isolation of Legionella pneumophila from surface and ground waters in Osogbo, Nigeria

Alli¹,

Olusoga²,

Adedokun³

et al. 2011

Afr. J. Microbiol. Res.

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Legionella is a ubiquitous water environmental organism. Isolation/detection of Legionellae has been reported worldwide. However, there is no reported isolation of Legionellae in countries in Africa with the exception of South Africa. The aim of this study was to survey the surface, ground waters and air conditioner water systems (ACWs) in Osogbo, Nigeria for the presence of Legionella pneumophila by cultural isolation method. A total of 313 water samples from the streams (surface water), wells (groundwater) and ACWS were cultured on buffered charcoal yeast extract (BCYE) medium. The isolates were identified by Gram staining techniques, biochemical tests and demonstration of pore forming activity. Polymerase chain reaction for amplification of 0.52 kb fragment of the part of dot/icm region of L. pneumophila was used for the final identification. The results obtained showed that the prevalence of L. pneumophila from streams (8%) was statistically significant when compared to wells (1%) (Chi square, P < 0.05). L. pneumophila was not isolated from any of the water samples taken from air-conditioner water systems. The study concludes that L. pneumophila is present in natural aquatic environment in Nigeria.

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Section: Discussionsupporting

confidence: 63%

Isolation of Legionella pneumophila from surface and ground waters in Osogbo, Nigeria

Alli¹,

Olusoga²,

Adedokun³

et al. 2011

Afr. J. Microbiol. Res.

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“…in water systems. A large diversity of Legionella spp., many of which are as yet uncultured, is ubiquitous in freshwater environments at temperatures of Ͻ20°C (36,42,43,44,45,46). L. pneumophila is not cultured or only sporadically cultured from these low-temperature environments.…”

Section: Discussionmentioning

confidence: 99%

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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“…Water temperatures in supplies A and B were below 20°C and thus were too low for growth of L. pneumophila (32), but uncultured Legionella species, including Legionella-like amoeba pathogens (82), can multiply in this temperature range in water supplies. A number of the detected free-living protozoa can probably serve as hosts for these uncultured Legionella bacteria.…”

Section: Discussionmentioning

confidence: 99%

Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

Valster

Wullings

Bakker³

et al. 2009

Appl Environ Microbiol

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Free-living protozoan communities in water supplies may include hosts for Legionella pneumophila and other undesired bacteria, as well as pathogens. This study aimed at identifying free-living protozoa in two unchlorinated groundwater supplies, using cultivation-independent molecular approaches. For this purpose, samples (<20°C) of treated water, distributed water, and distribution system biofilms were collected from supply A, with a low concentration of natural organic matter (NOM) (<0.5 ppm of C), and from supply B, with a high NOM concentration (7.9 ppm of C). Eukaryotic communities were studied using terminal restriction fragment length polymorphism and clone library analyses of partial 18S rRNA gene fragments and a Hartmannella vermiformis-specific quantitative PCR (qPCR). In both supplies, highly diverse eukaryotic communities were observed, including free-living protozoa, fungi, and metazoa. Sequences of protozoa clustered with Amoebozoa (10 operational taxonomic units [OTUs]), Cercozoa (39 OTUs), Choanozoa (26 OTUs), Ciliophora (29 OTUs), Euglenozoa (13 OTUs), Myzozoa (5 OTUs), and Stramenopiles (5 OTUs). A large variety of protozoa were present in both supplies, but the estimated values for protozoan richness did not differ significantly. H. vermiformis was observed in both supplies but was not a predominant protozoan. One OTU with the highest similarity to Acanthamoeba polyphaga, an opportunistic human pathogen and a host for undesired bacteria, was observed in supply A. The high level of NOM in supply B corresponded with an elevated level of active biomass and with elevated concentrations of H. vermiformis in distributed water. Hence, the application of qPCR may be promising in elucidating the relationship between drinking water quality and the presence of specific protozoa.Free-living protozoa are ubiquitous in natural freshwater environments (7,38,51,71) but also proliferate in engineered water systems, including water treatment systems (3,47,70), distribution systems (6, 75), and tap water installations inside buildings (54, 69). Concentrations of protozoa, determined using cultivation methods and microscopy, range from Ͻ1 to 10 4 cells liter Ϫ1 in treated water (3,47,70,75) and from Ͻ1 to 7 ϫ 10 5 cells liter Ϫ1 in distribution systems (6,61,64,75). Genera of free-living protozoa commonly observed in these systems and in tap water installations include Acanthamoeba,

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Occurrence and Genetic Diversity of Uncultured Legionella spp. in Drinking Water Treated at Temperatures below 15°C

Cited by 106 publications

References 58 publications

Isolation of Legionella pneumophila from surface and ground waters in Osogbo, Nigeria

Isolation of Legionella pneumophila from surface and ground waters in Osogbo, Nigeria

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

Free-Living Protozoa in Two Unchlorinated Drinking Water Supplies, Identified by Phylogenic Analysis of 18S rRNA Gene Sequences

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