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Valciņa O, Pūle D, Ķibilds J, Lazdāne A, Trofimova J, Makarova S, Konvisers G, Ķimse L, Krūmiņa A, Bērziņš A. Prevalence and Genetic Diversity of Legionella spp. in Hotel Water-Supply Systems in Latvia. Microorganisms 2023; 11:microorganisms11030596. [PMID: 36985170 PMCID: PMC10055240 DOI: 10.3390/microorganisms11030596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
Legionella is one of the most important waterborne pathogens that can lead to both outbreaks and sporadic cases. The majority of travel-associated Legionnaires’ disease (TALD) cases are contracted during hotel stays. The aim of this study was to evaluate the prevalence and genetic diversity of Legionella spp. in hotel water supply systems in Latvia. In total, 834 hot water samples were collected from the water systems of 80 hotels in Latvia. At least one Legionella spp. positive sample was detected in 47 out of 80 hotels (58.8%). Overall, 235 out of 834 samples (28.2%) were Legionella spp. positive. The average hot water temperature in Latvian hotels was 49.8 °C. The most predominant L. pneumophila serogroup (SG) was SG3 which was found in 113 (49.8%) positive samples from 27 hotels. For 79 sequenced L. pneumophila isolates, 21 different sequence types (ST) were obtained, including 3 new types—ST2582, ST2579, and ST2580. High Legionella contamination and high genetic diversity were found in the hotel water supply systems in Latvia, which, together with the insufficient hot water temperature, may indicate that the lack of regulation and control measures may promote the proliferation of Legionella.
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Affiliation(s)
- Olga Valciņa
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
| | - Daina Pūle
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
- Department of Water Engineering and Technology, Riga Technical University, 1048 Rīga, Latvia
| | - Juris Ķibilds
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
| | - Andžela Lazdāne
- Department of Metabolic Genetics Laboratory, Children’s Clinical University Hospital, 1004 Rīga, Latvia
| | - Jūlija Trofimova
- National Reference Laboratory, Riga East University Hospital, 1038 Rīga, Latvia
| | - Svetlana Makarova
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
| | - Genadijs Konvisers
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
| | - Laima Ķimse
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
| | - Angelika Krūmiņa
- Department of Infectology, Riga Stradiņš University, 1007 Rīga, Latvia
| | - Aivars Bērziņš
- Institute of Food Safety, Animal Health and Environment “BIOR”, 1076 Rīga, Latvia
- Correspondence: ; Tel.: +371-6780-8972
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Mercante JW, Caravas JA, Ishaq MK, Kozak-Muiznieks NA, Raphael BH, Winchell JM. Genomic heterogeneity differentiates clinical and environmental subgroups of Legionella pneumophila sequence type 1. PLoS One 2018; 13:e0206110. [PMID: 30335848 PMCID: PMC6193728 DOI: 10.1371/journal.pone.0206110] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/05/2018] [Indexed: 11/19/2022] Open
Abstract
Legionella spp. are the cause of a severe bacterial pneumonia known as Legionnaires' disease (LD). In some cases, current genetic subtyping methods cannot resolve LD outbreaks caused by common, potentially endemic L. pneumophila (Lp) sequence types (ST), which complicates laboratory investigations and environmental source attribution. In the United States (US), ST1 is the most prevalent clinical and environmental Lp sequence type. In order to characterize the ST1 population, we sequenced 289 outbreak and non-outbreak associated clinical and environmental ST1 and ST1-variant Lp strains from the US and, together with international isolate sequences, explored their genetic and geographic diversity. The ST1 population was highly conserved at the nucleotide level; 98% of core nucleotide positions were invariant and environmental isolates unassociated with human disease (n = 99) contained ~65% more nucleotide diversity compared to clinical-sporadic (n = 139) or outbreak-associated (n = 28) ST1 subgroups. The accessory pangenome of environmental isolates was also ~30-60% larger than other subgroups and was enriched for transposition and conjugative transfer-associated elements. Up to ~10% of US ST1 genetic variation could be explained by geographic origin, but considerable genetic conservation existed among strains isolated from geographically distant states and from different decades. These findings provide new insight into the ST1 population structure and establish a foundation for interpreting genetic relationships among ST1 strains; these data may also inform future analyses for improved outbreak investigations.
