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Mandel CG, Sanchez SE, Monahan CC, Phuklia W, Omsland A. Metabolism and physiology of pathogenic bacterial obligate intracellular parasites. Front Cell Infect Microbiol 2024; 14:1284701. [PMID: 38585652 PMCID: PMC10995303 DOI: 10.3389/fcimb.2024.1284701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 02/01/2024] [Indexed: 04/09/2024] Open
Abstract
Bacterial obligate intracellular parasites (BOIPs) represent an exclusive group of bacterial pathogens that all depend on invasion of a eukaryotic host cell to reproduce. BOIPs are characterized by extensive adaptation to their respective replication niches, regardless of whether they replicate within the host cell cytoplasm or within specialized replication vacuoles. Genome reduction is also a hallmark of BOIPs that likely reflects streamlining of metabolic processes to reduce the need for de novo biosynthesis of energetically costly metabolic intermediates. Despite shared characteristics in lifestyle, BOIPs show considerable diversity in nutrient requirements, metabolic capabilities, and general physiology. In this review, we compare metabolic and physiological processes of prominent pathogenic BOIPs with special emphasis on carbon, energy, and amino acid metabolism. Recent advances are discussed in the context of historical views and opportunities for discovery.
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Affiliation(s)
- Cameron G. Mandel
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Savannah E. Sanchez
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA, United States
| | - Colleen C. Monahan
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
| | - Weerawat Phuklia
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People’s Democratic Republic
| | - Anders Omsland
- Paul G. Allen School for Global Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States
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Kodori M, Amani J, Ahmadi A. Unveiling promising immunogenic targets in Coxiella burnetii through in silico analysis: paving the way for novel vaccine strategies. BMC Infect Dis 2023; 23:902. [PMID: 38129801 PMCID: PMC10740251 DOI: 10.1186/s12879-023-08904-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND Coxiella burnetii, an intracellular pathogen, serves as the causative agent of zoonotic Q fever. This pathogen presents a significant threat due to its potential for airborne transmission, environmental persistence, and pathogenicity. The current whole-cell vaccine (WCV) utilized in Australia to combat Q fever exhibits notable limitations, including severe adverse reactions and limited regulatory approval for human use. This research employed the reverse vaccinology (RV) approach to uncover antigenic proteins and epitopes of C. burnetii, facilitating the development of more potent vaccine candidates. METHODS The potential immunogenic proteins derived from C. burnetii RSA493/Nine Mile phase I (NMI) were extracted through manual, automated RV, and virulence factor database (VFDB) methods. Web tools and bioinformatics were used to evaluate physiochemical attributes, subcellular localization, antigenicity, allergenicity, human homology, B-cell epitopes, MHC I and II binding ratios, functional class scores, adhesion probabilities, protein-protein interactions, and molecular docking. RESULTS Out of the 1850 proteins encoded by RSA493/NMI, a subset of 178 demonstrated the potential for surface or membrane localization. Following a series of analytical iterations, 14 putative immunogenic proteins emerged. This collection included nine proteins (57.1%) intricately involved in cell wall/membrane/envelope biogenesis processes (CBU_0197 (Q83EW1), CBU_0311 (Q83EK8), CBU_0489 (Q83E43), CBU_0939 (Q83D08), CBU_1190 (P39917), CBU_1829 (Q83AQ2), CBU_1412 (Q83BU0), CBU_1414 (Q83BT8), and CBU_1600 (Q83BB2)). The CBU_1627 (Q83B86 ) (7.1%) implicated in intracellular trafficking, secretion, and vesicular transport, and CBU_0092 (Q83F57) (7.1%) contributing to cell division. Additionally, three proteins (21.4%) displayed uncharacterized functions (CBU_0736 (Q83DJ4), CBU_1095 (Q83CL9), and CBU_2079 (Q83A32)). The congruent results obtained from molecular docking and immune response stimulation lend support to the inclusion of all 14 putative proteins as potential vaccine candidates. Notably, seven proteins with well-defined functions stand out among these candidates. CONCLUSIONS The outcomes of this study introduce promising proteins and epitopes for the forthcoming formulation of subunit vaccines against Q fever, with a primary emphasis on cellular processes and the virulence factors of C. burnetii.
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Affiliation(s)
- Mansoor Kodori
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
- Non Communicable Diseases Research Center, Bam University of Medical Sciences, Bam, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Ahmadi
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran.
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Bauer BU, Knittler MR, Andrack J, Berens C, Campe A, Christiansen B, Fasemore AM, Fischer SF, Ganter M, Körner S, Makert GR, Matthiesen S, Mertens-Scholz K, Rinkel S, Runge M, Schulze-Luehrmann J, Ulbert S, Winter F, Frangoulidis D, Lührmann A. Interdisciplinary studies on Coxiella burnetii: From molecular to cellular, to host, to one health research. Int J Med Microbiol 2023; 313:151590. [PMID: 38056089 DOI: 10.1016/j.ijmm.2023.151590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 10/19/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023] Open
Abstract
The Q-GAPS (Q fever GermAn interdisciplinary Program for reSearch) consortium was launched in 2017 as a German consortium of more than 20 scientists with exceptional expertise, competence, and substantial knowledge in the field of the Q fever pathogen Coxiella (C.) burnetii. C. burnetii exemplifies as a zoonotic pathogen the challenges of zoonotic disease control and prophylaxis in human, animal, and environmental settings in a One Health approach. An interdisciplinary approach to studying the pathogen is essential to address unresolved questions about the epidemiology, immunology, pathogenesis, surveillance, and control of C. burnetii. In more than five years, Q-GAPS has provided new insights into pathogenicity and interaction with host defense mechanisms. The consortium has also investigated vaccine efficacy and application in animal reservoirs and identified expanded phenotypic and genotypic characteristics of C. burnetii and their epidemiological significance. In addition, conceptual principles for controlling, surveilling, and preventing zoonotic Q fever infections were developed and prepared for specific target groups. All findings have been continuously integrated into a Web-based, interactive, freely accessible knowledge and information platform (www.q-gaps.de), which also contains Q fever guidelines to support public health institutions in controlling and preventing Q fever. In this review, we will summarize our results and show an example of how an interdisciplinary consortium provides knowledge and better tools to control a zoonotic pathogen at the national level.
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Affiliation(s)
- Benjamin U Bauer
- Clinic for Swine and Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Michael R Knittler
- Friedrich-Loeffler-Institut, Institute of Immunology, Greifswald - Insel Riems, Germany
| | - Jennifer Andrack
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Christian Berens
- Friedrich-Loeffler-Institut, Institute of Molecular Pathogenesis, Jena, Germany
| | - Amely Campe
- Department of Biometry, Epidemiology and Information Processing, (IBEI), WHO Collaborating Centre for Research and Training for Health at the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Bahne Christiansen
- Friedrich-Loeffler-Institut, Institute of Immunology, Greifswald - Insel Riems, Germany
| | - Akinyemi M Fasemore
- Bundeswehr Institute of Microbiology, Munich, Germany; University of Würzburg, Würzburg, Germany; ZB MED - Information Centre for Life Science, Cologne, Germany
| | - Silke F Fischer
- Landesgesundheitsamt Baden-Württemberg, Ministerium für Soziales, Gesundheit und Integration, Stuttgart, Germany
| | - Martin Ganter
- Clinic for Swine and Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Sophia Körner
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany; Fraunhofer Institute for Cell Therapy and Immunology IZI, 04103 Leipzig, Germany
| | - Gustavo R Makert
- Fraunhofer Institute for Cell Therapy and Immunology IZI, 04103 Leipzig, Germany
| | - Svea Matthiesen
- Friedrich-Loeffler-Institut, Institute of Immunology, Greifswald - Insel Riems, Germany
| | - Katja Mertens-Scholz
- Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany
| | - Sven Rinkel
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
| | - Martin Runge
- Lower Saxony State Office for Consumer Protection and Food Safety (LAVES), Food and Veterinary Institute Braunschweig/Hannover, Hannover, Germany
| | - Jan Schulze-Luehrmann
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
| | - Sebastian Ulbert
- Fraunhofer Institute for Cell Therapy and Immunology IZI, 04103 Leipzig, Germany
| | - Fenja Winter
- Department of Biometry, Epidemiology and Information Processing, (IBEI), WHO Collaborating Centre for Research and Training for Health at the Human-Animal-Environment Interface, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Dimitrios Frangoulidis
- Bundeswehr Institute of Microbiology, Munich, Germany; Bundeswehr Medical Service Headquarters VI-2, Medical Intelligence & Information, Munich, Germany
| | - Anja Lührmann
- Institut für Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany.
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França DAD, Mioni MDSR, Fernandes J, Lemos ERSD, Duré AÍDL, Silva MVF, Langoni H, Megid J. Overview of Q fever in Brazil: an underestimated zoonosis. Rev Inst Med Trop Sao Paulo 2023; 65:e39. [PMID: 37377322 DOI: 10.1590/s1678-9946202365039] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/25/2023] [Indexed: 06/29/2023] Open
Abstract
This review aims to provide current information about Q fever, elucidating the etiological, epidemiological, pathogenic, clinical, diagnostic, therapeutic, and prophylactic aspects of the disease for the medical community. We discuss the main forms of presentation of the agent, its ability to persist in the body, the infinite possibilities of susceptible hosts, the main known forms of transmission, its importance in populations at occupational risk, and the role of arthropods in the natural history of the disease. Focusing on Brazil, we present the cases already described and studies developed since its first report, and how there is still much to unravel. We are aware of the possibilities of the persistence of the agent and the development of severe clinical pictures and the specific treatments currently instituted. We also wish to raise awareness about the future, the new genotypes that are emerging, the need to study the effects of vaccines, and the impact of Q fever on the population. Q fever is a poorly understood disease in Latin America, and recent studies, especially in Brazil, have revealed the importance of developing new studies.
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Affiliation(s)
- Danilo Alves de França
- Universidade Estadual Paulista, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, São Paulo, Brazil
| | | | - Jorlan Fernandes
- Instituto Oswaldo Cruz, Laboratório de Hantaviroses e Rickettsioses, Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Ana Íris de Lima Duré
- Fundação Ezequiel Dias, Instituto Otávio Magalhães, Belo Horizonte, Minas Gerais, Brazil
| | | | - Helio Langoni
- Universidade Estadual Paulista, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, São Paulo, Brazil
| | - Jane Megid
- Universidade Estadual Paulista, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, São Paulo, Brazil
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Tehrani M, Ownagh A. Genomic detection of Coxiellaburnetii based on plasmid genes in horses. VETERINARY RESEARCH FORUM : AN INTERNATIONAL QUARTERLY JOURNAL 2023; 14:317-322. [PMID: 37383652 PMCID: PMC10298835 DOI: 10.30466/vrf.2022.551663.3443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 08/01/2022] [Indexed: 06/30/2023]
Abstract
Q fever is a worldwide zoonosis caused by an obligate intra-cellular pathogen called Coxiella burnetii affecting a broad range of animal hosts including horses. Most of the isolates found carry plasmids which genetic studies of C. burnetii strains suggest a critical role in C. burnetii survival. The correlation between an isolated plasmid type and the chronic or acute nature of the disease has always been controversial. This study was conducted to investigate the prevalence of C. burnetii QpH1 and QpDG plasmids in horses and assess the potential role of these species as reservoirs of infection and transmission. Nested-polymerase chain reaction (PCR) assays were performed on 320 blood serum samples drawn from horses in West Azerbaijan province, Iran, in 2020. In total, 26 (8.13%) Q fever-positive samples based on containing the IS1111 gene were tested by nested-PCR approach to amplify QpH1 and QpDG plasmid segments. The QpH1 and QpRS plasmid-specific sequences were identified in 19 (73.07%) and none in the serum samples, respectively. According to the present study, the age of the animal can be considered as an important risk factor for the prevalence of C. burnetii; but, the season, sex, and breed of the horse had no effect on the prevalence of disease. The results indicate that nested-PCR method could be suitable for routine diagnosis, to gather new information about the shedding of C. burnetii, and to improve the knowledge of contamination routes.
