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Guzman RM, Voth DE. Embracing multiple infection models to tackle Q fever: A review of in vitro, in vivo, and lung ex vivo models. Cell Immunol 2024; 405-406:104880. [PMID: 39357100 DOI: 10.1016/j.cellimm.2024.104880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 09/06/2024] [Accepted: 09/23/2024] [Indexed: 10/04/2024]
Abstract
Multiple animal and cell culture models are employed to study pathogenesis of Coxiella burnetii, the causative agent of acute and chronic human Q fever. C. burnetii is a lung pathogen that is aerosolized in contaminated products and inhaled by humans to cause acute disease that can disseminate to other organs and establish chronic infection. Cellular models of Q fever include a variety of tissue-derived cell lines from mice and humans such as lung alveolar ex vivo cells. These models have the advantage of being cost-effective and reproducible. Similarly, animal models including mice and guinea pigs are cost-effective, although only immunocompromised SCID mice display a severe disease phenotype in response to Nine Mile I and Nine Mile II isolates of C. burnetii while immunocompetent guinea pigs display human-like symptoms and robust immune responses. Non-human primates such as macaques and marmosets are the closest model of human disease but are costly and largely used for adaptive immune response studies. All animal models are used for vaccine development but many differences exist in the pathogen's ability to establish lung infection when considering infection routes, bacterial isolates, and host genetic background. Similarly, while cellular models are useful for characterization of host-pathogen mechanisms, future developments should include use of a lung infection platform to draw appropriate conclusions. Here, we summarize the current state of the C. burnetii lung pathogenesis field by discussing the contribution of different animal and cell culture models and include suggestions for continuing to move the field forward.
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Affiliation(s)
- R M Guzman
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States
| | - Daniel E Voth
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
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2
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McMillan IA, Norris MH, Golon SJ, Franckowiak GA, Grinolds JM, Goldstein SM, Phelps DM, Bodenchuk MJ, Leland BR, Bowen RA, Brown VR, Borlee BR. Serosurveillance of Coxiella burnetii in feral swine populations of Hawai'i and Texas identifies overlap with human Q fever incidence. J Clin Microbiol 2024:e0078024. [PMID: 39189735 DOI: 10.1128/jcm.00780-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 08/08/2024] [Indexed: 08/28/2024] Open
Abstract
Feral swine are invasive in the United States and a reservoir for infectious diseases. The increase in feral swine population and the geographic range are a concern for the spread of zoonotic diseases to humans and livestock. Feral swine could contribute to the spread of Coxiella burnetii, the causative agent of human Q fever. In this study, we characterized the seroprevalence of C. burnetii in feral swine populations of Hawai'i and Texas, which have low and high rates of human Q fever, respectively. Seropositivity rates were as high as 0.19% and 6.03% in Hawai'i and Texas, respectively, indicating that feral swine cannot be ruled out as a potential reservoir for disease transmission and spread. In Texas, we identified the overlap between seropositivity of feral swine and human Q fever incidence. These results indicate that there is a potentially low but detectable risk of C. burnetii exposure associated with feral swine populations in Hawai'i and Texas.
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Affiliation(s)
- Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Michael H Norris
- Pathogen Analysis and Translational Health Group, School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, Hawai'i, USA
| | - Samuel J Golon
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Gregory A Franckowiak
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Feral Swine Damage Management Program, Fort Collins, Colorado, USA
| | - James M Grinolds
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Feral Swine Damage Management Program, Fort Collins, Colorado, USA
| | - Samuel M Goldstein
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Honolulu, Hawai'i, USA
| | - Darrin M Phelps
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Honolulu, Hawai'i, USA
| | - Michael J Bodenchuk
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, San Antonio, Texas, USA
| | - Bruce R Leland
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, San Antonio, Texas, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Vienna R Brown
- US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Feral Swine Damage Management Program, Fort Collins, Colorado, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, USA
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3
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Delahaye A, Eldin C, Bleibtreu A, Djossou F, Marrie TJ, Ghanem-Zoubi N, Roeden S, Epelboin L. Treatment of persistent focalized Q fever: time has come for an international randomized controlled trial. J Antimicrob Chemother 2024; 79:1725-1747. [PMID: 38888195 DOI: 10.1093/jac/dkae145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/15/2024] [Indexed: 06/20/2024] Open
Abstract
Q fever is a worldwide zoonosis due to Coxiella burnetii, responsible for endocarditis and endovascular infections. Since the 1990s, the combination hydroxychloroquine + doxycycline has constituted the curative and prophylactic treatment in persistent focalized Q fever. This combination appears to have significantly reduced the treatment's duration (from 60 to 26 months), yet substantial evidence of effectiveness remains lacking. Data are mostly based on in vitro and observational studies. We conducted a literature review to assess the effectiveness of this therapy, along with potential alternatives. The proposed in vitro mechanism of action describes the inhibition of Coxiella replication by doxycycline through the restoration of its bactericidal activity (inhibited in acidic environment) by alkalinization of phagolysosome-like vacuoles with hydroxychloroquine. So far, the rarity and heterogeneous presentation of cases have made it challenging to design prospective studies with statistical power. The main studies supporting this treatment are retrospective cohorts, dating back to the 1990s-2000s. Retrospective studies from the large Dutch outbreak of Q fever (>4000 cases between 2007 and 2010) did not corroborate a clear benefit of this combination, notably in comparison with other regimens. Thus, there is still no consensus among the medical community on this issue. However insufficient the evidence, today the doxycycline + hydroxychloroquine combination remains the regimen with the largest clinical experience in the treatment of 'chronic' Q fever. Reinforcing the guidelines' level of evidence is critical. We herein propose the creation of an extensive international registry, followed by a prospective cohort or ideally a randomized controlled trial.
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Affiliation(s)
- Audrey Delahaye
- Department of Infectious and Tropical Diseases, Andrée Rosemon Hospital, Cayenne, French Guiana
| | - Carole Eldin
- UMR UVE, Aix Marseille University, IRD 190 Inserm, 1207 EFS-IRBA, Marseille, France
| | - Alexandre Bleibtreu
- Department of Infectious and Tropical Diseases, University Hospitals Pitié Salpêtrière-Charles Foix, AP-HP, Paris, France
| | - Félix Djossou
- Infectious Diseases Institute, Rambam Health Care Campus, Haifa, Israel
| | - Thomas J Marrie
- Faculty of Medicine, Dalhousie University, 1459 Oxford Street, Halifax, NS B3H 4R2, Canada
| | - Nesrin Ghanem-Zoubi
- Ruth and Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, Haifa, Israel
| | - Sonja Roeden
- Internal Medicine and Dermatology, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Loïc Epelboin
- Department of Infectious and Tropical Diseases, Andrée Rosemon Hospital, Cayenne, French Guiana
- Clinical Investigation Center Antilles Guyane, Inserm 1424, Centre Hospitalier de Cayenne Andrée Rosemon, Cayenne, French Guiana
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4
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Boyer MA, Fischer NL, Shin S. TNF and type I IFN induction of the IRG1-itaconate pathway restricts Coxiella burnetii replication within mouse macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548079. [PMID: 37461589 PMCID: PMC10350068 DOI: 10.1101/2023.07.07.548079] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
The intracellular Gram-negative bacterium Coxiella burnetii replicates within macrophages and causes a zoonotic disease known as Q fever. In murine macrophages, the cytokine tumor necrosis factor (TNF) is critical for restriction of intracellular C. burnetii replication. Here, we show that TNF collaborates with type I interferon (IFN) signaling for maximal control of C. burnetii. We found that TNF and type I IFN upregulate the expression of the metabolic enzyme immune responsive gene 1 (IRG1), also known as cis-aconitate decarboxylase 1 (ACOD1), and that IRG1 is required to restrict C. burnetii T4SS translocation and replication within macrophages. Further, we show that itaconic acid, the metabolic product of IRG1, restricts C. burnetii replication both intracellularly and in axenic culture. These data reveal that TNF and type I IFN upregulate the IRG1-itaconate pathway to restrict intracellular C. burnetii replication within murine macrophages.
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Affiliation(s)
- Mark A. Boyer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Natasha Lopes Fischer
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
| | - Sunny Shin
- Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104
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5
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Laidoudi Y, Rousset E, Dessimoulie AS, Prigent M, Raptopoulo A, Huteau Q, Chabbert E, Navarro C, Fournier PE, Davoust B. Tracking the Source of Human Q Fever from a Southern French Village: Sentinel Animals and Environmental Reservoir. Microorganisms 2023; 11:microorganisms11041016. [PMID: 37110439 PMCID: PMC10142994 DOI: 10.3390/microorganisms11041016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 04/29/2023] Open
Abstract
Coxiella burnetii, also known as the causal agent of Q fever, is a zoonotic pathogen infecting humans and several animal species. Here, we investigated the epidemiological context of C. burnetii from an area in the Hérault department in southern France, using the One Health paradigm. In total, 13 human cases of Q fever were diagnosed over the last three years in an area comprising four villages. Serological and molecular investigations conducted on the representative animal population, as well as wind data, indicated that some of the recent cases are likely to have originated from a sheepfold, which revealed bacterial contamination and a seroprevalence of 47.6%. However, the clear-cut origin of human cases cannot be ruled out in the absence of molecular data from the patients. Multi-spacer typing based on dual barcoding nanopore sequencing highlighted the occurrence of a new genotype of C. burnetii. In addition, the environmental contamination appeared to be widespread across a perimeter of 6 km due to local wind activity, according to the seroprevalence detected in dogs (12.6%) and horses (8.49%) in the surrounding populations. These findings were helpful in describing the extent of the exposed area and thus supporting the use of dogs and horses as valuable sentinel indicators for monitoring Q fever. The present data clearly highlighted that the epidemiological surveillance of Q fever should be reinforced and improved.