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Affiliation(s)
- Jeffrey W. Mercante
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Jason A. Caravas
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Maliha K. Ishaq
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Natalia A. Kozak-Muiznieks
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Brian H. Raphael
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Jonas M. Winchell
- Pneumonia Response and Surveillance Laboratory, Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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Molecular typing of Legionella pneumophila isolates from environmental water samples and clinical samples using a five-gene sequence typing and standard Sequence-Based Typing. PLoS One 2018; 13:e0190986. [PMID: 29389983 PMCID: PMC5794064 DOI: 10.1371/journal.pone.0190986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 12/22/2017] [Indexed: 12/20/2022] Open
Abstract
Inadequate discriminatory power to distinguish between L. pneumophila isolates, especially those belonging to disease-related prevalent sequence types (STs) such as ST1, ST36 and ST47, is an issue of SBT scheme. In this study, we developed a multilocus sequence typing (MLST) scheme based on two non-virulence loci (trpA, cca) and three virulence loci (icmK, lspE, lssD), to genotype 110 L. pneumophila isolates from various natural and artificial water sources in Guangdong province of China, and compared with the SBT. The isolates were assigned to 33 STs of the SBT and 91 new sequence types (nSTs) of the MLST. The indices of discrimination (IODs) of SBT and MLST were 0.920 and 0.985, respectively. Maximum likelihood trees of the concatenated SBT and MLST sequences both showed distinct phylogenetic relationships between the isolates from the two environments. More intragenic recombinations were detected in nSTs than in STs, and they were both more abundant in natural water isolates. We found out the MLST had a high discriminatory ability for the disease-associated ST1 isolates: 22 ST1 isolates were assigned to 19 nSTs. Furthermore, we assayed the discrimination of the MLST for 29 reference strains (19 clinical and 10 environmental). The clinical strains were assigned to eight STs and ten nSTs. The MLST could also subtype the prevalent clinical ST36 or ST47 strains: eight ST36 strains were subtyped into three nSTs and two ST47 strains were subtyped into two nSTs. We found different distribution patterns of nSTs between the environmental and clinical ST36 isolates, and between the outbreak clinical ST36 isolates and the sporadic clinical ST36 isolates. These results together revealed the MLST scheme could be used as part of a typing scheme that increased discrimination when necessary.
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Mentasti M, Cassier P, David S, Ginevra C, Gomez-Valero L, Underwood A, Afshar B, Etienne J, Parkhill J, Chalker V, Buchrieser C, Harrison T, Jarraud S. Rapid detection and evolutionary analysis of Legionella pneumophila serogroup 1 sequence type 47. Clin Microbiol Infect 2017; 23:264.e1-264.e9. [DOI: 10.1016/j.cmi.2016.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/23/2016] [Accepted: 11/24/2016] [Indexed: 10/20/2022]
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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. Appl Environ Microbiol 2016; 82:6691-6700. [PMID: 27613680 DOI: 10.1128/aem.01107-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/01/2016] [Indexed: 12/11/2022] Open
Abstract
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 107 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. IMPORTANCE Growth 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.
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Khodr A, Kay E, Gomez-Valero L, Ginevra C, Doublet P, Buchrieser C, Jarraud S. Molecular epidemiology, phylogeny and evolution of Legionella. INFECTION GENETICS AND EVOLUTION 2016; 43:108-22. [PMID: 27180896 DOI: 10.1016/j.meegid.2016.04.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/29/2016] [Accepted: 04/30/2016] [Indexed: 12/12/2022]
Abstract
Legionella are opportunistic pathogens that develop in aquatic environments where they multiply in protozoa. When infected aerosols reach the human respiratory tract they may accidentally infect the alveolar macrophages leading to a severe pneumonia called Legionnaires' disease (LD). The ability of Legionella to survive within host-cells is strictly dependent on the Dot/Icm Type 4 Secretion System that translocates a large repertoire of effectors into the host cell cytosol. Although Legionella is a large genus comprising nearly 60 species that are worldwide distributed, only about half of them have been involved in LD cases. Strikingly, the species Legionella pneumophila alone is responsible for 90% of all LD cases. The present review summarizes the molecular approaches that are used for L. pneumophila genotyping with a major focus on the contribution of whole genome sequencing (WGS) to the investigation of local L. pneumophila outbreaks and global epidemiology studies. We report the newest knowledge regarding the phylogeny and the evolution of Legionella and then focus on virulence evolution of those Legionella species that are known to have the capacity to infect humans. Finally, we discuss the evolutionary forces and adaptation mechanisms acting on the Dot/Icm system itself as well as the role of mobile genetic elements (MGE) encoding T4ASSs and of gene duplications in the evolution of Legionella and its adaptation to different hosts and lifestyles.
