Presence and Chromosomal Subtyping of Legionella Species in Potable Water Systems in 20 Hospitals of Catalonia, Spain

Sabrià, Miquel; García-Núñez, Marian; Pedro‐Botet, María Luisa; Sopena, Nieves; Gimeno, Josep M.; Reynaga, Esteban; Morera, Josep; Rey-Joly, Celestino

doi:10.1086/501843

Cited by 46 publications

(34 citation statements)

References 31 publications

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“…A recent publication on the findings of a study carried out in 20 hospitals 4 showed that over 80% of their water supplies were contaminated with Legionella spp.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the effectiveness of the Pastormaster method for disinfection of legionella in a hospital water distribution system

Callizo

Sierra

Pombo

et al. 2005

Journal of Hospital Infection

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“…A recent publication on the findings of a study carried out in 20 hospitals 4 showed that over 80% of their water supplies were contaminated with Legionella spp.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the effectiveness of the Pastormaster method for disinfection of legionella in a hospital water distribution system

Callizo

Sierra

Pombo

et al. 2005

Journal of Hospital Infection

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“…Genetic diversity was also suggested using different typing methods (Selander et al 1985;Sabria et al 2001;Aurell et al 2003;Amemura-Maekawa et al 2005), but attempts to correlate sequence types (ST) and epidemiological characteristics of strains were unsuccessful (Aurell et al 2005). However, among L. pneumophila strains that cause human infections, significantly less diversity was found than among environmental isolates (Harrison et al 2007) and a correlation between specific clones and the ecological niche was shown (Amemura-Maekawa et al 2005).…”

mentioning

confidence: 99%

Multigenome analysis identifies a worldwide distributed epidemic Legionella pneumophila clone that emerged within a highly diverse species

Cazalet¹,

Jarraud²,

Ghavi-Helm³

et al. 2008

Genome Res.

156

174

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Genomics can provide the basis for understanding the evolution of emerging, lethal human pathogens such as Legionella pneumophila, the causative agent of Legionnaires’ disease. This bacterium replicates within amoebae and persists in the environment as a free-living microbe. Among the many Legionella species described, L. pneumophila is associated with 90% of human disease and within the 15 serogroups (Sg), L. pneumophila Sg1 causes over 84% of Legionnaires’ disease worldwide. Why L. pneumophila Sg1 is so predominant is unknown. Here, we report the first comprehensive screen of the gene content of 217 L. pneumophila and 32 non-L. pneumophila strains isolated from humans and the environment using a Legionella DNA-array. Strikingly, we uncovered a high conservation of virulence- and eukaryotic-like genes, indicating strong environmental selection pressures for their preservation. No specific hybridization profile differentiated clinical and environmental strains or strains of different serogroups. Surprisingly, the gene cluster coding the determinants of the core and the O side-chain synthesis of the lipopolysaccaride (LPS cluster) determining Sg1 was present in diverse genomic backgrounds, strongly implicating the LPS of Sg1 itself as a principal cause of the high prevalence of Sg1 strains in human disease and suggesting that the LPS cluster can be transferred horizontally. Genomic analysis also revealed that L. pneumophila is a genetically diverse species, in part due to horizontal gene transfer of mobile genetic elements among L. pneumophila strains, but also between different Legionella species. However, the genomic background also plays a role in disease causation as demonstrated by the identification of a globally distributed epidemic strain exhibiting the genotype of the sequenced L. pneumophila strain Paris.

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“…All isolates were analyzed by PFGE as described previously (10). According to the criteria of Tenover et al (13), chromosomal PFGE patterns differing in one or more bands were considered distinct in this study.…”

mentioning

confidence: 99%

Legionella pneumophila in Cooling Towers: Fluctuations in Counts, Determination of Genetic Variability by Pulsed-Field Gel Electrophoresis (PFGE), and Persistence of PFGE Patterns

Ragull¹,

García-Núñez²,

Pedro‐Botet³

et al. 2007

Appl Environ Microbiol

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The concentrations of Legionella pneumophila in cooling towers may vary considerably over short periods of time, producing significant fluctuations throughout the year. Despite genetic variability, in small geographical areas the same indistinguishable pulsed-field gel electrophoresis patterns may be shared among different cooling towers and persist over time.The involvement of cooling towers in some community outbreaks of legionellosis has been demonstrated (3,6,8,9,11), and it has been suggested that there may be an association between high Legionella counts in cooling towers and the occurrence of an outbreak of legionellosis (12). Although not all environmental isolates are associated with human disease, the present guidelines aimed at preventing legionellosis have proposed ranges of risk involving different environmental insults based on Legionella counts (4). However, the fluctuations in Legionella counts over short periods of time have led some authors to question these risk ranges (1).Since the recovery of a high inoculum of Legionella in a cooling tower is not necessarily related to an outbreak or sporadic cases of legionellosis, genetic studies are necessary to establish the link between environmental and clinical isolates. The "gold standard" technique for genotyping Legionella is the analysis of chromosomal restriction patterns by pulsed-field gel electrophoresis (PFGE). Isolation of Legionella strains from a cooling tower which are genetically indistinguishable from clinical isolates is considered to be clear evidence of the implication of the tower in an outbreak (1, 9). However, little is known regarding the genetic variability of Legionella within the same tower and in cooling towers from areas in the vicinity. Likewise, to our knowledge, no study has determined the persistence of molecular patterns in isolates in cooling towers. All these circumstances have epidemiological and legal consequences when assigning responsibility for an outbreak of legionellosis to a particular installation.The main objectives of this study were to establish the fluctuations in Legionella counts over time and to determine the genetic variability and persistence of PFGE patterns in cooling towers.Fifteen cooling towers (A to O) were selected within a radius of 3 km. Four of them (J, K, M, and N) shared the same main line for water distribution. The other cooling towers had a different domestic distribution system but were supplied by the same municipal water network. All the cooling towers followed the controls and hygiene measures required by Spanish regulations (RD 865/2003), and we were able to verify that the levels of disinfectant (sodium hypochlorite [0.2 to 0.5 ppm residual] in conjunction with the discontinuous dosage of nonoxidant biocide [dibromonitrilopropionamide]) were in accordance with legislation at the time of sampling. Cooling water samples were cultured for Legionella fortnightly over a 1-year period. The samples were concentrated by filtration, and four plates of GVPC agar (Oxoid, Wesel, Germany) we...

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Presence and Chromosomal Subtyping of Legionella Species in Potable Water Systems in 20 Hospitals of Catalonia, Spain

Cited by 46 publications

References 31 publications

Evaluation of the effectiveness of the Pastormaster method for disinfection of legionella in a hospital water distribution system

Evaluation of the effectiveness of the Pastormaster method for disinfection of legionella in a hospital water distribution system

Multigenome analysis identifies a worldwide distributed epidemic Legionella pneumophila clone that emerged within a highly diverse species

Legionella pneumophila in Cooling Towers: Fluctuations in Counts, Determination of Genetic Variability by Pulsed-Field Gel Electrophoresis (PFGE), and Persistence of PFGE Patterns

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