1
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Rehman S, Antonovic AK, McIntire IE, Zheng H, Cleaver L, Baczynska M, Adams CO, Portlock T, Richardson K, Shaw R, Oregioni A, Mastroianni G, Whittaker SBM, Kelly G, Lorenz CD, Fornili A, Cianciotto NP, Garnett JA. The Legionella collagen-like protein employs a distinct binding mechanism for the recognition of host glycosaminoglycans. Nat Commun 2024; 15:4912. [PMID: 38851738 PMCID: PMC11162425 DOI: 10.1038/s41467-024-49255-4] [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: 09/16/2023] [Accepted: 05/30/2024] [Indexed: 06/10/2024] Open
Abstract
Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires' disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual trimer arrangement with a positively charged external surface and negatively charged solvent exposed internal cavity. Through molecular dynamics simulations, we show how the glycosaminoglycan chondroitin-4-sulphate associates with the Lcl-CTD surface via distinct binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate-binding mechanism.
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Affiliation(s)
- Saima Rehman
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Anna Katarina Antonovic
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Ian E McIntire
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Leanne Cleaver
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
| | - Maria Baczynska
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
- Biological Physics & Soft Matter Research Group, Department of Physics, King's College London, London, UK
| | - Carlton O Adams
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Theo Portlock
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Katherine Richardson
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Rosie Shaw
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Alain Oregioni
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Giulia Mastroianni
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Sara B-M Whittaker
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Christian D Lorenz
- Biological Physics & Soft Matter Research Group, Department of Physics, King's College London, London, UK
| | - Arianna Fornili
- Department of Chemistry, School of Physical and Chemical Sciences, Queen Mary University of London, London, UK.
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - James A Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King's College London, London, UK.
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2
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Rehman S, Antonovic AK, McIntire IE, Zheng H, Cleaver L, Adams CO, Portlock T, Richardson K, Shaw R, Oregioni A, Mastroianni G, Whittaker SBM, Kelly G, Fornili A, Cianciotto NP, Garnett JA. The Legionella collagen-like protein employs a unique binding mechanism for the recognition of host glycosaminoglycans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.10.570962. [PMID: 38106198 PMCID: PMC10723406 DOI: 10.1101/2023.12.10.570962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Bacterial adhesion is a fundamental process which enables colonisation of niche environments and is key for infection. However, in Legionella pneumophila, the causative agent of Legionnaires' disease, these processes are not well understood. The Legionella collagen-like protein (Lcl) is an extracellular peripheral membrane protein that recognises sulphated glycosaminoglycans (GAGs) on the surface of eukaryotic cells, but also stimulates bacterial aggregation in response to divalent cations. Here we report the crystal structure of the Lcl C-terminal domain (Lcl-CTD) and present a model for intact Lcl. Our data reveal that Lcl-CTD forms an unusual dynamic trimer arrangement with a positively charged external surface and a negatively charged solvent exposed internal cavity. Through Molecular Dynamics (MD) simulations, we show how the GAG chondroitin-4-sulphate associates with the Lcl-CTD surface via unique binding modes. Our findings show that Lcl homologs are present across both the Pseudomonadota and Fibrobacterota-Chlorobiota-Bacteroidota phyla and suggest that Lcl may represent a versatile carbohydrate binding mechanism.