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Affiliation(s)
- A Khodr
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, France; CNRS, UMR 3525, 28, Rue du Dr Roux, 75724 Paris, France
| | - E Kay
- CIRI, International Center for Infectiology Research, Inserm, U1111, CNRS, UMR 5308, Université Lyon 1, École Normale Supérieure de Lyon, Lyon F-69008, France
| | - L Gomez-Valero
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, France; CNRS, UMR 3525, 28, Rue du Dr Roux, 75724 Paris, France
| | - C Ginevra
- CIRI, International Center for Infectiology Research, Inserm, U1111, CNRS, UMR 5308, Université Lyon 1, École Normale Supérieure de Lyon, Lyon F-69008, France; French National Reference Center of Legionella, Institut des agents infectieux, Hospices Civils de Lyon, Lyon, France
| | - P Doublet
- CIRI, International Center for Infectiology Research, Inserm, U1111, CNRS, UMR 5308, Université Lyon 1, École Normale Supérieure de Lyon, Lyon F-69008, France
| | - C Buchrieser
- Institut Pasteur, Unité de Biologie des Bactéries Intracellulaires, France; CNRS, UMR 3525, 28, Rue du Dr Roux, 75724 Paris, France
| | - S Jarraud
- CIRI, International Center for Infectiology Research, Inserm, U1111, CNRS, UMR 5308, Université Lyon 1, École Normale Supérieure de Lyon, Lyon F-69008, France; French National Reference Center of Legionella, Institut des agents infectieux, Hospices Civils de Lyon, Lyon, France
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7
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Subtyping of the Legionella pneumophila “Ulm” outbreak strain using the CRISPR–Cas system. Int J Med Microbiol 2015; 305:828-37. [DOI: 10.1016/j.ijmm.2015.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/13/2015] [Accepted: 08/04/2015] [Indexed: 12/24/2022] Open
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King NP, Newton P, Schuelein R, Brown DL, Petru M, Zarsky V, Dolezal P, Luo L, Bugarcic A, Stanley AC, Murray RZ, Collins BM, Teasdale RD, Hartland EL, Stow JL. Soluble NSF attachment protein receptor molecular mimicry by a Legionella pneumophila Dot/Icm effector. Cell Microbiol 2015; 17:767-84. [PMID: 25488819 DOI: 10.1111/cmi.12405] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/10/2014] [Accepted: 12/02/2014] [Indexed: 01/17/2023]
Abstract
Upon infection, Legionella pneumophila uses the Dot/Icm type IV secretion system to translocate effector proteins from the Legionella-containing vacuole (LCV) into the host cell cytoplasm. The effectors target a wide array of host cellular processes that aid LCV biogenesis, including the manipulation of membrane trafficking. In this study, we used a hidden Markov model screen to identify two novel, non-eukaryotic soluble NSF attachment protein receptor (SNARE) homologs: the bacterial Legionella SNARE effector A (LseA) and viral SNARE homolog A proteins. We characterized LseA as a Dot/Icm effector of L. pneumophila, which has close homology to the Qc-SNARE subfamily. The lseA gene was present in multiple sequenced L. pneumophila strains including Corby and was well distributed among L. pneumophila clinical and environmental isolates. Employing a variety of biochemical, cell biological and microbiological techniques, we found that farnesylated LseA localized to membranes associated with the Golgi complex in mammalian cells and LseA interacted with a subset of Qa-, Qb- and R-SNAREs in host cells. Our results suggested that LseA acts as a SNARE protein and has the potential to regulate or mediate membrane fusion events in Golgi-associated pathways.
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Affiliation(s)
- Nathan P King
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Patrice Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Vic., Australia
| | - Ralf Schuelein
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Vic., Australia
| | - Darren L Brown
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Marketa Petru
- Department of Parasitology, Charles University in Prague, Czech Republic
| | - Vojtech Zarsky
- Department of Parasitology, Charles University in Prague, Czech Republic
| | - Pavel Dolezal
- Department of Parasitology, Charles University in Prague, Czech Republic
| | - Lin Luo
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Andrea Bugarcic
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Amanda C Stanley
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Rachael Z Murray
- Tissue Repair and Regeneration Program, Institute of Health and Biomedical Innovation, School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, Qld., Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
| | - Elizabeth L Hartland
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Vic., Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Qld., Australia
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Cassier P, Campese C, Le Strat Y, Che D, Ginevra C, Etienne J, Jarraud S. Epidemiologic characteristics associated with ST23 clones compared to ST1 and ST47 clones of Legionnaires disease cases in France. New Microbes New Infect 2014; 3:29-33. [PMID: 25755889 PMCID: PMC4337934 DOI: 10.1016/j.nmni.2014.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 10/30/2014] [Indexed: 11/19/2022] Open
Abstract
In France, approximately 1200 cases of Legionnaires disease (LD) are reported annually, and isolates are available for approximately 20% of cases identified since 2000. All Legionella pneumophila serogroup 1 (sg1) isolates are characterized by sequence-based typing at the National Reference Centre. LD cases caused by L. pneumophila sg1 reported from 2008 through 2012 were considered for the study. Our study objective was to describe cases according to their sequence type (ST). We also constructed multivariable modified Poisson regression models to estimate the incidence rate ratio (IRR) and to identify characteristics potentially associated with ST23 clones compared to ST1 and ST47 clones. We studied 1192 patients infected by ST1 (n = 109), ST23 (n = 236), ST47 (n = 123) or other STs (n = 724). The geographic distribution of the ST23 cases across the country was significantly different compared to other ST groups. This genotype was significantly associated with the absence of corticosteroid therapy compared to ST1 (IRR = 0.56; p 0.016). Concerning exposure, the ST23 genotype was significantly less associated with hospital-acquired infections compared to ST1 (IRR = 0.32; p 0.001), but it was more associated with infections acquired in hospitals and elderly settings compared with ST47. Finally, the ST23 genotype was less frequently associated with travel than other STs. Despite the large number of cases of ST23 infection, we did not identify any characteristics specific to this ST. However, we identified independent associations between ST1 and nosocomial transmission and steroid therapy. These findings should encourage further exploration, especially in terms of environmental diffusion, strain virulence and host factors.
