Isolation of Legionella anisa from multiple sites of a hospital water system: the eradication of Legionella contamination

Yamamoto, Noriaki; Kubota, Takeshi; Tateyama, Masao; Koide, Michio; Nakasone, Chikara; Tohyama, Masato; Shinzato, Takashi; Higa, Futoshi; Kusano, Nobuchika; Kawakami, Kazuyoshi; Saitô, Atsushi

doi:10.1007/s10156-002-0228-0

Cited by 18 publications

(19 citation statements)

References 7 publications

(4 reference statements)

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“…In 2003, Yamamoto and his team isolated L. anisa from multiple sites of a hospital water system, including shower heads in an obstetrics ward. This marked the fi rst isolation of L. anisa in a hospital (30). As his Legionella species is more often isolated from environment than from clinical material, it is less pathogenic for humans compared with L. pneumophila.…”

Section: Discussionmentioning

confidence: 99%

Legionella spp. in dental unit waterlines

Jurásková¹,

Sedlackova²,

Janska³

et al. 2017

BLL

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OBJECTIVE: To determine the current presence of Legionella spp. in the output water of dental unit waterlines (DUWLs) and examine its mitigation by disinfection at the Institute of Dentistry and Oral Sciences, Faculty of Medicine and Dentistry, Palacky University Olomouc and University Hospital Olomouc. MATERIAL AND METHODS: The fi rst stage of our survey involved collecting samples of DUWL output water from 50 dental chair units (DCUs), and 2 samples of the incoming potable water. In October 2015, a one-time disinfection (1 % Stabimed) of DUWLs was conducted. This was followed by collecting 10 control samples (survey stage 2). RESULTS: From the total of 50 samples (survey stage 1), 18 samples (36.0 %) tested positive for Legionella spp. Following the disinfection, nine of the ten samples no longer showed any presence of Legionella. CONCLUSION: Based on culture results, the one-time disinfection (1 % Stabimed) was effective. We are unable to comment on the duration of positive effect of disinfection on the occurrence of Legionella spp. in the outlet water. It was a one-time survey (Tab. 2, Ref. 32). Text in PDF www.elis.sk. KEY WORDS: Legionella spp., water of dental unit waterlines, disinfection.

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Section: Discussionmentioning

confidence: 99%

Legionella spp. in dental unit waterlines

Jurásková¹,

Sedlackova²,

Janska³

et al. 2017

BLL

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“…Moreover, it cannot be excluded that free-living protozoa other than those tested in vitro can serve as hosts for L. pneumophila as well. Information is also lacking about protozoan hosts for Legionella anisa (13, 49), which is frequently present in water installations in temperate regions (11,62). Furthermore, it is unknown which free-living protozoa serve as hosts for uncultured Legionella bacteria that can grow at temperatures of about 15°C (61; B.…”

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Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

Valster

Wullings

Kooij

2010

Appl Environ Microbiol

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Legionella pneumophila proliferates in aquatic habitats within free-living protozoa, 17 species of which have been identified as hosts by using in vitro experiments. The present study aimed at identifying protozoan hosts for L. pneumophila by using a biofilm batch test (BBT). Samples (600 ml) collected from 21 engineered freshwater systems, with added polyethylene cylinders to promote biofilm formation, were inoculated with L. pneumophila and subsequently incubated at 37°C for 20 days. Growth of L. pneumophila was observed in 16 of 18 water types when the host protozoan Hartmannella vermiformis was added. Twelve of the tested water types supported growth of L. pneumophila or indigenous Legionella anisa without added H. vermiformis. In 12 of 19 BBT flasks H. vermiformis was indicated as a host, based on the ratio between maximum concentrations of L. pneumophila and H. vermiformis, determined with quantitative PCR (Q-PCR), and the composition of clone libraries of partial 18S rRNA gene fragments. Analyses of 609 eukaryotic clones from the BBTs revealed that 68 operational taxonomic units (OTUs) showed the highest similarity to free-living protozoa. Forty percent of the sequences clustering with protozoa showed >99.5% similarity to H. vermiformis. None of the other protozoa serving as hosts in in vitro studies were detected in the BBTs. In several tests with growth of L. pneumophila, the protozoa Diphylleia rotans, Echinamoeba thermarum, and Neoparamoeba sp. were identified as candidate hosts. In vitro studies are needed to confirm their role as hosts for L. pneumophila. Unidentified protozoa were implicated as hosts for uncultured Legionella spp. grown in BBT flasks at 15°C.Legionella pneumophila, the causative agent of Legionnaires' disease, is a common inhabitant of natural freshwater environments and human-made water systems, including cooling towers, whirlpools, air-conditioning systems, and installations for warm tap water (14). In the aquatic environment L. pneumophila proliferates within certain free-living protozoa, which serve as its hosts (15,30,59). Environmental factors favoring the growth and survival of L. pneumophila in freshwater systems include a water temperature between 20°C and 45°C (41, 60) and the presence of biofilms and sediments on which the protozoan hosts can graze (30,41,56).Rowbotham (44) was the first to report the growth of L. pneumophila within free-living amoebae, which belonged to the genera Acanthamoeba and Naegleria. In vitro studies with cocultures have revealed that 14 species of amoebae, viz., Acanthamoeba spp. (1, 35, A number of the free-living protozoa mentioned above and others, e.g., Vannella spp. and Saccamoeba spp., have been observed in aquatic environments from which L. pneumophila was cultivated or in which it was detected with PCR (4, 42, 51, 52). However, it remains unknown which of these protozoa actually serve as hosts for L. pneumophila in the aquatic environment, including human-made water systems. Moreover, it cannot be excluded that free-living protozoa oth...

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“…Legionella species are ubiquitous in many water systems (6,8,9,17,22,27)-including hospital water systems (30,31,39)-with Legionella pneumophila and Legionella species other than L. pneumophila isolated together (3,11) or alone (19,37). The most frequent species are L. pneumophila and L. anisa (5,12,16,18,36).…”

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Legionella anisa , a Possible Indicator of Water Contamination by Legionella pneumophila

et al. 2006

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Legionella anisa is one of the most frequent species of Legionella other than Legionella pneumophila in the environment and may be hospital acquired in rare cases. We found that L. anisa may mask water contamination by L. pneumophila, suggesting that there is a risk of L. pneumophila infection in immunocompromised patients if water is found to be contaminated with Legionella species other than L. pneumophila.

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Isolation of Legionella anisa from multiple sites of a hospital water system: the eradication of Legionella contamination

Cited by 18 publications

References 7 publications

Legionella spp. in dental unit waterlines

Legionella spp. in dental unit waterlines

Detection of Protozoan Hosts for Legionella pneumophila in Engineered Water Systems by Using a Biofilm Batch Test

Legionella anisa , a Possible Indicator of Water Contamination by Legionella pneumophila

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