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Affiliation(s)
- Saima Rehman
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - Anna K. Antonovic
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Ian E. McIntire
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Leanne Cleaver
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
| | - Carlton O. Adams
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Theo Portlock
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Katherine Richardson
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Rosie Shaw
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Alain Oregioni
- The Medical Research Council Biomedical NMR Centre, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Giulia Mastroianni
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Sara B-M. Whittaker
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Geoff Kelly
- The Medical Research Council Biomedical NMR Centre, the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Arianna Fornili
- School of Physical and Chemical Sciences, Queen Mary University of London, London, UK
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - James A. Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral & Craniofacial Sciences, King’s College London, London, UK
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Lara de Larrea J, MacIsaac SA, Rauch KD, Stoddart AK, Gagnon GA. Comparison of Legionella pneumophila and Pseudomonas fluorescens Quantification Methods for Assessing UV LED Disinfection. ACS ES&T WATER 2023; 3:3667-3675. [PMID: 37970541 PMCID: PMC10644340 DOI: 10.1021/acsestwater.3c00428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/17/2023]
Abstract
This study assesses the efficacy of ultraviolet light-emitting diodes (UV LEDs) for deactivating Legionella pneumophila (pure culture) and Pseudomonas fluorescens (pure culture and biofilms) on relevant drinking water distribution system surfaces (cast iron and stainless steel). UV LED treatment at 280 nm demonstrated superior performance compared to that at 365 nm, achieving a 4.8 log reduction value (LRV) for P. fluorescens pure cultures and, for biofilms, 4.02 LRV for stainless steel and 2.96 LRV for cast iron at 280 nm. Conversely, the results were less effective at 365 nm, with suspected photolytic reactions on cast iron. Quantification of L. pneumophila yielded varying results: 4 LRV using standard plate counts, 1.8 LRV with Legiolert, and 1 LRV with quantitative polymerase chain reaction at 280 nm, while the results were less than 1.5 LRV at 365 nm. This study provides insights into managing opportunistic pathogens and biofilms, emphasizing the need for improved quantification tools to better assess treatment efficacy.
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Affiliation(s)
- Jaser Lara de Larrea
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Sean A. MacIsaac
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Kyle D. Rauch
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Amina K. Stoddart
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
| | - Graham A. Gagnon
- Centre for Water
Resources
Studies. Department of Civil & Resource Engineering, Dalhousie University, Halifax B3H 4R2, NS, Canada
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Lopez AE, Grigoryeva LS, Barajas A, Cianciotto NP. Legionella pneumophila Rhizoferrin Promotes Bacterial Biofilm Formation and Growth within Amoebae and Macrophages. Infect Immun 2023; 91:e0007223. [PMID: 37428036 PMCID: PMC10429650 DOI: 10.1128/iai.00072-23] [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: 02/15/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023] Open
Abstract
Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene (lbtA) in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both lbtA and feoB. This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The lbtA feoB mutant, but not its lbtA-containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the lbtA feoB mutant, but not its complement containing lbtA, proved to be greatly impaired for growth in Acanthamoeba castellanii, Vermamoeba vermiformis, and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of Legionella. Outside of Legionella, the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.
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Affiliation(s)
- Alberto E. Lopez
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Lubov S. Grigoryeva
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Armando Barajas
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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5
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Human macrophages utilize a wide range of pathogen recognition receptors to recognize Legionella pneumophila, including Toll-Like Receptor 4 engaging Legionella lipopolysaccharide and the Toll-like Receptor 3 nucleic-acid sensor. PLoS Pathog 2021; 17:e1009781. [PMID: 34280250 PMCID: PMC8321404 DOI: 10.1371/journal.ppat.1009781] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/29/2021] [Accepted: 07/03/2021] [Indexed: 12/15/2022] Open
Abstract
Cytokines made by macrophages play a critical role in determining the course of Legionella pneumophila infection. Prior murine-based modeling indicated that this cytokine response is initiated upon recognition of L. pneumophila by a subset of Toll-like receptors, namely TLR2, TLR5, and TLR9. Through the use of shRNA/siRNA knockdowns and subsequently CRISPR/Cas9 knockouts (KO), we determined that TRIF, an adaptor downstream of endosomal TLR3 and TLR4, is required for full cytokine secretion by human primary and cell-line macrophages. By characterizing a further set of TLR KO's in human U937 cells, we discerned that, contrary to the viewpoint garnered from murine-based studies, TLR3 and TLR4 (along with TLR2 and TLR5) are in fact vital to the macrophage response in the early stages of L. pneumophila infection. This conclusion was bolstered by showing that i) chemical inhibitors of TLR3 and TLR4 dampen the cytokine output of primary human macrophages and ii) transfection of TLR3 and TLR4 into HEK cells conferred an ability to sense L. pneumophila. TLR3- and TLR4-dependent cytokines promoted migration of human HL-60 neutrophils across an epithelial layer, pointing to the biological importance for the newfound signaling pathway. The response of U937 cells to L. pneumophila LPS was dependent upon TLR4, a further contradiction to murine-based studies, which had concluded that TLR2 is the receptor for Legionella LPS. Given the role of TLR3 in sensing nucleic acid (i.e., dsRNA), we utilized newly-made KO U937 cells to document that DNA-sensing by cGAS-STING and DNA-PK are also needed for the response of human macrophages to L. pneumophila. Given the lack of attention given them in the bacterial field, C-type lectin receptors were similarly examined; but, they were not required. Overall, this study arguably represents the most extensive, single-characterization of Legionella-recognition receptors within human macrophages.