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Affiliation(s)
- P. Cassier
- Hospices Civils de Lyon, National Reference Centre of Legionella, Centre de Biologie Est, France
- CIRI, International Center for Infectiology Research, Legionella Pathogenosis Team, Université de Lyon, France
- Inserm, U1111, France
- Ecole Normale Supérieure de Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, France
- CNRS, UMR5308, Lyon, France
- Corresponding author: P. Cassier, Hospices Civils de Lyon, National Reference Centre of Legionella, Centre de Biologie Est, 59 Bd Pinel 69500 Bron, France.
| | - C. Campese
- French Institute for Public Health Surveillance, Saint Maurice, France
| | - Y. Le Strat
- French Institute for Public Health Surveillance, Saint Maurice, France
| | - D. Che
- French Institute for Public Health Surveillance, Saint Maurice, France
| | - C. Ginevra
- Hospices Civils de Lyon, National Reference Centre of Legionella, Centre de Biologie Est, France
- CIRI, International Center for Infectiology Research, Legionella Pathogenosis Team, Université de Lyon, France
- Inserm, U1111, France
- Ecole Normale Supérieure de Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, France
- CNRS, UMR5308, Lyon, France
| | - J. Etienne
- Hospices Civils de Lyon, National Reference Centre of Legionella, Centre de Biologie Est, France
| | - S. Jarraud
- Hospices Civils de Lyon, National Reference Centre of Legionella, Centre de Biologie Est, France
- CIRI, International Center for Infectiology Research, Legionella Pathogenosis Team, Université de Lyon, France
- Inserm, U1111, France
- Ecole Normale Supérieure de Lyon, France
- Université Lyon 1, Centre International de Recherche en Infectiologie, France
- CNRS, UMR5308, Lyon, France
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Moran-Gilad J, Mentasti M, Lazarovitch T, Huberman Z, Stocki T, Sadik C, Shahar T, Anis E, Valinsky L, Harrison T, Grotto I. Molecular epidemiology of Legionnaires‘ disease in Israel. Clin Microbiol Infect 2014; 20:690-6. [DOI: 10.1111/1469-0691.12425] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/26/2013] [Accepted: 10/05/2013] [Indexed: 11/30/2022]
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Molecular typing of Legionella pneumophila serogroup 1 clinical strains isolated in Italy. Int J Med Microbiol 2014; 304:597-602. [PMID: 24881962 DOI: 10.1016/j.ijmm.2014.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/07/2014] [Accepted: 04/19/2014] [Indexed: 11/20/2022] Open
Abstract
Molecular typing methods for discriminating different bacterial isolates are essential epidemiological tools in prevention and control of Legionella infections and outbreaks. A selection of 56 out of 184 Legionella pneumophila serogroup 1 (Lp1) clinical isolates, collected from different Italian regions between 1987 and 2012, and stored at the National Reference Laboratory for Legionella, were typed by monoclonal antibody (MAb) subgrouping, amplified fragment length polymorphism (AFLP) and sequence based typing (SBT). These strains were isolated from 39 community (69.6%), 14 nosocomial (25%) and 3 travel associated (5.4%) Legionnaires'disease cases. MAb typing results showed a prevalence of MAb 3/1 positive isolates (75%) with the Philadelphia subgroup representing 35.7%, followed by Knoxville (23.2%), Benidorm (12.5%), Allentown/France (1.8%), Allentown/France-Philadelphia (1.8%). The remaining 25% were MAb 3/1 negative, namely 11 Olda (19.6%), 2 Oxford (3.6%) and 1 Bellingham (1.8%) subgroups. AFLP analysis detected 20 different genomic profiles. SBT analysis revealed 32 different sequence types (STs) with high diversity of STs (IODSTs=0.952) 12 of which were never described before. ST1 and ST23 were most frequently isolated as observed worldwide. A helpful analysis of data from SBT, MAb subgrouping and AFLP is provided, as well as a comparison to the Lp1 types investigated from other countries. This study describes the first Italian Lp1 strains database, providing molecular epidemiology data useful for future epidemiological investigations, especially of travel associated Legionnaires' diseases (TALD) cases, Italy being the country associated with the highest number of clusters.
