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Sabaneyeva E, Kursacheva E, Vizichkanich G, Lebedev D, Lebedeva N. Rhodotorula mucilaginosa: a new potential human pathogen found in the ciliate Paramecium bursaria. PROTOPLASMA 2025; 262:595-607. [PMID: 39745522 DOI: 10.1007/s00709-024-02025-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2024] [Accepted: 12/18/2024] [Indexed: 04/24/2025]
Abstract
Ciliates often form symbiotic associations with other microorganisms, both prokaryotic and eukaryotic. We are now starting to rediscover the symbiotic systems recorded before molecular analysis became available. Here, we provide a morphological and molecular characterization of a symbiotic association between the ciliate Paramecium tritobursaria and the yeast Rhodotorula mucilaginosa (syn. Rhodotorula rubra) isolated from a natural population. This symbiotic system demonstrates certain similarities with the symbiotic system formed by P. bursaria and its conventional endosymbionts, the zoochlorellae. Experimental infections of the endosymbiont-free P. tritobursaria and Paramecium deuterobursaria cell lines with R. mucilaginosa demonstrated that the yeast infectivity is concentration-dependent, with ciliates digesting part of the yeast cells. The endosymbiotic yeast may serve as a food reserve, providing starvation stress tolerance to the host. Since R. mucilaginosa is currently regarded as a pathogen causing opportunistic infections in immunocompromised humans, our finding gives further support to the vision that ciliates can harbor potential human pathogens and can be a vector for their dissemination.
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Affiliation(s)
- Elena Sabaneyeva
- Department of Cytology and Histology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russian Federation.
| | - Ekaterina Kursacheva
- Department of Cytology and Histology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
| | - Galina Vizichkanich
- Department of Cytology and Histology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
- A.G. Knorre Department of Histology and Embryology, Saint-Petersburg State Pediatric Medical University, Saint-Petersburg, Russian Federation
| | - Dmitrii Lebedev
- Department of Cytology and Histology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russian Federation
- Department of Genetics, Genomics and Cancer Sciences, University of Leicester, Leicester, UK
| | - Natalia Lebedeva
- Core Facility Center "Cultivation of Microorganisms", Saint-Petersburg State University, Saint-Petersburg, Russian Federation
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2
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Cameron G, Faucher SP. Copper resistance in Legionella pneumophila: Role of genetic factors and host cells. THE SCIENCE OF THE TOTAL ENVIRONMENT 2025; 958:177943. [PMID: 39671930 DOI: 10.1016/j.scitotenv.2024.177943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2024] [Revised: 11/27/2024] [Accepted: 12/03/2024] [Indexed: 12/15/2024]
Abstract
Copper is frequently found in drinking water due to its presence in the natural environment and the widespread usage of copper pipes. This toxic metal has a well-known antimicrobial activity, an activity harnessed in copper‑silver ionization (CSI) to eliminate the opportunistic pathogen Legionella pneumophila from engineered water systems. Despite utilizing the antimicrobial properties of copper in Legionella control, little is known about how copper containing environments affect L.pneumophila populations. The goal of this study is to understand how L. pneumophila responds to copper within a hot water distribution system (HWDS) environment. To answer this question, different sequence types and regulatory mutants were exposed to copper to compare their survival. L. pneumophila isolates of 4 sequence types from 3 different HWDSs exhibited a wide diversity of phenotypes after copper stress. The ΔletA and ΔletS mutants were sensitive to copper, indicating that the LetAS two component system is important for copper resistance. Additionally, transmissive phase cultures were more resistant to copper than replicative phase cultures. Therefore, the regulation of entry into transmissive phase by the LetAS system is essential for L. pneumophila's ability to survive copper stress. In a water system, L. pneumophila replicates within eukaryotic hosts. When cocultured with the host ciliate Tetrahymena pyriformis, L. pneumophila was more resistant to copper than when the bacteria were in a monoculture. No difference in L. pneumophila replication inside of hosts in cocultures with or without copper was observed. This result confirms that the presence of host cells protects L. pneumophila from copper stress.
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Affiliation(s)
- Gillian Cameron
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada; Centreau - Centre québécois de recherche sur la gestion de l'eau, Université Laval, Québec, Québec, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, Québec H9X 3V9, Canada; Centreau - Centre québécois de recherche sur la gestion de l'eau, Université Laval, Québec, Québec, Canada; Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, Saint-Hyacinthe, Québec, Canada.
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3
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Patel DT, Stogios PJ, Jaroszewski L, Urbanus ML, Sedova M, Semper C, Le C, Takkouche A, Ichii K, Innabi J, Patel DH, Ensminger AW, Godzik A, Savchenko A. Global atlas of predicted functional domains in Legionella pneumophila Dot/Icm translocated effectors. Mol Syst Biol 2025; 21:59-89. [PMID: 39562741 PMCID: PMC11696984 DOI: 10.1038/s44320-024-00076-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 10/17/2024] [Accepted: 10/31/2024] [Indexed: 11/21/2024] Open
Abstract
Legionella pneumophila utilizes the Dot/Icm type IVB secretion system to deliver hundreds of effector proteins inside eukaryotic cells to ensure intracellular replication. Our understanding of the molecular functions of the largest pathogenic arsenal known to the bacterial world remains incomplete. By leveraging advancements in 3D protein structure prediction, we provide a comprehensive structural analysis of 368 L. pneumophila effectors, representing a global atlas of predicted functional domains summarized in a database ( https://pathogens3d.org/legionella-pneumophila ). Our analysis identified 157 types of diverse functional domains in 287 effectors, including 159 effectors with no prior functional annotations. Furthermore, we identified 35 cryptic domains in 30 effector models that have no similarity with experimentally structurally characterized proteins, thus, hinting at novel functionalities. Using this analysis, we demonstrate the activity of thirteen functional domains, including three cryptic domains, predicted in L. pneumophila effectors to cause growth defects in the Saccharomyces cerevisiae model system. This illustrates an emerging strategy of exploring synergies between predictions and targeted experimental approaches in elucidating novel effector activities involved in infection.
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Affiliation(s)
- Deepak T Patel
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Peter J Stogios
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada
| | - Lukasz Jaroszewski
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA
| | - Malene L Urbanus
- Department of Biochemistry, University of Toronto, Toronto, ON, M5G 1M1, Canada
| | - Mayya Sedova
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA
| | - Cameron Semper
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Cathy Le
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Abraham Takkouche
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA
| | - Keita Ichii
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA
| | - Julie Innabi
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA
| | - Dhruvin H Patel
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Alexander W Ensminger
- Department of Biochemistry, University of Toronto, Toronto, ON, M5G 1M1, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 1M1, Canada.
| | - Adam Godzik
- University of California, Riverside, School of Medicine, Biosciences Division, Riverside, CA, USA.
| | - Alexei Savchenko
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, T2N 4N1, Canada.
- BioZone, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, M5S 1A4, Canada.
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4
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Graham CI, MacMartin TL, de Kievit TR, Brassinga AKC. Molecular regulation of virulence in Legionella pneumophila. Mol Microbiol 2024; 121:167-195. [PMID: 37908155 DOI: 10.1111/mmi.15172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 11/02/2023]
Abstract
Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.
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Affiliation(s)
- Christopher I Graham
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teassa L MacMartin
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R de Kievit
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
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5
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Zacharias N, Waßer F, Freier L, Spies K, Koch C, Pleischl S, Mutters NT, Kistemann T. Legionella in drinking water: the detection method matters. JOURNAL OF WATER AND HEALTH 2023; 21:884-894. [PMID: 37515560 PMCID: wh_2023_035 DOI: 10.2166/wh.2023.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/31/2023]
Abstract
Legionella concentrations in drinking water have been regulated for decades and are evaluated with regard to their concentrations in drinking water plumbing systems (DWPS). The respective action levels differ at the international level. In Germany, the Federal Environment Agency (UBA) specifies the application of ISO 11731 for the detection of legionella in drinking water and gives a binding recommendation for the methods to be used for culturing and evaluation. Effective from 01 March 2019, the UBA recommendation was revised. The utilized culture media in the culture approach were altered, consequently affecting the spectrum of legionella colonies detected in drinking water. Using data from a routine legionella monitoring of a large laboratory, over a period of 6 years and 17,270 individual drinking water samples, allowed us to assess the impact of the alteration on the assessment of DWPS. By comparing the amount of action level exceedances before and after the method change, it could be demonstrated that exceedances are reported significantly more often under the new method. Consequently, the corresponding action level for evaluation of legionella contamination and the resulting risk to human health needs to be revised to avoid the misleading impression of increased health risk.
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Affiliation(s)
- Nicole Zacharias
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany E-mail:
| | - Felix Waßer
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Lia Freier
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Kirsten Spies
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Christoph Koch
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Stefan Pleischl
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Nico T Mutters
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany
| | - Thomas Kistemann
- Institute for Hygiene and Public Health, University Hospital Bonn, Venusberg-Campus 1, Bonn 53127, Germany; Department of Geography, University of Bonn, Meckenheimer Allee 166, Bonn 53115, Germany; Centre for Development Research, University of Bonn, Genscherallee 3, Bonn 53113, Germany
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6
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Blanford WJ, O'Mullan GD. Evaluation of a novel porous antimicrobial media for industrial and HVAC water biocontrol. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2023; 87:2457-2473. [PMID: 37257103 PMCID: wst_2023_076 DOI: 10.2166/wst.2023.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A novel treatment method, consisting of pea-gravel with a marine coating supplemented with alkyldimethylbenzylammonium chloride (ADBAC or benzalkonium chloride), has been examined for its antimicrobial performance and coating stability in aqueous environments. Initial column studies examining the porous media's ability to reduce bacterial loads in heating, ventilation, and air conditioning (HVAC) water found average reductions of 94% from pre-flush levels (106 colony forming unit (CFU)/mL) when assessed with R2A spread plates and 83% reductions with SimPlates. There was no observed statistical difference between the average of pre- and post-flush waters from four tests of the media without ADBAC. Taxonomic identification, by 16S rRNA gene sequencing, of colonies drawn from pre- and post-ABDAC R2A plates showed similarities with taxa observed in high frequency from prior cultivation-independent surveys of other cooling tower systems. With this proof of concept, two versions of the media were evaluated for potential coating components released during aqueous exposure. Neither released measurable volatile organic compounds (VOC) components, but one did release bisphenol A and ABDAC compounds. Subsequent column tests of the more durable coating were conducted using cultures of interest in industrial water and demonstrated significant reductions in neutralized post-column Enterococcus faecalis samples and near complete loss of Legionella pneumophila in non-neutralized fluids, but lower reductions in Pseudomonas aeruginosa.