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Hsieh TS, Lopez VA, Black MH, Osinski A, Pawłowski K, Tomchick DR, Liou J, Tagliabracci VS. Dynamic remodeling of host membranes by self-organizing bacterial effectors. Science 2021; 372:935-941. [PMID: 33927055 PMCID: PMC8543759 DOI: 10.1126/science.aay8118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/17/2021] [Accepted: 04/14/2021] [Indexed: 01/09/2023]
Abstract
During infection, intracellular bacterial pathogens translocate a variety of effectors into host cells that modify host membrane trafficking for their benefit. We found a self-organizing system consisting of a bacterial phosphoinositide kinase and its opposing phosphatase that formed spatiotemporal patterns, including traveling waves, to remodel host cellular membranes. The Legionella effector MavQ, a phosphatidylinositol (PI) 3-kinase, was targeted to the endoplasmic reticulum (ER). MavQ and the Legionella PI 3-phosphatase SidP, even in the absence of other bacterial components, drove rapid PI 3-phosphate turnover on the ER and spontaneously formed traveling waves that spread along ER subdomains inducing vesicle and tubule budding. Thus, bacteria can exploit a self-organizing membrane-targeting mechanism to hijack host cellular structures for survival.
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Affiliation(s)
- Ting-Sung Hsieh
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Victor A Lopez
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Miles H Black
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Adam Osinski
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Krzysztof Pawłowski
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences, Warsaw 02-776, Poland
| | - Diana R Tomchick
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen Liou
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vincent S Tagliabracci
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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7
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Richards J, Belasco JG. Widespread Protection of RNA Cleavage Sites by a Riboswitch Aptamer that Folds as a Compact Obstacle to Scanning by RNase E. Mol Cell 2020; 81:127-138.e4. [PMID: 33212019 DOI: 10.1016/j.molcel.2020.10.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/26/2022]
Abstract
Riboswitches are thought generally to function by modulating transcription elongation or translation initiation. In rare instances, ligand binding to a riboswitch has been found to alter the rate of RNA degradation by directly stimulating or inhibiting nearby cleavage. Here, we show that guanidine-induced pseudoknot formation by the aptamer domain of a guanidine III riboswitch from Legionella pneumophila has a different effect, stabilizing mRNA by protecting distal cleavage sites en masse from ribonuclease attack. It does so by creating a coaxially base-paired obstacle that impedes scanning from a monophosphorylated 5' end to those sites by the regulatory endonuclease RNase E. Ligand binding by other riboswitch aptamers peripheral to the path traveled by RNase E does not inhibit distal cleavage. These findings reveal that a riboswitch aptamer can function independently of any overlapping expression platform to regulate gene expression by acting directly to prolong mRNA longevity in response to ligand binding.