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Affiliation(s)
- Younes Laidoudi
- Aix Marseille University, IRD, AP-HM, MEPHI, 13005 Marseille, France
- IHU Méditerranée Infection, 13005 Marseille, France
| | - Elodie Rousset
- ANSES, Laboratoire de Sophia Antipolis, Unité fièvre Q animale, 06902 Sophia Antipolis, France
| | | | - Myriam Prigent
- ANSES, Laboratoire de Sophia Antipolis, Unité fièvre Q animale, 06902 Sophia Antipolis, France
| | - Alizée Raptopoulo
- ANSES, Laboratoire de Sophia Antipolis, Unité fièvre Q animale, 06902 Sophia Antipolis, France
| | - Quentin Huteau
- Aix Marseille University, IRD, AP-HM, MEPHI, 13005 Marseille, France
- IHU Méditerranée Infection, 13005 Marseille, France
| | | | | | - Pierre-Edouard Fournier
- IHU Méditerranée Infection, 13005 Marseille, France
- Aix Marseille University, IRD, AP-HM, SSA, VITROME, 13005 Marseille, France
- Centre National de Référence Rickettsies, Bartonella et Coxiella, 13005 Marseille, France
| | - Bernard Davoust
- Aix Marseille University, IRD, AP-HM, MEPHI, 13005 Marseille, France
- IHU Méditerranée Infection, 13005 Marseille, France
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6
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Wachter S, Larson CL, Virtaneva K, Kanakabandi K, Darwitz B, Crews B, Storrud K, Heinzen RA, Beare PA. A Survey of Two-Component Systems in Coxiella burnetii Reveals Redundant Regulatory Schemes and a Requirement for an Atypical PhoBR System in Mammalian Cell Infection. J Bacteriol 2023; 205:e0041622. [PMID: 36847507 PMCID: PMC10029714 DOI: 10.1128/jb.00416-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/20/2022] [Indexed: 03/01/2023] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever in humans. C. burnetii transitions between a replicative, metabolically active large-cell variant (LCV) and a spore-like, quiescent small-cell variant (SCV) as a likely mechanism to ensure survival between host cells and mammalian hosts. C. burnetii encodes three canonical two-component systems, four orphan hybrid histidine kinases, five orphan response regulators, and a histidine phosphotransfer protein, which have been speculated to play roles in the signaling required for C. burnetii morphogenesis and virulence. However, very few of these systems have been characterized. By employing a CRISPR interference system for genetic manipulation of C. burnetii, we created single- and multigene transcriptional knockdown strains targeting most of these signaling genes. Through this, we revealed a role for the C. burnetii PhoBR canonical two-component system in virulence, regulation of [Pi] maintenance, and Pi transport. We also outline a novel mechanism by which PhoBR function may be regulated by an atypical PhoU-like protein. We also determined that the GacA.2/GacA.3/GacA.4/GacS orphan response regulators coordinately and disparately regulate expression of SCV-associated genes in C. burnetii LCVs. These foundational results will inform future studies on the role of C. burnetii two-component systems in virulence and morphogenesis. IMPORTANCE C. burnetii is an obligate intracellular bacterium with a spore-like stability allowing it to survive long periods of time in the environment. This stability is likely due to its biphasic developmental cycle, whereby it can transition from an environmentally stable small-cell variant (SCV) to a metabolically active large-cell variant (LCV). Here, we define the role of two-component phosphorelay systems (TCS) in C. burnetii's ability to survive within the harsh environment contained in the phagolysosome of host cells. We show that the canonical PhoBR TCS has an important role in C. burnetii virulence and phosphate sensing. Further examination of the regulons controlled by orphan regulators indicated a role in modulating gene expression of SCV-associated genes, including genes essential for cell wall remodeling.
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Affiliation(s)
- Shaun Wachter
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
- Vaccine and Infectious Disease Organization, Saskatoon, Saskatchewan, Canada
| | - Charles L. Larson
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kimmo Virtaneva
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
| | - Kishore Kanakabandi
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
| | - Benjamin Darwitz
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Ben Crews
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
| | - Keelee Storrud
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
- Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, USA
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7
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Wachter S, Cockrell DC, Miller HE, Virtaneva K, Kanakabandi K, Darwitz B, Heinzen RA, Beare PA. The endogenous Coxiella burnetii plasmid encodes a functional toxin-antitoxin system. Mol Microbiol 2022; 118:744-764. [PMID: 36385554 PMCID: PMC10098735 DOI: 10.1111/mmi.15001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/25/2022] [Accepted: 11/08/2022] [Indexed: 11/18/2022]
Abstract
Coxiella burnetii is the causative agent of Q fever. All C. burnetii isolates encode either an autonomously replicating plasmid (QpH1, QpDG, QpRS, or QpDV) or QpRS-like chromosomally integrated plasmid sequences. The role of the ORFs present in these sequences is unknown. Here, the role of the ORFs encoded on QpH1 was investigated. Using a new C. burnetii shuttle vector (pB-TyrB-QpH1ori), we cured the C. burnetii Nine Mile Phase II strain of QpH1. The ΔQpH1 strain grew normally in axenic media but had a significant growth defect in Vero cells, indicating QpH1 was important for C. burnetii virulence. We developed an inducible CRISPR interference system to examine the role of individual QpH1 plasmid genes. CRISPRi of cbuA0027 resulted in significant growth defects in axenic media and THP-1 cells. The cbuA0028/cbuA0027 operon encodes CBUA0028 (ToxP) and CBUA0027 (AntitoxP), which are homologous to the HigB2 toxin and HigA2 antitoxin, respectively, from Vibrio cholerae. Consistent with toxin-antitoxin systems, overexpression of toxP resulted in a severe intracellular growth defect that was rescued by co-expression of antitoxP. ToxP inhibited protein translation. AntitoxP bound the toxP promoter (PtoxP) and ToxP, with the resulting complex binding also PtoxP. In summary, our data indicate that C. burnetii maintains an autonomously replicating plasmid because of a plasmid-based toxin-antitoxin system.
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Affiliation(s)
- Shaun Wachter
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.,Vaccine and Infectious Disease Organization, Saskatoon, Saskatchewan, Canada
| | - Diane C Cockrell
- Vector-Pathogen-Host Interaction unit, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | | | - Kimmo Virtaneva
- Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kishore Kanakabandi
- Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Benjamin Darwitz
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Robert A Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.,Genomics Research Section, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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8
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Anastácio S, de Sousa SR, Saavedra MJ, da Silva GJ. Role of Goats in the Epidemiology of Coxiella burnetii. BIOLOGY 2022; 11:biology11121703. [PMID: 36552213 PMCID: PMC9774940 DOI: 10.3390/biology11121703] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022]
Abstract
Since its first description in the late 1930s, Q fever has raised many questions. Coxiella burnetii, the causative agent, is a zoonotic pathogen affecting a wide range of hosts. This airborne organism leads to an obligate, intracellular lifecycle, during which it multiplies in the mononuclear cells of the immune system and in the trophoblasts of the placenta in pregnant females. Although some issues about C. burnetii and its pathogenesis in animals remain unclear, over the years, some experimental studies on Q fever have been conducted in goats given their excretion pattern. Goats play an important role in the epidemiology and economics of C. burnetii infections, also being the focus of several epidemiological studies. Additionally, variants of the agent implicated in human long-term disease have been found circulating in goats. The purpose of this review is to summarize the latest research on C. burnetii infection and the role played by goats in the transmission of the infection to humans.
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Affiliation(s)
- Sofia Anastácio
- Vasco da Gama Research Centre (CIVG), Department of Veterinary Sciences, Vasco da Gama University School, Avenida José R. Sousa Fernandes 197 Lordemão, 3020-210 Coimbra, Portugal
- Center of Neurosciences and Cell Biology, Health Science Campus, 3000-548 Coimbra, Portugal
- Correspondence:
| | - Sérgio Ramalho de Sousa
- Vasco da Gama Research Centre (CIVG), Department of Veterinary Sciences, Vasco da Gama University School, Avenida José R. Sousa Fernandes 197 Lordemão, 3020-210 Coimbra, Portugal
| | - Maria José Saavedra
- Laboratory Medical Microbiology—Antimicrobials, Biocides and Biofilms Unit, Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal
- Centre for the Research and Technology Agro-Environmental and Biological Sciences and Inov4Agro—Institute for Innovation, Capacity Building and Sustainability of Agri-Food Production, 5000-801 Vila Real, Portugal
| | - Gabriela Jorge da Silva
- Center of Neurosciences and Cell Biology, Health Science Campus, 3000-548 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal
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Abstract
Coxiella burnetii, the causative agent of query (Q) fever in humans, is an obligate intracellular bacterium. C. burnetii can naturally infect a broad range of host organisms (e.g., mammals and arthropods) and cell types. This amphotropic nature of C. burnetii, in combination with its ability to utilize both glycolytic and gluconeogenic carbon sources, suggests that the pathogen relies on metabolic plasticity to replicate in nutritionally diverse intracellular environments. To test the significance of metabolic plasticity in C. burnetii host cell colonization, C. burnetii intracellular replication in seven distinct cell lines was compared between a metabolically competent parental strain and a mutant, CbΔpckA, unable to undergo gluconeogenesis. Both the parental strain and CbΔpckA mutant exhibited host cell-dependent infection phenotypes, which were influenced by alterations to host glycolytic or gluconeogenic substrate availability. Because the nutritional environment directly impacts host cell physiology, our analysis was extended to investigate the response of C. burnetii replication in mammalian host cells cultivated in a novel physiological medium based on the nutrient composition of mammalian interstitial fluid, interstitial fluid-modeled medium (IFmM). An infection model based on IFmM resulted in exacerbation of a replication defect exhibited by the CbΔpckA mutant in specific cell lines. The CbΔpckA mutant was also attenuated during infection of an animal host. Overall, the study underscores that gluconeogenic capacity aids C. burnetii amphotropism and that the amphotropic nature of C. burnetii should be considered when resolving virulence mechanisms in this pathogen.
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Delaney MA, Hartigh AD, Carpentier SJ, Birkland TP, Knowles DP, Cookson BT, Frevert CW. Avoidance of the NLRP3 Inflammasome by the Stealth Pathogen, Coxiella burnetii. Vet Pathol 2021; 58:624-642. [PMID: 33357072 DOI: 10.1177/0300985820981369] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Coxiella burnetii, a highly adapted obligate intracellular bacterial pathogen and the cause of the zoonosis Q fever, is a reemerging public health threat. C. burnetii employs a Type IV secretion system (T4SS) to establish and maintain its intracellular niche and modulate host immune responses including the inhibition of apoptosis. Interactions between C. burnetii and caspase-1-mediated inflammasomes are not fully elucidated. This study confirms that C. burnetii does not activate caspase-1 during infection of mouse macrophages in vitro. C. burnetii-infected cells did not develop NLRP3 and ASC foci indicating its ability to avoid cytosolic detection. C. burnetii is unable to inhibit the pyroptosis and IL-1β secretion that is induced by potent inflammasome stimuli but rather enhances these caspase-1-mediated effects. We found that C. burnetii upregulates pro-IL-1β and robustly primes NLRP3 inflammasomes via TLR2 and MyD88 signaling. As for wildtype C. burnetii, T4SS-deficient mutants primed and potentiated NLRP3 inflammasomes. An in vivo model of pulmonary infection in C57BL/6 mice was developed. Mice deficient in NLRP3 or caspase-1 were like wildtype mice in the development and resolution of splenomegaly due to red pulp hyperplasia, and histologic lesions and macrophage kinetics, but had slightly higher pulmonary bacterial burdens at the greatest measured time point. Together these findings indicate that C. burnetii primes but avoids cytosolic detection by NLRP3 inflammasomes, which are not required for the clinical resistance of C57BL/6 mice. Determining mechanisms employed by C. burnetii to avoid cytosolic detection via NLRP3 inflammasomes will be beneficial to the development of preventative and interventional therapies for Q fever.