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Affiliation(s)
- Manizheh Tehrani
- MSc student, Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran;
| | - Abdolghaffar Ownagh
- Department of Microbiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran.
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Riffaud CM, Rucks EA, Ouellette SP. Persistence of obligate intracellular pathogens: alternative strategies to overcome host-specific stresses. Front Cell Infect Microbiol 2023; 13:1185571. [PMID: 37284502 PMCID: PMC10239878 DOI: 10.3389/fcimb.2023.1185571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
In adapting to the intracellular niche, obligate intracellular bacteria usually undergo a reduction of genome size by eliminating genes not needed for intracellular survival. These losses can include, for example, genes involved in nutrient anabolic pathways or in stress response. Living inside a host cell offers a stable environment where intracellular bacteria can limit their exposure to extracellular effectors of the immune system and modulate or outright inhibit intracellular defense mechanisms. However, highlighting an area of vulnerability, these pathogens are dependent on the host cell for nutrients and are very sensitive to conditions that limit nutrient availability. Persistence is a common response shared by evolutionarily divergent bacteria to survive adverse conditions like nutrient deprivation. Development of persistence usually compromises successful antibiotic therapy of bacterial infections and is associated with chronic infections and long-term sequelae for the patients. During persistence, obligate intracellular pathogens are viable but not growing inside their host cell. They can survive for a long period of time such that, when the inducing stress is removed, reactivation of their growth cycles resumes. Given their reduced coding capacity, intracellular bacteria have adapted different response mechanisms. This review gives an overview of the strategies used by the obligate intracellular bacteria, where known, which, unlike model organisms such as E. coli, often lack toxin-antitoxin systems and the stringent response that have been linked to a persister phenotype and amino acid starvation states, respectively.
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7
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Yadav A, Brewer MN, Elshahed MS, Shaw EI. Comparative Transcriptomics and Genomics from Continuous Axenic Media Growth Identifies Coxiella burnetii Intracellular Survival Strategies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.527305. [PMID: 36798183 PMCID: PMC9934583 DOI: 10.1101/2023.02.06.527305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Coxiella burnetii (Cb) is an obligate intracellular pathogen in nature and the causative agent of acute Q fever as well as chronic diseases. In an effort to identify genes and proteins crucial to their normal intracellular growth lifestyle, we applied a "Reverse evolution" approach where the avirulent Nine Mile Phase II strain of Cb was grown for 67 passages in chemically defined ACCM-D media and gene expression patterns and genome integrity from various passages was compared to passage number one following intracellular growth. Transcriptomic analysis identified a marked downregulation of the structural components of the type 4B secretion system (T4BSS), the general secretory (sec) pathway, as well as 14 out of 118 previously identified genes encoding effector proteins. Additional downregulated pathogenicity determinants genes included several chaperones, LPS, and peptidoglycan biosynthesis. A general marked downregulation of central metabolic pathways was also observed, which was balanced by a marked upregulation of genes encoding transporters. This pattern reflected the richness of the media and diminishing anabolic and ATP-generation needs. Finally, genomic sequencing and comparative genomic analysis demonstrated an extremely low level of mutation across passages, despite the observed Cb gene expression changes following acclimation to axenic media.
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Affiliation(s)
- Archana Yadav
- Department of Microbiology and Molecular Genetics. Oklahoma State University. Stillwater, OK.USA
| | - Melissa N. Brewer
- Department of Microbiology and Molecular Genetics. Oklahoma State University. Stillwater, OK.USA
- Biological Sciences. Southeastern Oklahoma State University. Durant, OK. USA
| | - Mostafa S. Elshahed
- Department of Microbiology and Molecular Genetics. Oklahoma State University. Stillwater, OK.USA
| | - Edward I. Shaw
- Department of Microbiology and Molecular Genetics. Oklahoma State University. Stillwater, OK.USA
- Department of Biomedical Sciences. Philadelphia College of Osteopathic Medicine. Moultrie, GA. USA
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Metters G, Hemsley C, Norville I, Titball R. Identification of essential genes in Coxiella burnetii. Microb Genom 2023; 9:mgen000944. [PMID: 36723494 PMCID: PMC9997736 DOI: 10.1099/mgen.0.000944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Coxiella burnetii is an intracellular pathogen responsible for causing Q fever in humans, a disease with varied presentations ranging from a mild flu-like sickness to a debilitating illness that can result in endocarditis. The intracellular lifestyle of C. burnetii is unique, residing in an acidic phagolysosome-like compartment within host cells. An understanding of the core molecular biology of C. burnetii will greatly increase our understanding of C. burnetii growth, survival and pathogenesis. We used transposon-directed insertion site sequencing (TraDIS) to reveal C. burnetii Nine Mile Phase II genes fundamental for growth and in vitro survival. Screening a transposon library containing >10 000 unique transposon mutants revealed 512 predicted essential genes. Essential routes of synthesis were identified for the mevalonate pathway, as well as peptidoglycan and biotin synthesis. Some essential genes identified (e.g. predicted type IV secretion system effector genes) are typically considered to be associated with C. burnetii virulence, a caveat concerning the axenic media used in the study. Investigation into the conservation of the essential genes identified revealed that 78 % are conserved across all C. burnetii strains sequenced to date, which probably play critical functions. This is the first report of a whole genome transposon screen in C. burnetii that has been undertaken for the identification of essential genes.
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Affiliation(s)
- Georgie Metters
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Defence Science and Technology Laboratories, CBR Division, Porton Down, Salisbury SP4 0JQ, UK
| | - Claudia Hemsley
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Present address: Molecular Microbiology Division, School of Life Sciences, University of Dundee, Dundee, DD1 5AA, UK
| | - Isobel Norville
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.,Defence Science and Technology Laboratories, CBR Division, Porton Down, Salisbury SP4 0JQ, UK
| | - Richard Titball
- Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
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Yadav A, Brewer MN, Elshahed MS, Shaw EI. Comparative transcriptomics and genomics from continuous axenic media growth identifies Coxiella burnetii intracellular survival strategies. Pathog Dis 2023; 81:ftad009. [PMID: 37193663 PMCID: PMC10237335 DOI: 10.1093/femspd/ftad009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/17/2023] [Accepted: 05/15/2023] [Indexed: 05/18/2023] Open
Abstract
Coxiella burnetii (Cb) is an obligate intracellular pathogen in nature and the causative agent of acute Q fever as well as chronic diseases. In an effort to identify genes and proteins crucial to their normal intracellular growth lifestyle, we applied a 'reverse evolution' approach where the avirulent Nine Mile Phase II strain of Cb was grown for 67 passages in chemically defined ACCM-D media and gene expression patterns and genome integrity from various passages was compared to passage number one following intracellular growth. Transcriptomic analysis identified a marked downregulation of the structural components of the type 4B secretion system (T4BSS), the general secretory (Sec) pathway, as well as 14 out of 118 previously identified genes encoding effector proteins. Additional downregulated pathogenicity determinants genes included several chaperones, LPS, and peptidoglycan biosynthesis. A general marked downregulation of central metabolic pathways was also observed, which was balanced by a marked upregulation of genes encoding transporters. This pattern reflected the richness of the media and diminishing anabolic, and ATP-generation needs. Finally, genomic sequencing and comparative genomic analysis demonstrated an extremely low level of mutation across passages, despite the observed Cb gene expression changes following acclimation to axenic media.
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Affiliation(s)
- Archana Yadav
- Department of Microbiology and Molecular Genetics, Oklahoma State University,, 74078 Stillwater, OK, United States
| | - Melissa N Brewer
- Department of Microbiology and Molecular Genetics, Oklahoma State University,, 74078 Stillwater, OK, United States
- Biological Sciences, Southeastern Oklahoma State University, 74078 Durant, OK, United States
| | - Mostafa S Elshahed
- Department of Microbiology and Molecular Genetics, Oklahoma State University,, 74078 Stillwater, OK, United States
| | - Edward I Shaw
- Department of Microbiology and Molecular Genetics, Oklahoma State University,, 74078 Stillwater, OK, United States
- Department of Biomedical Sciences, Philadelphia College of Osteopathic Medicine, 74078 Moultrie, GA, United States
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The inside scoop: Comparative genomics of two intranuclear bacteria, "Candidatus Berkiella cookevillensis" and "Candidatus Berkiella aquae". PLoS One 2022; 17:e0278206. [PMID: 36584052 PMCID: PMC9803151 DOI: 10.1371/journal.pone.0278206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/12/2022] [Indexed: 12/31/2022] Open
Abstract
"Candidatus Berkiella cookevillensis" (strain CC99) and "Candidatus Berkiella aquae" (strain HT99), belonging to the Coxiellaceae family, are gram-negative bacteria isolated from amoebae in biofilms present in human-constructed water systems. Both bacteria are obligately intracellular, requiring host cells for growth and replication. The intracellular bacteria-containing vacuoles of both bacteria closely associate with or enter the nuclei of their host cells. In this study, we analyzed the genome sequences of CC99 and HT99 to better understand their biology and intracellular lifestyles. The CC99 genome has a size of 2.9Mb (37.9% GC) and contains 2,651 protein-encoding genes (PEGs) while the HT99 genome has a size of 3.6Mb (39.4% GC) and contains 3,238 PEGs. Both bacteria encode high proportions of hypothetical proteins (CC99: 46.5%; HT99: 51.3%). The central metabolic pathways of both bacteria appear largely intact. Genes for enzymes involved in the glycolytic pathway, the non-oxidative branch of the phosphate pathway, the tricarboxylic acid pathway, and the respiratory chain were present. Both bacteria, however, are missing genes for the synthesis of several amino acids, suggesting reliance on their host for amino acids and intermediates. Genes for type I and type IV (dot/icm) secretion systems as well as type IV pili were identified in both bacteria. Moreover, both bacteria contain genes encoding large numbers of putative effector proteins, including several with eukaryotic-like domains such as, ankyrin repeats, tetratricopeptide repeats, and leucine-rich repeats, characteristic of other intracellular bacteria.
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Mobile Element Integration Reveals a Chromosome Dimer Resolution System in Legionellales. mBio 2022; 13:e0217122. [PMID: 36314797 PMCID: PMC9765430 DOI: 10.1128/mbio.02171-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In bacteria, the mechanisms used to repair DNA lesions during genome replication include homologous recombination between sister chromosomes. This can lead to the formation of chromosome dimers if an odd number of crossover events occurs. The dimers must be resolved before cell separation to ensure genomic stability and cell viability. Dimer resolution is achieved by the broadly conserved dif/Xer system, which catalyzes one additional crossover event immediately prior to cell separation. While dif/Xer systems have been characterized or predicted in the vast majority of proteobacteria, no homologs to dif or xer have been identified in the order Legionellales. Here, we report the discovery of a distinct single-recombinase dif/Xer system in the intracellular pathogen Legionella pneumophila. The dif site was uncovered by our analysis of Legionella mobile element-1 (LME-1), which harbors a dif site mimic and integrates into the L. pneumophila genome via site-specific recombination. We demonstrate that lpg1867 (here named xerL) encodes a tyrosine recombinase that is necessary and sufficient for catalyzing recombination at the dif site and that deletion of dif or xerL causes filamentation along with extracellular and intracellular growth defects. We show that the dif/XerL system is present throughout Legionellales and that Coxiella burnetii XerL and its cognate dif site can functionally substitute for the native system in L. pneumophila. Finally, we describe an unexpected link between C. burnetii dif/Xer and the maintenance of its virulence plasmids. IMPORTANCE The maintenance of circular chromosomes depends on the ability to resolve aberrant chromosome dimers after they form. In most proteobacteria, broadly conserved Xer recombinases catalyze single crossovers at short, species-specific dif sites located near the replication terminus. Chromosomal dimerization leads to the formation of two copies of dif within the same molecule, leading to rapid site-specific recombination and conversion back into chromosome monomers. The apparent absence of chromosome dimer resolution mechanisms in Legionellales has been a mystery to date. By studying a phage-like mobile genetic element, LME-1, we have identified a previously unknown single-recombinase dif/Xer system that is not only widespread across Legionellales but whose activity is linked to virulence in two important human pathogens.