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12
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Kozak-Muiznieks NA, Lucas CE, Brown E, Pondo T, Taylor TH, Frace M, Miskowski D, Winchell JM. Prevalence of sequence types among clinical and environmental isolates of Legionella pneumophila serogroup 1 in the United States from 1982 to 2012. J Clin Microbiol 2014; 52:201-11. [PMID: 24197883 PMCID: PMC3911437 DOI: 10.1128/jcm.01973-13] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 10/28/2013] [Indexed: 11/20/2022] Open
Abstract
Since the establishment of sequence-based typing as the gold standard for DNA-based typing of Legionella pneumophila, the Legionella laboratory at the Centers for Disease Control and Prevention (CDC) has conducted routine sequence-based typing (SBT) analysis of all incoming L. pneumophila serogroup 1 (Lp1) isolates to identify potential links between cases and to better understand genetic diversity and clonal expansion among L. pneumophila bacteria. Retrospective genotyping of Lp1 isolates from sporadic cases and Legionnaires' disease (LD) outbreaks deposited into the CDC reference collection since 1982 has been completed. For this study, we compared the distribution of sequence types (STs) among Lp1 isolates implicated in 26 outbreaks in the United States, 571 clinical isolates from sporadic cases of LD in the United States, and 149 environmental isolates with no known association with LD. The Lp1 isolates under study had been deposited into our collection between 1982 and 2012. We identified 17 outbreak-associated STs, 153 sporadic STs, and 49 environmental STs. We observed that Lp1 STs from outbreaks and sporadic cases are more similar to each other than either group is to environmental STs. The most frequent ST for both sporadic and environmental isolates was ST1, accounting for 25% and 49% of the total number of isolates, respectively. The STs shared by both outbreak-associated and sporadic Lp1 included ST1, ST35, ST36, ST37, and ST222. The STs most commonly found in sporadic and outbreak-associated Lp1 populations may have an increased ability to cause disease and thus may require special attention when detected.
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Affiliation(s)
- Natalia A. Kozak-Muiznieks
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Claressa E. Lucas
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ellen Brown
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Tracy Pondo
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Thomas H. Taylor
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Michael Frace
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Jonas M. Winchell
- Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Lanternier F, Tubach F, Ravaud P, Salmon D, Dellamonica P, Bretagne S, Couret M, Bouvard B, Debandt M, Gueit I, Gendre JP, Leone J, Nicolas N, Che D, Mariette X, Lortholary O. Incidence and Risk Factors of Legionella pneumophila Pneumonia During Anti-Tumor Necrosis Factor Therapy. Chest 2013; 144:990-998. [DOI: 10.1378/chest.12-2820] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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14
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Legionella pneumophila sequence type 1/Paris pulsotype subtyping by spoligotyping. J Clin Microbiol 2012; 50:696-701. [PMID: 22205819 DOI: 10.1128/jcm.06180-11] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Endemic strains of Legionella pneumophila sequence type 1 (ST1), in particular the ST1/Paris pulsotype, are dispersed worldwide and represent about 10% of culture-proven clinical cases of Legionnaires' disease in France. The high rate of isolation of this strain from both clinical and environmental samples makes identification of the source of infection difficult during epidemiological investigations. The full-length genome sequence of this strain was recently determined, and it revealed the presence of a CRISPR/cas complex. The aim of this study was to develop and evaluate a spoligotyping tool based on the diversity of this CRISPR locus that would allow the accurate subtyping of the L. pneumophila serogroup 1 ST1/Paris pulsotype. The CRISPR loci of 28 L. pneumophila ST1/Paris pulsotype isolates were sequenced, and 42 different spacers regions were characterized. A membrane-based spoligotyping method was developed and used to determine the subtypes of 406 L. pneumophila isolates, including 233 with the ST1/Paris pulsotype profile that were collected in France from 2000 to 2011. A total of 46 different spoligotypes were detected, and 41 of these were specifically identified in the ST1/Paris pulsotype isolates. In 27 of 33 epidemiological investigations, the environmental source of contamination was confirmed by comparing spoligotypes of clinical isolates with those of environmental isolates. With an index of discrimination of 79.72% (95% confidence interval, 75.82 to 83.63), spoligotyping of the L. pneumophila ST1/Paris pulsotype has the potential to be a useful complementary genotyping tool for discriminating isolates with undistinguishable pulsed-field gel electrophoresis (PFGE) and ST genotypes, which could help to identify environmental sources of infection.
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15
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Gomez-Valero L, Rusniok C, Jarraud S, Vacherie B, Rouy Z, Barbe V, Medigue C, Etienne J, Buchrieser C. Extensive recombination events and horizontal gene transfer shaped the Legionella pneumophila genomes. BMC Genomics 2011; 12:536. [PMID: 22044686 PMCID: PMC3218107 DOI: 10.1186/1471-2164-12-536] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 11/01/2011] [Indexed: 02/06/2023] Open
Abstract
Background Legionella pneumophila is an intracellular pathogen of environmental protozoa. When humans inhale contaminated aerosols this bacterium may cause a severe pneumonia called Legionnaires' disease. Despite the abundance of dozens of Legionella species in aquatic reservoirs, the vast majority of human disease is caused by a single serogroup (Sg) of a single species, namely L. pneumophila Sg1. To get further insights into genome dynamics and evolution of Sg1 strains, we sequenced strains Lorraine and HL 0604 1035 (Sg1) and compared them to the available sequences of Sg1 strains Paris, Lens, Corby and Philadelphia, resulting in a comprehensive multigenome analysis. Results We show that L. pneumophila Sg1 has a highly conserved and syntenic core genome that comprises the many eukaryotic like proteins and a conserved repertoire of over 200 Dot/Icm type IV secreted substrates. However, recombination events and horizontal gene transfer are frequent. In particular the analyses of the distribution of nucleotide polymorphisms suggests that large chromosomal fragments of over 200 kbs are exchanged between L. pneumophila strains and contribute to the genome dynamics in the natural population. The many secretion systems present might be implicated in exchange of these fragments by conjugal transfer. Plasmids also play a role in genome diversification and are exchanged among strains and circulate between different Legionella species. Conclusion Horizontal gene transfer among bacteria and from eukaryotes to L. pneumophila as well as recombination between strains allows different clones to evolve into predominant disease clones and others to replace them subsequently within relatively short periods of time.