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Affiliation(s)
- Martha A Delaney
- Departments of Comparative Medicine and Pathology, and the Comparative Pathology Program, 7284University of Washington, Seattle, WA
- Current address: Martha A. Delaney, Zoological Pathology Program, University of Illinois, Brookfield, IL, USA
| | - Andreas den Hartigh
- Departments of Microbiology and Lab Medicine, 7284University of Washington, Seattle, WA
| | - Samuel J Carpentier
- Departments of Microbiology and Lab Medicine, 7284University of Washington, Seattle, WA
| | - Timothy P Birkland
- Departments of Comparative Medicine and Pathology, and the Comparative Pathology Program, 7284University of Washington, Seattle, WA
| | - Donald P Knowles
- Animal Disease Research Unit, Agricultural Research Service, United States Department of Agriculture, Pullman, WA
- Department of Veterinary Microbiology and Pathology, 6760Washington State University, Pullman, WA
| | - Brad T Cookson
- Departments of Microbiology and Lab Medicine, 7284University of Washington, Seattle, WA
| | - Charles W Frevert
- Departments of Comparative Medicine and Pathology, and the Comparative Pathology Program, 7284University of Washington, Seattle, WA
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11
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From Coxiella burnetii Infection to Pregnancy Complications: Key Role of the Immune Response of Placental Cells. Pathogens 2021; 10:pathogens10050627. [PMID: 34069587 PMCID: PMC8160966 DOI: 10.3390/pathogens10050627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 01/17/2023] Open
Abstract
The infection of pregnant animals and women by Coxiella burnetii, an intracellular bacterium, compromises both maternal health and foetal development. The placenta is targeted by C. burnetii, as demonstrated by bacteriological and histological evidence. It now appears that placental strains of C. burnetii are highly virulent compared to reference strains and that placental injury involves different types of placental cells. Trophoblasts, the major placental cells, are largely infected by C. burnetii and may represent a replicating niche for the bacteria. The placenta also contains numerous immune cells, including macrophages, dendritic cells, and mast cells. Placental macrophages are infected and activated by C. burnetii in an unusual way of M1 polarisation associated with bacterial elimination. Placental mast cells eliminate bacteria through a mechanism including the release of extracellular actin filaments and antimicrobial peptides. In contrast, C. burnetii impairs the maturation of decidual dendritic cells, favouring bacterial pathogenicity. Our aim is to review C. burnetii infections of human placentas, paying special attention to both the action and function of the different cell types, immune cells, and trophoblasts targeted by C. burnetii in relation to foetal injury.
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Schijven J, Vermeulen LC, Swart A, Meijer A, Duizer E, de Roda Husman AM. Quantitative Microbial Risk Assessment for Airborne Transmission of SARS-CoV-2 via Breathing, Speaking, Singing, Coughing, and Sneezing. ENVIRONMENTAL HEALTH PERSPECTIVES 2021; 129:47002. [PMID: 33793301 PMCID: PMC8016178 DOI: 10.1289/ehp7886] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 03/02/2021] [Accepted: 03/10/2021] [Indexed: 05/18/2023]
Abstract
BACKGROUND Evidence for indoor airborne transmission of SARS-CoV-2 is accumulating. OBJECTIVES We assessed of the risk of illness due to airborne SARS-CoV-2 particles from breathing, speaking, singing, coughing, and sneezing in indoor environments. METHODS A risk assessment model, AirCoV2, for exposure to SARS-CoV-2 particles in aerosol droplets was developed. Previously published data on droplets expelled by breathing, speaking, singing, coughing, and sneezing by an infected person were used as inputs. Scenarios encompassed virus concentration, exposure time, and ventilation. Newly collected data of virus RNA copies in mucus from patients are presented. RESULTS The expelled volume of aerosols was highest for a sneeze, followed by a cough, singing, speaking, and breathing. After 20 min of exposure, at 107 RNA copies/mL in mucus, all mean illness risks were largely estimated to be below 0.001, except for the "high" sneeze scenario. At virus concentrations above 108 RNA copies/mL, and after 2 h of exposure, in the high and "low" sneeze scenarios, the high cough scenario and the singing scenario, risks exceeded 0.01 and may become very high, whereas the low coughing scenario, the high and low speaking scenarios and the breathing scenario remained below 0.1. After 2 h of exposure, singing became the second highest risk scenario. One air exchange per hour reduced risk of illness by about a factor of 2. Six air exchanges per hour reduced risks of illness by a factor of 8-13 for the sneeze and cough scenarios and by a factor of 4-9 for the other scenarios. DISCUSSION The large variation in the volume of expelled aerosols is discussed. The model calculations indicated that SARS-CoV-2 transmission via aerosols outside of the 1.5-m social distancing norm can occur. Virus concentrations in aerosols and/or the amount of expelled aerosol droplets need to be high for substantial transmission via this route. AirCoV2 is made available as interactive computational tool. https://doi.org/10.1289/EHP7886.
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Affiliation(s)
- Jack Schijven
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
- *Shared first author. Address correspondence to Jack Schijven, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, Netherlands.
| | - Lucie C. Vermeulen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- *Shared first author. Address correspondence to Jack Schijven, National Institute for Public Health and the Environment, P.O. Box 1, 3720 BA Bilthoven, Netherlands.
| | - Arno Swart
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Adam Meijer
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Erwin Duizer
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Ana Maria de Roda Husman
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
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13
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Schijven J, Vermeulen LC, Swart A, Meijer A, Duizer E, de Roda Husman AM. Quantitative Microbial Risk Assessment for Airborne Transmission of SARS-CoV-2 via Breathing, Speaking, Singing, Coughing, and Sneezing. ENVIRONMENTAL HEALTH PERSPECTIVES 2021. [PMID: 33793301 DOI: 10.1101/2020.07.02.20144832] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
BACKGROUND Evidence for indoor airborne transmission of SARS-CoV-2 is accumulating. OBJECTIVES We assessed of the risk of illness due to airborne SARS-CoV-2 particles from breathing, speaking, singing, coughing, and sneezing in indoor environments. METHODS A risk assessment model, AirCoV2, for exposure to SARS-CoV-2 particles in aerosol droplets was developed. Previously published data on droplets expelled by breathing, speaking, singing, coughing, and sneezing by an infected person were used as inputs. Scenarios encompassed virus concentration, exposure time, and ventilation. Newly collected data of virus RNA copies in mucus from patients are presented. RESULTS The expelled volume of aerosols was highest for a sneeze, followed by a cough, singing, speaking, and breathing. After 20 min of exposure, at 107 RNA copies/mL in mucus, all mean illness risks were largely estimated to be below 0.001, except for the "high" sneeze scenario. At virus concentrations above 108 RNA copies/mL, and after 2 h of exposure, in the high and "low" sneeze scenarios, the high cough scenario and the singing scenario, risks exceeded 0.01 and may become very high, whereas the low coughing scenario, the high and low speaking scenarios and the breathing scenario remained below 0.1. After 2 h of exposure, singing became the second highest risk scenario. One air exchange per hour reduced risk of illness by about a factor of 2. Six air exchanges per hour reduced risks of illness by a factor of 8-13 for the sneeze and cough scenarios and by a factor of 4-9 for the other scenarios. DISCUSSION The large variation in the volume of expelled aerosols is discussed. The model calculations indicated that SARS-CoV-2 transmission via aerosols outside of the 1.5-m social distancing norm can occur. Virus concentrations in aerosols and/or the amount of expelled aerosol droplets need to be high for substantial transmission via this route. AirCoV2 is made available as interactive computational tool. https://doi.org/10.1289/EHP7886.
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Affiliation(s)
- Jack Schijven
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- Department of Earth Sciences, Utrecht University, Utrecht, Netherlands
| | - Lucie C Vermeulen
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Arno Swart
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Adam Meijer
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Erwin Duizer
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
| | - Ana Maria de Roda Husman
- Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, Netherlands
- Institute for Risk Assessment Sciences, Utrecht University, Utrecht, Netherlands
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Schäfer W, Schmidt T, Cordsmeier A, Borges V, Beare PA, Pechstein J, Schulze-Luehrmann J, Holzinger J, Wagner N, Berens C, Heydel C, Gomes JP, Lührmann A. The anti-apoptotic Coxiella burnetii effector protein AnkG is a strain specific virulence factor. Sci Rep 2020; 10:15396. [PMID: 32958854 PMCID: PMC7506536 DOI: 10.1038/s41598-020-72340-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 08/26/2020] [Indexed: 11/24/2022] Open
Abstract
The ability to inhibit host cell apoptosis is important for the intracellular replication of the obligate intracellular pathogen Coxiella burnetii, as it allows the completion of the lengthy bacterial replication cycle. Effector proteins injected into the host cell by the C. burnetii type IVB secretion system (T4BSS) are required for the inhibition of host cell apoptosis. AnkG is one of these anti-apoptotic effector proteins. The inhibitory effect of AnkG requires its nuclear localization, which depends on p32-dependent intracellular trafficking and importin-α1-mediated nuclear entry of AnkG. Here, we compared the sequences of ankG from 37 C. burnetii isolates and classified them in three groups based on the predicted protein size. The comparison of the three different groups allowed us to identify the first 28 amino acids as essential and sufficient for the anti-apoptotic activity of AnkG. Importantly, only the full-length protein from the first group is a bona fide effector protein injected into host cells during infection and has anti-apoptotic activity. Finally, using the Galleria mellonella infection model, we observed that AnkG from the first group has the ability to attenuate pathology during in vivo infection, as it allows survival of the larvae despite bacterial replication.
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Affiliation(s)
- Walter Schäfer
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Teresa Schmidt
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Arne Cordsmeier
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Vítor Borges
- Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Julian Pechstein
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Jan Schulze-Luehrmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Jonas Holzinger
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany
| | - Nicole Wagner
- Institut für Molekulare Pathogenese, Friedrich-Loeffler-Institut, 07743, Jena, Germany
| | - Christian Berens
- Institut für Molekulare Pathogenese, Friedrich-Loeffler-Institut, 07743, Jena, Germany
| | - Carsten Heydel
- Institut für Hygiene und Infektionskrankheiten der Tiere, Justus Liebig Universität Gießen, Frankfurter Straße 85-89, 35392, Gießen, Germany
| | - João Paulo Gomes
- Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Anja Lührmann
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany.
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Mezouar S, Lepidi H, Omar Osman I, Gorvel JP, Raoult D, Mege JL, Bechah Y. T-Bet Controls Susceptibility of Mice to Coxiella burnetii Infection. Front Microbiol 2020; 11:1546. [PMID: 32765448 PMCID: PMC7381240 DOI: 10.3389/fmicb.2020.01546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 06/15/2020] [Indexed: 01/13/2023] Open
Abstract
T-bet is a transcription factor known to initiate and coordinate the gene expression program during Th1 differentiation, which is crucial for clearance of intracellular pathogens. Q fever is a worldwide zoonosis caused by Coxiella burnetii. This bacterium is transmitted to humans by aerosol. Indeed, the inhibition of the Coxiella-specific adaptive Th1 immune response leads to persistent infection and organ injury. How deficiency of T-bet affects host infection by C. burnetii has not been investigated. Here, using mice with a deletion of the T-bet gene and an airborne mode of infection to reproduce the natural conditions of C. burnetii infection, we show that infected T-bet–/– mice were more affected than wild-type mice. The lack of T-bet leads to defective bacterial control, intense replication, persistent infection, and organ injury manifesting as an increased number of granulomas. The absence of T-bet was also associated with an impaired immune response. Indeed, the production of the immunomodulatory cytokines interleukin (IL)-6 and IL-10 was increased, whereas the expression of microbicidal genes by splenocytes was impaired. Moreover, the absence of T-bet exhibited impaired production of interferon-γ, the principal cytokine released by Th1 effector cells. Thus, our study highlights the key role of T-bet in the control of C. burnetii infection in mice and leads to a reappraisal of granulomas in the pathogenesis of Q fever disease.