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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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13
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Sobotta K, Bonkowski K, Heydel C, Henning K, Menge C. Phenotype of Coxiella burnetii Strains of Different Sources and Genotypes in Bovine Mammary Gland Epithelial Cells. Pathogens 2022; 11:pathogens11121422. [PMID: 36558755 PMCID: PMC9786247 DOI: 10.3390/pathogens11121422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 11/29/2022] Open
Abstract
Despite the high prevalence of C. burnetii in dairy herds and continuous shedding via milk by chronically infected cows, bovine milk is not recognized as a relevant source of human Q fever. We hypothesized that the bovine mammary gland epithelial cell line PS represents a suitable in vitro model for the identification of C. burnetii-strain-specific virulence properties that may account for this discrepancy. Fifteen C. burnetii strains were selected to represent different host species and multiple loci variable number of tandem repeat analysis (MLVA) genotypes (I, II, III and IV). The replication efficiencies of all strains were similar, even though strains of the MLVA-genotype II replicated significantly better than genotype I strains, and bovine and ovine isolates replicated better than caprine ones. Bovine milk isolates replicated with similar efficiencies to isolates from other bovine organs. One sheep isolate (Cb30/14, MLVA type I, isolated from fetal membranes) induced a remarkable up-regulation of IL-1β and TNF-α, whereas prototypic strains and bovine milk isolates tended to suppress pro-inflammatory responses. While infection with strain Nine Mile I rendered the cells partially refractory to re-stimulation with E. coli lipopolysaccharide, Cb30/14 exerted a selective suppressive effect which was restricted to IL-6 and TNF-α and spared IL-1β. PS cells support the replication of different strains of C. burnetii and respond in a strain-specific manner, but isolates from bovine milk did not display a common pattern, which distinguishes them from strains identified as a public health concern.
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Affiliation(s)
- Katharina Sobotta
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Katharina Bonkowski
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Carsten Heydel
- Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-University (JLU), Frankfurter Strasse 85-89, 35392 Giessen, Germany
| | - Klaus Henning
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
| | - Christian Menge
- Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Naumburger Strasse 96a, 07743 Jena, Germany
- Correspondence:
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14
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Guo Y, Wu C, Sun J. Pathogenic bacteria significantly increased under oxygen depletion in coastal waters: A continuous observation in the central Bohai Sea. Front Microbiol 2022; 13:1035904. [DOI: 10.3389/fmicb.2022.1035904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 10/19/2022] [Indexed: 11/22/2022] Open
Abstract
The spread of pathogenic bacteria in coastal waters endangers the health of the local people and jeopardizes the safety of the marine environment. However, their dynamics during seasonal hypoxia in the Bohai Sea (BHS) have not been studied. Here, pathogenic bacteria were detected from the 16S rRNA gene sequencing database and were used to explore their dynamics and driving factors with the progressively deoxygenating in the BHS. Our results showed that pathogenic bacteria were detected in all samples, accounting for 0.13 to 24.65% of the total number of prokaryotic sequences in each sample. Pathogenic Proteobacteria was dominated in all samples, followed by Firmicutes, Actinobacteria, Tenericutes, and Bacteroidetes, etc. β-diversity analysis showed that pathogenic bacteria are highly temporally heterogeneous and regulated by environmental factors. According to RDA analysis, these variations may be influenced by salinity, ammonia, DO, phosphate, silicate, and Chl a. Additionally, pathogenic bacteria in surface water and hypoxia zone were found to be significantly separated in August. The vertical distribution of pathogenic bacterial communities is influenced by several variables, including DO and nutrition. It is noteworthy that the hypoxia zones increase the abundance of certain pathogenic genera, especially Vibrio and Arcobacter, and the stability of the pathogenic bacterial community increased from May to August. These phenomena indicate that the central Bohai Sea is threatened by an increasingly serious pathogenic community from May to August. And the developing hypoxia zone in the future may intensify this phenomenon and pose a more serious threat to human health. This study provides new insight into the changes of pathogenic bacteria in aquatic ecosystems and may help to make effective policies to control the spread of pathogenic bacteria.
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15
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Abou Abdallah R, Million M, Delerce J, Anani H, Diop A, Caputo A, Zgheib R, Rousset E, Sidi Boumedine K, Raoult D, Fournier PE. Pangenomic analysis of Coxiella burnetii unveils new traits in genome architecture. Front Microbiol 2022; 13:1022356. [PMID: 36478861 PMCID: PMC9721466 DOI: 10.3389/fmicb.2022.1022356] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/10/2022] [Indexed: 08/25/2023] Open
Abstract
Coxiella burnetii is the etiological agent of Q fever, a worldwide zoonosis able to cause large outbreaks. The disease is polymorphic. Symptomatic primary infection is named acute Q fever and is associated with hepatitis, pneumonia, fever, and auto-immune complications while persistent focalized infections, mainly endocarditis, and vascular infections, occur in a minority of patients but are potentially lethal. In order to evaluate the genomic features, genetic diversity, evolution, as well as genetic determinants of antibiotic resistance, pathogenicity, and ability to cause outbreaks of Q fever, we performed a pangenomic analysis and genomic comparison of 75 C. burnetii strains including 63 newly sequenced genomes. Our analysis demonstrated that C. burnetii has an open pangenome, unique genes being found in many strains. In addition, pathogenicity islands were detected in all genomes. In consequence C. burnetii has a high genomic plasticity, higher than that of other intracellular bacteria. The core- and pan-genomes are made of 1,211 and 4,501 genes, respectively (ratio 0.27). The core gene-based phylogenetic analysis matched that obtained from multi-spacer typing and the distribution of plasmid types. Genomic characteristics were associated to clinical and epidemiological features. Some genotypes were associated to specific clinical forms and countries. MST1 genotype strains were associated to acute Q fever. A significant association was also found between clinical forms and plasmids. Strains harboring the QpRS plasmid were never found in acute Q fever and were only associated to persistent focalized infections. The QpDV and QpH1 plasmids were associated to acute Q fever. In addition, the Guyanese strain CB175, the most virulent strain to date, exhibited a unique MST genotype, a distinct COG profile and an important variation in gene number that may explain its unique pathogenesis. Therefore, strain-specific factors play an important role in determining the epidemiological and clinical manifestations of Q fever alongside with host-specific factors (valvular and vascular defects notably).
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Affiliation(s)
- Rita Abou Abdallah
- Aix Marseille Université, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Matthieu Million
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Jeremy Delerce
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Hussein Anani
- Aix Marseille Université, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Awa Diop
- Aix Marseille Université, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Aurelia Caputo
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Rita Zgheib
- Aix Marseille Université, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Elodie Rousset
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Sophia Antipolis Laboratory, Animal Q Fever Unit, Sophia Antipolis, France
| | - Karim Sidi Boumedine
- French Agency for Food, Environmental and Occupational Health Safety (ANSES), Sophia Antipolis Laboratory, Animal Q Fever Unit, Sophia Antipolis, France
| | - Didier Raoult
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Pierre-Edouard Fournier
- Aix Marseille Université, Institut de Recherche pour le Développement (IRD), Service de Santé des Armées, AP-HM, UMR Vecteurs Infections Tropicales et Méditerranéennes (VITROME), Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
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16
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Tesfamariam M, Binette P, Cockrell D, Beare PA, Heinzen RA, Shaia C, Long CM. Characterization of Coxiella burnetii Dugway Strain Host-Pathogen Interactions In Vivo. Microorganisms 2022; 10:2261. [PMID: 36422331 PMCID: PMC9692954 DOI: 10.3390/microorganisms10112261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 12/12/2023] Open
Abstract
Coxiella burnetii is a Gram-negative, intracellular bacterium that causes the zoonosis Q fever. Among the many natural isolates of C. burnetii recovered from various sources, the Dugway group exhibits unique genetic characteristics, including the largest C. burnetii genomes. These strains were isolated during 1954-1958 from wild rodents from the Utah, USA desert. Despite retaining phase I lipopolysaccharide and the type 4B secretion system, two critical virulence factors, avirulence has been reported in a guinea pig infection model. Using guinea pig models, we evaluated the virulence, whole-cell vaccine (WCV) efficacy, and post-vaccination hypersensitivity (PVH) potential of a representative Dugway strain. Consistent with prior reports, Dugway appeared to be highly attenuated compared to a virulent strain. Indeed, Dugway-infected animals showed similarly low levels of fever, body weight loss, and splenomegaly like Nine Mile II-infected animals. When compared to a human Q fever vaccine, QVax®, Dugway WCV exhibited analogous protection against a heterologous Nine Mile I challenge. PVH was investigated in a skin-testing model which revealed significantly decreased maximum erythema in Dugway Δdot/icm WCV-skin-tested animals compared to that of QVax®. These data provide insight into this unique bacterial strain and implicate its potential use as a mutated WCV candidate.
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Affiliation(s)
- Mahelat Tesfamariam
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Picabo Binette
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Diane Cockrell
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Paul A. Beare
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Robert A. Heinzen
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Carl Shaia
- Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
| | - Carrie Mae Long
- Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA
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17
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Tian J, Hou X, Ge M, Xu H, Yu B, Liu J, Shao R, Holmes EC, Lei C, Shi M. The diversity and evolutionary relationships of ticks and tick-borne bacteria collected in China. Parasit Vectors 2022; 15:352. [PMID: 36182913 PMCID: PMC9526939 DOI: 10.1186/s13071-022-05485-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 09/13/2022] [Indexed: 01/12/2023] Open
Abstract
Background Ticks (order Ixodida) are ectoparasites, vectors and reservoirs of many infectious agents affecting humans and domestic animals. However, the lack of information on tick genomic diversity leaves significant gaps in the understanding of the evolution of ticks and associated bacteria. Results We collected > 20,000 contemporary and historical (up to 60 years of preservation) tick samples representing a wide range of tick biodiversity across diverse geographic regions in China. Metagenomic sequencing was performed on individual ticks to obtain the complete or near-complete mitochondrial (mt) genome sequences from 46 tick species, among which mitochondrial genomes of 23 species were recovered for the first time. These new mt genomes data greatly expanded the diversity of many tick groups and revealed five cryptic species. Utilizing the same metagenomic sequence data we identified divergent and abundant bacteria in Haemaphysalis, Ixodes, Dermacentor and Carios ticks, including nine species of pathogenetic bacteria and potentially new species within the genus Borrelia. We also used these data to explore the evolutionary relationship between ticks and their associated bacteria, revealing a pattern of long-term co-divergence relationship between ticks and Rickettsia and Coxiella bacteria. Conclusions In sum, our study provides important new information on the genetic diversity of ticks based on an analysis of mitochondrial DNA as well as on the prevalence of tick-borne pathogens in China. It also sheds new light on the long-term evolutionary and ecological relationships between ticks and their associated bacteria. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05485-3.