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Affiliation(s)
- William James Blanford
- School of Earth and Environmental Science, Queens College, CUNY, 6530 Kissena Boulevard, D202 SB, Flushing, NY 11367, USA E-mail: ;
| | - Gregory D O'Mullan
- School of Earth and Environmental Science, Queens College, CUNY, 6530 Kissena Boulevard, D202 SB, Flushing, NY 11367, USA E-mail: ;
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7
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Rozas-Serri M. Why Does Piscirickettsia salmonis Break the Immunological Paradigm in Farmed Salmon? Biological Context to Understand the Relative Control of Piscirickettsiosis. Front Immunol 2022; 13:856896. [PMID: 35386699 PMCID: PMC8979166 DOI: 10.3389/fimmu.2022.856896] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/22/2022] [Indexed: 11/28/2022] Open
Abstract
Piscirickettsiosis (SRS) has been the most important infectious disease in Chilean salmon farming since the 1980s. It was one of the first to be described, and to date, it continues to be the main infectious cause of mortality. How can we better understand the epidemiological situation of SRS? The catch-all answer is that the Chilean salmon farming industry must fight year after year against a multifactorial disease, and apparently only the environment in Chile seems to favor the presence and persistence of Piscirickettsia salmonis. This is a fastidious, facultative intracellular bacterium that replicates in the host’s own immune cells and antigen-presenting cells and evades the adaptive cell-mediated immune response, which is why the existing vaccines are not effective in controlling it. Therefore, the Chilean salmon farming industry uses a lot of antibiotics—to control SRS—because otherwise, fish health and welfare would be significantly impaired, and a significantly higher volume of biomass would be lost per year. How can the ever-present risk of negative consequences of antibiotic use in salmon farming be balanced with the productive and economic viability of an animal production industry, as well as with the care of the aquatic environment and public health and with the sustainability of the industry? The answer that is easy, but no less true, is that we must know the enemy and how it interacts with its host. Much knowledge has been generated using this line of inquiry, however it remains insufficient. Considering the state-of-the-art summarized in this review, it can be stated that, from the point of view of fish immunology and vaccinology, we are quite far from reaching an effective and long-term solution for the control of SRS. For this reason, the aim of this critical review is to comprehensively discuss the current knowledge on the interaction between the bacteria and the host to promote the generation of more and better measures for the prevention and control of SRS.
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8
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Logan-Jackson A, Rose JB. Cooccurrence of Five Pathogenic Legionella spp. and Two Free-Living Amoebae Species in a Complete Drinking Water System and Cooling Towers. Pathogens 2021; 10:pathogens10111407. [PMID: 34832563 PMCID: PMC8619718 DOI: 10.3390/pathogens10111407] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/13/2022] Open
Abstract
Pathogenic Legionella species grow optimally inside free-living amoebae to concentrations that increase risks to those who are exposed. The aim of this study was to screen a complete drinking water system and cooling towers for the occurrence of Acanthamoeba spp. and Naegleria fowleri and their cooccurrence with Legionella pneumophila, Legionella anisa, Legionella micdadei, Legionella bozemanii, and Legionella longbeachae. A total of 42 large-volume water samples, including 12 from the reservoir (water source), 24 from two buildings (influents to the buildings and exposure sites (taps)), and six cooling towers were collected and analyzed using droplet digital PCR (ddPCR). N. fowleri cooccurred with L. micdadei in 76 (32/42) of the water samples. In the building water system, the concentrations of N. fowleri and L. micdadei ranged from 1.5 to 1.6 Log10 gene copies (GC)/100 mL, but the concentrations of species increased in the cooling towers. The data obtained in this study illustrate the ecology of pathogenic Legionella species in taps and cooling towers. Investigating Legionella’s ecology in drinking and industrial waters will hopefully lead to better control of these pathogenic species in drinking water supply systems and cooling towers.
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Affiliation(s)
- Alshae Logan-Jackson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- Correspondence:
| | - Joan B. Rose
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI 48824, USA;
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9
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Croze A, Carlino A, Quélard B, Saha A, Convert T, Eberst JB, Demanèche S. Intracellular Behaviour of Legionella Non- pneumophila Strains within Three Amoeba Strains, Including Willaertia magna C2c Maky. Pathogens 2021; 10:pathogens10101350. [PMID: 34684299 PMCID: PMC8538512 DOI: 10.3390/pathogens10101350] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/07/2021] [Accepted: 10/15/2021] [Indexed: 01/05/2023] Open
Abstract
Legionellosis, an often-lethal pneumonia, is generally associated with contamination by Legionella pneumophila. This bacterium can persist in the environment and resist chemical treatment when it is internalized by amoebae. In addition, there is increasing medical proof that other Legionella species can be causative agents of Legionellosis. The objective of this study was to evaluate whether Legionella non-pneumophila (Lnp) strains were able to use the machinery of amoeba to multiply, or whether amoebae were able to limit their proliferation. Seven strains belonging to the species L. longbeachae, L. anisa, L. bozemanae, L. taurinensis, and L. dumoffii were cocultured with three amoebae, Acanthamoeba castellanii, Willaertia magna T5(S)44, and Willaertia magna C2c Maky, at two temperatures, 22 and 37 °C. We found that at 22 °C, all amoebae were able to phagocytose the seven Lnp strains and to avoid intracellular development, except for L. longbeachae, which was able to multiply inside W. magna T5(S)44. At 37 °C, four Lnp strains were able to hijack the machinery of one or two amoebae and to use it to proliferate, but none were able to multiply inside W. magna C2c Maky.
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10
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Kim SJ, Sin JI, Kim MJ. CD8 + T Cells Directed Against a Peptide Epitope Derived From Peptidoglycan-Associated Lipoprotein of Legionella pneumophila Confer Disease Protection. Front Immunol 2020; 11:604413. [PMID: 33363545 PMCID: PMC7752948 DOI: 10.3389/fimmu.2020.604413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/06/2020] [Indexed: 01/10/2023] Open
Abstract
Legionella pneumophila, an intracellular bacterium, may cause life-threatening pneumonia in immunocompromised individuals. Mononuclear cells and antibodies have been reported to be associated with the host defense response against L. pneumophila. This study is to determine whether Legionella peptidoglycan-associated lipoprotein (PAL)-specific CD8+ T cells are directly associated with protection against L. pneumophila, with a focus on potential epitopes. Synthetic peptides derived from PAL of L. pneumophila were obtained and tested through in vitro and in vivo cytotoxic T lymphocyte (CTL) assays for immunogenicity. PAL DNA vaccines or a peptide epitope with or without CpG-oligodeoxynucleotides (ODN) was evaluated for protection against L. pneumophila infection in animal models. When mice were immunized with DNA vaccines expressing the PAL of L. pneumophila, they were significantly protected against a lethal challenge with L. pneumophila through induction of antigen-specific CD8+ CTLs. Of the 13 PAL peptides tested, PAL92-100 (EYLKTHPGA) was the most immunogenic and induced the strongest CTL responses. When mice were immunized with the PAL92-100 peptide plus CpG-ODN, they were protected against the lethal challenge, while control mice died within 3–6 days after the challenge. Consistent with lung tissue histological data, bacterial counts in the lungs of immunized mice were significantly lower than those in control mice. Also, the amino acid sequence of PAL92-100 peptides is conserved among various Legionella species. To our knowledge, this study is the first to demonstrate that PAL92-100-specific CD8+ T cells play a central role in the host defense response against L. pneumophila.
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Affiliation(s)
- Sun Jin Kim
- Department of Medicine, College of Medicine, Korea University, Seoul, South Korea
| | - Jeong-Im Sin
- Department of Microbiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, South Korea
| | - Min Ja Kim
- Department of Medicine, College of Medicine, Korea University, Seoul, South Korea.,Division of Infectious Diseases, Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, South Korea.,Institute of Emerging Infectious Diseases, Korea University College of Medicine, Seoul, South Korea
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11
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George AS, Rehfuss MYM, Parker CT, Brandl MT. The transcriptome of Escherichia coli O157: H7 reveals a role for oxidative stress resistance in its survival from predation by Tetrahymena. FEMS Microbiol Ecol 2020; 96:5721237. [PMID: 32009174 DOI: 10.1093/femsec/fiaa014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/28/2020] [Indexed: 11/14/2022] Open
Abstract
Pathogenic E. coli remains undigested upon phagocytosis by Tetrahymena and is egested from the ciliate as viable cells in its fecal pellets. Factors that are involved in the survival of Shiga toxin-producing E. coli serovar O157: H7 (EcO157) from digestion by Tetrahymena were identified by microarray analysis of its transcriptome in the protozoan phagosome. Numerous genes belonging to anaerobic metabolism and various stress responses were upregulated significantly ≥ 2-fold in EcO157 cells in the food vacuoles compared with in planktonic cells that remained uningested by the protist. Among these were the oxidative stress response genes, ahpF and katG. Fluorescence microscopy and staining with CellROX® Orange confirmed the presence of reactive oxygen species in food vacuoles containing EcO157 cells. Frequency distribution analysis of the percentage of EcO157 viable cells in Tetrahymena fecal pellets revealed that the ΔahpCF and ΔahpCFΔkatG mutants were less fit than the wild type strain and ΔkatG mutant after passage through the protist. Given the broad use of oxidants as sanitizers in the food industry, our observation of the oxidative stress response in EcO157 during its interaction with Tetrahymena emphasizes the importance of furthering our knowledge of the physiology of this human pathogen in environments relevant to its ecology and to food safety.
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Affiliation(s)
- Andree Sherlon George
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Marc Yi Ming Rehfuss
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Craig Thomas Parker
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
| | - Maria Theresa Brandl
- Produce Safety and Microbiology Research Unit, Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, CA, USA
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12
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Dey R, Mameri MR, Trajkovic-Bodennec S, Bodennec J, Pernin P. Impact of inter-amoebic phagocytosis on the L. pneumophila growth. FEMS Microbiol Lett 2020; 367:5899054. [PMID: 32860684 DOI: 10.1093/femsle/fnaa147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2020] [Indexed: 01/21/2023] Open
Abstract
Free-living amoebae are known to act as replication niches for the pathogenic bacterium Legionella pneumophila in freshwater environments. However, we previously reported that some strains of the Willaertia magna species are more resistant to L. pneumophila infection and differ in their ability to support its growth. From this observation, we hypothesize that L. pneumophila growth in environment could be partly dependent on the composition of amoebic populations and on the possible interactions between different amoebic species. We tested this hypothesis by studying the growth of L. pneumophila and of a permissive free-living amoeba, Vermamoeba vermiformis (formerly named Hartmannella vermiformis), in co-culture with or without other free-living amoebae (Acanthamoeba castellanii and W. magna). We demonstrate the occurrence of inter-amoebic phagocytosis with A. castellanii and W. magna being able to ingest V. vermiformis infected or not infected with L. pneumophila. We also found that L. pneumophila growth is strongly impacted by the permissiveness of each interactive amoeba demonstrating that L. pneumophila proliferation and spread are controlled, at least in part, by inter-amoebic interactions.
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Affiliation(s)
- Rafik Dey
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France.,School of public health. University of Alberta, Edmonton AB, Canada
| | - Mouh Rayane Mameri
- Amoeba R & D Center, 38 Av des Frères Montgolfier, Chassieu F-69680, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France
| | | | - Jacques Bodennec
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1, Lyon Neuroscience Research Center CNRS, UMR 5292, Villeurbanne, F-69622, France.,Université Lyon 1, INSERM, U1028, Tiger Team, Bron, F-69500, France
| | - Pierre Pernin
- Université claude Bernard Lyon I, 43 boulevard du 11 Novembre 1918, 69100 Villeurbanne, France.,Université Lyon 1; ISPB-Faculté de Pharmacie Laboratoire de Biologie Cellulaire, 8, Avenue Rockefeller, F-69373, France
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Lanzas C, Davies K, Erwin S, Dawson D. On modelling environmentally transmitted pathogens. Interface Focus 2020; 10:20190056. [PMID: 31897293 PMCID: PMC6936006 DOI: 10.1098/rsfs.2019.0056] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2019] [Indexed: 12/11/2022] Open
Abstract
Many pathogens are able to replicate or survive in abiotic environments. Disease transmission models that include environmental reservoirs and environment-to-host transmission have used a variety of functional forms and modelling frameworks without a clear connection to pathogen ecology or space and time scales. We present a conceptual framework to organize microparasites based on the role that abiotic environments play in their lifecycle. Mean-field and individual-based models for environmental transmission are analysed and compared. We show considerable divergence between both modelling approaches when conditions do not facilitate well mixing and for pathogens with fast dynamics in the environment. We conclude with recommendations for modelling environmentally transmitted pathogens based on the pathogen lifecycle and time and spatial scales of the host-pathogen system under consideration.