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Affiliation(s)
- Soraya Mezouar
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Hubert Lepidi
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Ikram Omar Osman
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | | | - Didier Raoult
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France
| | - Jean-Louis Mege
- IRD, AP-HM, MEPHI, Aix-Marseille University, Marseille, France.,IHU-Méditerranée Infection, Marseille, France.,AP-HM, IHU-Méditerranée Infection, UF Immunologie, Marseille, France
| | - Yassina Bechah
- IHU-Méditerranée Infection, Marseille, France.,IRD, AP-HM, VITROME, Aix-Marseille University, Marseille, France.,INSERM, Marseille, France
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Lee YW, Wang J, Newton HJ, Lithgow T. Mapping bacterial effector arsenals: in vivo and in silico approaches to defining the protein features dictating effector secretion by bacteria. Curr Opin Microbiol 2020; 57:13-21. [PMID: 32505919 DOI: 10.1016/j.mib.2020.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 04/20/2020] [Accepted: 04/26/2020] [Indexed: 12/25/2022]
Abstract
Many bacterial pathogens rely on dedicated secretion systems to translocate virulence proteins termed 'effectors' into host cells. These effectors engage and manipulate host cellular functions to support bacterial colonization and propagation. The secretion systems are molecular machines that recognize targeting 'features' in these effector proteins in vivo to selectively and efficiently secrete them. The joint analysis of whole genome sequencing data and computational predictions of amino acid characteristics of effector proteins has made available extensive lists of candidate effectors for many bacterial pathogens, among which Dot/Icm type IVB secretion system in Legionella pneumophila reigns with the largest number of effectors identified to-date. This system is also used by the causative agent of Q fever, Coxiella burnetii, to secrete a large pool of distinct effectors. By comparing these two pathogens, we provide an understanding of the rationale behind effector repertoire expansion. We will also discuss recent bioinformatic advances facilitating high-throughput discovery of secreted effectors through in silico 'feature' recognition, and the current challenge to substantiate the biological relevance and bona fide nature of effectors identified in silico.
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Affiliation(s)
- Yi Wei Lee
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000 Victoria, Australia
| | - Jiawei Wang
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, 3000 Victoria, Australia.
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia.
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Abstract
Coxiella burnetii, the causative agent of Q fever, is widely present in dairy products around the world. It has been isolated from unpasteurised milk and cheese and can survive for extended periods of time under typical storage conditions for these products. Although consumption of contaminated dairy products has been suggested as a potential route for transmission, it remains controversial. Given the high prevalence of C. burnetii in dairy products, we sought to examine the feasibility of transmitting the major sequence types (ST16, ST8 and ST20) of C. burnetii circulating in the United States. We delivered three strains of C. burnetii, comprising each sequence type, directly into the stomachs of immunocompetent BALB/c mice via oral gavage (OG) and assessed them for clinical symptoms, serological response and bacterial dissemination. We found that mice receiving C. burnetii by OG had notable splenomegaly only after infection with ST16. A robust immune response and persistence in the stomach and mesenteric lymph nodes were observed in mice receiving ST16 and ST20 by OG, and dissemination of C. burnetii to peripheral tissues was observed in all OG infected mice. These findings support the oral route as a mode of transmission for C. burnetii.
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Hu X, Yu Y, Feng J, Fu M, Dai L, Lu Z, Luo W, Wang J, Zhou D, Xiong X, Wen B, Zhao B, Jiao J. Pathologic changes and immune responses against Coxiella burnetii in mice following infection via non-invasive intratracheal inoculation. PLoS One 2019; 14:e0225671. [PMID: 31805090 PMCID: PMC6894818 DOI: 10.1371/journal.pone.0225671] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 11/08/2019] [Indexed: 11/18/2022] Open
Abstract
Q fever is a worldwide zoonosis caused by Coxiella burnetii. Human Q fever is typically acquired through inhalation of contaminated aerosols, resulting in an initial pulmonary infection. In this study, BALB/c mice were infected with C. burnetii via an intratracheal (IT) route using a non-invasive aerosol pulmonary delivery device to directly place the living C. burnetii organisms into the lungs of the mice. The bacterial loads, pathological lesions, and antibody and cellular responses were analyzed and compared with those of mice infected via an intraperitoneal (IP) route. Compared with mice infected via an IP route, mice infected via an IT route exhibited a higher bacterial load and more severe pathological lesions in the heart and lungs at days 3 and 7 post-infection (pi). The levels of interferon-γ and IL-12p70 in the serum of mice infected via the IT route were significantly higher than those of mice infected via the IP route at day 3 pi. In conclusion, this murine model of acute C. burnetii infection via IT inoculation closely resembles the natural route of C. burnetii infection than that of IP injection. Thus, this newly developed model will be useful for investigating the pathogenesis and immunity of C. burnetii aerosol infection, as well as for the evaluation of therapeutic drugs and preventive vaccines of Q fever.
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Affiliation(s)
- Xueyuan Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
- College of Life Sciences, Hebei Normal University, Yuhua District, Shijiazhuang, Hebei, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Junxia Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Mengjiao Fu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Lupeng Dai
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Zhiyu Lu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Wenbo Luo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Jinglin Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Bohai Wen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
| | - Baohua Zhao
- College of Life Sciences, Hebei Normal University, Yuhua District, Shijiazhuang, Hebei, China
- * E-mail: (JJ); (BHZ)
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Fengtai District, Beijing, China
- * E-mail: (JJ); (BHZ)
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Dependency of Coxiella burnetii Type 4B Secretion on the Chaperone IcmS. J Bacteriol 2019; 201:JB.00431-19. [PMID: 31501284 DOI: 10.1128/jb.00431-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/03/2019] [Indexed: 12/22/2022] Open
Abstract
Macrophage parasitism by Coxiella burnetii, the cause of human Q fever, requires the translocation of proteins with effector functions directly into the host cell cytosol via a Dot/Icm type 4B secretion system (T4BSS). Secretion by the analogous Legionella pneumophila T4BSS involves signal sequences within the C-terminal and internal domains of effector proteins. The cytoplasmic chaperone pair IcmSW promotes secretion and binds internal sites distinct from signal sequences. In the present study, we investigated requirements of C. burnetii IcmS for host cell parasitism and effector translocation. A C. burnetii icmS deletion mutant (ΔicmS) exhibited impaired replication in Vero epithelial cells, deficient formation of the Coxiella-containing vacuole, and aberrant T4BSS secretion. Three secretion phenotypes were identified from a screen of 50 Dot/Icm substrates: IcmS dependent (secreted by only wild-type bacteria), IcmS independent (secreted by both wild-type and ΔicmS bacteria), or IcmS inhibited (secreted by only ΔicmS bacteria). Secretion was assessed for N-terminal or C-terminal truncated forms of CBU0794 and CBU1525. IcmS-inhibited secretion of CBU1525 required a C-terminal secretion signal whereas IcmS-dependent secretion of CBU0794 was directed by C-terminal and internal signals. Interchange of the C-terminal 50 amino acids of CBU0794 and CBU1525 revealed that sites within the C terminus regulate IcmS dependency. Glutathione S-transferase-tagged IcmSW bound internal sequences of IcmS-dependent and -inhibited substrates. Thus, the growth defect of the C. burnetii ΔicmS strain is associated with a loss of T4BSS chaperone activity that both positively and negatively regulates effector translocation.IMPORTANCE The intracellular pathogen Coxiella burnetii employs a type 4B secretion system (T4BSS) that promotes growth by translocating effectors of eukaryotic pathways into host cells. T4BSS regulation modeled in Legionella pneumophila indicates IcmS facilitates effector translocation. Here, we characterized type 4B secretion by a Coxiella ΔicmS mutant that exhibits intracellular growth defects. T4BSS substrates demonstrated increased, equivalent, or decreased secretion by the ΔicmS mutant relative to wild-type Coxiella Similar to the Legionella T4BSS, IcmS dependency in Coxiella was determined by C-terminal and/or internal secretion signals. However, IcmS inhibited secretion of some effectors by Coxiella that were previously shown to be translocated by Legionella Thus, Coxiella has a unique IcmS regulatory mechanism that both positively and negatively regulates T4BSS export.
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20
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Metters G, Norville IH, Titball RW, Hemsley CM. From cell culture to cynomolgus macaque: infection models show lineage-specific virulence potential of Coxiella burnetii. J Med Microbiol 2019; 68:1419-1430. [PMID: 31424378 DOI: 10.1099/jmm.0.001064] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular pathogen that causes the zoonotic disease Q fever in humans, which can occur in either an acute or a chronic form with serious complications. The bacterium has a wide host range, including unicellular organisms, invertebrates, birds and mammals, with livestock representing the most significant reservoir for human infections. Cell culture models have been used to decipher the intracellular lifestyle of C. burnetii, and several infection models, including invertebrates, rodents and non-human primates, are being used to investigate host-pathogen interactions and to identify bacterial virulence factors and vaccine candidates. However, none of the models replicate all aspects of human disease. Furthermore, it is becoming evident that C. burnetii isolates belonging to different lineages exhibit differences in their virulence in these models. Here, we compare the advantages and disadvantages of commonly used infection models and summarize currently available data for lineage-specific virulence.
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Affiliation(s)
- Georgina Metters
- College of Life and Environmental Sciences - Biosciences, University of Exeter, Exeter, UK
| | - Isobel H Norville
- Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - Richard W Titball
- College of Life and Environmental Sciences - Biosciences, University of Exeter, Exeter, UK
| | - Claudia M Hemsley
- College of Life and Environmental Sciences - Biosciences, University of Exeter, Exeter, UK
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21
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Evaluation of the Possibility of C. Burnetii Transmission by the Alimentary Route in a Guinea Pig Model. J Vet Res 2019; 63:311-315. [PMID: 31572809 PMCID: PMC6749735 DOI: 10.2478/jvetres-2019-0055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 08/12/2019] [Indexed: 11/21/2022] Open
Abstract
Introduction Q fever (coxiellosis) is an infectious disease of animals and humans, caused by.C. burnetii and widely distributed throughout the world. It is known that people and animals acquire the disease predominantly.via inhalation of infectious aerosols. The possibility of transmission of the pathogen by the alimentary route is still a matter of debate and remains controversial. Therefore the aim of this study was to fill the gaps in knowledge of oral transmission of.C. burnetii by conducting biological tests on the guinea pig model. Material and Methods Guinea pigs, divided into five groups comprising a negative control and four experimental groups, received specified concentrations of.C. burnetii per os. To determine the presence of specific antibodies, blood samples were tested using CFT. Also, internal organs collected during necropsy were screened by a real-time PCR targeting I.1111. Additionally, histopathological evaluation of the tissues was performed. Results The presence of antibodies and pathogen DNA in caecum was confirmed in one guinea pig from experimental group IV..C. burnetii was also detected in testicular tissue collected from one animal of experimental group II. Conclusions The presence of pathogen DNA in the testicular tissue indicates that infection spreads haematogenously. In the majority of experimental animals specific antibodies and genetic material of.C. burnetii were not detected. This fact suggests that development of infection depends on many factors, such as animal immune status.