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Affiliation(s)
- JunHua Tian
- Hubei Key Laboratory of Resources Utilization and Sustainable Pest Management, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, China.,Wuhan Centers for Disease Control and Prevention, Wuhan, Hubei Province, 430015, China
| | - Xin Hou
- School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, Guangdong Province, 518107, China
| | - MiHong Ge
- Wuhan Academy of Agricultural Sciences, Wuhan, Hubei Province, 430345, China
| | - HongBin Xu
- Jiangxi Province Center for Disease Control and Prevention, Nanchang, Jiangxi Province, 330029, China
| | - Bin Yu
- Wuhan Centers for Disease Control and Prevention, Wuhan, Hubei Province, 430015, China
| | - Jing Liu
- Wuhan Centers for Disease Control and Prevention, Wuhan, Hubei Province, 430015, China
| | - RenFu Shao
- School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia.,GeneCology Research Centre, University of the Sunshine Coast, Sippy Downs, QLD, 4558, Australia
| | - Edward C Holmes
- Sydney Institute for Infectious Diseases, School of Life & Environmental Sciences and School of Medical Sciences, The University of Sydney, Camperdown, NSW, 2006, Australia
| | - ChaoLiang Lei
- Hubei Key Laboratory of Resources Utilization and Sustainable Pest Management, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, China.
| | - Mang Shi
- School of Medicine, Shenzhen Campus of Sun Yat-Sen University, Sun Yat-Sen University, Shenzhen, Guangdong Province, 518107, China.
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18
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Nicholson KR, Champion PA. Bacterial secretion systems: Networks of pathogenic regulation and adaptation in mycobacteria and beyond. PLoS Pathog 2022; 18:e1010610. [PMID: 35834482 PMCID: PMC9282442 DOI: 10.1371/journal.ppat.1010610] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Kathleen R. Nicholson
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Patricia A. Champion
- Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
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19
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Cross AR, Roy S, Vivoli Vega M, Rejzek M, Nepogodiev SA, Cliff M, Salmon D, Isupov MN, Field RA, Prior JL, Harmer NJ. Spinning sugars in antigen biosynthesis: characterization of the Coxiella burnetii and Streptomyces griseus TDP-sugar epimerases. J Biol Chem 2022; 298:101903. [PMID: 35398092 PMCID: PMC9095892 DOI: 10.1016/j.jbc.2022.101903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 04/02/2022] [Accepted: 04/04/2022] [Indexed: 11/25/2022] Open
Abstract
The sugars streptose and dihydrohydroxystreptose (DHHS) are unique to the bacteria Streptomyces griseus and Coxiella burnetii, respectively. Streptose forms the central moiety of the antibiotic streptomycin, while DHHS is found in the O-antigen of the zoonotic pathogen C. burnetii. Biosynthesis of these sugars has been proposed to follow a similar path to that of TDP-rhamnose, catalyzed by the enzymes RmlA, RmlB, RmlC, and RmlD, but the exact mechanism is unclear. Streptose and DHHS biosynthesis unusually requires a ring contraction step that could be performed by orthologs of RmlC or RmlD. Genome sequencing of S. griseus and C. burnetii has identified StrM and CBU1838 proteins as RmlC orthologs in these respective species. Here, we demonstrate that both enzymes can perform the RmlC 3'',5'' double epimerization activity necessary to support TDP-rhamnose biosynthesis in vivo. This is consistent with the ring contraction step being performed on a double epimerized substrate. We further demonstrate that proton exchange is faster at the 3''-position than the 5''-position, in contrast to a previously studied ortholog. We additionally solved the crystal structures of CBU1838 and StrM in complex with TDP and show that they form an active site highly similar to those of the previously characterized enzymes RmlC, EvaD, and ChmJ. These results support the hypothesis that streptose and DHHS are biosynthesized using the TDP pathway and that an RmlD paralog most likely performs ring contraction following double epimerization. This work will support the elucidation of the full pathways for biosynthesis of these unique sugars.
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Affiliation(s)
- Alice R Cross
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Sumita Roy
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Mirella Vivoli Vega
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Martin Rejzek
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Sergey A Nepogodiev
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom
| | - Matthew Cliff
- Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom
| | - Debbie Salmon
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Michail N Isupov
- Department of Biosciences, University of Exeter, Exeter, United Kingdom
| | - Robert A Field
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, United Kingdom; Manchester Institute of Biotechnology, University of Manchester, Manchester, United Kingdom
| | - Joann L Prior
- Dstl, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Nicholas J Harmer
- Living Systems Institute, University of Exeter, Exeter, United Kingdom; Department of Biosciences, University of Exeter, Exeter, United Kingdom.
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20
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Abstract
Coxiella burnetii replicates in a phagolysosome-like vacuole called the Coxiella-containing vacuole (CCV). While host cholesterol readily traffics to the CCV, cholesterol accumulation leads to CCV acidification and bacterial death. Thus, bacterial regulation of CCV cholesterol content is essential for Coxiella pathogenesis. Coxiella expresses a sterol-modifying protein, Stmp1, that may function to lower CCV cholesterol through enzymatic modification. Using an Stmp1 knockout (Δstmp1), we determined that Stmp1 is not essential for axenic growth. Inside host cells, however, Δstmp1 mutant bacteria form smaller CCVs which accumulate cholesterol, preferentially fuse with lysosomes, and become more acidic, correlating with a significant growth defect. However, in cholesterol-free cells, Δstmp1 mutant bacteria grow similarly to wild-type bacteria but are hypersensitive to cholesterol supplementation. To better understand the underlying mechanism behind the Δstmp1 mutant phenotype, we performed sterol profiling. Surprisingly, we found that Δstmp1 mutant-infected macrophages accumulated the potent cholesterol homeostasis regulator 25-hydroxycholesterol (25-HC). We next determined whether dysregulated 25-HC alters Coxiella infection by treating wild-type Coxiella-infected cells with 25-HC. Similar to the Δstmp1 mutant phenotype, 25-HC increased CCV proteolytic activity and inhibited bacterial growth. Collectively, these data indicate that Stmp1 alters host cholesterol metabolism and is essential to establish a mature CCV which supports Coxiella growth. IMPORTANCE Coxiella burnetii is the causative agent of human Q fever, an emerging infectious disease and significant cause of culture-negative endocarditis. Acute infections are often undiagnosed, there are no licensed vaccines in the United States, and chronic Q fever requires a prolonged antibiotic treatment. Therefore, new treatment and preventive options are critically needed. Coxiella is an obligate intracellular bacterium that replicates within a large acidic phagolysosome-like compartment, the Coxiella-containing vacuole (CCV). We previously discovered that cholesterol accumulation in the CCV increases its acidification, leading to bacterial death. Therefore, in order to survive in this harsh environment, Coxiella likely regulates CCV cholesterol levels. Here, we found that Coxiella sterol modifying protein (Stmp1) facilitates bacterial growth by reducing CCV cholesterol and host cell 25-hydroxycholesterol (25-HC) levels, which prevents excessive CCV fusion with host lysosomes and CCV acidification. This study establishes that Stmp1-mediated regulation of host cholesterol homeostasis is essential for Coxiella intracellular survival.
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21
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Gregory AE, van Schaik EJ, Fratzke AP, Russell-Lodrigue KE, Farris CM, Samuel JE. Soluble antigens derived from Coxiella burnetii elicit protective immunity in three animal models without inducing hypersensitivity. Cell Rep Med 2021; 2:100461. [PMID: 35028605 PMCID: PMC8714860 DOI: 10.1016/j.xcrm.2021.100461] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/27/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022]
Abstract
Q fever is caused by the intracellular bacterium Coxiella burnetii, for which there is no approved vaccine in the United States. A formalin-inactivated whole-cell vaccine (WCV) from virulent C. burnetii NMI provides single-dose long-lived protection, but concerns remain over vaccine reactogenicity. We therefore sought an alternate approach by purifying native C. burnetii antigens from the clonally derived avirulent NMII strain. A soluble bacterial extract, termed Sol II, elicits high-titer, high-avidity antibodies and induces a CD4 T cell response that confers protection in naive mice. In addition, Sol II protects against pulmonary C. burnetii challenge in three animal models without inducing hypersensitivity. An NMI-derived extract, Sol I, enhances protection further and outperforms the WCV gold standard. Collectively, these data represent a promising approach to design highly effective, non-reactogenic Q fever vaccines.
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Affiliation(s)
- Anthony E. Gregory
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Medical Research and Education Building, Bryan, TX 77807, USA
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, Irvine, CA 92617, USA
| | - Erin J. van Schaik
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Medical Research and Education Building, Bryan, TX 77807, USA
| | - Alycia P. Fratzke
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Medical Research and Education Building, Bryan, TX 77807, USA
| | - Kasi E. Russell-Lodrigue
- Tulane University, School of Medicine, Tulane National Primate Research Center, Covington, LA 70433, USA
| | - Christina M. Farris
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Medical Research and Education Building, Bryan, TX 77807, USA
| | - James E. Samuel
- Department of Microbial Pathogenesis and Immunology, College of Medicine, Texas A&M University, Medical Research and Education Building, Bryan, TX 77807, USA
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22
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Kovacs-Simon A, Metters G, Norville I, Hemsley C, Titball RW. Coxiella burnetii replicates in Galleria mellonella hemocytes and transcriptome mapping reveals in vivo regulated genes. Virulence 2021; 11:1268-1278. [PMID: 32970966 PMCID: PMC7549970 DOI: 10.1080/21505594.2020.1819111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Larvae of the greater wax moth (Galleria mellonella) are susceptible to infection with C. burnetii, an obligate intracellular bacterial pathogen. We show that bacteria are found in hemocytes after infection, and occupy vacuoles which are morphologically similar to Coxiella-containing vacuoles seen in infected mammalian phagocytes. We characterized the infection by transcriptome profiling of bacteria isolated from the hemocytes of infected larvae and identified 46 highly upregulated genes. The encoded proteins are predicted to be involved in translation, LPS biosynthesis, biotin synthesis, scavenging of reactive oxygen species, and included a T4SS effector and 30 hypothetical proteins. Some of these genes had previously been shown to be upregulated in buffalo green monkey (BGM) cells or in mice, whilst others appear to be regulated in a host-specific manner. Altogether, our results demonstrate the value of the G. mellonella model to study intracellular growth and identify potential virulence factors of C. burnetii.
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Affiliation(s)
- Andrea Kovacs-Simon
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Georgie Metters
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Isobel Norville
- CBR Division, Defence Science and Technology Laboratory , Porton Down,Salisbury, UK
| | - Claudia Hemsley
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
| | - Richard W Titball
- College of Life and Environmental Sciences - Biosciences, University of Exeter , Exeter, UK
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23
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Sanchez SE, Omsland A. Conditional impairment of Coxiella burnetii by glucose-6P dehydrogenase activity. Pathog Dis 2021; 79:6321164. [PMID: 34259815 PMCID: PMC8292140 DOI: 10.1093/femspd/ftab034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 07/06/2021] [Indexed: 11/12/2022] Open
Abstract
Coxiella burnetii is a bacterial obligate intracellular parasite and the etiological agent of query (Q) fever. While the C. burnetii genome has been reduced to ∼2 Mb as a likely consequence of genome streamlining in response to parasitism, enzymes for a nearly complete central metabolic machinery are encoded by the genome. However, lack of a canonical hexokinase for phosphorylation of glucose and an apparent absence of the oxidative branch of the pentose phosphate pathway, a major mechanism for regeneration of the reducing equivalent nicotinamide adenine dinucleotide phosphate (NADPH), have been noted as potential metabolic limitations of C. burnetii. By complementing C. burnetii with the gene zwf encoding the glucose-6-phosphate-consuming and NADPH-producing enzyme glucose-6-phosphate dehydrogenase (G6PD), we demonstrate a severe metabolic fitness defect for C. burnetii under conditions of glucose limitation. Supplementation of the medium with the gluconeogenic carbon source glutamate did not rescue the growth defect of bacteria complemented with zwf. Absence of G6PD in C. burnetii therefore likely relates to the negative effect of its activity under conditions of glucose limitation. Coxiella burnetii central metabolism with emphasis on glucose, NAD+, NADP+ and NADPH is discussed in a broader perspective, including comparisons with other bacterial obligate intracellular parasites.