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Affiliation(s)
- Jamie Richards
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA; Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016, USA
| | - Joel G Belasco
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA; Department of Microbiology, New York University School of Medicine, 430 E. 29th Street, New York, NY 10016, USA.
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8
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Abstract
We highlight a rare presentation of Legionella infection in a 77-year-old woman with a clinical diagnosis of giant cell arteritis 2 months prior to presentation. She was started on 60 mg prednisone that was tapered to 10 mg after 4 weeks following her diagnosis. She presented with a 1-month progressive dyspnoea in the absence of any other symptoms. Her exposure history was significant only for a recent trip to Florida where she stayed at a hotel. Initial laboratory workup was significant for hyponatraemia (127 mmol/L). Workup including bronchoalveolar lavage (BAL) and induced sputum for gram stain, acid fast stain and bacterial culture were negative for Pneumocystis jirovecii pneumonia and other opportunistic infectious agents. However, BAL was positive for Legionella pneumophila via PCR that was confirmed by a positive urinary Legionella antigen. The patient received treatment with levofloxacin that led to full resolution of her symptoms.
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Affiliation(s)
- Hasan Ahmad Hasan Albitar
- Faculty of Medicine, University of Jordan, Amman, Jordan.,Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Alice Gallo de Moraes
- Department of Medicine, Division of Pulmonary and Critical Care, Mayo Clinic, Rochester, Minnesota, USA
| | - Kaiser G Lim
- Department of Medicine, Division of Pulmonary and Critical Care, Mayo Clinic, Rochester, Minnesota, USA
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Burillo A, Pedro-Botet ML, Bouza E. Microbiology and Epidemiology of Legionnaire's Disease. Infect Dis Clin North Am 2017; 31:7-27. [PMID: 28159177 DOI: 10.1016/j.idc.2016.10.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Legionnaire's disease (LD) is the pneumonic form of legionellosis caused by aerobic gram-negative bacilli of the genus Legionella. Individuals become infected when they inhale aerosolized water droplets contaminated with Legionella species. Forty years after the identification of Legionella pneumophila as the cause of the 1976 pneumonia outbreak in a hotel in Philadelphia, we have non-culture-based diagnostic tests, effective antibiotics, and preventive measures to handle LD. With a mortality rate still around 10%, underreporting, and sporadic outbreaks, there is still much work to be done. In this article, the authors review the microbiology, laboratory diagnosis, and epidemiology of LD.
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Affiliation(s)
- Almudena Burillo
- Division of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo 46, 28007 Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Doctor Esquerdo 46, 28007 Madrid, Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain
| | - María Luisa Pedro-Botet
- Infectious Diseases Unit, Hospital Universitario German Trías i Pujol, Carretera de Canyet s/n, 08916 Badalona, Spain; Departamento de Medicina, Area de Medicina, Universidad Autónoma de Barcelona, Plaza Cívica, Campus de la UAB, 08193 Bellaterra, Sardañola del Vallés (Barcelona), Spain; CIBER de Enfermedades Respiratorias (CIBERES CB06/06/1089), Instituto de Salud Carlos III, Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain
| | - Emilio Bouza
- Division of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo 46, 28007 Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón, Doctor Esquerdo 46, 28007 Madrid, Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense de Madrid, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES CB06/06/0058), Instituto de Salud Carlos III, Monforte de Lemos 3-5, Pabellón 11, 28029 Madrid, Spain.
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10
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Pécastaings S, Allombert J, Lajoie B, Doublet P, Roques C, Vianney A. New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling. BIOFOULING 2016; 32:935-948. [PMID: 27494738 DOI: 10.1080/08927014.2016.1212988] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 07/07/2016] [Indexed: 06/06/2023]
Abstract
The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species.