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Feng J, Hu X, Fu M, Dai L, Yu Y, Luo W, Zhao Z, Lu Z, Du Z, Zhou D, Wen B, Jiao J, Xiong X. Enhanced protection against Q fever in BALB/c mice elicited by immunization of chloroform-methanol residue of Coxiella burnetii via intratracheal inoculation. Vaccine 2019; 37:6076-6084. [PMID: 31477436 DOI: 10.1016/j.vaccine.2019.08.041] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 08/07/2019] [Accepted: 08/19/2019] [Indexed: 12/11/2022]
Abstract
Human Q fever is recognized as a worldwide public health problem. It often occurs by inhalation of airborne aerosols contaminated with Coxiella burnetii, a gram-negative intracellular bacterium, mainly from domestic livestock. In this study, we analyzed the possibility to establish mucosal and systemic immunity against C. burnetii infection using a pulmonary delivery of chloroform-methanol residue of C. burnetii (CMR) vaccine. Mice were immunized by the intratracheal inoculation of CMR (IT-CMR) or the subcutaneous injection of CMR (SC-CMR), and the immunized mice were challenged with C. burnetii by the intratracheal route. The levels of IFN-γ, IL-12p70, IL-5, and IL-4 in the IT-CMR group in splenic T cells stimulated ex vivo were significantly higher than in the SC-CMR group. Significantly elevated sIgA to C. burnetii was detected in the bronchoalveolar lavage fluid of mice immunized by IT-CMR but not by SC-CMR, which might have contributed to the significant reduction in C. burnetii load and pathological lesions in the lungs of the mice after the challenge of C. burnetii. These results suggest that compared with SC-CMR in mice, IT-CMR was more efficient to elicit cellular and lung mucosal immune responses against aerosol infection of C. burnetii.
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Affiliation(s)
- Junxia Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Xueyuan Hu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Mengjiao Fu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Lupeng Dai
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Wenbo Luo
- Anhui Medical University, Mei-Shan Road, Hefei, Anhui 230032, China
| | - Zengming Zhao
- Center for Disease Control and Prevention of Chinese People's Liberation Army, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Zhiyu Lu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Zongmin Du
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Dongsheng Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Bohai Wen
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China
| | - Jun Jiao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China.
| | - Xiaolu Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20(#) Dong-Dia-Jie Street, Fengtai, Beijing 100071, China.
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Hemsley CM, O’Neill PA, Essex-Lopresti A, Norville IH, Atkins TP, Titball RW. Extensive genome analysis of Coxiella burnetii reveals limited evolution within genomic groups. BMC Genomics 2019; 20:441. [PMID: 31164106 PMCID: PMC6549354 DOI: 10.1186/s12864-019-5833-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/23/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Coxiella burnetii is a zoonotic pathogen that resides in wild and domesticated animals across the globe and causes a febrile illness, Q fever, in humans. An improved understanding of the genetic diversity of C. burnetii is essential for the development of diagnostics, vaccines and therapeutics, but genotyping data is lacking from many parts of the world. Sporadic outbreaks of Q fever have occurred in the United Kingdom, but the local genetic make-up of C. burnetii has not been studied in detail. RESULTS Here, we report whole genome data for nine C. burnetii sequences obtained in the UK. All four genomes of C. burnetii from cattle, as well as one sheep sample, belonged to Multi-spacer sequence type (MST) 20, whereas the goat samples were MST33 (three genomes) and MST32 (one genome), two genotypes that have not been described to be present in the UK to date. We established the phylogenetic relationship between the UK genomes and 67 publically available genomes based on single nucleotide polymorphisms (SNPs) in the core genome, which confirmed tight clustering of strains within genomic groups, but also indicated that sub-groups exist within those groups. Variation is mainly achieved through SNPs, many of which are non-synonymous, thereby confirming that evolution of C. burnetii is based on modification of existing genes. Finally, we discovered genomic-group specific genome content, which supports a model of clonal expansion of previously established genotypes, with large scale dissemination of some of these genotypes across continents being observed. CONCLUSIONS The genetic make-up of C. burnetii in the UK is similar to the one in neighboring European countries. As a species, C. burnetii has been considered a clonal pathogen with low genetic diversity at the nucleotide level. Here, we present evidence for significant variation at the protein level between isolates of different genomic groups, which mainly affects secreted and membrane-associated proteins. Our results thereby increase our understanding of the global genetic diversity of C. burnetii and provide new insights into the evolution of this emerging zoonotic pathogen.
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Affiliation(s)
- Claudia M. Hemsley
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
| | - Paul A. O’Neill
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
| | | | | | - Tim P. Atkins
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
- Defence Science and Technology Laboratory, Porton Down, Salisbury, UK
| | - Richard W. Titball
- College of Life and Environmental Sciences – Biosciences, University of Exeter, Exeter, UK
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24
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Autoimmune Manifestations of Acute Q Fever Infection. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2018. [DOI: 10.1097/ipc.0000000000000629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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25
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Coxiella burnetii Blocks Intracellular Interleukin-17 Signaling in Macrophages. Infect Immun 2018; 86:IAI.00532-18. [PMID: 30061378 DOI: 10.1128/iai.00532-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 12/15/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterium and the etiological agent of Q fever. Successful host cell infection requires the Coxiella type IVB secretion system (T4BSS), which translocates bacterial effector proteins across the vacuole membrane into the host cytoplasm, where they manipulate a variety of cell processes. To identify host cell targets of Coxiella T4BSS effector proteins, we determined the transcriptome of murine alveolar macrophages infected with a Coxiella T4BSS effector mutant. We identified a set of inflammatory genes that are significantly upregulated in T4BSS mutant-infected cells compared to mock-infected cells or cells infected with wild-type (WT) bacteria, suggesting that Coxiella T4BSS effector proteins downregulate the expression of these genes. In addition, the interleukin-17 (IL-17) signaling pathway was identified as one of the top pathways affected by the bacteria. While previous studies demonstrated that IL-17 plays a protective role against several pathogens, the role of IL-17 during Coxiella infection is unknown. We found that IL-17 kills intracellular Coxiella in a dose-dependent manner, with the T4BSS mutant exhibiting significantly more sensitivity to IL-17 than WT bacteria. In addition, quantitative PCR confirmed the increased expression of IL-17 downstream signaling genes in T4BSS mutant-infected cells compared to WT- or mock-infected cells, including the proinflammatory cytokine genes Il1a, Il1b, and Tnfa, the chemokine genes Cxcl2 and Ccl5, and the antimicrobial protein gene Lcn2 We further confirmed that the Coxiella T4BSS downregulates macrophage CXCL2/macrophage inflammatory protein 2 and CCL5/RANTES protein levels following IL-17 stimulation. Together, these data suggest that Coxiella downregulates IL-17 signaling in a T4BSS-dependent manner in order to escape the macrophage immune response.
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Draft Genome Sequences of Three Coxiella burnetii Strains Isolated from Q Fever Patients. GENOME ANNOUNCEMENTS 2017; 5:5/38/e00986-17. [PMID: 28935742 PMCID: PMC5609421 DOI: 10.1128/genomea.00986-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the current study, we determined the draft genome sequences of three Coxiella burnetii human disease isolates. The Coxiella burnetii Turkey (RSA315) and Dyer (RSA345) strains were isolated from acute Q fever patients, while the Ko (Q229) strain was isolated from a Q fever endocarditis patient.
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Winfree S, Gilk SD. Quantitative Dextran Trafficking to the Coxiella burnetii Parasitophorous Vacuole. ACTA ACUST UNITED AC 2017; 46:6C.2.1-6C.2.12. [PMID: 28800156 DOI: 10.1002/cpmc.34] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The gram-negative bacterium Coxiella burnetii causes human Q fever, a disease characterized by a debilitating flu-like illness in acute cases and endocarditis in chronic patients. An obligate intracellular pathogen, Coxiella burnetii survives within a large, lysosome-like vacuole inside the host cell. A unique feature of the Coxiella parasitophorous vacuole (PV) is high levels of fusion with the host endocytic pathway, with PV-endosome fusion critical for Coxiella survival within the host cell. This unit describes quantitating PV-endosome fusion by measuring delivery of the fluid phase endosome marker dextran to the PV using live cell imaging. To study the effect of host cell proteins involved in PV-endosome fusion, details are provided for using siRNA knockdown host cells. This method is a powerful tool for understanding mechanisms underlying Coxiella's ability to manipulate host cell trafficking pathways. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Seth Winfree
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Stacey D Gilk
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
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Host and Bacterial Factors Control Susceptibility of Drosophila melanogaster to Coxiella burnetii Infection. Infect Immun 2017; 85:IAI.00218-17. [PMID: 28438980 DOI: 10.1128/iai.00218-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 04/17/2017] [Indexed: 12/12/2022] Open
Abstract
Coxiella burnetii is the causative agent of Q fever, a zoonotic disease that threatens both human and animal health. Due to the paucity of experimental animal models, little is known about how host factors interface with bacterial components and affect pathogenesis. Here, we used Drosophila melanogaster, in conjunction with the biosafety level 2 (BSL2) Nine Mile phase II (NMII) clone 4 strain of C. burnetii, as a model to investigate host and bacterial components implicated in infection. We demonstrate that adult Drosophila flies are susceptible to C. burnetii NMII infection and that this bacterial strain, which activates the immune deficiency (IMD) pathway, is able to replicate and cause mortality in the animals. We show that in the absence of Eiger, the only known tumor necrosis factor (TNF) superfamily homolog in Drosophila, Coxiella-infected flies exhibit reduced mortality from infection. We also demonstrate that the Coxiella type 4 secretion system (T4SS) is critical for the formation of the Coxiella-containing vacuole and establishment of infection in Drosophila Altogether, our data reveal that the Drosophila TNF homolog Eiger and the Coxiella T4SS are implicated in the pathogenesis of C. burnetii in flies. The Drosophila/NMII model mimics relevant aspects of the infection in mammals, such as a critical role of host TNF and the bacterial T4SS in pathogenesis. Our work also demonstrates the usefulness of this BSL2 model to investigate both host and Coxiella components implicated in infection.
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Cockrell DC, Long CM, Robertson SJ, Shannon JG, Miller HE, Myers L, Larson CL, Starr T, Beare PA, Heinzen RA. Robust growth of avirulent phase II Coxiella burnetii in bone marrow-derived murine macrophages. PLoS One 2017; 12:e0173528. [PMID: 28278296 PMCID: PMC5344453 DOI: 10.1371/journal.pone.0173528] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/21/2017] [Indexed: 11/19/2022] Open
Abstract
Published data show that murine bone marrow-derived macrophages (BMDM) restrict growth of avirulent phase II, but not virulent phase I, Coxiella burnetii. Growth restriction of phase II bacteria is thought to result from potentiated recognition of pathogen-associated molecular patterns, which leads to production of inhibitory effector molecules. Past studies have used conditioned medium from L-929 murine fibroblasts as a source of macrophage-colony stimulating factor (M-CSF) to promote differentiation of bone marrow-derived myeloid precursors into macrophages. However, uncharacterized components of conditioned medium, such as variable amounts of type I interferons, can affect macrophage activation status and their permissiveness for infection. In the current study, we show that the C. burnetii Nine Mile phase II (NMII) strain grows robustly in primary macrophages from C57BL/6J mice when bone marrow cells are differentiated with recombinant murine M-CSF (rmM-CSF). Bacteria were readily internalized by BMDM, and replicated within degradative, LAMP1-positive vacuoles to achieve roughly 3 logs of growth over 6 days. Uninfected BMDM did not appreciably express CD38 or Egr2, markers of classically (M1) and alternatively (M2) activated macrophages, respectively, nor did infection change the lack of polarization. In accordance with an M0 phenotype, infected BMDM produced moderate amounts of TNF and nitric oxide. Similar NMII growth results were obtained using C57BL/6J myeloid progenitors immortalized with an estrogen-regulated Hoxb8 (ER-Hoxb8) oncogene. To demonstrate the utility of the ER-Hoxb8 system, myeloid progenitors from natural resistance-associated macrophage protein 1 (Nramp1) C57BL/6J knock-in mice were transduced with ER-Hoxb8, and macrophages were derived from immortalized progenitors using rmM-CSF and infected with NMII. No difference in growth was observed when compared to macrophages from wild type mice, indicating depletion of metal ions by the Nramp1 transporter does not negatively impact NMII growth. Results with NMII were recapitulated in primary macrophages where C57BL/6J Nramp1+ BMDM efficiently killed Salmonella enterica serovar Typhimurium. M-CSF differentiated murine macrophages from bone marrow and conditional ER-Hoxb8 myeloid progenitors will be useful ex vivo models for studying Coxiella-macrophage interactions.