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Affiliation(s)
- Savannah E Sanchez
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA.,School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA
| | - Anders Omsland
- Paul G. Allen School for Global Health, Washington State University, Pullman, WA 99164, USA
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24
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Piel LMW, Durfee CJ, White SN. Proteome-wide analysis of Coxiella burnetii for conserved T-cell epitopes with presentation across multiple host species. BMC Bioinformatics 2021; 22:296. [PMID: 34078271 PMCID: PMC8170629 DOI: 10.1186/s12859-021-04181-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 05/10/2021] [Indexed: 12/29/2022] Open
Abstract
Background Coxiella burnetii is the Gram-negative bacterium responsible for Q fever in humans and coxiellosis in domesticated agricultural animals. Previous vaccination efforts with whole cell inactivated bacteria or surface isolated proteins confer protection but can produce a reactogenic immune responses. Thereby a protective vaccine that does not cause aberrant immune reactions is required. The critical role of T-cell immunity in control of C. burnetii has been made clear, since either CD8+ or CD4+ T cells can empower clearance. The purpose of this study was to identify C. burnetii proteins bearing epitopes that interact with major histocompatibility complexes (MHC) from multiple host species (human, mouse, and cattle). Results Of the annotated 1815 proteins from the Nine Mile Phase I (RSA 493) assembly, 402 proteins were removed from analysis due to a lack of inter-isolate conservation. An additional 391 proteins were eliminated from assessment to avoid potential autoimmune responses due to the presence of host homology. We analyzed the remaining 1022 proteins for their ability to produce peptides that bind MHCI or MHCII. MHCI and MHCII predicted epitopes were filtered and compared between species yielding 777 MHCI epitopes and 453 MHCII epitopes. These epitopes were further examined for presentation by both MHCI and MHCII, and for proteins that contained multiple epitopes. There were 31 epitopes that overlapped positionally between MHCI and MHCII across host species. Of these, there were 9 epitopes represented within proteins containing ≥ 5 total epitopes, where an additional 24 proteins were also epitope dense. In all, 55 proteins were found to contain high scoring T-cell epitopes. Besides the well-studied protein Com1, most identified proteins were novel when compared to previously studied vaccine candidates. Conclusion These data represent the first proteome-wide evaluation of C. burnetii peptide epitopes. Furthermore, the inclusion of human, mouse, and bovine data capture a range of hosts for this zoonotic pathogen plus an important model organism. This work provides new vaccine targets for future vaccination efforts and enhances opportunities for selecting multiple T-cell epitope types to include within a vaccine. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04181-w.
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Affiliation(s)
| | - Codie J Durfee
- USDA-ARS Animal Disease Research Unit, Pullman, WA, 99164, USA
| | - Stephen N White
- USDA-ARS Animal Disease Research Unit, Pullman, WA, 99164, USA. .,Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, 99164, USA. .,Center for Reproductive Biology, Washington State University, Pullman, WA, 99164, USA.
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25
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Brenner AE, Muñoz-Leal S, Sachan M, Labruna MB, Raghavan R. Coxiella burnetii and Related Tick Endosymbionts Evolved from Pathogenic Ancestors. Genome Biol Evol 2021; 13:6278299. [PMID: 34009306 PMCID: PMC8290121 DOI: 10.1093/gbe/evab108] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2021] [Indexed: 12/11/2022] Open
Abstract
Both symbiotic and pathogenic bacteria in the family Coxiellaceae cause morbidity and mortality in humans and animals. For instance, Coxiella-like endosymbionts (CLEs) improve the reproductive success of ticks—a major disease vector, while Coxiella burnetii causes human Q fever, and uncharacterized coxiellae infect both animals and humans. To better understand the evolution of pathogenesis and symbiosis in this group of intracellular bacteria, we sequenced the genome of a CLE present in the soft tick Ornithodoros amblus (CLEOA) and compared it to the genomes of other bacteria in the order Legionellales. Our analyses confirmed that CLEOA is more closely related to C. burnetii, the human pathogen, than to CLEs in hard ticks, and showed that most clades of CLEs contain both endosymbionts and pathogens, indicating that several CLE lineages have evolved independently from pathogenic Coxiella. We also determined that the last common ancestorof CLEOA and C. burnetii was equipped to infect macrophages and that even though horizontal gene transfer (HGT) contributed significantly to the evolution of C. burnetii, most acquisition events occurred primarily in ancestors predating the CLEOA–C. burnetii divergence. These discoveries clarify the evolution of C. burnetii, which previously was assumed to have emerged when an avirulent tick endosymbiont recently gained virulence factors via HGT. Finally, we identified several metabolic pathways, including heme biosynthesis, that are likely critical to the intracellular growth of the human pathogen but not the tick symbiont, and show that the use of heme analog is a promising approach to controlling C. burnetii infections.
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Affiliation(s)
- Amanda E Brenner
- Department of Biology and Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Sebastián Muñoz-Leal
- Departamento de Patología y Medicina Preventiva, Facultad de Ciencias Veterinarias, Universidad de Concepción, Chillán, Ñuble, Chile
| | - Madhur Sachan
- Department of Biology and Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Rahul Raghavan
- Department of Biology and Center for Life in Extreme Environments, Portland State University, Portland, OR, USA.,Department of Biology and South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, USA
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26
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Correlating Genotyping Data of Coxiella burnetii with Genomic Groups. Pathogens 2021; 10:pathogens10050604. [PMID: 34069306 PMCID: PMC8156542 DOI: 10.3390/pathogens10050604] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 11/17/2022] Open
Abstract
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. Several distinct genetic lineages or genomic groups have been shown to exist, with evidence for different virulence potential of these lineages. Multispacer Sequence Typing (MST) and Multiple-Locus Variable number tandem repeat Analysis (MLVA) are being used to genotype strains. However, it is unclear how these typing schemes correlate with each other or with the classification into different genomic groups. Here, we created extensive databases for published MLVA and MST genotypes of C. burnetii and analysed the associated metadata, revealing associations between animal host and human disease type. We established a new classification scheme that assigns both MST and MLVA genotypes to a genomic group and which revealed additional sub-lineages in two genomic groups. Finally, we report a novel, rapid genomotyping method for assigning an isolate into a genomic group based on the Cox51 spacer sequence. We conclude that by pooling and streamlining existing datasets, associations between genotype and clinical outcome or host source were identified, which in combination with our novel genomotyping method, should enable an estimation of the disease potential of new C. burnetii isolates.
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27
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Nooroong P, Trinachartvanit W, Baimai V, Anuracpreeda P, Ahantarig A. Partial DnaK protein expression from Coxiella-like endosymbiont of Rhipicephalus annulatus tick. PLoS One 2021; 16:e0249354. [PMID: 33793664 PMCID: PMC8016282 DOI: 10.1371/journal.pone.0249354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/16/2021] [Indexed: 11/19/2022] Open
Abstract
Q fever is one of the most important zoonotic diseases caused by the obligate intracellular bacteria, Coxiella burnetii. This bacterial infection has been frequently reported in both humans and animals, especially ruminants. Ticks are important ectoparasite and serve as reservoir hosts of Coxiella-like endosymbionts (CLEs). In this study, we have attempted to express chaperone-coding genes from CLEs of Rhipicephalus annulatus ticks collected fromcow path. The partial DnaK coding sequence has been amplified and expressed by Escherichia coli. Amino acid sequences have been analyzed by MS-MS spectrometry and the UniProt database. Despites nucleotide sequences indicating high nucleotide variation and diversity, many nucleotide substitutions are synonymous. In addition, amino acid substitutions compensate for the physicochemical properties of the original amino acids. Immune Epitope Database and Analysis Resource (IEDB-AR) was employed to indicate the antigenicity of the partial DnaK protein and predict the epitopes of B-and T-cells. Interestingly, some predicted HLA-A and B alleles of the MHC-I and HLA-DR alleles belonging to MHC-II were similar to T-cell responses to C. burnetii in Q fever patients. Therefore, the partial DnaK protein of CLE from R. annulatus could be considered a vaccine candidate and immunogenic marker with future prospects.
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Affiliation(s)
- Pornpiroon Nooroong
- Department of Biology, Biodiversity Research Cluster, Faculty of Science, Mahidol University, Bangkok, Thailand
| | | | - Visut Baimai
- Department of Biology, Biodiversity Research Cluster, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Panat Anuracpreeda
- Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhon Pathom, Thailand
| | - Arunee Ahantarig
- Department of Biology, Biodiversity Research Cluster, Faculty of Science, Mahidol University, Bangkok, Thailand
- Center of Excellence for Vectors and Vector-Borne Diseases, Faculty of Science, Mahidol University, Salaya, Nakhon Pathom, Thailand
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28
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Long CM, Beare PA, Cockrell DC, Fintzi J, Tesfamariam M, Shaia CI, Heinzen RA. Contributions of lipopolysaccharide and the type IVB secretion system to Coxiella burnetii vaccine efficacy and reactogenicity. NPJ Vaccines 2021; 6:38. [PMID: 33741986 PMCID: PMC7979919 DOI: 10.1038/s41541-021-00296-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 02/12/2021] [Indexed: 12/15/2022] Open
Abstract
Coxiella burnetii is the bacterial causative agent of the zoonosis Q fever. The current human Q fever vaccine, Q-VAX®, is a fixed, whole cell vaccine (WCV) licensed solely for use in Australia. C. burnetii WCV administration is associated with a dermal hypersensitivity reaction in people with pre-existing immunity to C. burnetii, limiting wider use. Consequently, a less reactogenic vaccine is needed. Here, we investigated contributions of the C. burnetii Dot/Icm type IVB secretion system (T4BSS) and lipopolysaccharide (LPS) in protection and reactogenicity of fixed WCVs. A 32.5 kb region containing 23 dot/icm genes was deleted in the virulent Nine Mile phase I (NMI) strain and the resulting mutant was evaluated in guinea pig models of C. burnetii infection, vaccination-challenge, and post-vaccination hypersensitivity. The NMI ∆dot/icm strain was avirulent, protective as a WCV against a robust C. burnetii challenge, and displayed potentially altered reactogenicity compared to NMI. Nine Mile phase II (NMII) strains of C. burnetii that produce rough LPS, were similarly tested. NMI was significantly more protective than NMII as a WCV; however, both vaccines exhibited similar reactogenicity. Collectively, our results indicate that, like phase I LPS, the T4BSS is required for full virulence by C. burnetii. Conversely, unlike phase I LPS, the T4BSS is not required for vaccine-induced protection. LPS length does not appear to contribute to reactogenicity while the T4BSS may contribute to this response. NMI ∆dot/icm represents an avirulent phase I strain with full vaccine efficacy, illustrating the potential of genetically modified C. burnetii as improved WCVs.
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Affiliation(s)
- Carrie M Long
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
| | - Paul A Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Diane C Cockrell
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Jonathan Fintzi
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Mahelat Tesfamariam
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Carl I Shaia
- Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Robert A Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
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29
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Fielden LF, Scott NE, Palmer CS, Khoo CA, Newton HJ, Stojanovski D. Proteomic Identification of Coxiella burnetii Effector Proteins Targeted to the Host Cell Mitochondria During Infection. Mol Cell Proteomics 2020; 20:100005. [PMID: 33177156 PMCID: PMC7950127 DOI: 10.1074/mcp.ra120.002370] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/11/2020] [Indexed: 11/06/2022] Open
Abstract
Modulation of the host cell is integral to the survival and replication of microbial pathogens. Several intracellular bacterial pathogens deliver bacterial proteins, termed "effector proteins" into the host cell during infection by sophisticated protein translocation systems, which manipulate cellular processes and functions. The functional contribution of individual effectors is poorly characterized, particularly in intracellular bacterial pathogens with large effector protein repertoires. Technical caveats have limited the capacity to study these proteins during a native infection, with many effector proteins having only been demonstrated to be translocated during over-expression of tagged versions. Here, we developed a novel strategy to examine effector proteins in the context of infection. We coupled a broad, unbiased proteomics-based screen with organelle purification to study the host-pathogen interactions occurring between the host cell mitochondrion and the Gram-negative, Q fever pathogen Coxiella burnetii. We identify four novel mitochondrially-targeted C. burnetii effector proteins, renamed Mitochondrial Coxiella effector protein (Mce) B to E. Examination of the subcellular localization of ectopically expressed proteins confirmed their mitochondrial localization, demonstrating the robustness of our approach. Subsequent biochemical analysis and affinity enrichment proteomics of one of these effector proteins, MceC, revealed the protein localizes to the inner membrane and can interact with components of the mitochondrial quality control machinery. Our study adapts high-sensitivity proteomics to study intracellular host-pathogen interactions, providing a robust strategy to examine the subcellular localization of effector proteins during native infection. This approach could be applied to a range of pathogens and host cell compartments to provide a rich map of effector dynamics throughout infection.