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Affiliation(s)
- Sophie Pécastaings
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Julie Allombert
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Barbora Lajoie
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Patricia Doublet
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
| | - Christine Roques
- a Laboratoire de Génie chimique UMR 5503 , UPS, Université de Toulouse , Toulouse , France
| | - Anne Vianney
- b CIRI, International Center for Infectiology Research , Legionella Pathogenesis Group, Université de Lyon , Lyon , France
- c Inserm , Lyon , France
- d Ecole Normale Supérieure de Lyon , Lyon , France
- e Université Lyon 1, CIRI, International Center for Infectiology Research , Lyon , France
- f CNRS , Lyon , France
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Abstract
Since first identified in early 1977, bacteria of the genus Legionella are recognised as a common cause of community-acquired pneumonia and a rare cause of hospital-acquired pneumonia. Legionella bacteria multisystem manifestations mainly affect susceptible patients as a result of age, underlying debilitating conditions, or immunosuppression. Water is the major natural reservoir for Legionella, and the pathogen is found in many different natural and artificial aquatic environments such as cooling towers or water systems in buildings, including hospitals. The term given to the severe pneumonia and systemic infection caused by Legionella bacteria is Legionnaires' disease. Over time, the prevalence of legionellosis or Legionnaires' disease has risen, which might indicate a greater awareness and reporting of the disease. Advances in microbiology have led to a better understanding of the ecological niches and pathogenesis of the condition. Legionnaires' disease is not always suspected because of its non-specific symptoms, and the diagnostic tests routinely available do not offer the desired sensitivity. However, effective antibiotics are available. Disease notification systems provide the basis for initiating investigations and limiting the scale and recurrence of outbreaks. This report reviews our current understanding of this disease.
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Affiliation(s)
- Burke A Cunha
- Infectious Disease Division, Winthrop-University Hospital, Mineola, NY, USA; School of Medicine, State University of New York, Stony Brook, NY, USA.
| | - Almudena Burillo
- Division of Clinical Microbiology and Infectious Disease, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Universidad Complutense de Madrid, Madrid, Spain
| | - Emilio Bouza
- Division of Clinical Microbiology and Infectious Disease, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Universidad Complutense de Madrid, Madrid, Spain; CIBER de Enfermedades Respiratorias (CIBERES CB06/06/0058), Madrid, Spain
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12
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The Legionella pneumophila Siderophore Legiobactin Is a Polycarboxylate That Is Identical in Structure to Rhizoferrin. Infect Immun 2015. [PMID: 26195554 DOI: 10.1128/iai.00808-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Legionella pneumophila, the agent of Legionnaires' disease, secretes a siderophore (legiobactin) that promotes bacterial infection of the lung. In past work, we determined that cytoplasmic LbtA (from Legiobactin gene A) promotes synthesis of legiobactin, inner membrane LbtB aids in export of the siderophore, and outer membrane LbtU and inner membrane LbtC help mediate ferrilegiobactin uptake and assimilation. However, the past studies examined legiobactin contained within bacterial culture supernatants. By utilizing high-pressure liquid chromatography that incorporates hydrophilic interaction-based chemistry, we have now purified legiobactin from supernatants of virulent strain 130b that is suitable for detailed chemical analysis. High-resolution mass spectrometry (MS) revealed that the molecular mass of (protonated) legiobactin is 437.140 Da. On the basis of the results obtained from both MS analysis and various forms of nuclear magnetic resonance, we found that legiobactin is composed of two citric acid residues linked by a putrescine bridge and thus is identical in structure to rhizoferrin, a polycarboxylate-type siderophore made by many fungi and several unrelated bacteria. Both purified legiobactin and rhizoferrin obtained from the fungus Cunninghamella elegans were able to promote Fe(3+) uptake by wild-type L. pneumophila as well as enhance growth of iron-starved bacteria. These results did not occur with 130b mutants lacking lbtU or lbtC, indicating that both endogenously made legiobactin and exogenously derived rhizoferrin are assimilated by L. pneumophila in an LbtU- and LbtC-dependent manner.