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Affiliation(s)
- Diane C. Cockrell
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Carrie M. Long
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Shelly J. Robertson
- Innate Immunity and Pathogenesis Unit, Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Jeffrey G. Shannon
- Plague Section, Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Heather E. Miller
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Lara Myers
- Retroviral Immunology Section, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Charles L. Larson
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Tregei Starr
- Salmonella-Host Cell Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
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Larson CL, Heinzen RA. High-Content Imaging Reveals Expansion of the Endosomal Compartment during Coxiella burnetii Parasitophorous Vacuole Maturation. Front Cell Infect Microbiol 2017; 7:48. [PMID: 28293541 PMCID: PMC5329641 DOI: 10.3389/fcimb.2017.00048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/07/2017] [Indexed: 11/18/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular pathogen and the causative agent of human Q fever. Replication of the bacterium within a large parasitophorous vacuole (PV) resembling a host phagolysosome is required for pathogenesis. PV biogenesis is a pathogen driven process that requires engagement of several host cell vesicular trafficking pathways to acquire vacuole components. The goal of this study was to determine if infection by C. burnetii modulates endolysosomal flux to potentially benefit PV formation. HeLa cells, infected with C. burnetii or left uninfected, were incubated with fluorescent transferrin (Tf) for 0–30 min, and the amount of Tf internalized by cells quantitated by high-content imaging. At 3 and 5 days, but not 1 day post-infection, the maximal amounts of fluorescent Tf internalized by infected cells were significantly greater than uninfected cells. The rates of Tf uptake and recycling were the same for infected and uninfected cells; however, residual Tf persisted in EEA.1 positive compartments adjacent to large PV after 30 min of recycling in the absence of labeled Tf. On average, C. burnetii-infected cells contained significantly more CD63-positive endosomes than uninfected cells. In contrast, cells containing large vacuoles generated by Chlamydia trachomatis exhibited increased rates of Tf internalization without increased CD63 expression. Our results suggest that C. burnetii infection expands the endosomal system to increase capacity for endocytic material. Furthermore, this study demonstrates the power of high-content imaging for measurement of cellular responses to infection by intracellular pathogens.
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Affiliation(s)
- Charles L Larson
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health Hamilton, MT, USA
| | - Robert A Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health Hamilton, MT, USA
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Bechah Y, Raoult D. Transmission of Coxiella burnetii to cage mates using murine animal model. Comp Immunol Microbiol Infect Dis 2017; 50:29-33. [DOI: 10.1016/j.cimid.2016.11.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 11/04/2016] [Accepted: 11/14/2016] [Indexed: 11/28/2022]
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32
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Eldin C, Mélenotte C, Mediannikov O, Ghigo E, Million M, Edouard S, Mege JL, Maurin M, Raoult D. From Q Fever to Coxiella burnetii Infection: a Paradigm Change. Clin Microbiol Rev 2017; 30:115-190. [PMID: 27856520 PMCID: PMC5217791 DOI: 10.1128/cmr.00045-16] [Citation(s) in RCA: 554] [Impact Index Per Article: 79.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Coxiella burnetii is the agent of Q fever, or "query fever," a zoonosis first described in Australia in 1937. Since this first description, knowledge about this pathogen and its associated infections has increased dramatically. We review here all the progress made over the last 20 years on this topic. C. burnetii is classically a strict intracellular, Gram-negative bacterium. However, a major step in the characterization of this pathogen was achieved by the establishment of its axenic culture. C. burnetii infects a wide range of animals, from arthropods to humans. The genetic determinants of virulence are now better known, thanks to the achievement of determining the genome sequences of several strains of this species and comparative genomic analyses. Q fever can be found worldwide, but the epidemiological features of this disease vary according to the geographic area considered, including situations where it is endemic or hyperendemic, and the occurrence of large epidemic outbreaks. In recent years, a major breakthrough in the understanding of the natural history of human infection with C. burnetii was the breaking of the old dichotomy between "acute" and "chronic" Q fever. The clinical presentation of C. burnetii infection depends on both the virulence of the infecting C. burnetii strain and specific risks factors in the infected patient. Moreover, no persistent infection can exist without a focus of infection. This paradigm change should allow better diagnosis and management of primary infection and long-term complications in patients with C. burnetii infection.
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Affiliation(s)
- Carole Eldin
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Cléa Mélenotte
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Oleg Mediannikov
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Eric Ghigo
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Matthieu Million
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Sophie Edouard
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Jean-Louis Mege
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
| | - Max Maurin
- Institut de Biologie et de Pathologie, CHU de Grenoble, Grenoble, France
| | - Didier Raoult
- URMITE, UMR CNRS 7278, IRD 198, INSERM U1095, Faculté de Médecine, Marseille, France
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Larson CL, Martinez E, Beare PA, Jeffrey B, Heinzen RA, Bonazzi M. Right on Q: genetics begin to unravel Coxiella burnetii host cell interactions. Future Microbiol 2016; 11:919-39. [PMID: 27418426 DOI: 10.2217/fmb-2016-0044] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Invasion of macrophages and replication within an acidic and degradative phagolysosome-like vacuole are essential for disease pathogenesis by Coxiella burnetii, the bacterial agent of human Q fever. Previous experimental constraints imposed by the obligate intracellular nature of Coxiella limited knowledge of pathogen strategies that promote infection. Fortunately, new genetic tools facilitated by axenic culture now allow allelic exchange and transposon mutagenesis approaches for virulence gene discovery. Phenotypic screens have illuminated the critical importance of Coxiella's type 4B secretion system in host cell subversion and discovered genes encoding translocated effector proteins that manipulate critical infection events. Here, we highlight the cellular microbiology and genetics of Coxiella and how recent technical advances now make Coxiella a model organism to study macrophage parasitism.
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Affiliation(s)
- Charles L Larson
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy & Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
| | - Eric Martinez
- CNRS, FRE3698, CPBS, 1919 Route de Mende, 34293 Montpellier, France.,Université de Montpellier, Montpellier, France
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy & Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
| | - Brendan Jeffrey
- Bioinformatics & Computational Biosciences Branch, Rocky Mountain Laboratories, National Institute of Allergy & Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
| | - Robert A Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy & Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
| | - Matteo Bonazzi
- CNRS, FRE3698, CPBS, 1919 Route de Mende, 34293 Montpellier, France.,Université de Montpellier, Montpellier, France
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Melenotte C, Lepidi H, Nappez C, Bechah Y, Audoly G, Terras J, Raoult D, Brégeon F. Mouse Model of Coxiella burnetii Aerosolization. Infect Immun 2016; 84:2116-2123. [PMID: 27160294 PMCID: PMC4936361 DOI: 10.1128/iai.00108-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/28/2016] [Indexed: 11/20/2022] Open
Abstract
Coxiella burnetii is mainly transmitted by aerosols and is responsible for multiple-organ lesions. Animal models have shown C. burnetii pathogenicity, but long-term outcomes still need to be clarified. We used a whole-body aerosol inhalation exposure system to mimic the natural route of infection in immunocompetent (BALB/c) and severe combined immunodeficient (SCID) mice. After an initial lung inoculum of 10(4) C. burnetii cells/lung, the outcome, serological response, hematological disorders, and deep organ lesions were described up to 3 months postinfection. C. burnetii-specific PCR, anti-C. burnetii immunohistochemistry, and fluorescent in situ hybridization (FISH) targeting C. burnetii-specific 16S rRNA completed the detection of the bacterium in the tissues. In BALB/c mice, a thrombocytopenia and lymphopenia were first observed, prior to evidence of C. burnetii replication. In all SCID mouse organs, DNA copies increased to higher levels over time than in BALB/c ones. Clinical signs of discomfort appeared in SCID mice, so follow-up had to be shortened to 2 months in this group. At this stage, all animals presented bone, cervical, and heart lesions. The presence of C. burnetii could be attested in situ for all organs sampled using immunohistochemistry and FISH. This mouse model described C. burnetii Nine Mile strain spread using aerosolization in a way that corroborates the pathogenicity of Q fever described in humans and completes previously published data in mouse models. C. burnetii infection occurring after aerosolization in mice thus seems to be a useful tool to compare the pathogenicity of different strains of C. burnetii.
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Affiliation(s)
- Cléa Melenotte
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
- Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique des Hôpitaux de Marseille, Marseille, France
| | - Hubert Lepidi
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Claude Nappez
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Yassina Bechah
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Gilles Audoly
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Jérôme Terras
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Didier Raoult
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
- Pôle des Maladies Infectieuses et Tropicales Clinique et Biologique, Fédération de Bactériologie-Hygiène-Virologie, Centre Hospitalo-Universitaire Timone, Assistance Publique des Hôpitaux de Marseille, Marseille, France
| | - Fabienne Brégeon
- Aix Marseille Université, URMITE, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
- Service des Explorations Fonctionnelles Respiratoires Centre Hospitalo-Universitaire Nord, Pôle Cardio-Vasculaire et Thoracique, Assistance Publique Hôpitaux de Marseille, Marseille, France
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Coxiella burnetii Infects Primary Bovine Macrophages and Limits Their Host Cell Response. Infect Immun 2016; 84:1722-1734. [PMID: 27021246 DOI: 10.1128/iai.01208-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/18/2016] [Indexed: 12/21/2022] Open
Abstract
Although domestic ruminants have long been recognized as the main source of human Q fever, little is known about the lifestyle that the obligate intracellular Gram-negative bacterium Coxiella burnetii adopts in its animal host. Because macrophages are considered natural target cells of the pathogen, we established primary bovine monocyte-derived macrophages (MDM) as an in vitro infection model to study reservoir host-pathogen interactions at the cellular level. In addition, bovine alveolar macrophages were included to take cell type peculiarities at a host entry site into account. Cell cultures were inoculated with the virulent strain Nine Mile I (NMI; phase I) or the avirulent strain Nine Mile II (NMII; phase II). Macrophages from both sources internalized NMI and NMII. MDM were particularly permissive for NMI internalization, but NMI and NMII replicated with similar kinetics in these cells. MDM responded to inoculation with a general upregulation of Th1-related cytokines such as interleukin-1β (IL-1β), IL-12, and tumor necrosis factor alpha (TNF-α) early on (3 h postinfection). However, inflammatory responses rapidly declined when C. burnetii replication started. C. burnetii infection inhibited translation and release of IL-1β and vastly failed to stimulate increased expression of activation markers, such as CD40, CD80, CD86, and major histocompatibility complex (MHC) molecules. Such capability of limiting proinflammatory responses may help Coxiella to protect itself from clearance by the host immune system. The findings provide the first detailed insight into C. burnetii-macrophage interactions in ruminants and may serve as a basis for assessing the virulence and the host adaptation of C. burnetii strains.