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Affiliation(s)
- Cristina Lanzas
- Department of Population Health and Pathobiology, North Carolina State University, Raleigh, NC, USA
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14
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Von Dwingelo J, Chung IYW, Price CT, Li L, Jones S, Cygler M, Abu Kwaik Y. Interaction of the Ankyrin H Core Effector of Legionella with the Host LARP7 Component of the 7SK snRNP Complex. mBio 2019; 10:e01942-19. [PMID: 31455655 PMCID: PMC6712400 DOI: 10.1128/mbio.01942-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 12/18/2022] Open
Abstract
Species of the Legionella genus encode at least 18,000 effector proteins that are translocated through the Dot/Icm type IVB translocation system into macrophages and protist hosts to enable intracellular growth. Eight effectors, including ankyrin H (AnkH), are common to all Legionella species. The AnkH effector is also present in Coxiella and Rickettsiella To date, no pathogenic effectors have ever been described that directly interfere with host cell transcription. We determined that the host nuclear protein La-related protein 7 (LARP7), which is a component of the 7SK small nuclear ribonucleoprotein (snRNP) complex, interacts with AnkH in the host cell nucleus. The AnkH-LARP7 interaction partially impedes interactions of the 7SK snRNP components with LARP7, interfering with transcriptional elongation by polymerase (Pol) II. Consistent with that, our data show AnkH-dependent global reprogramming of transcription of macrophages infected by Legionella pneumophila The crystal structure of AnkH shows that it contains four N-terminal ankyrin repeats, followed by a cysteine protease-like domain and an α-helical C-terminal domain. A substitution within the β-hairpin loop of the third ankyrin repeat results in diminishment of LARP7-AnkH interactions and phenocopies the ankH null mutant defect in intracellular growth. LARP7 knockdown partially suppresses intracellular proliferation of wild-type (WT) bacteria and increases the severity of the defect of the ΔankH mutant, indicating a role for LARP7 in permissiveness of host cells to intracellular bacterial infection. We conclude that the AnkH-LARP7 interaction impedes interaction of LARP7 with 7SK snRNP, which would block transcriptional elongation by Pol II, leading to host global transcriptional reprogramming and permissiveness to L. pneumophilaIMPORTANCE For intracellular pathogens to thrive in host cells, an environment that supports survival and replication needs to be established. L. pneumophila accomplishes this through the activity of the ∼330 effector proteins that are injected into host cells during infection. Effector functions range from hijacking host trafficking pathways to altering host cell machinery, resulting in altered cell biology and innate immunity. One such pathway is the host protein synthesis pathway. Five L. pneumophila effectors have been identified that alter host cell translation, and 2 effectors have been identified that indirectly affect host cell transcription. No pathogenic effectors have been described that directly interfere with host cell transcription. Here we show a direct interaction of the AnkH effector with a host cell transcription complex involved in transcriptional elongation. We identify a novel process by which AnkH interferes with host transcriptional elongation through interference with formation of a functional complex and show that this interference is required for pathogen proliferation.
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Affiliation(s)
- Juanita Von Dwingelo
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Ivy Yeuk Wah Chung
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Christopher T Price
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Lei Li
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Snake Jones
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Louisville, Kentucky, USA
- Center for Predictive Medicine, College of Medicine, University of Louisville, Louisville, Kentucky, USA
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15
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Sharaby Y, Rodríguez-Martínez S, Höfle MG, Brettar I, Halpern M. Quantitative microbial risk assessment of Legionella pneumophila in a drinking water supply system in Israel. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 671:404-410. [PMID: 30933796 DOI: 10.1016/j.scitotenv.2019.03.287] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/13/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Legionella pneumophila cause human infections via inhalation of contaminated water aerosols, resulting in severe pneumonia. Legionella spp. prevalence was monitored in a drinking-water distribution system (DWDS) in Northern Israel. Five points (toilet faucets and showers) were sampled seasonally along a three years period. Toilet faucets and shower use, both generating aerosols, are known transmission routes for this pathogen and thus, present a potential health risk. Quantitative Microbial Risk Assessment (QMRA) was applied in order to assess the health risks posed by Legionella for these two exposure scenarios, while considering Legionella seasonality. The obtained results were compared with estimated tolerable risk levels of infection and of disease set by the USEPA and WHO. Both limits were expressed as Disability-Adjusted Life Years index (DALY) being 1 × 10-4 and 1 × 10-6, respectively. The QMRA revealed that the annual risk levels for both faucets and showers use exceeded the acceptable risk of infection with an average of 5.52 × 10-4 and 2.37 × 10-3 DALY'S per person per year, respectively. Annual risk levels were stable with no significant differences between the three years. Risk levels varied significantly between seasons by up to three orders of magnitude. Risk levels were highest during summer, autumn, and lowest during winter. The highest seasonal infection risk values were found in summer for both faucets and showers, which corresponded to 8.09 × 10-4 and 2.75 × 10-3 DALY'S per person per year, respectively. In conclusion, during summer and autumn there is a significant increase of the infection risk associated with exposure to Legionella-contaminated aerosols, in the studied water system. Public health assessment and prevention measures should focus on these seasons.
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Affiliation(s)
- Y Sharaby
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel.
| | - S Rodríguez-Martínez
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - M G Höfle
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - I Brettar
- Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany
| | - M Halpern
- Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel; Department of Biology and Environment, Faculty of Natural Sciences, University of Haifa, Oranim, Tivon, Israel
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16
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White RC, Cianciotto NP. Assessing the impact, genomics and evolution of type II secretion across a large, medically important genus: the Legionella type II secretion paradigm. Microb Genom 2019; 5. [PMID: 31166887 PMCID: PMC6617341 DOI: 10.1099/mgen.0.000273] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type II secretion system (T2SS) plays a major role in promoting bacterial survival in the environment and in human hosts. One of the best characterized T2SS is that of Legionella pneumophila, the agent of Legionnaires’ disease. Secreting at least 25 proteins, including degradative enzymes, eukaryotic-like proteins and novel effectors, this T2SS contributes to the ability of L. pneumophila to grow at low temperatures, infect amoebal and macrophage hosts, damage lung tissue, evade the immune system, and undergo sliding motility. The genes encoding the T2SS are conserved across the genus Legionella, which includes 62 species and >30 pathogens in addition to L. pneumophila. The vast majority of effectors associated with L. pneumophila are shared by a large number of Legionella species, hinting at a critical role for them in the ecology of Legionella as a whole. However, no other species has the same repertoire as L. pneumophila, with, as a general rule, phylogenetically more closely related species sharing similar sets of effectors. T2SS effectors that are involved in infection of a eukaryotic host(s) are more prevalent throughout Legionella, indicating that they are under stronger selective pressure. The Legionella T2SS apparatus is closest to that of Aquicella (another parasite of amoebae), and a significant number of L. pneumophila effectors have their closest homologues in Aquicella. Thus, the T2SS of L. pneumophila probably originated within the order Legionellales, with some of its effectors having arisen within that Aquicella-like progenitor, while other effectors derived from the amoebal host, mimiviruses, fungi and less closely related bacteria.
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Affiliation(s)
- Richard C White
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
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17
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Caicedo C, Rosenwinkel KH, Exner M, Verstraete W, Suchenwirth R, Hartemann P, Nogueira R. Legionella occurrence in municipal and industrial wastewater treatment plants and risks of reclaimed wastewater reuse: Review. WATER RESEARCH 2019; 149:21-34. [PMID: 30445393 DOI: 10.1016/j.watres.2018.10.080] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/26/2018] [Accepted: 10/27/2018] [Indexed: 05/22/2023]
Abstract
Wastewater treatment plants (WWTPs) have been identified as confirmed but until today underestimated sources of Legionella, playing an important role in local and community cases and outbreaks of Legionnaires' disease. In general, aerobic biological systems provide an optimum environment for the growth of Legionella due to high organic nitrogen and oxygen concentrations, ideal temperatures and the presence of protozoa. However, few studies have investigated the occurrence of Legionella in WWTPs, and many questions in regards to the interacting factors that promote the proliferation and persistence of Legionella in these treatment systems are still unanswered. This critical review summarizes the current knowledge about Legionella in municipal and industrial WWTPs, the conditions that might support their growth, as well as control strategies that have been applied. Furthermore, an overview of current quantification methods, guidelines and health risks associated with Legionella in reclaimed wastewater is also discussed in depth. A better understanding of the conditions promoting the occurrence of Legionella in WWTPs will contribute to the development of improved wastewater treatment technologies and/or innovative mitigation approaches to minimize future Legionella outbreaks.
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Affiliation(s)
- C Caicedo
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
| | - K-H Rosenwinkel
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany
| | - M Exner
- University of Bonn, Institute for Hygiene and Public Health, Bonn, Germany
| | - W Verstraete
- Ghent University, CMET, Ghent, and Avecom, Wondelgem, Belgium
| | - R Suchenwirth
- Public Health Office of Lower Saxony, Hannover, Germany
| | - P Hartemann
- Faculty of Medicine, Department of Environment and Public Health, Nancy University-CHU Nancy, Vandoeuvre Les Nancy, France
| | - R Nogueira
- Leibniz University Hannover, Institute for Sanitary Engineering and Waste Management, Hannover, 30167, Germany.
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18
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KİREÇCİ E, DAĞLI S. Kahramanmaraş İlindeki Camilerin Klima ve Şadırvanlarından Legionella Cinsi Bakterilerin İdentifikasyonu. DÜZCE ÜNIVERSITESI SAĞLIK BILIMLERI ENSTITÜSÜ DERGISI 2019. [DOI: 10.33631/duzcesbed.492223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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19
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Baqer NN, Hammood AH, Hassan KF, Hassan ESAD. DETECTION OF WATER-BORNE PARASITES IN DRINKING WATER OF BAGHDAD, IRAQ. Afr J Infect Dis 2018; 12:1-6. [PMID: 30109279 PMCID: PMC6085744 DOI: 10.21010/ajid.v12i2.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 09/13/2017] [Accepted: 10/13/2017] [Indexed: 11/23/2022] Open
Abstract
Background: Within the past few decades, there has been an increase in the number of water-borne disease outbreaks and emergence of newly recognized waterborne parasites. Several factors which contribute to the spread of these diseases include: water, heavy rains and agricultural residues which transfer the parasites to water surface from the soil. The aim of this study was to detect the presence of parasites in the river and drinking water of Al-Wahdaa and Al-Rasheed Drinking Project and household water tanks from some regions of Baghdad. Method: Forty samples were collected from river and drinking water of Drinking Project. Fifty four samples of household water tanks were collected from some regions of Baghdad. Results: Cryptosporidium oocyst, which was founded in river water samples are more than those in drinking water. Furthermore, it was existed in Diyala Bridge &Taha Mosque from April – August and oocyst was diagnosed by using of Zheil-Neelson. Wet mount slide method was applied to detect cysts of free-living amoeba Acanthomoeba, Naegleria. The number of cysts in July and August were higher than other months for Drinking Project and the water tanks for all regions. Conclusion: These results emphasize the importance screening of the water to prevent possible of the spread of parasitic protozoan and that the cracks occurrence in drinking water pipes between the stations and houses led to contamination of water with the infective stage of parasites, especially in the areas that are near agricultural fields which polluted with the cows’ waste.