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Affiliation(s)
- Laura Gomez-Valero
- Institut Pasteur, Biologie des Bactéries Intracellulaires, 75724, Paris, France
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16
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High-throughput typing method to identify a non-outbreak-involved Legionella pneumophila strain colonizing the entire water supply system in the town of Rennes, France. Appl Environ Microbiol 2011; 77:6899-907. [PMID: 21821761 DOI: 10.1128/aem.05556-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two legionellosis outbreaks occurred in the city of Rennes, France, during the past decade, requiring in-depth monitoring of Legionella pneumophila in the water network and the cooling towers in the city. In order to characterize the resulting large collection of isolates, an automated low-cost typing method was developed. The multiplex capillary-based variable-number tandem repeat (VNTR) (multiple-locus VNTR analysis [MLVA]) assay requiring only one PCR amplification per isolate ensures a high level of discrimination and reduces hands-on and time requirements. In less than 2 days and using one 4-capillary apparatus, 217 environmental isolates collected between 2000 and 2009 and 5 clinical isolates obtained during outbreaks in 2000 and 2006 in Rennes were analyzed, and 15 different genotypes were identified. A large cluster of isolates with closely related genotypes and representing 77% of the population was composed exclusively of environmental isolates extracted from hot water supply systems. It was not responsible for the known Rennes epidemic cases, although strains showing a similar MLVA profile have regularly been involved in European outbreaks. The clinical isolates in Rennes had the same genotype as isolates contaminating a mall's cooling tower. This study further demonstrates that unknown environmental or genetic factors contribute to the pathogenicity of some strains. This work illustrates the potential of the high-throughput MLVA typing method to investigate the origin of legionellosis cases by allowing the systematic typing of any new isolate and inclusion of data in shared databases.
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17
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Légionelles et légionellose : qu’a-t-on découvert depuis 30 ans ? ACTA ACUST UNITED AC 2011; 59:134-6. [DOI: 10.1016/j.patbio.2009.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 04/03/2009] [Indexed: 11/20/2022]
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18
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Visca P, D'Arezzo S, Ramisse F, Gelfand Y, Benson G, Vergnaud G, Fry NK, Pourcel C. Investigation of the population structure of Legionella pneumophila by analysis of tandem repeat copy number and internal sequence variation. MICROBIOLOGY-SGM 2011; 157:2582-2594. [PMID: 21622529 DOI: 10.1099/mic.0.047258-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The population structure of the species Legionella pneumophila was investigated by multilocus variable number of tandem repeats (VNTR) analysis (MLVA) and sequencing of three VNTRs (Lpms01, Lpms04 and Lpms13) in selected strains. Of 150 isolates of diverse origins, 136 (86 %) were distributed into eight large MLVA clonal complexes (VACCs) and the rest were either unique or formed small clusters of up to two MLVA genotypes. In spite of the lower degree of genome-wide linkage disequilibrium of the MLVA loci compared with sequence-based typing, the clustering achieved by the two methods was highly congruent. The detailed analysis of VNTR Lpms04 alleles showed a very complex organization, with five different repeat unit lengths and a high level of internal variation. Within each MLVA-defined VACC, Lpms04 was endowed with a common recognizable pattern with some interesting exceptions. Evidence of recombination events was suggested by analysis of internal repeat variations at the two additional VNTR loci, Lpms01 and Lpms13. Sequence analysis of L. pneumophila VNTR locus Lpms04 alone provides a first-line assay for allocation of a new isolate within the L. pneumophila population structure and for epidemiological studies.