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Affiliation(s)
- Laura F Fielden
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Catherine S Palmer
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Chen Ai Khoo
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
| | - Diana Stojanovski
- Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia.
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30
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Pechstein J, Schulze-Luehrmann J, Bisle S, Cantet F, Beare PA, Ölke M, Bonazzi M, Berens C, Lührmann A. The Coxiella burnetii T4SS Effector AnkF Is Important for Intracellular Replication. Front Cell Infect Microbiol 2020; 10:559915. [PMID: 33282747 PMCID: PMC7691251 DOI: 10.3389/fcimb.2020.559915] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 10/19/2020] [Indexed: 12/20/2022] Open
Abstract
Coxiella burnetii is an obligate intracellular pathogen and the causative agent of the zoonotic disease Q fever. Following uptake by alveolar macrophages, the pathogen replicates in an acidic phagolysosomal vacuole, the C. burnetii-containing vacuole (CCV). Effector proteins translocated into the host cell by the type IV secretion system (T4SS) are important for the establishment of the CCV. Here we focus on the effector protein AnkF and its role in establishing the CCV. The C. burnetii AnkF knock out mutant invades host cells as efficiently as wild-type C. burnetii, but this mutant is hampered in its ability to replicate intracellularly, indicating that AnkF might be involved in the development of a replicative CCV. To unravel the underlying reason(s), we searched for AnkF interactors in host cells and identified vimentin through a yeast two-hybrid approach. While AnkF does not alter vimentin expression at the mRNA or protein levels, the presence of AnkF results in structural reorganization and vesicular co-localization with recombinant vimentin. Ectopically expressed AnkF partially accumulates around the established CCV and endogenous vimentin is recruited to the CCV in a time-dependent manner, suggesting that AnkF might attract vimentin to the CCV. However, knocking-down endogenous vimentin does not affect intracellular replication of C. burnetii. Other cytoskeletal components are recruited to the CCV and might compensate for the lack of vimentin. Taken together, AnkF is essential for the establishment of the replicative CCV, however, its mode of action is still elusive.
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Affiliation(s)
- Julian Pechstein
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Schulze-Luehrmann
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stephanie Bisle
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Franck Cantet
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Centre National de la Recherche Scientifique (CNRS), Université de Montpellier, Montpellier, France
| | - 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, United States
| | - Martha Ölke
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Matteo Bonazzi
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Centre National de la Recherche Scientifique (CNRS), Université de Montpellier, Montpellier, France
| | - Christian Berens
- Friedrich-Loeffler-Institut, Institut für Molekulare Pathogenese, Jena, Germany
| | - Anja Lührmann
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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31
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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: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [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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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: 6] [Impact Index Per Article: 1.5] [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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Kuba M, Neha N, Newton P, Lee YW, Bennett-Wood V, Hachani A, De Souza DP, Nijagal B, Dayalan S, Tull D, McConville MJ, Sansom FM, Newton HJ. EirA Is a Novel Protein Essential for Intracellular Replication of Coxiella burnetii. Infect Immun 2020; 88:e00913-19. [PMID: 32205404 PMCID: PMC7240097 DOI: 10.1128/iai.00913-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/18/2020] [Indexed: 02/06/2023] Open
Abstract
The zoonotic bacterial pathogen Coxiella burnetii is the causative agent of Q fever, a febrile illness which can cause a serious chronic infection. C. burnetii is a unique intracellular bacterium which replicates within host lysosome-derived vacuoles. The ability of C. burnetii to replicate within this normally hostile compartment is dependent on the activity of the Dot/Icm type 4B secretion system. In a previous study, a transposon mutagenesis screen suggested that the disruption of the gene encoding the novel protein CBU2072 rendered C. burnetii incapable of intracellular replication. This protein, subsequently named EirA (essential for intracellular replication A), is indispensable for intracellular replication and virulence, as demonstrated by infection of human cell lines and in vivo infection of Galleria mellonella The putative N-terminal signal peptide is essential for protein function but is not required for localization of EirA to the bacterial inner membrane compartment and axenic culture supernatant. In the absence of EirA, C. burnetii remains viable but nonreplicative within the host phagolysosome, as coinfection with C. burnetii expressing native EirA rescues the replicative defect in the mutant strain. In addition, while the bacterial ultrastructure appears to be intact, there is an altered metabolic profile shift in the absence of EirA, suggesting that EirA may impact overall metabolism. Most strikingly, in the absence of EirA, Dot/Icm effector translocation was inhibited even when EirA-deficient C. burnetii replicated in the wild type (WT)-supported Coxiella containing vacuoles. EirA may therefore have a novel role in the control of Dot/Icm activity and represent an important new therapeutic target.
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Affiliation(s)
- Miku Kuba
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Nitika Neha
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Patrice Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Yi Wei Lee
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Vicki Bennett-Wood
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Abderrahman Hachani
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - David P De Souza
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Brunda Nijagal
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Saravanan Dayalan
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Dedreia Tull
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Malcolm J McConville
- Metabolomics Australia, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, The Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Fiona M Sansom
- Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
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Dragan AL, Voth DE. Coxiella burnetii: international pathogen of mystery. Microbes Infect 2020; 22:100-110. [PMID: 31574310 PMCID: PMC7101257 DOI: 10.1016/j.micinf.2019.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 12/19/2022]
Abstract
Coxiella burnetii is an intracellular bacterium that causes acute and chronic Q fever. This unique pathogen has been historically challenging to study due to obstacles in genetically manipulating the organism and the inability of small animal models to fully mimic human Q fever. Here, we review the current state of C. burnetii research, highlighting new approaches that allow the mechanistic study of infection in disease relevant settings.
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Affiliation(s)
- Amanda L Dragan
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Daniel E Voth
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA.
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Samanta D, Clemente TM, Schuler BE, Gilk SD. Coxiella burnetii Type 4B Secretion System-dependent manipulation of endolysosomal maturation is required for bacterial growth. PLoS Pathog 2019; 15:e1007855. [PMID: 31869379 PMCID: PMC6953889 DOI: 10.1371/journal.ppat.1007855] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 01/10/2020] [Accepted: 12/05/2019] [Indexed: 01/24/2023] Open
Abstract
Upon host cell infection, the obligate intracellular bacterium Coxiella burnetii resides and multiplies within the Coxiella–Containing Vacuole (CCV). The nascent CCV progresses through the endosomal maturation pathway into a phagolysosome, acquiring endosomal and lysosomal markers, as well as acidic pH and active proteases and hydrolases. Approximately 24–48 hours post infection, heterotypic fusion between the CCV and host endosomes/lysosomes leads to CCV expansion and bacterial replication in the mature CCV. Initial CCV acidification is required to activate C. burnetii metabolism and the Type 4B Secretion System (T4BSS), which secretes effector proteins required for CCV maturation. However, we found that the mature CCV is less acidic (pH~5.2) than lysosomes (pH~4.8). Further, inducing CCV acidification to pH~4.8 causes C. burnetii lysis, suggesting C. burnetii actively regulates pH of the mature CCV. Because heterotypic fusion with host endosomes/lysosomes may influence CCV pH, we investigated endosomal maturation in cells infected with wildtype (WT) or T4BSS mutant (ΔdotA) C. burnetii. In WT-infected cells, we observed a significant decrease in proteolytically active, LAMP1-positive endolysosomal vesicles, compared to mock or ΔdotA-infected cells. Using a ratiometric assay to measure endosomal pH, we determined that the average pH of terminal endosomes in WT-infected cells was pH~5.8, compared to pH~4.75 in mock and ΔdotA-infected cells. While endosomes progressively acidified from the periphery (pH~5.5) to the perinuclear area (pH~4.7) in both mock and ΔdotA-infected cells, endosomes did not acidify beyond pH~5.2 in WT-infected cells. Finally, increasing lysosomal biogenesis by overexpressing the transcription factor EB resulted in smaller, more proteolytically active CCVs and a significant decrease in C. burnetii growth, indicating host lysosomes are detrimental to C. burnetii. Overall, our data suggest that C. burnetii inhibits endosomal maturation to reduce the number of proteolytically active lysosomes available for heterotypic fusion with the CCV, possibly as a mechanism to regulate CCV pH. The obligate intracellular bacterium Coxiella burnetii causes human Q fever, which manifests as a flu-like illness but can develop into a life-threatening and difficult to treat endocarditis. C. burnetii, in contrast to many other intracellular bacteria, thrives within a lysosome-like vacuole in host cells. However, we previously found that the C. burnetii vacuole is not as acidic as lysosomes and increased acidification kills the bacteria, suggesting that C. burnetii regulates the pH of its vacuole. Here, we discovered that C. burnetii blocks endolysosomal maturation and acidification during host cell infection, resulting in fewer lysosomes in the host cell. Moreover, increasing lysosomes in the host cells inhibited C. burnetii growth. Together, our study suggests that C. burnetii regulates vacuole acidity and blocks endosomal maturation in order to produce a permissive intracellular niche.
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Affiliation(s)
- Dhritiman Samanta
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Tatiana M. Clemente
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Baleigh E. Schuler
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Stacey D. Gilk
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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Cordsmeier A, Wagner N, Lührmann A, Berens C. Defying Death - How Coxiella burnetii Copes with Intentional Host Cell Suicide. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:619-628. [PMID: 31866777 PMCID: PMC6913804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The obligate intracellular pathogen Coxiella burnetii is the causative agent of the worldwide zoonotic disease Q fever. This Gram-negative bacterium infects macrophages where it establishes a replicative niche in an acidic and phagolysosome-like vacuole. Establishing and maintaining the niche requires a functional type IV secretion system (T4SS) which translocates multiple effector proteins into the host cell. These effector proteins act by manipulating diverse cellular processes allowing the bacterium to establish an infection and complete its complex biphasic developmental cycle. The lengthy nature of this life cycle suggests that C. burnetii has to successfully deal with cellular defense processes. Cell death is one mechanism infected cells frequently utilize to control or to at least minimize the impact of an infection. To date, four effector proteins have been identified in C. burnetii, which interfere with the induction of cell death. Three, AnkG, CaeA, and CaeB, affect intrinsic apoptosis, CaeA additionally extrinsic apoptosis. The proteins target different steps of the apoptotic pathway and are not conserved among isolates suggesting redundancy as an important feature of cell death inhibition. The fourth effector protein, IcaA, interferes with the non-canonical pathway of pyroptosis, an important inflammatory cell death pathway for controlling infectious disease. Autophagy is relevant for the C. burnetii life-cycle, but to which extent autophagic cell death is a factor in bacterial survival and proliferation is still not clear. To convincingly understand how bacterial manipulation of autophagy affects cell death either directly or indirectly will require further experiments. Collectively, C. burnetii modulates the extrinsic and intrinsic apoptotic pathways and non-canonical pyroptosis to inhibit host cell death, thereby providing a stable, intracellular niche for the course of the pathogen's infectious cycle.