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Affiliation(s)
- Noor Nihad Baqer
- Ministry of Science and Technology, Directorate of Water and Environment, Iraq
| | - Amel Hamzah Hammood
- Ministry of Science and Technology, Directorate of Water and Environment, Iraq
| | - Khalid Falih Hassan
- Ministry of Science and Technology, Directorate of Water and Environment, Iraq
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20
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Virulence Traits of Environmental and Clinical Legionella pneumophila Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Genotypes. Appl Environ Microbiol 2018. [PMID: 29523542 DOI: 10.1128/aem.00429-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Legionella pneumophila causes water-based infections resulting in severe pneumonia. Recently, we showed that different MLVA-8 (multilocus variable-number tandem-repeat analysis using 8 loci) genotypes dominated different sites of a drinking-water distribution system. Each genotype displayed a unique temperature-dependent growth behavior. Here we compared the pathogenicity potentials of different MLVA-8 genotypes of environmental and clinical strains. The virulence traits studied were hemolytic activity and cytotoxicity toward amoebae and macrophages. Clinical strains were significantly more hemolytic than environmental strains, while their cytotoxicity toward amoebae was significantly lower at 30°C. No significant differences were detected between clinical and environmental strains in cytotoxicity toward macrophages. Significant differences in virulence were observed between the environmental genotypes (Gt). Gt15 strains showed a significantly higher hemolytic activity. In contrast, Gt4 and Gt6 strains were more infective toward Acanthamoeba castellanii Moreover, Gt4 strains exhibited increased cytotoxicity toward macrophages and demonstrated a broader temperature range of amoebal lysis than Gt6 and Gt15 strains. Understanding the virulence traits of Legionella genotypes may improve the assessment of public health risks of Legionella in drinking water.IMPORTANCELegionella pneumophila is the causative agent of a severe form of pneumonia. Here we demonstrated that clinical strains were significantly more cytotoxic toward red blood cells than environmental strains, while their cytotoxicity toward macrophages was similar. Genotype 4 (Gt4) strains were highly cytotoxic toward amoebae and macrophages and lysed amoebae in a broader temperature range than to the other studied genotypes. The results can explain the relatively high success of Gt4 in the environment and in clinical samples; thus, Gt4 strains should be considered a main factor for the assessment of public health risks of Legionella in drinking water. Our findings shed light on the ecology, virulence, and pathogenicity potential of different L. pneumophila genotypes, which can be a valuable parameter for future modeling and quantitative microbial risk assessment of Legionella in drinking-water systems.
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21
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McBurnett LR, Holt NT, Alum A, Abbaszadegan M. Legionella - A threat to groundwater: Pathogen transport in recharge basin. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 621:1485-1490. [PMID: 29054644 DOI: 10.1016/j.scitotenv.2017.10.080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 10/03/2017] [Accepted: 10/09/2017] [Indexed: 06/07/2023]
Abstract
This study elucidates the potential risk posed by Legionella during aquifer recharge practices. Experiments were conducted using pilot-scale column simulating infiltration of bacterial surrogate and pathogen, E. coli and Legionella pneumophila, under central Arizona recharge basin conditions. A column was packed with a loamy sand media collected from a recharge basin and was fitted with six sampling ports at soil depths of 15, 30, 60, 92, 122cm and acclimated for a month with tertiary treated wastewater. Transport of Legionella appeared to be delayed compared to E. coli. The breakthrough of E. coli and Legionella at 122cm depth occurred at 3 and 24h, respectively. Slow transport of Legionella is consistent with its pleomorphic nature and variation in size and shape under low nutrient conditions. Legionella persisted for a longer time in the column, but at lower concentrations. Given the novel results of this study, the transport of Legionella into groundwater aquifers can occur through engineering recharge basin conditions creating a potential public health risk.
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Affiliation(s)
- Lauren R McBurnett
- School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, United States.
| | - Nathan T Holt
- School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, United States.
| | - Absar Alum
- School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, United States.
| | - Morteza Abbaszadegan
- School of Sustainable Engineering and the Built Environment, Ira A. Fulton Schools of Engineering, Arizona State University, United States.
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22
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Knowledge to Predict Pathogens: Legionella pneumophila Lifecycle Critical Review Part I Uptake into Host Cells. WATER 2018. [DOI: 10.3390/w10020132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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23
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Trnková K, Kotrbancová M, Špaleková M, Fulová M, Boledovičová J, Vesteg M. MALDI-TOF MS analysis as a useful tool for an identification of Legionella pneumophila, a facultatively pathogenic bacterium interacting with free-living amoebae: A case study from water supply system of hospitals in Bratislava (Slovakia). Exp Parasitol 2017; 184:97-102. [PMID: 29225047 DOI: 10.1016/j.exppara.2017.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 10/20/2017] [Accepted: 12/05/2017] [Indexed: 01/30/2023]
Abstract
Legionellae, i.e. Legionella pneumophila, are human bacterial hydrophilic facultative pathogens causing pneumonia (Legionnaires' disease). Free-living amoebae (FLA) can serve as natural hosts and thus as reservoirs of many amoebae-resistant bacteria. An encysted amoeba can contribute to the resistance of intracellular L. pneumophila to various chemical and physical treatments. Humans can be infected by droplets containing bacteria from an environmental source or human-made devices such as shower heads, bathtubs, air-conditioning units or whirlpools. In this study, we were investigating the presence of FLA and L. pneumophila in plumbing systems of healthcare facilities in Bratislava (Slovakia) by standard diagnostic methods, while the presence of L. pneumophila was verified also by MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) analysis. The results showed the occurrence of L. pneumophila and FLA in 62.26% and 66.4% of samples taken from four paediatric clinics, respectively. Both standard methods and MALDI-TOF MS showed comparable results and they can be successfully applied for the identification of L. pneumophila strains in environmental samples. Our approach could be useful for further monitoring, prevention and decreasing risk of Legionella infection also in other hospitals.
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Affiliation(s)
- Katarína Trnková
- Department of the Environment, Faculty of Natural Sciences, Matej Bel University, Tajovského 55, 974 01 Banská Bystrica, Slovakia.
| | - Martina Kotrbancová
- Institute of Epidemiology, Faculty of Medicine, Comenius University Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia.
| | - Margita Špaleková
- Institute of Epidemiology, Faculty of Medicine, Comenius University Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia.
| | - Miriam Fulová
- Institute of Epidemiology, Faculty of Medicine, Comenius University Bratislava, Špitálska 24, 813 72 Bratislava, Slovakia.
| | - Jana Boledovičová
- Children's Faculty Hospital and Clinic, Limbová 1, 833 40, Bratislava, Slovakia.
| | - Matej Vesteg
- Department of Biology and Ecology, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, 974 01 Banská Bystrica, Slovakia.
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24
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Lama A, Drennan SL, Johnson RC, Rubenstein GL, Cambronne ED. Identification of Conserved ABC Importers Necessary for Intracellular Survival of Legionella pneumophila in Multiple Hosts. Front Cell Infect Microbiol 2017; 7:485. [PMID: 29250489 PMCID: PMC5714930 DOI: 10.3389/fcimb.2017.00485] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 11/13/2017] [Indexed: 11/13/2022] Open
Abstract
It is established that the human pathogen Legionella pneumophila becomes significantly augmented for infection of macrophages after intracellular growth in amoebae when compared to like-strains cultivated in laboratory media. Based on this observation, we reasoned that the most critical virulence determinants of L.p. are expressed by responding to stimuli generated by the protozoan host specifically; a process we term "protozoan-priming." We sought to identify L.p. virulence factors that were required for replication in amoebae in order to highlight the genes necessary for production of the most infectious form of the bacterium. Using a transposon mutagenesis screen, we successfully identified 12 insertions that produced bacteria severely attenuated for growth in amoebae, while retaining a functional Dot/Icm type IVb secretion system. Seven of these insertion mutants were found dispensable for growth in macrophages, revealing attractive therapeutic targets that reside upstream of the pathogen-human interface. Two candidates identified, lpg0730 and lpg0122 were required for survival and replication in amoebae and macrophage host cells. Both genes are conserved among numerous important human pathogenic bacteria that can persist or replicate in amoebae. Each gene encodes a component of an ATP binding cassette (ABC) transport complex of unknown function. We demonstrate the lpg0730 ortholog in Francisella tularensis subsp. novicida to be essential for colonization of both protozoan and mammalian host cells, highlighting conserved survival mechanisms employed by bacteria that utilize protozoa as an environmental reservoir for replication.
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Affiliation(s)
- Amrita Lama
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, United States
| | - Samuel L Drennan
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, United States
| | - Rudd C Johnson
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, United States
| | - Grace L Rubenstein
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, United States
| | - Eric D Cambronne
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR, United States
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25
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Arslan-Aydoğdu EÖ, Kimiran A. An investigation of virulence factors of Legionella pneumophila environmental isolates. Braz J Microbiol 2017; 49:189-199. [PMID: 29037504 PMCID: PMC5790574 DOI: 10.1016/j.bjm.2017.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 11/23/2022] Open
Abstract
Nine Legionella pneumophila strains isolated from cooling towers and a standard strain (L. pneumophila serogroup 1, ATCC 33152, Philadelphia 1) were analyzed and compared in terms of motility, flagella structure, ability to form biofilms, enzymatic activities (hemolysin, nucleases, protease, phospholipase A, phospholipase C, acid phosphatase, alkaline phosphatase and lipase), hemagglutination capabilities, and pathogenicity in various host cells (Acanthamoeba castellanii ATCC 30234, mouse peritoneal macrophages and human peripheral monocytes). All the isolates of bacteria appeared to be motile and polar-flagellated and possessed the type-IV fimbria. Upon the evaluation of virulence factors, isolate 4 was found to be the most pathogenic strain, while 6 out of the 9 isolates (the isolates 1, 2, 3, 4, 5, and 7) were more virulent than the ATCC 33152 strain. The different bacterial strains exhibited differences in properties such as adhesion, penetration and reproduction in the hosts, and preferred host type. To our knowledge, this is the first study to compare the virulence of environmental L. pneumophila strains isolated in Turkey, and it provides important information relevant for understanding the epidemiology of L. pneumophila.
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Affiliation(s)
| | - Ayten Kimiran
- Istanbul University, Faculty of Science, Department of Biology, Istanbul, Turkey
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26
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Kuhn P, Thiem S, Steinert M, Purvis D, Lugmayr V, Treutlein U, Plobner L, Leiser RM, Hust M, Dübel S. Human Anti-Lipopolysaccharid (LPS) antibodies against Legionella with high species specificity. Hum Antibodies 2017; 26:29-38. [PMID: 28582852 DOI: 10.3233/hab-170318] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Legionella are Gram-negative bacteria that are ubiquitously present in natural and man-made water reservoirs. When humans inhale aerosolized water contaminated with Legionella, alveolar macrophages can be infected, which may lead to a life-threatening pneumonia called Legionnaires' disease. Due to the universal distribution of Legionella in water and their potential threat to human health, the Legionella concentration in water for human use must be strictly monitored, which is difficult since the standard detection still relies on lengthy cultivation and analysis of bacterial morphology. In this study, an antibody against L. pneumophila has been generated from the naïve human HAL antibody libraries by phage-display for the first time. The panning was performed on whole bacterial cells in order to select antibodies that bind specifically to the cell surface of untreated Legionella. The bacterial cell wall component lipopolysaccharide (LPS) was identified as the target structure. Specific binding to the important pathogenic L. pneumophila strains Corby, Philadelphia-1 and Knoxville was observed, while no binding was detected to seven members of the families Enterobacteriaceae, Pseudomonadaceae or Clostridiaceae. Production of this antibody in the recombinant scFv-Fc format using either a murine or a human Fc part allowed the set-up of a sandwich-ELISA for detection of Legionella cells. The scFv-Fc construct proved to be very stable, even when stored for several weeks at elevated temperatures. A sensitivity limit of 4,000 cells was achieved. The scFv-Fc antibody pair was integrated on a biosensor, demonstrating the specific and fast detection of L. pneumophila on a portable device. With this system, 10,000 Legionella cells were detected within 35 min. Combined with a water filtration/concentration system, this antibody may be developed into a promising reagent for rapid on-site Legionella monitoring.