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Affiliation(s)
- Paolo Visca
- Dipartimento di Biologia, Università Roma Tre, Rome, Italy
| | - Silvia D'Arezzo
- Istituto Nazionale per le Malattie Infettive 'Lazzaro Spallanzani' IRCCS, Rome, Italy
| | - Françoise Ramisse
- Division of Analytical Microbiology, DGA CBRN Defence, Vert le Petit, France
| | - Yevgeniy Gelfand
- Department of Computer Science, Department of Biology, Program in Bioinformatics, Boston University, Boston, MA, USA.,Laboratory for Biocomputing and Informatics, Boston University, Boston, MA, USA
| | - Gary Benson
- Laboratory for Biocomputing and Informatics, Boston University, Boston, MA, USA
| | - Gilles Vergnaud
- DGA/MRIS, Mission pour la Recherche et l'Innovation Scientifique, Bagneux, France.,Université Paris-Sud, Institut de Génétique et Microbiologie, Orsay, France
| | - Norman K Fry
- Respiratory and Systemic Infection Laboratory, Health Protection Agency Centre for Infections, London, UK
| | - Christine Pourcel
- Université Paris-Sud, Institut de Génétique et Microbiologie, Orsay, France
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19
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Ali S, Phillips CA, Phillips PS, Bates M. Isolation and identification of Legionella pneumophila from material reclamation facilities. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2010; 20:367-377. [PMID: 20853198 DOI: 10.1080/09603123.2010.484859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Sampling points at a material reclamation facility (MRF) were monitored over three months for the presence of Legionella spp. A number of different Legionellae were isolated and typed to identify L. pneumophila serogroup 1, the serotype which is the most common human pathogen. Phenotypic methods resulted in a total of 61 presumptive isolates of Legionella spp. Using latex agglutination, 26 out of the 61 were identified as L. pneumophila serogroup 1, 23 as L. pneumophila serogroups 2-14, and the remaining 12 were Legionella spp. However, on typing using pulse field gel electrophoresis, the 26 L. pneumophila serotype 1 isolates were a diverse group of 25 PFGE types with none persisting in the environment over time. This diversity suggests that there are a number of contamination sources for this important human pathogen in the MRF environment which constitute a risk to health for operatives in these facilities.
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Affiliation(s)
- Shanom Ali
- School of Health, University of Northampton, Northampton, UK
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20
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Gosselin F, Duval JFL, Simonet J, Ginevra C, Gaboriaud F, Jarraud S, Mathieu L. Impact of the virulence-associated MAb3/1 epitope on the physicochemical surface properties of Legionella pneumophila sg1: An issue to explain infection potential? Colloids Surf B Biointerfaces 2010; 82:283-90. [PMID: 20889314 DOI: 10.1016/j.colsurfb.2010.08.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 08/26/2010] [Indexed: 11/25/2022]
Abstract
The relationship between the presence/absence of the virulence-associated MAb3/1 epitope of sixteen Legionella pneumophila serogroup 1 strains and their respective surface physicochemical properties is evidenced from electrokinetic measurements (microelectrophoresis) performed as a function of KNO(3) electrolyte concentration (range 1-100mM, pH∼6.5). Among the bacteria selected, nine original strains constitute the Dresden reference panel and differ according to the presence/absence of the virulence-associated monoclonal antibody MAb3/1 of the O-specific chain of the lipopolysaccharides (LPS). Five isogenic Lens strains, also investigated in the current study, present the epitope MAb3/1 of their LPS and were involved to some extent in the outbreak that stroke the Nord Pas-de-Calais region (France) in 2004. All bacteria exhibit the typical electrokinetic features of soft (permeable) particles. On the basis of Ohshima's model, analysis of the electrophoretic mobility data allows evaluating the intraparticular flow penetration length 1/λ(0) and the (negative) volume charge density ρ(0) that both reflect the structure and chemical composition of the soft bacterial component. Our results show that the virulent MAb3/1 positive strains are characterized on average by 1/λ(0) and ǀρ(0)ǀ values that are about 1.5 times larger and 5 times lower, respectively, than those derived for lesser virulent (MAb3/1 negative) strains. In other words, on average the soft surface layer of MAb3/1 positive strains is significantly less charged and more permeable than those of MAb3/1 negative strains. The intimate correlation between virulence-associated MAb3/1 epitope and charge density carried by the bacterial envelop was further confirmed by lower 1/λ(0) and greater ǀρ(0)ǀ values for lag-1 mutant CS332 strain, lacking the MAb3/1 epitope, compared to the parental strain AM511. A closer inspection of the dispersion in 1/λ(0) and ǀρ(0)ǀ data over the ensemble of analysed bacteria together with the reported number of Legionnaires' disease cases they are responsible for, points out the charge density ǀρ(0)ǀ as the parameter that is most suitable for discriminating highly virulent (MAb3/1 positive) from less virulent (MAb3/1 negative) strains. Although short-range interaction determines infection process, our results suggest that the infection potential of Legionella pneumophila serogroup 1 may be also controlled significantly by non-specific long-range electrostatic repulsion the bacteria undergo when approaching negatively charged host cells to be infected.