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Sandoz KM, Popham DL, Beare PA, Sturdevant DE, Hansen B, Nair V, Heinzen RA. Transcriptional Profiling of Coxiella burnetii Reveals Extensive Cell Wall Remodeling in the Small Cell Variant Developmental Form. PLoS One 2016; 11:e0149957. [PMID: 26909555 PMCID: PMC4766238 DOI: 10.1371/journal.pone.0149957] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/05/2016] [Indexed: 11/19/2022] Open
Abstract
A hallmark of Coxiella burnetii, the bacterial cause of human Q fever, is a biphasic developmental cycle that generates biologically, ultrastructurally, and compositionally distinct large cell variant (LCV) and small cell variant (SCV) forms. LCVs are replicating, exponential phase forms while SCVs are non-replicating, stationary phase forms. The SCV has several properties, such as a condensed nucleoid and an unusual cell envelope, suspected of conferring enhanced environmental stability. To identify genetic determinants of the LCV to SCV transition, we profiled the C. burnetii transcriptome at 3 (early LCV), 5 (late LCV), 7 (intermediate forms), 14 (early SCV), and 21 days (late SCV) post-infection of Vero epithelial cells. Relative to early LCV, genes downregulated in the SCV were primarily involved in intermediary metabolism. Upregulated SCV genes included those involved in oxidative stress responses, arginine acquisition, and cell wall remodeling. A striking transcriptional signature of the SCV was induction (>7-fold) of five genes encoding predicted L,D transpeptidases that catalyze nonclassical 3-3 peptide cross-links in peptidoglycan (PG), a modification that can influence several biological traits in bacteria. Accordingly, of cross-links identified, muropeptide analysis showed PG of SCV with 46% 3-3 cross-links as opposed to 16% 3-3 cross-links for LCV. Moreover, electron microscopy revealed SCV with an unusually dense cell wall/outer membrane complex as compared to LCV with its clearly distinguishable periplasm and inner and outer membranes. Collectively, these results indicate the SCV produces a unique transcriptome with a major component directed towards remodeling a PG layer that likely contributes to Coxiella's environmental resistance.
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Affiliation(s)
- Kelsi M. Sandoz
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - David L. Popham
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Daniel E. Sturdevant
- Genomics Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Bryan Hansen
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Vinod Nair
- Electron Microscopy Unit, Research Technologies Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America
- * E-mail:
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D’Amato F, Eldin C, Raoult D. The contribution of genomics to the study of Q fever. Future Microbiol 2016; 11:253-72. [DOI: 10.2217/fmb.15.137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis that can result in large outbreaks. The birth of genomics and sequencing of C. burnetii strains has revolutionized many fields of study of this infection. Accurate genotyping methods and comparative genomic analysis have enabled description of the diversity of strains around the world and their link with pathogenicity. Genomics has also permitted the development of qPCR tools and axenic culture medium, facilitating the diagnosis of Q fever. Moreover, several pathophysiological mechanisms can now be predicted and therapeutic strategies can be determined thanks to in silico genome analysis. An extensive pan-genomic analysis will allow for a comprehensive view of the clonal diversity of C. burnetii and its link with virulence.
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Affiliation(s)
- Felicetta D’Amato
- Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Carole Eldin
- Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
| | - Didier Raoult
- Aix-Marseille Université, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UM63, CNRS 7278, IRD 198, INSERM 1095, Marseille, France
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Bisle S, Klingenbeck L, Borges V, Sobotta K, Schulze-Luehrmann J, Menge C, Heydel C, Gomes JP, Lührmann A. The inhibition of the apoptosis pathway by the Coxiella burnetii effector protein CaeA requires the EK repetition motif, but is independent of survivin. Virulence 2016; 7:400-12. [PMID: 26760129 DOI: 10.1080/21505594.2016.1139280] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
ABSRTACT Coxiella burnetii is an obligate intracellular bacterium that causes Query (Q) fever, a zoonotic disease. It requires a functional type IV secretion system (T4SS) which translocate bacterial effector proteins into the host cell cytoplasm and thereby facilitates bacterial replication. To date, more than 130 effector proteins have been identified, but their functions remain largely unknown. Recently, we demonstrated that one of these proteins, CaeA (CBU1524) localized to the host cell nucleus and inhibited intrinsic apoptosis of HEK293 or CHO cells. In the present study we addressed the question whether CaeA also affects the extrinsic apoptosis pathway. Ectopic expression of CaeA reduced extrinsic apoptosis and prevented the cleavage of the executioner caspase 7, but did not impair the activation of initiator caspase 9. CaeA expression resulted in an up-regulation of survivin (an inhibitor of activated caspases), which, however, was not causal for the anti-apoptotic effect of CaeA. Comparing the sequence of CaeA from 25 different C. burnetii isolates we identified an EK (glutamic acid/ lysine) repetition motif as a site of high genetic variability. The EK motif of CaeA was essential for the anti-apoptotic activity of CaeA. From these data, we conclude that the C. burnetii effector protein CaeA interferes with the intrinsic and extrinsic apoptosis pathway. The process requires the EK repetition motif of CaeA, but is independent of the upregulated expression of survivin.
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Affiliation(s)
- Stephanie Bisle
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Leonie Klingenbeck
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Vítor Borges
- b Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - Katharina Sobotta
- c Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis , Jena , Germany
| | - Jan Schulze-Luehrmann
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
| | - Christian Menge
- c Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis , Jena , Germany
| | - Carsten Heydel
- d Institut für Hygiene und Infektionskrankheiten der Tiere, Justus Liebig Universität Gießen , Gießen , Germany
| | - João Paulo Gomes
- b Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health , Lisbon , Portugal
| | - Anja Lührmann
- a Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität (FAU) Erlangen-Nürnberg , Erlangen , Germany
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Bontje D, Backer J, Hogerwerf L, Roest H, van Roermund H. Analysis of Q fever in Dutch dairy goat herds and assessment of control measures by means of a transmission model. Prev Vet Med 2016; 123:71-89. [DOI: 10.1016/j.prevetmed.2015.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 10/30/2015] [Accepted: 11/01/2015] [Indexed: 10/22/2022]
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Abstract
Q fever is a zoonosis of worldwide distribution with the exception of New Zealand. It is caused by an intracellular bacterium, Coxiella burnetii. The disease often goes underdiagnosed because the main manifestation of its acute form is a general self-limiting flu-like syndrome. The Dutch epidemics renewed attention to this disease, which was less considered before. This review summarizes the description of C. burnetii (taxonomy, intracellular cycle, and genome) and Q fever disease (description, diagnosis, epidemiology, and pathogenesis). Finally, vaccination in humans and animals is also considered.
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Affiliation(s)
- Samira Boarbi
- Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique.,Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique
| | - David Fretin
- Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique.,Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique
| | - Marcella Mori
- Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique.,Centre d'étude et de recherches vétérinaires et agrochimiques (CERVA), Direction opérationnelle des maladies bactériennes, Zoonoses bactériennes des animaux de rente, Groeselenberg 99, 1180 Bruxelles, Belgique
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Sidi-Boumedine K, Adam G, Angen Ø, Aspán A, Bossers A, Roest HJ, Prigent M, Thiéry R, Rousset E. Whole genome PCR scanning (WGPS) of Coxiella burnetii strains from ruminants. Microbes Infect 2015; 17:772-5. [DOI: 10.1016/j.micinf.2015.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/14/2015] [Accepted: 08/14/2015] [Indexed: 11/30/2022]
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Kuley R, Smith HE, Frangoulidis D, Smits MA, Jan Roest HI, Bossers A. Cell-free propagation of Coxiella burnetii does not affect its relative virulence. PLoS One 2015; 10:e0121661. [PMID: 25793981 PMCID: PMC4368683 DOI: 10.1371/journal.pone.0121661] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 02/02/2015] [Indexed: 12/02/2022] Open
Abstract
Q fever is caused by the obligate intracellular bacterium Coxiella burnetii. In vitro growth of the bacterium is usually limited to viable eukaryotic host cells imposing experimental constraints for molecular studies, such as the identification and characterisation of major virulence factors. Studies of pathogenicity may benefit from the recent development of an extracellular growth medium for C. burnetii. However, it is crucial to investigate the consistency of the virulence phenotype of strains propagated by the two fundamentally different culturing systems. In the present study, we assessed the viability of C. burnetii and the lipopolysaccaride (LPS) encoding region of the bacteria in both culture systems as indirect but key parameters to the infection potential of C. burnetii. Propidium monoazide (PMA) treatment-based real-time PCR was used for enumeration of viable C. burnetii which were validated by fluorescent infectious focus forming unit counting assays. Furthermore, RNA isolated from C. burnetiipropagated in both the culture systems was examined for LPS-related gene expression. All thus far known LPS-related genes were found to be expressed in early passages in both culturing systems indicating the presence of predominantly the phase I form of C. burnetii. Finally, we used immune-competent mice to provide direct evidence, that the relative virulence of different C. burnetii strains is essentially the same for both axenic and cell-based methods of propagation.
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Affiliation(s)
- Runa Kuley
- Department of Infection Biology, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands
- Host Microbe Interactomics, Wageningen University, Wageningen, The Netherlands
| | - Hilde E. Smith
- Department of Infection Biology, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands
| | | | - Mari A. Smits
- Department of Infection Biology, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands
- Host Microbe Interactomics, Wageningen University, Wageningen, The Netherlands
| | - Hendrik I. Jan Roest
- Department of Bacteriology and TSEs, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands
| | - Alex Bossers
- Department of Infection Biology, Central Veterinary Institute part of Wageningen UR, Lelystad, The Netherlands
- * E-mail:
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Schoffelen T, Self JS, Fitzpatrick KA, Netea MG, van Deuren M, Joosten LAB, Kersh GJ. Early cytokine and antibody responses against Coxiella burnetii in aerosol infection of BALB/c mice. Diagn Microbiol Infect Dis 2014; 81:234-9. [PMID: 25618420 DOI: 10.1016/j.diagmicrobio.2014.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/19/2014] [Accepted: 12/21/2014] [Indexed: 12/28/2022]
Abstract
Coxiella burnetii, a Gram-negative intracellular bacterium, can give rise to Q fever in humans and is transmitted mainly by inhalation of infected aerosols from animal reservoirs. Serology is commonly used to diagnose Q fever, but the early cellular immune response-i.e., C. burnetii-specific interferon γ (IFN-γ) production in response to antigen challenge-might be an additional diagnostic. Detection of IFN-γ responses has been used to identify past and chronic Q fever infections, but the IFN-γ response in acute Q fever has not been described. By challenging immunocompetent BALB/c mice with aerosols containing phase I C. burnetii, the timing and extent of IFN-γ recall responses were evaluated in an acute C. burnetii infection. Other cytokines were also measured in an effort to identify other potential diagnostic markers. The data show that after initial expansion of bacteria first in lungs and then in other tissues, the infection was cleared from day 10 onwards as reflected by the decreasing number of bacteria. The antigen-induced IFN-γ production by splenocytes coincided with emergence of IgM phase II antibodies at day 10 postinfection and preceded appearance of IgG antibodies. This was accompanied by the production of proinflammatory cytokines including interleukin (IL) 6, keratinocyte-derived cytokine, and IFN-γ-induced protein 10, followed by monocyte chemotactic protein 1, but not by IL-1β and tumor necrosis factor α, and only very low production of the anti-inflammatory cytokine IL-10. These data suggest that analysis of antigen-specific IFN-γ responses could be a useful tool for diagnosis of acute Q fever. Moreover, the current model of C. burnetii infection could be used to give new insights into immunological factors that predispose to development of persistent infection.
