Pan-European Study on Culture-Proven Legionnaires' Disease: Distribution of Legionella pneumophila Serogroups and Monoclonal Subgroups

Helbig, Jörg; Bernander, Sverker; Pastoris, Maddalena Castellani; Etienne, Jérôme; Gaia, Valéria; Lauwers, Sabine; Lindsay, Diane; Lück, Paul Christian; Marques, Teresa; Mentula, Silja; Peeters, Marcel; Peláz, Carmen; Struelens, Marc; Uldum, Søren A.; Wewalka, G.; Harrison, Tim

doi:10.1007/s10096-002-0820-3

Cited by 228 publications

(81 citation statements)

References 16 publications

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“…The use of monoclonal antibodies (MAbs) revealed more heterogeneity in L. pneumophila, and nine phenons reacting with different MAbs have been defined within SG1 (12). A vast majority of clinical SG1 isolates are MAb3/1 positive, but this type is significantly less frequently isolated from environmental samples (7,8,10,12,13). The introduction of molecular methods enabled a further refinement of the classification of representatives of L. pneumophila.…”

Section: Importancementioning

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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Section: Importancementioning

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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“…Some strains of the L. pneumophila sg 1 population have an enhanced ability to cause disease: the clinical predominance of L. pneumophila sg 1 strains with specific genotypes suggests that they have the ability to cause infections in humans [28, 29, 14]. Among the L. pneumophila sg 1 strains, some monoclonal subgroups (Knoxville, Philadelphia, Benidorm, France/Allentown) display the virulence-associated epitope recognised by MAb 3/1; these strains seem to be associated with hospital outbreaks, travel-associated infections or community-acquired infections [26, 10]. There are some published data [10, 13, 14, 30, 31] on the serogroup and monoclonal subgroup distribution of L. pneumophila in man-made water systems that are associated or not associated with human disease.…”

Section: Discussionmentioning

confidence: 99%

“…Among the L. pneumophila sg 1 strains, some monoclonal subgroups (Knoxville, Philadelphia, Benidorm, France/Allentown) display the virulence-associated epitope recognised by MAb 3/1; these strains seem to be associated with hospital outbreaks, travel-associated infections or community-acquired infections [26, 10]. There are some published data [10, 13, 14, 30, 31] on the serogroup and monoclonal subgroup distribution of L. pneumophila in man-made water systems that are associated or not associated with human disease. This paper describes the first Italian study in which information about the environmental distribution of strains according to their MAb 3/1 profile has been examined.…”

Section: Discussionmentioning

confidence: 99%

Virulence of Legionella pneumophila strains isolated from hospital water system and healthcare-associated Legionnaires’ disease in Northern Italy between 2004 and 2009

et al. 2014

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BackgroundWorldwide, L. pneumophila sg 1 is the most common agent of Legionnaires’ disease ( 80 to 90% of the reported cases). In contrast, L. pneumophila sg 2–14 account for only 15 to 20% of community-acquired cases, although they account for over 50% of the environmental isolates. The discrepancy between environmental isolates and clinical cases of disease suggested that there are differences in virulence.We decided to subtype the environmental Legionella strains isolated from health care facilities (HCFs) and to compare the distribution of strains with the occurrence of hospital-acquired legionellosis.MethodsObservational ecological study based on the data provided by the regional surveillance of legionellosis and on data obtained from hospitals environmental monitoring.Using the monoclonal antibody MAb 3/1 of the Dresden Panel we collected and typed environmental strains of L. pneumophila sg 1 obtained during routine testing in 56 health care facilities from 2004 to 2009.The results of the laboratory analyses of the environmental samples were compared with the number of cases that each health care facility reported during the study period.ResultsThe association between the type of colonisation (L. pneumophila sg 1 vs others serogroups) and the incidence of reported cases was statistically significant (p = 0.03 according to the χ2 test).Legionella strains with the virulence–associated epitope recognised by MAb 3/1 were isolated in 8 of the 26 HCFs colonised by L. pneumophila sg 1; 7 of the HCFs colonised by MAb 3/1-positive strains accounted for 85% of the cases of hospital-acquired legionellosis reported during the 6-year study period. There was a statistically significant association (p = 0.003) between the presence of cases and colonisation by MAb 3/1-positive Legionella strains.ConclusionThis study suggests that hospitals colonised by more virulent strains should be aware of the increased risk and consider the opportunities of increase their monitoring efforts and implement more effective contamination control strategies.

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“…Legionella pneumophila serogroup 1 is the major causative agent associated with both community-and hospitalacquired legionellosis (85% versus 5% due to other serogroups) (Helbig et al 2002;Doleans et al 2004;Rota et al 2006;Stout et al 2007), although the diagnosis of Legionella spp. infection is mainly based on urinary antigen detection, which only detects L. pneumophila sg 1.…”

Section: Introductionmentioning

confidence: 98%

Comparison of two molecular methods used for subtyping of Legionella pneumophila 1 strains isolated from a hospital water supply

Casini

Valentini

Baggiani

et al. 2008

Water Science and Technology

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The results of the pulsed-field gel electrophoresis and the sequence-based typing (using the loci flaA, pilE, asd, mip, mompS and proA) were compared for subtyping of Legionella pneumophila 1 strains isolated from a hospital water supply. Molecular typing was carried out on 61 isolates (38% of the positive samples) selected on space and temporal criteria in order to follow the evolution of the water-system colonization. For all the 61 isolates, the sequence of the amplified mip gene fragment identified Legionella pneumophila strain Wadsworth. Genotype testing by PFGE analysis showed three different patterns, correspondent to three SBT types according to the allelic profiles. Both PFGE and SBT indicated the circulation and the persistence in the hospital potable water-system of three types randomly distributed in space and time. The two molecular methods adopted showed a 100% concordance, although a low degree of genetic heterogeneity characterized the isolates. The electrophoretic patterns were sufficiently unambiguous to consider PFGE a highly discriminatory typing method, but the SBT technique besides accurately characterizing isolates, was able to identify Legionella strains through analysis of the mip gene. A typing method with this level of discriminatory power has great potential for assisting in epidemiological studies.

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Pan-European Study on Culture-Proven Legionnaires' Disease: Distribution of Legionella pneumophila Serogroups and Monoclonal Subgroups

Cited by 228 publications

References 16 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

Virulence of Legionella pneumophila strains isolated from hospital water system and healthcare-associated Legionnaires’ disease in Northern Italy between 2004 and 2009

Comparison of two molecular methods used for subtyping of Legionella pneumophila 1 strains isolated from a hospital water supply

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