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Affiliation(s)
- F Gosselin
- Ecole Pratique des Hautes Etudes, UMR 7564 CNRS/Nancy Université, Pôle de l'Eau, F-54505 Vandoeuvre-lès-Nancy, France
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21
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Tijet N, Tang P, Romilowych M, Duncan C, Ng V, Fisman DN, Jamieson F, Low DE, Guyard C. New endemic Legionella pneumophila serogroup I clones, Ontario, Canada. Emerg Infect Dis 2010; 16:447-54. [PMID: 20202420 PMCID: PMC3322000 DOI: 10.3201/eid1603.081689] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Identifying geographic distribution can improve surveillance and clinical testing procedures. The water-borne pathogen Legionella pneumophila serogroup 1 (Lp1) is the most commonly reported etiologic agent of legionellosis. To examine the genetic diversity, the long-term epidemiology, and the molecular evolution of Lp1 clinical isolates, we conducted sequence-based typing on a collection of clinical isolates representing 3 decades of culture-confirmed legionellosis in Ontario, Canada. Analysis showed that the population of Lp1 in Ontario is highly diverse and combines lineages identified worldwide with local strains. Identical types were identified in sporadic and outbreak-associated strains. In the past 15 years, the incidence of some lineages distributed worldwide has tended to decrease, and local endemic clones and lineages have emerged. Comparative geographic distribution analysis suggests that some lineages are specific to eastern North America. These findings have general clinical implications for the study of Lp1 molecular evolution and for the identification of Lp1 circulating strains in North America.
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Affiliation(s)
- Nathalie Tijet
- Ontario Agency for Health Protection and Promotion, Toronto, Ontario, Canada
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22
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Hilbi H, Jarraud S, Hartland E, Buchrieser C. Update on Legionnaires' disease: pathogenesis, epidemiology, detection and control. Mol Microbiol 2010; 76:1-11. [PMID: 20149105 PMCID: PMC2914503 DOI: 10.1111/j.1365-2958.2010.07086.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Legionellosis or Legionnaires' disease is an emerging and often-fatal form of pneumonia that is most severe in elderly and immunocompromised people, an ever-increasing risk group for infection. In recent years, the genomics of Legionella spp. has significantly increased our knowledge of the pathogenesis of this disease by providing new insights into the evolution and genetic and physiological basis of Legionella-host interactions. The seventh international conference on Legionella, Legionella 2009, illustrated many recent conceptual advances in epidemiology, pathogenesis and ecology. Experts in different fields presented new findings on basic mechanisms of pathogen-host interactions and bacterial evolution, as well as the clinical management and environmental prevalence and persistence of Legionella. The presentations revealed remarkable facts about the genetic and metabolic basis of the intracellular lifestyle of Legionella and reported on its striking ability to manipulate host cell processes by molecular mimicry. Together, these investigations will lead to new approaches for the treatment and prevention of Legionnaires' disease.
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Affiliation(s)
- Hubert Hilbi
- Institute of Molecular Life Sciences, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Sophie Jarraud
- Centre National de Référence des Legionella, Université de Lyon, INSERM U851, Faculté de Médecine, IFR 128, Lyon, France
| | - Elizabeth Hartland
- Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France
- CNRS URA 2171, Paris, France
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23
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Edelstein PH, Metlay JP. Legionella pneumophila goes clonal--Paris and Lorraine strain-specific risk factors. Clin Infect Dis 2009; 49:192-4. [PMID: 19508166 DOI: 10.1086/599826] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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24
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Evaluation of a nested-PCR-derived sequence-based typing method applied directly to respiratory samples from patients with Legionnaires' disease. J Clin Microbiol 2009; 47:981-7. [PMID: 19225096 DOI: 10.1128/jcm.02071-08] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sequence-based typing (SBT) is a powerful method based on the sequencing of seven genes of Legionella pneumophila isolates. SBT performed directly on clinical samples has been used only in a limited number of cases. In our study, its efficiency was tested with 63 legionellosis respiratory samples. Sixty-three clinical samples, which included 23 samples from sporadic cases and 40 collected during four French outbreaks, confirmed by culture or urinary antigen testing and all positive by L. pneumophila quantitative PCR were subtyped by SBT according to the European Working Group for Legionella Infections standard scheme. Only 28.6% of the samples provided nucleotide sequences by SBT. Nested-PCR-based SBT (NPSBT) applied to the same respiratory samples was thus evaluated with new PCR primers surrounding the first set of primers used for the SBT. Sequencing results were obtained with 90.5% of the samples. Complete allelic profiles (seven genes sequenced) were obtained for 3.2% versus 53.9% of the samples by SBT and NPSBT, respectively. More importantly, of the 28 culture-negative samples, only 4 did not give any sequencing results. Taken together, NPSBT applied directly to clinical specimens significantly improved epidemiological typing compared to the initial SBT, in particular when no isolates are available.
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25
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Harrison TG, Afshar B, Doshi N, Fry NK, Lee JV. Distribution of Legionella pneumophila serogroups, monoclonal antibody subgroups and DNA sequence types in recent clinical and environmental isolates from England and Wales (2000–2008). Eur J Clin Microbiol Infect Dis 2009; 28:781-91. [PMID: 19156453 DOI: 10.1007/s10096-009-0705-9] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 01/11/2009] [Indexed: 11/25/2022]
Affiliation(s)
- T G Harrison
- Respiratory and Systemic Infections Department, HPA Centre for Infections, 61 Colindale Avenue, London, NW9 5HT, UK.
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