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Affiliation(s)
- Teske Schoffelen
- Radboud University Medical Center, Department of Internal Medicine, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Joshua S Self
- Centers for Disease Control and Prevention, Rickettsial Zoonoses Branch, 1600 Clifton Rd, MS G13, Atlanta, GA 30333, USA
| | - Kelly A Fitzpatrick
- Centers for Disease Control and Prevention, Rickettsial Zoonoses Branch, 1600 Clifton Rd, MS G13, Atlanta, GA 30333, USA
| | - Mihai G Netea
- Radboud University Medical Center, Department of Internal Medicine, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Marcel van Deuren
- Radboud University Medical Center, Department of Internal Medicine, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Leo A B Joosten
- Radboud University Medical Center, Department of Internal Medicine, Geert Grooteplein-Zuid 10, 6525 GA, Nijmegen, The Netherlands
| | - Gilbert J Kersh
- Centers for Disease Control and Prevention, Rickettsial Zoonoses Branch, 1600 Clifton Rd, MS G13, Atlanta, GA 30333, USA.
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Eldin C, Mahamat A, Demar M, Abboud P, Djossou F, Raoult D. Q fever in French Guiana. Am J Trop Med Hyg 2014; 91:771-6. [PMID: 25092817 DOI: 10.4269/ajtmh.14-0282] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Coxiella burnetii, the causative agent of Q fever, is present worldwide. Recent studies have shown that this bacterium is an emerging pathogen in French Guiana and has a high prevalence (24% of community-acquired pneumonia). In this review, we focus on the peculiar epidemiology of Q fever in French Guiana. We place it in the context of the epidemiology of the disease in the surrounding countries of South America. We also review the clinical features of Q fever in this region, which has severe initial presentation but low mortality rates. These characteristics seem to be linked to a unique genotype (genotype 17). Finally, we discuss the issue of the animal reservoir of C. burnetii in French Guiana, which is still unknown. Further studies are necessary to identify this reservoir. Identification of this reservoir will improve the understanding of the Q fever epidemic in French Guiana and will provide new tools to control this public health problem.
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Affiliation(s)
- Carole Eldin
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
| | - Aba Mahamat
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
| | - Magalie Demar
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
| | - Philippe Abboud
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
| | - Félix Djossou
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
| | - Didier Raoult
- Unité de Recherche sur Les Maladies Infectieuses et Ttropicales Émergentes, Unités Mxtes de Rcherche, Centre National de la Recherche Scientifique 7278, Institut de Recherche pour le Développement 198, Institut National de la Santé et de la Recherche Médicale Unite 1095, Faculté de Médecine, Aix Marseille Université, Marseille, France; Unité de Maladies Infectieuses et Tropicales, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
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Edouard S, Mahamat A, Demar M, Abboud P, Djossou F, Raoult D. Comparison between emerging Q fever in French Guiana and endemic Q fever in Marseille, France. Am J Trop Med Hyg 2014; 90:915-9. [PMID: 24639301 DOI: 10.4269/ajtmh.13-0164] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Q fever is an emergent disease in French Guiana. We compared the incidence clinical and serologic profiles between patients from Cayenne, French Guiana and Marseille in metropolitan France during a four-year period. The annual incidence of diagnosed acute Q fever was significantly higher in Cayenne (17.5/100,000) than in Marseille (1.9/100,000) (P = 0.0004), but not the annual incidence of endocarditis (1.29 versus 0.34/100,000). Most patients had fever (97%) and pneumonia (83%) in Cayenne versus 81% and 8% in Marseille (P < 0.0001 and P < 0.0001, respectively) but transaminitis was more common in patients from Marseille (54% versus 32%; P < 0.0001). The proportion of patients with cardiovascular infections was significantly lower in Cayenne (7%) than in Marseille (17%) (P = 0.017), although they showed a stronger immune response with higher levels of phase I IgG (P = 0.024). The differing epidemiology, clinical, and serologic responses of patients from Cayenne and Marseille suggest a different source of infection and a different strain of Coxiella burnetii.
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Affiliation(s)
- Sophie Edouard
- Aix Marseille Université, Marseille, France; Department of Infectious and Tropical Disease, Centre Hospitalier Andrée Rosemon, Cayenne, French Guiana
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Essential role for the response regulator PmrA in Coxiella burnetii type 4B secretion and colonization of mammalian host cells. J Bacteriol 2014; 196:1925-40. [PMID: 24610709 DOI: 10.1128/jb.01532-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Successful host cell colonization by the Q fever pathogen, Coxiella burnetii, requires translocation of effector proteins into the host cytosol by a Dot/Icm type 4B secretion system (T4BSS). In Legionella pneumophila, the two-component system (TCS) PmrAB regulates the Dot/Icm T4BSS and several additional physiological processes associated with pathogenesis. Because PmrA consensus regulatory elements are associated with some dot/icm and substrate genes, a similar role for PmrA in regulation of the C. burnetii T4BSS has been proposed. Here, we constructed a C. burnetii pmrA deletion mutant to directly probe PmrA-mediated gene regulation. Compared to wild-type bacteria, C. burnetii ΔpmrA exhibited severe intracellular growth defects that coincided with failed secretion of effector proteins. Luciferase gene reporter assays demonstrated PmrA-dependent expression of 5 of 7 dot/icm operons and 9 of 11 effector-encoding genes with a predicted upstream PmrA regulatory element. Mutational analysis verified consensus sequence nucleotides required for PmrA-directed transcription. RNA sequencing and whole bacterial cell mass spectrometry of wild-type C. burnetii and the ΔpmrA mutant uncovered new components of the PmrA regulon, including several genes lacking PmrA motifs that encoded Dot/Icm substrates. Collectively, our results indicate that the PmrAB TCS is a critical virulence factor that regulates C. burnetii Dot/Icm secretion. The presence of PmrA-responsive genes lacking PmrA regulatory elements also suggests that the PmrAB TCS controls expression of regulatory systems associated with the production of additional C. burnetii proteins involved in host cell parasitism.
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Coxiella burnetii interaction with neutrophils and macrophages in vitro and in SCID mice following aerosol infection. Infect Immun 2013; 81:4604-14. [PMID: 24082077 DOI: 10.1128/iai.00973-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular bacterium that causes acute and chronic Q fever in humans. Human Q fever is mainly transmitted by aerosol infection. However, there is a fundamental gap in the knowledge regarding the mechanisms of pulmonary immunity against C. burnetii infection. This study focused on understanding the interaction between C. burnetii and innate immune cells in vitro and in vivo. Both virulent C. burnetii Nine Mile phase I (NMI) and avirulent Nine Mile phase II (NMII) were able to infect neutrophils, while the infection rates were lower than 29%, suggesting that C. burnetii can infect neutrophils, but infection is limited. Interestingly, C. burnetii inside neutrophils can infect and replicate within macrophages, suggesting that neutrophils cannot kill C. burnetii and C. burnetii may be using infection of neutrophils as an evasive strategy to infect macrophages. To elucidate the mechanisms of the innate immune response to C. burnetii natural infection, SCID mice were exposed to aerosolized C. burnetii. Surprisingly, neutrophil influx into the lungs was delayed until day 7 postinfection in both NMI- and NMII-infected mice. This result suggests that neutrophils may play a unique role in the early immune response against aerosolized C. burnetii. Studying the interaction between C. burnetii and the innate immune system can provide a model system for understanding how the bacteria evade early immune responses to cause infection.
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Salcedo SP, Marchesini MI, Degos C, Terwagne M, Von Bargen K, Lepidi H, Herrmann CK, Santos Lacerda TL, Imbert PRC, Pierre P, Alexopoulou L, Letesson JJ, Comerci DJ, Gorvel JP. BtpB, a novel Brucella TIR-containing effector protein with immune modulatory functions. Front Cell Infect Microbiol 2013; 3:28. [PMID: 23847770 PMCID: PMC3703528 DOI: 10.3389/fcimb.2013.00028] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/18/2013] [Indexed: 12/29/2022] Open
Abstract
Several bacterial pathogens have TIR domain-containing proteins that contribute to their pathogenesis. We identified a second TIR-containing protein in Brucella spp. that we have designated BtpB. We show it is a potent inhibitor of TLR signaling, probably via MyD88. BtpB is a novel Brucella effector that is translocated into host cells and interferes with activation of dendritic cells. In vivo mouse studies revealed that BtpB is contributing to virulence and control of local inflammatory responses with relevance in the establishment of chronic brucellosis. Together, our results show that BtpB is a novel Brucella effector that plays a major role in the modulation of host innate immune response during infection.
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Affiliation(s)
- Suzana P Salcedo
- Aix-Marseille Univ UM 2, Centre d'Immunologie de Marseille-Luminy Marseille, France
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In vitro and in vivo infectious potential of coxiella burnetii: a study on Belgian livestock isolates. PLoS One 2013; 8:e67622. [PMID: 23840751 PMCID: PMC3695903 DOI: 10.1371/journal.pone.0067622] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 05/21/2013] [Indexed: 12/21/2022] Open
Abstract
Q-fever is a zoonosis caused by the gram-negative obligate intracellular pathogen Coxiella burnetii. Since its discovery, and particularly following the recent outbreaks in the Netherlands, C. burnetii appeared as a clear public health concern. In the present study, the infectious potential displayed by goat and cattle isolates of C. burnetii was compared to a reference strain (Nine Mile) using both in vitro (human HeLa and bovine macrophage cells) and in vivo (BALB/c mice) models. The isolates had distant genomic profiles with one - the goat isolate - being identical to the predominant strain circulating in the Netherlands during the 2007–2010 outbreaks. Infective doses were established with ethidium monoazide-PCR for the first time here applied to C. burnetii. This method allowed for the preparation of reproducible and characterized inocula thanks to its capacity to discriminate between live and dead cells. Globally, the proliferative capacity of the Nine Mile strain in cell lines and mice was higher compared to the newly isolated field strains. In vitro, the bovine C. burnetii isolate multiplied faster in a bovine macrophage cell line, an observation tentatively explained by the preferential specificity of this strain for allogeneic host cells. In the BALB/c mouse model, however, the goat and bovine isolates multiplied at about the same rate indicating no peculiar hypervirulent behavior in this animal model.
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Vranakis I, Papadioti A, Tselentis Y, Psaroulaki A, Tsiotis G. The contribution of proteomics towards deciphering the enigma ofCoxiella burnetii. Proteomics Clin Appl 2013; 7:193-204. [DOI: 10.1002/prca.201200096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 11/15/2012] [Accepted: 11/20/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Iosif Vranakis
- Regional Laboratory of Public Health of Crete; Heraklion; Greece
| | - Anastasia Papadioti
- Division of Biochemistry; Department of Chemistry; University of Crete; Voutes; Greece
| | - Yannis Tselentis
- Regional Laboratory of Public Health of Crete; Heraklion; Greece
| | | | - Georgios Tsiotis
- Division of Biochemistry; Department of Chemistry; University of Crete; Voutes; Greece
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