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Affiliation(s)
- Arne Cordsmeier
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Nicole Wagner
- Institut für molekulare Pathogenese, Friedrich-Loeffler-Institut, Jena, Germany
| | - Anja Lührmann
- Mikrobiologisches Institut, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Christian Berens
- Institut für molekulare Pathogenese, Friedrich-Loeffler-Institut, Jena, Germany,To whom all correspondence should be addressed: Christian Berens, Institut für molekulare Pathogenese, Friedrich-Loeffler-Institut, Naumburger Str. 96a, 07743 Jena, Germany; Tel: +49-3641-804-2500, Fax: +49-3641-804-2482, E-mail:
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Long CM, Beare PA, Cockrell DC, Larson CL, Heinzen RA. Comparative virulence of diverse Coxiella burnetii strains. Virulence 2019; 10:133-150. [PMID: 30782062 PMCID: PMC6389282 DOI: 10.1080/21505594.2019.1575715] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 12/31/2022] Open
Abstract
Coxiella burnetii is an intracellular, gram-negative bacterium that causes the zoonosis Q fever. This disease typically presents as an acute flu-like illness with persistent, focalized infections occurring less frequently. Clinical outcomes of Q fever have been associated with distinct genomic groups of C. burnetii, suggesting that gene content is responsible for virulence potential. To investigate this hypothesis, the virulence of thirteen C. burnetii strains (representing genomic groups I-VI) was evaluated in a guinea pig infection model by intraperitoneal injection. Seven strains caused a sustained fever (at least two days ≥39.5°C) in at least half of the animals within each experimental group. At fourteen days post infection, animals were euthanized and additional endpoints were evaluated, including splenomegaly and serology. The magnitude of these endpoints roughly correlated with the onset, duration, and severity of fever. The most severe disease was caused by group I strains. Intermediate and no virulence were evidenced following infection with group II-V and group VI strains, respectively. Flow cytometric analysis of the mesenteric lymph nodes revealed decreased CD4+ T cell frequency following infection with highly virulent group I strains. These findings buttress the hypothesis that the pathogenic potential of C. burnetii strains correlates with genomic grouping. These data, combined with comparative genomics and genetic manipulation, will improve our understanding of C. burnetii virulence determinants.
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Affiliation(s)
- Carrie M Long
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 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, MT, USA
| | - Diane C Cockrell
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - 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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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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Gaiarsa S, Bitar I, Comandatore F, Corbella M, Piazza A, Scaltriti E, Villa L, Postiglione U, Marone P, Nucleo E, Pongolini S, Migliavacca R, Sassera D. Can Insertion Sequences Proliferation Influence Genomic Plasticity? Comparative Analysis of Acinetobacter baumannii Sequence Type 78, a Persistent Clone in Italian Hospitals. Front Microbiol 2019; 10:2080. [PMID: 31572316 PMCID: PMC6751323 DOI: 10.3389/fmicb.2019.02080] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/23/2019] [Indexed: 01/23/2023] Open
Abstract
Acinetobacter baumannii is a known opportunistic pathogen, dangerous for public health mostly due to its ability to rapidly acquire antibiotic-resistance traits. Its genome was described as characterized by remarkable plasticity, with a high frequency of homologous recombinations and proliferation of Insertion Sequences (IS). The SMAL pulsotype is an A. baumannii strain currently isolated only in Italy, characterized by a low incidence and a high persistence over the years. In this present work, we have conducted a comparative genomic analysis on this clone. The genome of 15 SMAL isolates was obtained and characterized in comparison with 24 other assemblies of evolutionary related isolates. The phylogeny highlighted the presence of a monophyletic clade (named ST78A), which includes the SMAL isolates. ST78A isolates have a low rate of homologous recombination and low gene content variability when compared to two related clades (ST78B and ST49) and to the most common A. baumannii variants worldwide (International Clones I and II). Remarkably, genomes in the ST78A clade present a high number of IS, including classes mostly absent in the other related genomes. Among these IS, one copy of IS66 was found to interrupt the gene comEC/rec2, involved in the acquisition of exogenous DNA. The genomic characterization of SMAL isolates shed light on the surprisingly low genomic plasticity and the high IS proliferation present in this strain. The interruption of the gene comEC/rec2 by an IS in the SMAL genomes brought us to formulate an evolutionary hypothesis according to which the proliferation of IS is slowing the acquisition of exogenous DNA, thus limiting genome plasticity. Such genomic architecture could explain the epidemiological behavior of high persistence and low incidence of the clone and provides an interesting framework to compare ST78 with the highly epidemic International Clones, characterized by high genomic plasticity.
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Affiliation(s)
- Stefano Gaiarsa
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Ibrahim Bitar
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Francesco Comandatore
- Pediatric Clinical Research Center, Dipartimento di Scienze Biomediche e Cliniche “Luigi Sacco”, Università degli Studi di Milano, Milan, Italy
| | - Marta Corbella
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Servizio di Epidemiologia Clinica e Biometria, Direzione Scientifica, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Aurora Piazza
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
- Pediatric Clinical Research Center, Dipartimento di Scienze Biomediche e Cliniche “Luigi Sacco”, Università degli Studi di Milano, Milan, Italy
| | - Erika Scaltriti
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Parma, Italy
| | - Laura Villa
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanitá, Rome, Italy
| | - Umberto Postiglione
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, Università degli Studi di Pavia, Pavia, Italy
| | - Piero Marone
- UOC Microbiologia e Virologia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Elisabetta Nucleo
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Stefano Pongolini
- Risk Analysis and Genomic Epidemiology Unit, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, Parma, Italy
| | - Roberta Migliavacca
- Dipartimento di Scienze Clinico-Chirurgiche, Diagnostiche e Pediatriche, Università degli Studi di Pavia, Pavia, Italy
| | - Davide Sassera
- Dipartimento di Biologia e Biotecnologie “L. Spallanzani”, Università degli Studi di Pavia, Pavia, Italy
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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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Lipid Droplets: A Significant but Understudied Contributor of Host⁻Bacterial Interactions. Cells 2019; 8:cells8040354. [PMID: 30991653 PMCID: PMC6523240 DOI: 10.3390/cells8040354] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 04/05/2019] [Accepted: 04/12/2019] [Indexed: 12/13/2022] Open
Abstract
Lipid droplets (LDs) are cytosolic lipid storage organelles that are important for cellular lipid metabolism, energy homeostasis, cell signaling, and inflammation. Several bacterial, viral and protozoal pathogens exploit host LDs to promote infection, thus emphasizing the importance of LDs at the host–pathogen interface. In this review, we discuss the thus far reported relation between host LDs and bacterial pathogens including obligate and facultative intracellular bacteria, and extracellular bacteria. Although there is less evidence for a LD–extracellular bacterial interaction compared to interactions with intracellular bacteria, in this review, we attempt to compare the bacterial mechanisms that target LDs, the host signaling pathways involved and the utilization of LDs by these bacteria. Many intracellular bacteria employ unique mechanisms to target host LDs and potentially obtain nutrients and lipids for vacuolar biogenesis and/or immune evasion. However, extracellular bacteria utilize LDs to either promote host tissue damage or induce host death. We also identify several areas that require further investigation. Along with identifying LD interactions with bacteria besides the ones reported, the precise mechanisms of LD targeting and how LDs benefit pathogens should be explored for the bacteria discussed in the review. Elucidating LD–bacterial interactions promises critical insight into a novel host–pathogen interaction.
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42
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Coxiella burnetii RpoS Regulates Genes Involved in Morphological Differentiation and Intracellular Growth. J Bacteriol 2019; 201:JB.00009-19. [PMID: 30745369 DOI: 10.1128/jb.00009-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 01/30/2019] [Indexed: 12/19/2022] Open
Abstract
Coxiella burnetii, the etiological agent of Q fever, undergoes a unique biphasic developmental cycle where bacteria transition from a replicating (exponential-phase) large cell variant (LCV) form to a nonreplicating (stationary-phase) small cell variant (SCV) form. The alternative sigma factor RpoS is an essential regulator of stress responses and stationary-phase physiology in several bacterial species, including Legionella pneumophila, which has a developmental cycle superficially similar to that of C. burnetii Here, we used a C. burnetii ΔrpoS mutant to define the role of RpoS in intracellular growth and SCV development. Growth yields following infection of Vero epithelial cells or THP-1 macrophage-like cells with the rpoS mutant in the SCV form, but not the LCV form, were significantly lower than that of wild-type bacteria. RNA sequencing and whole-cell mass spectrometry of the C. burnetii ΔrpoS mutant revealed that a substantial portion of the C. burnetii genome is regulated by RpoS during SCV development. Regulated genes include those involved in stress responses, arginine transport, peptidoglycan remodeling, and synthesis of the SCV-specific protein ScvA. Genes comprising the dot/icm locus, responsible for production of the Dot/Icm type 4B secretion system, were also dysregulated in the rpoS mutant. These data were corroborated with independent assays demonstrating that the C. burnetii ΔrpoS strain has increased sensitivity to hydrogen peroxide and carbenicillin and a thinner cell wall/outer membrane complex. Collectively, these results demonstrate that RpoS is an important regulator of genes involved in C. burnetii SCV development and intracellular growth.IMPORTANCE The Q fever bacterium Coxiella burnetii has spore-like environmental stability, a characteristic that contributes to its designation as a potential bioweapon. Stability is likely conferred by a highly resistant, small cell variant (SCV) stationary-phase form that arises during a biphasic developmental cycle. Here, we define the role of the alternative sigma factor RpoS in regulating genes associated with SCV development. Genes involved in stress responses, amino acid transport, cell wall remodeling, and type 4B effector secretion were dysregulated in the rpoS mutant. Cellular impairments included defects in intracellular growth, cell wall structure, and resistance to oxidants. These results support RpoS as a central regulator of the Coxiella developmental cycle and identify developmentally regulated genes involved in morphological differentiation.
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Shaw EI, Voth DE. Coxiella burnetii: A Pathogenic Intracellular Acidophile. MICROBIOLOGY (READING, ENGLAND) 2019; 165:1-3. [PMID: 30422108 PMCID: PMC6600347 DOI: 10.1099/mic.0.000707] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/25/2018] [Indexed: 11/28/2022]
Abstract
Coxiella burnetii is an obligate intracellular pathogen that causes acute and chronic Q fever. C. burnetii grows within a eukaryotic host cell in a vacuole highly similar to a phagolysosome. Found worldwide, this environmentally stable pathogen is maintained in nature via chronic infection of ruminants. Aerosol-mediated infection of humans results in infection and usurpation of alveolar macrophages through mechanisms using a bacterial Type 4B Secretion System and secreted effector proteins. Advances in axenic culture and genetic systems are changing our understanding of the pathogen's physiology and intimate molecular manipulations of host cells during infection.
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Affiliation(s)
- Edward I. Shaw
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Daniel E. Voth
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Duron O, Doublet P, Vavre F, Bouchon D. The Importance of Revisiting Legionellales Diversity. Trends Parasitol 2018; 34:1027-1037. [PMID: 30322750 DOI: 10.1016/j.pt.2018.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/19/2018] [Accepted: 09/24/2018] [Indexed: 12/15/2022]
Abstract
Bacteria of the order Legionellales, such as Legionella pneumophila, the agent of Legionnaires' disease, and Coxiella burnetii, the agent of Q fever, are widely recognized as human pathogens. While our view of the Legionellales is often limited to clinical isolates, ecological surveys are continually uncovering new members of the Legionellales that do not fall into the recognized pathogenic species. Here we emphasize that most of these Legionellales are nonpathogenic forms that have evolved symbiotic lifestyles with nonvertebrate hosts. The diversity of nonpathogenic forms remains, however, largely underexplored. We conjecture that its characterization, once contrasted with the data on pathogenic species, will reveal novel highlights on the mechanisms underlying lifestyle transitions of intracellular bacteria, including the emergence of pathogenesis and mutualism, transmission routes, and host specificity.