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Affiliation(s)
- Philipp Kuhn
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
- YUMAB GmbH, Rebenring, Braunschweig, Germany
| | - Stefanie Thiem
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Department of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Michael Steinert
- Institute for Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
- Helmholtz Center for Infection Research, Braunschweig, Germany
| | | | | | | | | | | | - Michael Hust
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
| | - Stefan Dübel
- Biotechnology and Bioinformatics, Institute for Biochemistry, Technische Universität Braunschweig, Braunschweig, Germany
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Sepin Özen N, Tuğlu Ataman Ş, Emek M. Exploring the Legionella pneumophila positivity rate in hotel water samples from Antalya, Turkey. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:12238-12242. [PMID: 28353109 DOI: 10.1007/s11356-017-8864-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 03/17/2017] [Indexed: 06/06/2023]
Abstract
The genus Legionella is a fastidious Gram-negative bacteria widely distributed in natural waters and man made water supply systems. Legionella pneumophila is the aetiological agent of approximately 90% of reported Legionellosis cases, and serogroup 1 is the most frequent cause of infections. Legionnaires' disease is often associated with travel and continues to be a public health concern at present. The correct water management quality practices and rapid methods for analyzing Legionella species in environmental water is a key point for the prevention of Legionnaires' disease outbreaks. This study aimed to evaluate the positivity rates and serotyping of Legionella species from water samples in the region of Antalya, Turkey, which is an important tourism center. During January-December 2010, a total of 1403 samples of water that were collected from various hotels (n = 56) located in Antalya were investigated for Legionella pneumophila. All samples were screened for L. pneumophila by culture method according to "ISO 11731-2" criteria. The culture positive Legionella strains were serologically identified by latex agglutination test. A total of 142 Legionella pneumophila isolates were recovered from 21 (37.5%) of 56 hotels. The total frequency of L. pneumophila isolation from water samples was found as 10.1%. Serological typing of 142 Legionella isolates by latex agglutination test revealed that strains belonging to L. pneumophila serogroups 2-14 predominated in the examined samples (85%), while strains of L. pneumophila serogroup 1 were less numerous (15%). According to our knowledge, our study with the greatest number of water samples from Turkey demonstrates that L. pneumophila serogroups 2-14 is the most common isolate. Rapid isolation of L. pneumophila from environmental water samples is essential for the investigation of travel related outbreaks and the possible resources. Further studies are needed to have epidemiological data and to determine the types of L. pneumophila isolates from Turkey.
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Affiliation(s)
| | | | - Mestan Emek
- Epidemiology, Public Health Laboratory, Antalya, Turkey
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Temperature-Dependent Growth Modeling of Environmental and Clinical Legionella pneumophila Multilocus Variable-Number Tandem-Repeat Analysis (MLVA) Genotypes. Appl Environ Microbiol 2017; 83:AEM.03295-16. [PMID: 28159784 DOI: 10.1128/aem.03295-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 01/25/2017] [Indexed: 01/02/2023] Open
Abstract
Legionella pneumophila causes waterborne infections resulting in severe pneumonia. High-resolution genotyping of L. pneumophila isolates can be achieved by multiple-locus variable-number tandem-repeat analysis (MLVA). Recently, we found that different MLVA genotypes of L. pneumophila dominated different sites in a small drinking-water network, with a genotype-related temperature and abundance regime. The present study focuses on understanding the temperature-dependent growth kinetics of the genotypes that dominated the water network. Our aim was to model mathematically the influence of temperature on the growth kinetics of different environmental and clinical L. pneumophila genotypes and to compare it with the influence of their ecological niches. Environmental strains showed a distinct temperature preference, with significant differences among the growth kinetics of the three studied genotypes (Gt4, Gt6, and Gt15). Gt4 strains exhibited superior growth at lower temperatures (25 and 30°C), while Gt15 strains appeared to be best adapted to relatively higher temperatures (42 and 45°C). The temperature-dependent growth traits of the environmental genotypes were consistent with their distribution and temperature preferences in the water network. Clinical isolates exhibited significantly higher growth rates and reached higher maximal cell densities at 37°C and 42°C than the environmental strains. Further research on the growth preferences of L. pneumophila clinical and environmental genotypes will result in a better understanding of their ecological niches in drinking-water systems as well as in the human body.IMPORTANCELegionella pneumophila is a waterborne pathogen that threatens humans in developed countries. The bacteria inhabit natural and man-made freshwater environments. Here we demonstrate that different environmental L. pneumophila genotypes have different temperature-dependent growth kinetics. Moreover, Legionella strains that belong to the same species but were isolated from environmental and clinical sources possess adaptations for growth at different temperatures. These growth preferences may influence the bacterial colonization at specific ecological niches within the drinking-water network. Adaptations for growth at human body temperatures may facilitate the abilities of some L. pneumophila strains to infect and cause illness in humans. Our findings may be used as a tool to improve Legionella monitoring in drinking-water networks. Risk assessment models for predicting the risk of legionellosis should take into account not only Legionella concentrations but also the temperature-dependent growth kinetics of the isolates.
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Jung AL, Hoffmann K, Herkt CE, Schulz C, Bertrams W, Schmeck B. Legionella pneumophila Outer Membrane Vesicles: Isolation and Analysis of Their Pro-inflammatory Potential on Macrophages. J Vis Exp 2017. [PMID: 28287548 PMCID: PMC5409326 DOI: 10.3791/55146] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Bacteria are able to secrete a variety of molecules via various secretory systems. Besides the secretion of molecules into the extracellular space or directly into another cell, Gram-negative bacteria can also form outer membrane vesicles (OMVs). These membrane vesicles can deliver their cargo over long distances, and the cargo is protected from degradation by proteases and nucleases. Legionella pneumophila (L. pneumophila) is an intracellular, Gram-negative pathogen that causes a severe form of pneumonia. In humans, it infects alveolar macrophages, where it blocks lysosomal degradation and forms a specialized replication vacuole. Moreover, L. pneumophila produces OMVs under various growth conditions. To understand the role of OMVs in the infection process of human macrophages, we set up a protocol to purify bacterial membrane vesicles from liquid culture. The method is based on differential ultracentrifugation. The enriched OMVs were subsequently analyzed with regard to their protein and lipopolysaccharide (LPS) amount and were then used for the treatment of a human monocytic cell line or murine bone marrow-derived macrophages. The pro-inflammatory responses of those cells were analyzed by enzyme-linked immunosorbent assay. Furthermore, alterations in a subsequent infection were analyzed. To this end, the bacterial replication of L. pneumophila in macrophages was studied by colony-forming unit assays. Here, we describe a detailed protocol for the purification of L. pneumophila OMVs from liquid culture by ultracentrifugation and for the downstream analysis of their pro-inflammatory potential on macrophages.
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Affiliation(s)
- Anna Lena Jung
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg
| | - Kerstin Hoffmann
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg
| | - Christina E Herkt
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg
| | - Christine Schulz
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg
| | - Wilhelm Bertrams
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg
| | - Bernd Schmeck
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg; German Center for Lung Research; Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Center Giessen and Marburg;
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Hamidou Soumana I, Linz B, Harvill ET. Environmental Origin of the Genus Bordetella. Front Microbiol 2017; 8:28. [PMID: 28174558 PMCID: PMC5258731 DOI: 10.3389/fmicb.2017.00028] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 01/05/2017] [Indexed: 01/01/2023] Open
Abstract
Members of the genus Bordetella include human and animal pathogens that cause a variety of respiratory infections, including whooping cough in humans. Despite the long known ability to switch between a within-animal and an extra-host lifestyle under laboratory growth conditions, no extra-host niches of pathogenic Bordetella species have been defined. To better understand the distribution of Bordetella species in the environment, we probed the NCBI nucleotide database with the 16S ribosomal RNA (16S rRNA) gene sequences from pathogenic Bordetella species. Bacteria of the genus Bordetella were frequently found in soil, water, sediment, and plants. Phylogenetic analyses of their 16S rRNA gene sequences showed that Bordetella recovered from environmental samples are evolutionarily ancestral to animal-associated species. Sequences from environmental samples had a significantly higher genetic diversity, were located closer to the root of the phylogenetic tree and were present in all 10 identified sequence clades, while only four sequence clades possessed animal-associated species. The pathogenic bordetellae appear to have evolved from ancestors in soil and/or water. We show that, despite being animal-adapted pathogens, Bordetella bronchiseptica, and Bordetella hinzii have preserved the ability to grow and proliferate in soil. Our data implicate soil as a probable environmental origin of Bordetella species, including the animal-pathogenic lineages. Soil may further constitute an environmental niche, allowing for persistence and dissemination of the bacterial pathogens. Spread of pathogenic bordetellae from an environmental reservoir such as soil may potentially explain their wide distribution as well as frequent disease outbreaks that start without an obvious infectious source.
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Affiliation(s)
- Illiassou Hamidou Soumana
- Department of Infectious Diseases, University of GeorgiaAthens, GA, USA; Center for Vaccines and Immunology, University of GeorgiaAthens, GA, USA
| | - Bodo Linz
- Center for Vaccines and Immunology, University of GeorgiaAthens, GA, USA; Department of Veterinary and Biomedical Sciences, Pennsylvania State UniversityUniversity Park, PA, USA
| | - Eric T Harvill
- Department of Infectious Diseases, University of GeorgiaAthens, GA, USA; Center for Vaccines and Immunology, University of GeorgiaAthens, GA, USA; Department of Veterinary and Biomedical Sciences, Pennsylvania State UniversityUniversity Park, PA, USA
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31
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Caicedo C, Beutel S, Scheper T, Rosenwinkel KH, Nogueira R. Occurrence of Legionella in wastewater treatment plants linked to wastewater characteristics. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:16873-16881. [PMID: 27376367 DOI: 10.1007/s11356-016-7090-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/13/2016] [Indexed: 06/06/2023]
Abstract
In recent years, the occurrence of Legionella in wastewater treatment plants (WWTP) has often been reported. However, until now there is limited knowledge about the factors that promote Legionella's growth in such systems. The aim of this study was to investigate the chemical wastewater parameters that might be correlated to the concentration of Legionella spp. in WWTP receiving industrial effluents. For this purpose, samples were collected at different processes in three WWTP. In 100 % of the samples taken from the activated sludge tanks Legionella spp. were detected at varying concentrations (4.8 to 5.6 log GU/mL) by the quantitative real-time polymerase chain reaction method, but not by the culture method. Statistical analysis with various parameters yielded positive correlations of Legionella spp. concentration with particulate chemical oxygen demand, Kjeldahl nitrogen and protein concentration. Amino acids were quantified in wastewater and activated sludge samples at concentrations that may not support the growth of Legionella, suggesting that in activated sludge tanks this bacterium multiplied in protozoan hosts.
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Affiliation(s)
- C Caicedo
- Institute for Sanitary Engineering and Waste Management, Leibniz University Hannover, Welfengarten 1, Hannover, 30167, Germany
| | - S Beutel
- Institute of Technical Chemistry, Leibniz University Hannover, Hannover, 30167, Germany
| | - T Scheper
- Institute of Technical Chemistry, Leibniz University Hannover, Hannover, 30167, Germany
| | - K H Rosenwinkel
- Institute for Sanitary Engineering and Waste Management, Leibniz University Hannover, Welfengarten 1, Hannover, 30167, Germany
| | - R Nogueira
- Institute for Sanitary Engineering and Waste Management, Leibniz University Hannover, Welfengarten 1, Hannover, 30167, Germany.