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Jeong KC, Sexton JA, Vogel JP. Spatiotemporal regulation of a Legionella pneumophila T4SS substrate by the metaeffector SidJ. PLoS Pathog 2015; 11:e1004695. [PMID: 25774515 PMCID: PMC4361747 DOI: 10.1371/journal.ppat.1004695] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 01/22/2015] [Indexed: 11/18/2022] Open
Abstract
Modulation of host cell function is vital for intracellular pathogens to survive and replicate within host cells. Most commonly, these pathogens utilize specialized secretion systems to inject substrates (also called effector proteins) that function as toxins within host cells. Since it would be detrimental for an intracellular pathogen to immediately kill its host cell, it is essential that secreted toxins be inactivated or degraded after they have served their purpose. The pathogen Legionella pneumophila represents an ideal system to study interactions between toxins as it survives within host cells for approximately a day and its Dot/Icm type IVB secretion system (T4SS) injects a vast number of toxins. Previously we reported that the Dot/Icm substrates SidE, SdeA, SdeB, and SdeC (known as the SidE family of effectors) are secreted into host cells, where they localize to the cytoplasmic face of the Legionella containing vacuole (LCV) in the early stages of infection. SidJ, another effector that is unrelated to the SidE family, is also encoded in the sdeC-sdeA locus. Interestingly, while over-expression of SidE family proteins in a wild type Legionella strain has no effect, we found that their over-expression in a ∆sidJ mutant completely inhibits intracellular growth of the strain. In addition, we found expression of SidE proteins is toxic in both yeast and mammalian HEK293 cells, but this toxicity can be suppressed by co-expression of SidJ, suggesting that SidJ may modulate the function of SidE family proteins. Finally, we were able to demonstrate both in vivo and in vitro that SidJ acts on SidE proteins to mediate their disappearance from the LCV, thereby preventing lethal intoxication of host cells. Based on these findings, we propose that SidJ acts as a metaeffector to control the activity of other Legionella effectors. A key attribute of many pathogens is their ability to survive and replicate within eukaryotic host cells. One such pathogen, Legionella pneumophila, is able to grow within macrophages in the lungs, thereby causing a form of pneumonia called Legionnaires’ Disease. L. pneumophila causes disease by translocating several hundred proteins into the host cell. These proteins are typically referred to as ‘‘effectors’’, as they function as toxins to alter normal host cell function. However, since L. pneumophila remains within the host cells for approximately one day, continual poisoning of the eukaryotic cells by the bacterial effectors will result in the premature death of the host cell, thus restricting the growth of the pathogen. Previously the L. pneumophila secreted protein LubX was described as a “metaeffector”, which has been defined as an effector that acts directly on another effector to modulate its function inside the host cell. LubX accomplishes this task by directing the degradation of another effector, SidH. Here we report a second L. pneumophila metaeffector, SidJ, acts in a similar manner to neutralize SidE family effectors by removing them from the intracellular compartment that contains the bacterium. This further establishes the concept of metaeffectors, which are likely to be critical to how Legionella and many other pathogens cause disease.
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Affiliation(s)
- Kwang Cheol Jeong
- Department of Animal Sciences & Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jessica A. Sexton
- Chemical Engineering Department, University of California, Santa Barbara, Santa Barbara, California, United States of America
| | - Joseph P. Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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Jeong KC, Sutherland MC, Vogel JP. Novel export control of aLegionella Dot/Icm substrate is mediated by dual, independent signal sequences. Mol Microbiol 2015; 96:175-88. [DOI: 10.1111/mmi.12928] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2015] [Indexed: 12/11/2022]
Affiliation(s)
- Kwang Cheol Jeong
- Department of Animal Sciences & Emerging Pathogens Institute; University of Florida; Gainesville FL USA
| | | | - Joseph P. Vogel
- Department of Molecular Microbiology; Washington University School of Medicine; St. Louis MO USA
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