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Affiliation(s)
- Olivier Duron
- Laboratoire Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), Centre National de la Recherche Scientifique (CNRS) - Institut pour la Recherche et le Développement (IRD) - Université de Montpellier (UM), 911 Avenue Agropolis, F-34394 Montpellier, France.
| | - Patricia Doublet
- CIRI, Centre International de Recherche en Infectiologie, INSERM, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, École Normale Supérieure de Lyon, Université Lyon, F-69100 Villeurbanne, France
| | - Fabrice Vavre
- Univ Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive UMR5558, 43 Boulevard du 11 novembre 1918, F-69622 Villeurbanne, France
| | - Didier Bouchon
- Université de Poitiers, Laboratoire Ecologie et Biologie des Interactions - UMR CNRS 7267, F-86073 Poitiers, France
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Schrader L, Schmitz J. The impact of transposable elements in adaptive evolution. Mol Ecol 2018; 28:1537-1549. [PMID: 30003608 DOI: 10.1111/mec.14794] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/06/2018] [Indexed: 12/16/2022]
Abstract
The growing knowledge about the influence of transposable elements (TEs) on (a) long-term genome and transcriptome evolution; (b) genomic, transcriptomic and epigenetic variation within populations; and (c) patterns of somatic genetic differences in individuals continues to spur the interest of evolutionary biologists in the role of TEs in adaptive evolution. As TEs can trigger a broad range of molecular variation in a population with potentially severe fitness and phenotypic consequences for individuals, different mechanisms evolved to keep TE activity in check, allowing for a dynamic interplay between the host, its TEs and the environment in evolution. Here, we review evidence for adaptive phenotypic changes associated with TEs and the basic molecular mechanisms by which the underlying genetic changes arise: (a) domestication, (b) exaptation, (c) host gene regulation, (d) TE-mediated formation of intronless gene copies-so-called retrogenes and (e) overall increased genome plasticity. Furthermore, we review and discuss how the stress-dependent incapacitation of defence mechanisms against the activity of TEs might facilitate adaptive responses to environmental challenges and how such mechanisms might be particularly relevant in species frequently facing novel environments, such as invasive, pathogenic or parasitic species.
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Affiliation(s)
- Lukas Schrader
- Institute for Evolution and Biodiversity (IEB), University of Münster, Münster, Germany
| | - Jürgen Schmitz
- Institute of Experimental Pathology, University of Münster, Münster, Germany
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Sanchez SE, Vallejo-Esquerra E, Omsland A. Use of Axenic Culture Tools to StudyCoxiella burnetii. ACTA ACUST UNITED AC 2018; 50:e52. [DOI: 10.1002/cpmc.52] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Savannah E. Sanchez
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University; Pullman Washington
- School of Molecular Biosciences, College of Veterinary Medicine, Washington State University; Pullman Washington
| | - Eduardo Vallejo-Esquerra
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University; Pullman Washington
| | - Anders Omsland
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University; Pullman Washington
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Stead CM, Cockrell DC, Beare PA, Miller HE, Heinzen RA. A Coxiella burnetii phospholipase A homolog pldA is required for optimal growth in macrophages and developmental form lipid remodeling. BMC Microbiol 2018; 18:33. [PMID: 29661138 PMCID: PMC5902883 DOI: 10.1186/s12866-018-1181-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/09/2018] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Many gram-negative bacteria produce an outer membrane phospholipase A (PldA) that plays an important role in outer membrane function and is associated with virulence. RESULTS In the current study, we characterized a pldA mutant of Coxiella burnetii, an intracellular gram-negative pathogen and the agent of human Q fever. The C. burnetti pldA open reading frame directs synthesis of a protein with conserved PldA active site residues. A C. burnetii ΔpldA deletion mutant had a significant growth defect in THP-1 macrophages, but not axenic medium, that was rescued by complementation. Thin layer chromatography was employed to assess whether pldA plays a role in remodeling membrane lipids during C. burnetii morphological differentiation. Extracted lipids were analyzed from replicating, logarithmic phase large cell variants (LCVs), non-replicating, stationary phase small cell variants (SCVs), and a mixture of LCVs and SCVs. Similar to Escherichia coli, all three forms contained cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). However, PE and PG were present in lower quantities in the SCV while three additional lipid species were present in higher quantities. Co-migration with standards tentatively identified two of the three SCV-enriched lipids as lyso-phosphatidylethanolamine, a breakdown product of PE, and free fatty acids, which are generally toxic to bacteria. Developmental form lipid modifications required the activity of PldA. CONCLUSIONS Collectively, these results indicate developmentally-regulated lipid synthesis by C. burnetii contributes to colonization of macrophages and may contribute to the environmental stability and the distinct biological properties of the SCV.
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Affiliation(s)
- Christopher M. Stead
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana USA
- Department of Chemistry, New Mexico Highlands University, Las Vegas, New Mexico USA
| | - 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 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
| | - 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 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
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Wachter S, Raghavan R, Wachter J, Minnick MF. Identification of novel MITEs (miniature inverted-repeat transposable elements) in Coxiella burnetii: implications for protein and small RNA evolution. BMC Genomics 2018; 19:247. [PMID: 29642859 PMCID: PMC5896051 DOI: 10.1186/s12864-018-4608-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/16/2018] [Indexed: 01/05/2023] Open
Abstract
Background Coxiella burnetii is a Gram-negative gammaproteobacterium and zoonotic agent of Q fever. C. burnetii’s genome contains an abundance of pseudogenes and numerous selfish genetic elements. MITEs (miniature inverted-repeat transposable elements) are non-autonomous transposons that occur in all domains of life and are thought to be insertion sequences (ISs) that have lost their transposase function. Like most transposable elements (TEs), MITEs are thought to play an active role in evolution by altering gene function and expression through insertion and deletion activities. However, information regarding bacterial MITEs is limited. Results We describe two MITE families discovered during research on small non-coding RNAs (sRNAs) of C. burnetii. Two sRNAs, Cbsr3 and Cbsr13, were found to originate from a novel MITE family, termed QMITE1. Another sRNA, CbsR16, was found to originate from a separate and novel MITE family, termed QMITE2. Members of each family occur ~ 50 times within the strains evaluated. QMITE1 is a typical MITE of 300-400 bp with short (2-3 nt) direct repeats (DRs) of variable sequence and is often found overlapping annotated open reading frames (ORFs). Additionally, QMITE1 elements possess sigma-70 promoters and are transcriptionally active at several loci, potentially influencing expression of nearby genes. QMITE2 is smaller (150-190 bps), but has longer (7-11 nt) DRs of variable sequences and is mainly found in the 3′ untranslated region of annotated ORFs and intergenic regions. QMITE2 contains a GTAG repetitive extragenic palindrome (REP) that serves as a target for IS1111 TE insertion. Both QMITE1 and QMITE2 display inter-strain linkage and sequence conservation, suggesting that they are adaptive and existed before divergence of C. burnetii strains. Conclusions We have discovered two novel MITE families of C. burnetii. Our finding that MITEs serve as a source for sRNAs is novel. QMITE2 has a unique structure and occurs in large or small versions with unique DRs that display linkage and sequence conservation between strains, allowing for tracking of genomic rearrangements. QMITE1 and QMITE2 copies are hypothesized to influence expression of neighboring genes involved in DNA repair and virulence through transcriptional interference and ribonuclease processing. Electronic supplementary material The online version of this article (10.1186/s12864-018-4608-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shaun Wachter
- Program in Cellular, Molecular and Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Rahul Raghavan
- Biology Department and Center for Life in Extreme Environments, Portland State University, Portland, OR, USA
| | - Jenny Wachter
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th St, Hamilton, MT, USA
| | - Michael F Minnick
- Program in Cellular, Molecular and Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, MT, USA.
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Shpynov S, Tarasevich I, Skiba A, Pozdnichenko N, Gumenuk A. Comparison of genomes of Coxiella burnetii strains using formal order analysis. New Microbes New Infect 2018; 23:86-92. [PMID: 29692911 PMCID: PMC5913358 DOI: 10.1016/j.nmni.2018.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/27/2018] [Accepted: 02/06/2018] [Indexed: 12/31/2022] Open
Abstract
The Coxiella burnetii strain NL3262 was isolated during the Q fever outbreak in the Netherlands in 2007–2010. Formal-order analysis (FOA) was used to study the similarity of the genome (chromosome and plasmid) of this strain with the genomes from other strains. Chromosomes from ten C. burnetii strains and eight plasmids were studied with FOA tools such as ‘Map of genes’ and ‘Matrix of similarity.’ The ‘Map of genes’ tool showed that the chromosome of strain C. burnetii str. NL3262 distanced itself by the index of average remoteness (g) of 1.449640 (x-axis) from chromosomes of other strains (g 1.448295–1.448865). The ‘Matrix of similarity’ was used for an advanced analysis of the obtained results. The complete similarity of the components of chromosomes and plasmids was determined by pairwise comparison and the identification of nucleotides matching with them. A total of 84.90% of the chromosomal components of C. burnetii strain NL3262 coincided completely with the chromosomal components of strain Z3055. For chromosomes of other strains, this percentage varied from 12.06% to 47.14%. The plasmid of strain NL3262 had 50.0% of the components being completely coincident with the components of the plasmid of RSA 331; with RSA 493 it was 29.89%. Thus, C. burnetii str. NL3262 is the closest to str. Z3055 by the similarity of the chromosomal components, but on the index of average remoteness of the chromosome and the similarity of the plasmids' QpH1 components, it is the closest to strain RSA 331.
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Affiliation(s)
- S.N. Shpynov
- N. F. Gamaleya FRCEM, Moscow, Russia
- Corresponding author: S.N. Shpynov, 18, N.F. Gamaleya str., Moscow, 123098 Russia.
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Beare PA, Jeffrey BM, Long CM, Martens CM, Heinzen RA. Genetic mechanisms of Coxiella burnetii lipopolysaccharide phase variation. PLoS Pathog 2018; 14:e1006922. [PMID: 29481553 PMCID: PMC5843353 DOI: 10.1371/journal.ppat.1006922] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/08/2018] [Accepted: 02/05/2018] [Indexed: 12/30/2022] Open
Abstract
Coxiella burnetii is an intracellular pathogen that causes human Q fever, a disease that normally presents as a severe flu-like illness. Due to high infectivity and disease severity, the pathogen is considered a risk group 3 organism. Full-length lipopolysaccharide (LPS) is required for full virulence and disease by C. burnetii and is the only virulence factor currently defined by infection of an immunocompetent animal. Transition of virulent phase I bacteria with smooth LPS, to avirulent phase II bacteria with rough LPS, occurs during in vitro passage. Semi-rough intermediate forms are also observed. Here, the genetic basis of LPS phase conversion was investigated to obtain a more complete understanding of C. burnetii pathogenesis. Whole genome sequencing of strains producing intermediate and/or phase II LPS identified several common mutations in predicted LPS biosynthesis genes. After passage in broth culture for 30 weeks, phase I strains from different genomic groups exhibited similar phase transition kinetics and elevation of mutations in LPS biosynthesis genes. Targeted mutagenesis and genetic complementation using a new C. burnetii nutritional selection system based on lysine auxotrophy confirmed that six of the mutated genes were necessary for production of phase I LPS. Disruption of two of these genes in a C. burnetii phase I strain resulted in production of phase II LPS, suggesting inhibition of the encoded enzymes could represent a new therapeutic strategy for treatment of Q fever. Additionally, targeted mutagenesis of genes encoding LPS biosynthesis enzymes can now be used to construct new phase II strains from different genomic groups for use in pathogen-host studies at a risk group 2 level.
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Affiliation(s)
- 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
| | - Brendan M. Jeffrey
- Bioinformatics and Computational Biosciences Branch, 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
| | - Craig M. Martens
- Research Technologies Section, 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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