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32
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Trigui H, Paquet VE, Charette SJ, Faucher SP. Packaging of Campylobacter jejuni into Multilamellar Bodies by the Ciliate Tetrahymena pyriformis. Appl Environ Microbiol 2016; 82:2783-90. [PMID: 26921427 PMCID: PMC4836424 DOI: 10.1128/aem.03921-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/23/2016] [Indexed: 12/23/2022] Open
Abstract
Campylobacter jejuniis the leading cause of bacterial gastroenteritis worldwide. Transmission to humans occurs through consumption of contaminated food or water. The conditions affecting the persistence of C. jejuniin the environment are poorly understood. Some protozoa package and excrete bacteria into multilamellar bodies (MLBs). Packaged bacteria are protected from deleterious conditions, which increases their survival. We hypothesized that C. jejuni could be packaged under aerobic conditions by the amoeba Acanthamoeba castellanii or the ciliate Tetrahymena pyriformis, both of which are able to package other pathogenic bacteria.A. castellanii did not produce MLBs containing C. jejuni In contrast, when incubated with T. pyriformis,C. jejuni was ingested, packaged in MLBs, and then expelled into the milieu. The viability of the bacteria inside MLBs was confirmed by microscopic analyses. The kinetics of C. jejuni culturability showed that packaging increased the survival of C. jejuniup to 60 h, in contrast to the strong survival defect seen in ciliate-free culture. This study suggests that T. pyriformis may increase the risk of persistence of C. jejuniin the environment and its possible transmission between different reservoirs in food and potable water through packaging.
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Affiliation(s)
- Hana Trigui
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Pavillon Charles-Eugène-Marchand, Université Laval, Quebec City, QC, Canada Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Quebec City, QC, Canada Département de Biochimie, de Microbiologie, et de Bio-informatique, Faculté des Sciences et de Génie, Université Laval, Quebec City, QC, Canada
| | - Sébastien P Faucher
- McGill University, Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
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Jung AL, Stoiber C, Herkt CE, Schulz C, Bertrams W, Schmeck B. Legionella pneumophila-Derived Outer Membrane Vesicles Promote Bacterial Replication in Macrophages. PLoS Pathog 2016; 12:e1005592. [PMID: 27105429 PMCID: PMC4841580 DOI: 10.1371/journal.ppat.1005592] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 04/01/2016] [Indexed: 02/07/2023] Open
Abstract
The formation and release of outer membrane vesicles (OMVs) is a phenomenon of Gram-negative bacteria. This includes Legionella pneumophila (L. pneumophila), a causative agent of severe pneumonia. Upon its transmission into the lung, L. pneumophila primarily infects and replicates within macrophages. Here, we analyzed the influence of L. pneumophila OMVs on macrophages. To this end, differentiated THP-1 cells were incubated with increasing doses of Legionella OMVs, leading to a TLR2-dependent classical activation of macrophages with the release of pro-inflammatory cytokines. Inhibition of TLR2 and NF-κB signaling reduced the induction of pro-inflammatory cytokines. Furthermore, treatment of THP-1 cells with OMVs prior to infection reduced replication of L. pneumophila in THP-1 cells. Blocking of TLR2 activation or heat denaturation of OMVs restored bacterial replication in the first 24 h of infection. With prolonged infection-time, OMV pre-treated macrophages became more permissive for bacterial replication than untreated cells and showed increased numbers of Legionella-containing vacuoles and reduced pro-inflammatory cytokine induction. Additionally, miRNA-146a was found to be transcriptionally induced by OMVs and to facilitate bacterial replication. Accordingly, IRAK-1, one of miRNA-146a's targets, showed prolonged activation-dependent degradation, which rendered THP-1 cells more permissive for Legionella replication. In conclusion, L. pneumophila OMVs are initially potent pro-inflammatory stimulators of macrophages, acting via TLR2, IRAK-1, and NF-κB, while at later time points, OMVs facilitate L. pneumophila replication by miR-146a-dependent IRAK-1 suppression. OMVs might thereby promote spreading of L. pneumophila in the host.
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Affiliation(s)
- Anna Lena Jung
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany
| | - Cornelia Stoiber
- Institute for Virology, Philipps-University Marburg, Marburg, Germany
| | - Christina E. Herkt
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany
| | - Christine Schulz
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany
| | - Wilhelm Bertrams
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany
| | - Bernd Schmeck
- Institute for Lung Research, Universities of Giessen and Marburg Lung Center, Philipps-University Marburg, Member of the German Center for Lung Research (DZL), Marburg, Germany
- Department of Medicine, Pulmonary and Critical Care Medicine, University Medical Center Giessen and Marburg, Philipps-University, Member of the German Center for Lung Research (DZL), Marburg, Germany
- * E-mail:
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Krause K, Amer AO. Caspase Exploitation by Legionella pneumophila. Front Microbiol 2016; 7:515. [PMID: 27148204 PMCID: PMC4829591 DOI: 10.3389/fmicb.2016.00515] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022] Open
Abstract
Legionella pneumophila remains a major health concern, especially for hospitalized patients. L. pneumophila in the environment can survive extracellular or as protozoan parasite within amoeba. After human infection it efficiently replicates in alveolar macrophages without activating inflammasome assembly and cleavage of caspase-1. In contrast murine macrophages actively recognize intracellular L. pneumophila via inflammasome components which initiate pro-inflammatory cytokine secretion, phagosomal maturation and pyroptotic cell death thereby leading to bacterial restriction. During this process flagellin-dependent and -independent signaling pathways trigger the canonical as well as the non-canonical inflammasome. This review describes the current knowledge about L. pneumophila-induced inflammasome pathways in permissive and restrictive host cells.
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Affiliation(s)
- Kathrin Krause
- Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
| | - Amal O Amer
- Department of Microbial Infection and Immunity, The Ohio State University Columbus, OH, USA
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Berjeaud JM, Chevalier S, Schlusselhuber M, Portier E, Loiseau C, Aucher W, Lesouhaitier O, Verdon J. Legionella pneumophila: The Paradox of a Highly Sensitive Opportunistic Waterborne Pathogen Able to Persist in the Environment. Front Microbiol 2016; 7:486. [PMID: 27092135 PMCID: PMC4824771 DOI: 10.3389/fmicb.2016.00486] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/23/2016] [Indexed: 01/28/2023] Open
Abstract
Legionella pneumophila, the major causative agent of Legionnaires’ disease, is found in freshwater environments in close association with free-living amoebae and multispecies biofilms, leading to persistence, spread, biocide resistance, and elevated virulence of the bacterium. Indeed, legionellosis outbreaks are mainly due to the ability of this bacterium to colonize and persist in water facilities, despite harsh physical and chemical treatments. However, these treatments are not totally efficient and, after a lag period, L. pneumophila may be able to quickly re-colonize these systems. Several natural compounds (biosurfactants, antimicrobial peptides…) with anti-Legionella properties have recently been described in the literature, highlighting their specific activities against this pathogen. In this review, we first consider this hallmark of Legionella to resist killing, in regard to its biofilm or host-associated life style. Then, we focus more accurately on natural anti-Legionella molecules described so far, which could provide new eco-friendly and alternative ways to struggle against this important pathogen in plumbing.
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Affiliation(s)
- Jean-Marc Berjeaud
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Sylvie Chevalier
- Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen Evreux, France
| | - Margot Schlusselhuber
- Laboratoire Aliments Bioprocédés Toxicologie Environnements, EA 4651, Université de Caen Caen, France
| | - Emilie Portier
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Clémence Loiseau
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Willy Aucher
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
| | - Olivier Lesouhaitier
- Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Université de Rouen Evreux, France
| | - Julien Verdon
- Laboratoire Ecologie and Biologie des Interactions, UMR CNRS 7267, Université de Poitiers Poitiers, France
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Dupuy M, Binet M, Bouteleux C, Herbelin P, Soreau S, Héchard Y. Permissiveness of freshly isolated environmental strains of amoebae for growth ofLegionella pneumophila. FEMS Microbiol Lett 2016; 363:fnw022. [DOI: 10.1093/femsle/fnw022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2016] [Indexed: 12/24/2022] Open
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Hsu TK, Wu SF, Hsu BM, Kao PM, Tao CW, Shen SM, Ji WT, Huang WC, Fan CW. Surveillance of parasitic Legionella in surface waters by using immunomagnetic separation and amoebae enrichment. Pathog Glob Health 2015; 109:328-35. [PMID: 26373823 DOI: 10.1179/2047773215y.0000000034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Free-living amoebae (FLA) are potential reservoirs of Legionella in aquatic environments. However, the parasitic relationship between various Legionella and amoebae remains unclear. In this study, surface water samples were gathered from two rivers for evaluating parasitic Legionella. Warmer water temperature is critical to the existence of Legionella. This result suggests that amoebae may be helpful in maintaining Legionella in natural environments because warmer temperatures could enhance parasitisation of Legionella in amoebae. We next used immunomagnetic separation (IMS) to identify extracellular Legionella and remove most free Legionella before detecting the parasitic ones in selectively enriched amoebae. Legionella pneumophila was detected in all the approaches, confirming that the pathogen is a facultative amoebae parasite. By contrast, two obligate amoebae parasites, Legionella-like amoebal pathogens (LLAPs) 8 and 9, were detected only in enriched amoebae. However, several uncultured Legionella were detected only in the extracellular samples. Because the presence of potential hosts, namely Vermamoeba vermiformis, Acanthamoeba spp. and Naegleria gruberi, was confirmed in the samples that contained intracellular Legionella, uncultured Legionella may survive independently of amoebae. Immunomagnetic separation and amoebae enrichment may have referential value for detecting parasitic Legionella in surface waters.
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Affiliation(s)
- Tsui-Kang Hsu
- Department of Ophthalmology, Cheng Hsin General Hospital , Taipei, Taiwan, Republic of China
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Vance PH, Schaeffer F, Trevino E, Weissfeld AS. Legionella: a Fascinating Bacterium Uncovered in the Twentieth Century. ACTA ACUST UNITED AC 2015; 37:119-123. [PMID: 32287685 PMCID: PMC7115303 DOI: 10.1016/j.clinmicnews.2015.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In July 1976, the American Legion held a conference at the Bellevue Stratford Hotel in Philadelphia, PA, to celebrate the nation's bicentennial. This convention resulted in transmission of a gram-negative bacterium to over 200 attendees, who developed a respiratory illness; 34 deaths were attributed to the infections. An investigation of the illness revealed a bacterium that had not been documented before. The disease became known as Legionnaires' disease, and the etiological agent was subsequently named Legionella pneumophila. This is the story of Legionella, with special emphasis on its ecological niche, the diagnosis of human infection, and its isolation from the environment. There are only a handful of diseases that debuted in the 20th or 21st century. They include Legionnaires' disease (the subject of this review), Lyme disease, AIDS, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and West Nile virus.
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Affiliation(s)
- Paula H Vance
- Microbiology Specialists Incorporated, Houston, Texas
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HIKAL W, ZAKI B, SABRY H. Evaluation of Ozone Application in Dental Unit Water Lines Contaminated with Pathogenic Acanthamoeba. IRANIAN JOURNAL OF PARASITOLOGY 2015; 10:410-9. [PMID: 26622296 PMCID: PMC4662741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 06/20/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND In this study morphological and molecular characterization of Acanthamoeba strains, isolated from dental unit waterlines (DUWLs) were surveyed and the levels of disinfection achievable in vitro by the application of ozone disinfectant to DUWLs were evaluate. METHODS Water samples were collected from air-water syringes, cup fillers and tap water before and at the end of the working day. They were cultured on non-nutrient agar (NNA) plates. Species identification was carried out with a PCR assay based on sequence analysis of the 18S rRNA gene. The cellular response to ozone was tested on Acanthamoeba cyst with different doses at different contact time in vitro twice. RESULTS Prevalence rates for Acanthamoeba contamination were 100, 100 and 72% for air-water syringes, cup fillers and tap water, respectively. The morphological analysis revealed the presence of A. castellanii, A. griffin, A. hatchitti and A. lenticulata. Phylogenetic analysis of the sequences showed the four strains to be closely related to a sequence type (T3, T4, T5 and T11). Acanthamoeba cells were stained with trypan blue, which revealed killed of Acanthamoeba instantaneously after 10 minutes in ozonized water. There was no growth of Acanthamoeba occurred after ozone treatment in water bottles for 5 minutes with a flow rate of 500 mg/hour. Conclusion : Ozone can play an important role in controlling the problem of contamination of DUWLs as a potent disinfectant.
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Affiliation(s)
- Wafaa HIKAL
- Parasitology Lab, Water Pollution Research Department, National Research Centre, Egypt
| | - Basma ZAKI
- Oral Medicine and Periodontology, Surgery and Oral Medicine Department, National Research Centre, Egypt
| | - Hany SABRY
- Laser applications in Fixed Prosthodontics, Prosthodontics Research Department, National Research Centre, Egypt
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Vakulskas CA, Potts AH, Babitzke P, Ahmer BMM, Romeo T. Regulation of bacterial virulence by Csr (Rsm) systems. Microbiol Mol Biol Rev 2015; 79:193-224. [PMID: 25833324 PMCID: PMC4394879 DOI: 10.1128/mmbr.00052-14] [Citation(s) in RCA: 266] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Most bacterial pathogens have the remarkable ability to flourish in the external environment and in specialized host niches. This ability requires their metabolism, physiology, and virulence factors to be responsive to changes in their surroundings. It is no surprise that the underlying genetic circuitry that supports this adaptability is multilayered and exceedingly complex. Studies over the past 2 decades have established that the CsrA/RsmA proteins, global regulators of posttranscriptional gene expression, play important roles in the expression of virulence factors of numerous proteobacterial pathogens. To accomplish these tasks, CsrA binds to the 5' untranslated and/or early coding regions of mRNAs and alters translation, mRNA turnover, and/or transcript elongation. CsrA activity is regulated by noncoding small RNAs (sRNAs) that contain multiple CsrA binding sites, which permit them to sequester multiple CsrA homodimers away from mRNA targets. Environmental cues sensed by two-component signal transduction systems and other regulatory factors govern the expression of the CsrA-binding sRNAs and, ultimately, the effects of CsrA on secretion systems, surface molecules and biofilm formation, quorum sensing, motility, pigmentation, siderophore production, and phagocytic avoidance. This review presents the workings of the Csr system, the paradigm shift that it generated for understanding posttranscriptional regulation, and its roles in virulence networks of animal and plant pathogens.
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Affiliation(s)
- Christopher A Vakulskas
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Anastasia H Potts
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Paul Babitzke
- Department of Biochemistry and Molecular Biology, Center for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Brian M M Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA Department of Microbiology, The Ohio State University, Columbus, Ohio, USA
| | - Tony Romeo
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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Ji WT, Hsu BM, Chang TY, Hsu TK, Kao PM, Huang KH, Tsai SF, Huang YL, Fan CW. Surveillance and evaluation of the infection risk of free-living amoebae and Legionella in different aquatic environments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 499:212-219. [PMID: 25192927 DOI: 10.1016/j.scitotenv.2014.07.116] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 07/29/2014] [Accepted: 07/30/2014] [Indexed: 06/03/2023]
Abstract
Free-living amoebae (FLA) are ubiquitous in various aquatic environments. Several amoebae species are pathogenic and host other pathogens such as Legionella, but the presence of FLA and its parasites as well as the related infection risk are not well known. In this study, the presence of pathogenic FLA and Legionella in various water bodies was investigated. Water samples were collected from a river, intake areas of drinking water treatment plants, and recreational hot spring complexes in central and southern Taiwan. A total of 140 water samples were tested for the presence of Acanthamoeba spp., Naegleria spp., Vermamoeba vermiformis, and Legionella. In addition, phylogenetic characteristics and water quality parameters were also assessed. The pathogenic genotypes of FLA included Acanthamoeba T4 and Naegleria australiensis, and both were abundant in the hot spring water. In contrast, Legionella pneumophila was detected in different aquatic environments. Among the FLA assessed, V. vermiformis was most likely to coexist with Legionella spp. The total bacteria level was associated with the presence of FLA and Legionella especially in hot spring water. Taken together, FLA contamination in recreational hot springs and drinking water source warrants more attention on potential legionellosis and amoebae infections.
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Affiliation(s)
- Wen-Tsai Ji
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Bing-Mu Hsu
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC.
| | - Tien-Yu Chang
- Department of Radiology, Taipei Medical University Hospital, 252 Wu Hsing Street, Taipei, Taiwan, ROC
| | - Tsui-Kang Hsu
- Department of Ophthalmology, Cheng Hsin General Hospital, Taipei, Taiwan, ROC; Department of Life Science, Institute of Molecular Biology and Institute of Biomedical Science, National Chung Cheng University, Min-Hsiung, Chiayi, Taiwan, ROC
| | - Po-Min Kao
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Kuan-Hao Huang
- Department of Life Science, Institute of Molecular Biology and Institute of Biomedical Science, National Chung Cheng University, Min-Hsiung, Chiayi, Taiwan, ROC
| | - Shiou-Feng Tsai
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
| | - Yu-Li Huang
- Department of Safety Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, Kaohsiung, Taiwan, ROC
| | - Cheng-Wei Fan
- Department of Earth and Environmental Sciences, National Chung Cheng University, Chiayi, Taiwan, ROC
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Zhang J, Ketola T, Örmälä-Odegrip AM, Mappes J, Laakso J. Coincidental loss of bacterial virulence in multi-enemy microbial communities. PLoS One 2014; 9:e111871. [PMID: 25365586 PMCID: PMC4218854 DOI: 10.1371/journal.pone.0111871] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 10/03/2014] [Indexed: 01/17/2023] Open
Abstract
The coincidental virulence evolution hypothesis suggests that outside-host selection, such as predation, parasitism and resource competition can indirectly affect the virulence of environmentally-growing bacterial pathogens. While there are some examples of coincidental environmental selection for virulence, it is also possible that the resource acquisition and enemy defence is selecting against it. To test these ideas we conducted an evolutionary experiment by exposing the opportunistic pathogen bacterium Serratia marcescens to the particle-feeding ciliate Tetrahymena thermophila, the surface-feeding amoeba Acanthamoeba castellanii, and the lytic bacteriophage Semad11, in all possible combinations in a simulated pond water environment. After 8 weeks the virulence of the 384 evolved clones were quantified with fruit fly Drosophila melanogaster oral infection model, and several other life-history traits were measured. We found that in comparison to ancestor bacteria, evolutionary treatments reduced the virulence in most of the treatments, but this reduction was not clearly related to any changes in other life-history traits. This suggests that virulence traits do not evolve in close relation with these life-history traits, or that different traits might link to virulence in different selective environments, for example via resource allocation trade-offs.
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Affiliation(s)
- Ji Zhang
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Biological and Environmental Science, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Tarmo Ketola
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | | | - Johanna Mappes
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Jouni Laakso
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- Department of Biological and Environmental Science, University of Helsinki, Helsinki, Finland
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Taylor MJ, Bentham RH, Ross KE. Limitations of Using Propidium Monoazide with qPCR to Discriminate between Live and Dead Legionella in Biofilm Samples. Microbiol Insights 2014; 7:15-24. [PMID: 25288885 PMCID: PMC4167484 DOI: 10.4137/mbi.s17723] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 01/17/2023] Open
Abstract
Accurately quantifying Legionella for regulatory purposes to protect public health is essential. Real-time PCR (qPCR) has been proposed as a better method for detecting and enumerating Legionella in samples than conventional culture method. However, since qPCR amplifies any target DNA in the sample, the technique’s inability to discriminate between live and dead cells means that counts are generally significantly overestimated. Propidium monoazide (PMA) has been used successfully in qPCR to aid live/dead discrimination. We tested PMA use as a method to count only live Legionella cells in samples collected from a modified chemostat that generates environmentally comparable samples. Counts from PMA-treated samples that were pretreated with either heat or three types of disinfectants (to kill the cells) were highly variable, with the only consistent trend being the relationship between biofilm mass and numbers of Legionella cells. Two possibilities explain this result: 1. PMA treatment worked and the subsequent muted response of Legionella to disinfection treatment is a factor of biofilm/microbiological effects; although this does not account for the relationship between the amount of biofilm sampled and the viable Legionella count as determined by PMA-qPCR; or 2. PMA treatment did not work, and any measured decrease or increase in detectable Legionella is because of other factors affecting the method. This is the most likely explanation for our results, suggesting that higher concentrations of PMA might be needed to compensate for the presence of other compounds in an environmental sample or that lower amounts of biofilm need to be sampled. As PMA becomes increasingly toxic at higher concentrations and is very expensive, augmenting the method to include higher PMA concentrations is both counterproductive and cost prohibitive. Conversely, if smaller volumes of biofilm are used, the reproducibility of the method is reduced. Our results suggest that using PMA is not an appropriate method for discriminating between live and dead cells to enumerate Legionella for regulatory purposes.
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Affiliation(s)
- Michael J Taylor
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
| | - Richard H Bentham
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
| | - Kirstin E Ross
- Health and Environment, School of the Environment, Flinders University, Adelaide, Australia
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Amissah NA, Gryseels S, Tobias NJ, Ravadgar B, Suzuki M, Vandelannoote K, Durnez L, Leirs H, Stinear TP, Portaels F, Ablordey A, Eddyani M. Investigating the role of free-living amoebae as a reservoir for Mycobacterium ulcerans. PLoS Negl Trop Dis 2014; 8:e3148. [PMID: 25188535 PMCID: PMC4154674 DOI: 10.1371/journal.pntd.0003148] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/25/2014] [Indexed: 11/20/2022] Open
Abstract
Background The reservoir and mode of transmission of Mycobacterium ulcerans, the causative agent of Buruli ulcer, still remain a mystery. It has been suggested that M. ulcerans persists with difficulty as a free-living organism due to its natural fragility and inability to withstand exposure to direct sunlight, and thus probably persists within a protective host environment. Methodology/Principal Findings We investigated the role of free-living amoebae as a reservoir of M. ulcerans by screening the bacterium in free-living amoebae (FLA) cultures isolated from environmental specimens using real-time PCR. We also followed the survival of M. ulcerans expressing green fluorescence protein (GFP) in Acanthameoba castellanii by flow cytometry and observed the infected cells using confocal and transmission electron microscopy for four weeks in vitro. IS2404 was detected by quantitative PCR in 4.64% of FLA cultures isolated from water, biofilms, detritus and aerosols. While we could not isolate M. ulcerans, 23 other species of mycobacteria were cultivated from inside FLA and/or other phagocytic microorganisms. Laboratory experiments with GFP-expressing M. ulcerans in A. castellani trophozoites for 28 days indicated the bacteria did not replicate inside amoebae, but they could remain viable at low levels in cysts. Transmission electron microscopy of infected A. castellani confirmed the presence of bacteria within both trophozoite vacuoles and cysts. There was no correlation of BU notification rate with detection of the IS2404 in FLA (r = 0.07, n = 539, p = 0.127). Conclusion/Significance This study shows that FLA in the environment are positive for the M. ulcerans insertion sequence IS2404. However, the detection frequency and signal strength of IS2404 positive amoabae was low and no link with the occurrence of BU was observed. We conclude that FLA may host M. ulcerans at low levels in the environment without being directly involved in the transmission to humans. Mycobacterium ulcerans, the causative agent of Buruli ulcer (BU) is an environmental pathogen known to reside in aquatic habitat. However, the reservoir and modes of transmission to humans still remain unknown. M. ulcerans can probably not live freely due to its natural fragility and inability to withstand exposure to direct sunlight. This study investigated the hypothesis that free-living amoebae (FLA) can serve as a reservoir of M. ulcerans by testing for its presence in amoebae isolated from water bodies in BU endemic and non-endemic communities and whether the pathogen can remain viable when experimentally infected in amoebae in the laboratory. We detected only one (IS2404) of the three (IS2606 and KRB) targets for the presence of M. ulcerans in amoebae cultures and found no correlation between its presence in the environment and BU notification rate. M. ulcerans remained viable at low levels in amoebae for 28 days in vitro. We therefore conclude that FLA may host M. ulcerans at low levels in the environment without being directly involved in the transmission to humans.
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Affiliation(s)
- Nana Ama Amissah
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
- * E-mail:
| | - Sophie Gryseels
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Nicholas J. Tobias
- Department of Microbiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Bahram Ravadgar
- Department of Microbiology, Monash University, Victoria, Australia
| | - Mitsuko Suzuki
- Parasitology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Koen Vandelannoote
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Lies Durnez
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Herwig Leirs
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Antwerp, Belgium
| | - Timothy P. Stinear
- Department of Microbiology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Victoria, Australia
| | - Françoise Portaels
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Anthony Ablordey
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Miriam Eddyani
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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Vaerewijck MJ, Baré J, Lambrecht E, Sabbe K, Houf K. Interactions of Foodborne Pathogens with Free-living Protozoa: Potential Consequences for Food Safety. Compr Rev Food Sci Food Saf 2014. [DOI: 10.1111/1541-4337.12100] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Julie Baré
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Ellen Lambrecht
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
| | - Koen Sabbe
- Laboratory of Protistology and Aquatic Ecology; Dept. of Biology, Ghent Univ; Belgium
| | - Kurt Houf
- Dept. of Veterinary Public Health and Food Safety, Ghent Univ; Belgium
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Lévesque S, Plante PL, Mendis N, Cantin P, Marchand G, Charest H, Raymond F, Huot C, Goupil-Sormany I, Desbiens F, Faucher SP, Corbeil J, Tremblay C. Genomic characterization of a large outbreak of Legionella pneumophila serogroup 1 strains in Quebec City, 2012. PLoS One 2014; 9:e103852. [PMID: 25105285 PMCID: PMC4126679 DOI: 10.1371/journal.pone.0103852] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 07/02/2014] [Indexed: 11/20/2022] Open
Abstract
During the summer of 2012, a major Legionella pneumophila serogroup 1 outbreak occurred in Quebec City, Canada, which caused 182 declared cases of Legionnaire's disease and included 13 fatalities. Legionella pneumophila serogroup 1 isolates from 23 patients as well as from 32 cooling towers located in the vicinity of the outbreak were recovered for analysis. In addition, 6 isolates from the 1996 Quebec City outbreak and 4 isolates from patients unrelated to both outbreaks were added to allow comparison. We characterized the isolates using pulsed-field gel electrophoresis, sequence-based typing, and whole genome sequencing. The comparison of patients-isolated strains to cooling tower isolates allowed the identification of the tower that was the source of the outbreak. Legionella pneumophila strain Quebec 2012 was identified as a ST-62 by sequence-based typing methodology. Two new Legionellaceae plasmids were found only in the epidemic strain. The LVH type IV secretion system was found in the 2012 outbreak isolates but not in the ones from the 1996 outbreak and only in half of the contemporary human isolates. The epidemic strains replicated more efficiently and were more cytotoxic to human macrophages than the environmental strains tested. At least four Icm/Dot effectors in the epidemic strains were absent in the environmental strains suggesting that some effectors could impact the intracellular replication in human macrophages. Sequence-based typing and pulsed-field gel electrophoresis combined with whole genome sequencing allowed the identification and the analysis of the causative strain including its likely environmental source.
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Affiliation(s)
- Simon Lévesque
- Laboratoire de Santé Publique du Québec (LSPQ)/Institut National de Santé Publique du Québec, Québec, Canada
- * E-mail:
| | - Pier-Luc Plante
- Université Laval, Department of Molecular Medicine, Québec, Canada
| | - Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Québec, Canada
| | - Philippe Cantin
- Centre d'Expertise en Analyse Environnementale du Québec, Québec, Canada
| | - Geneviève Marchand
- Institut de Recherche Robert-Sauvé en Santé et en Sécurité du Travail, Québec, Canada
| | - Hugues Charest
- Laboratoire de Santé Publique du Québec (LSPQ)/Institut National de Santé Publique du Québec, Québec, Canada
- Département de Microbiologie, Immunologie et Infectiologie, Université de Montréal, Québec, Canada
| | - Frédéric Raymond
- Université Laval, Department of Molecular Medicine, Québec, Canada
| | - Caroline Huot
- Direction Régionale de Santé Publique de la Capitale-Nationale, Québec, Canada
| | | | - François Desbiens
- Direction Régionale de Santé Publique de la Capitale-Nationale, Québec, Canada
| | - Sébastien P. Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Québec, Canada
| | - Jacques Corbeil
- Université Laval, Department of Molecular Medicine, Québec, Canada
| | - Cécile Tremblay
- Laboratoire de Santé Publique du Québec (LSPQ)/Institut National de Santé Publique du Québec, Québec, Canada
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Québec, Canada
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Denoncourt AM, Paquet VE, Charette SJ. Potential role of bacteria packaging by protozoa in the persistence and transmission of pathogenic bacteria. Front Microbiol 2014; 5:240. [PMID: 24904553 PMCID: PMC4033053 DOI: 10.3389/fmicb.2014.00240] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/02/2014] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria live in close association with protozoa. These unicellular eukaryotic microorganisms are ubiquitous in various environments. A number of protozoa such as amoebae and ciliates ingest pathogenic bacteria, package them usually in membrane structures, and then release them into the environment. Packaged bacteria are more resistant to various stresses and are more apt to survive than free bacteria. New evidence indicates that protozoa and not bacteria control the packaging process. It is possible that packaging is more common than suspected and may play a major role in the persistence and transmission of pathogenic bacteria. To confirm the role of packaging in the propagation of infections, it is vital that the molecular mechanisms governing the packaging of bacteria by protozoa be identified as well as elements related to the ecology of this process in order to determine whether packaging acts as a Trojan Horse.
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Affiliation(s)
- Alix M Denoncourt
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Valérie E Paquet
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval Quebec City, QC, Canada ; Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec Quebec City, QC, Canada ; Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval Quebec City, QC, Canada
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Free-living amoebae (FLA) co-occurring with legionellae in industrial waters. Eur J Protistol 2014; 50:422-9. [PMID: 25062389 PMCID: PMC4155075 DOI: 10.1016/j.ejop.2014.04.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/30/2014] [Accepted: 04/30/2014] [Indexed: 11/23/2022]
Abstract
Legionella pneumophila is known as the causative agent of Legionnaires’ disease and free-living amoebae (FLA) can serve as vehicles for legionellae. The aim of this study was to screen industrial waters for the occurrence of FLA and their co-occurrence with legionellae. A total of 201 water samples, including 129 cooling waters and 72 process waters, and 30 cooling lubricants were included in the study. Treated waters were screened periodically, pre and post treatment. Altogether, 72.6% of the water samples were positive for FLA, acanthamoebae being most prevalent (in 23.9% of the samples) followed by Vermamoeba vermiformis (19.4%). Only one cooling lubricant was positive (Acanthamoeba genotype T4). Legionella spp. were detected in 34.8% of the water samples and in 15% in high concentrations (>1000 CFU/100 ml). Altogether, 81.4% of the Legionella-positive samples were positive for FLA by standard methods. By applying a highly sensitive nested PCR to a representative set of random samples it was revealed that Legionella spp. always co-occurred with Acanthamoeba spp. Although the addition of disinfectants did influence amoebal density and diversity, treated waters showed no difference concerning FLA in the interphases of disinfection. It appears that FLA can re-colonize treated waters within a short period of time.
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Sampson TR, Weiss DS. CRISPR-Cas systems: new players in gene regulation and bacterial physiology. Front Cell Infect Microbiol 2014; 4:37. [PMID: 24772391 PMCID: PMC3983513 DOI: 10.3389/fcimb.2014.00037] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 02/24/2014] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas systems are bacterial defenses against foreign nucleic acids derived from bacteriophages, plasmids or other sources. These systems are targeted in an RNA-dependent, sequence-specific manner, and are also adaptive, providing protection against previously encountered foreign elements. In addition to their canonical function in defense against foreign nucleic acid, their roles in various aspects of bacterial physiology are now being uncovered. We recently revealed a role for a Cas9-based Type II CRISPR-Cas system in the control of endogenous gene expression, a novel form of prokaryotic gene regulation. Cas9 functions in association with two small RNAs to target and alter the stability of an endogenous transcript encoding a bacterial lipoprotein (BLP). Since BLPs are recognized by the host innate immune protein Toll-like Receptor 2 (TLR2), CRISPR-Cas-mediated repression of BLP expression facilitates evasion of TLR2 by the intracellular bacterial pathogen Francisella novicida, and is essential for its virulence. Here we describe the Cas9 regulatory system in detail, as well as data on its role in controlling virulence traits of Neisseria meningitidis and Campylobacter jejuni. We also discuss potential roles of CRISPR-Cas systems in the response to envelope stress and other aspects of bacterial physiology. Since ~45% of bacteria and ~83% of Archaea encode these machineries, the newly appreciated regulatory functions of CRISPR-Cas systems are likely to play broad roles in controlling the pathogenesis and physiology of diverse prokaryotes.
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Affiliation(s)
- Timothy R Sampson
- Department of Microbiology and Immunology, Microbiology and Molecular Genetics Program, Emory University School of Medicine Atlanta, GA, USA ; Emory Vaccine Center, Emory University School of Medicine Atlanta, GA, USA ; Yerkes National Primate Research Center, Emory University School of Medicine Atlanta, GA, USA
| | - David S Weiss
- Emory Vaccine Center, Emory University School of Medicine Atlanta, GA, USA ; Yerkes National Primate Research Center, Emory University School of Medicine Atlanta, GA, USA ; Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine Atlanta, GA, USA
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The Legionella pneumophila collagen-like protein mediates sedimentation, autoaggregation, and pathogen-phagocyte interactions. Appl Environ Microbiol 2013; 80:1441-54. [PMID: 24334670 DOI: 10.1128/aem.03254-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Although only partially understood, multicellular behavior is relatively common in bacterial pathogens. Bacterial aggregates can resist various host defenses and colonize their environment more efficiently than planktonic cells. For the waterborne pathogen Legionella pneumophila, little is known about the roles of autoaggregation or the parameters which allow cell-cell interactions to occur. Here, we determined the endogenous and exogenous factors sufficient to allow autoaggregation to take place in L. pneumophila. We show that isolates from Legionella species which do not produce the Legionella collagen-like protein (Lcl) are deficient in autoaggregation. Targeted deletion of the Lcl-encoding gene (lpg2644) and the addition of Lcl ligands impair the autoaggregation of L. pneumophila. In addition, Lcl-induced autoaggregation requires divalent cations. Escherichia coli producing surface-exposed Lcl is able to autoaggregate and shows increased biofilm production. We also demonstrate that L. pneumophila infection of Acanthamoeba castellanii and Hartmanella vermiformis is potentiated under conditions which promote Lcl dependent autoaggregation. Overall, this study shows that L. pneumophila is capable of autoaggregating in a process that is mediated by Lcl in a divalent-cation-dependent manner. It also reveals that Lcl potentiates the ability of L. pneumophila to come in contact, attach, and infect amoebae.
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