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Kneubehl AR, Lopez JE. Comparative genomics analysis of three conserved plasmid families in the Western Hemisphere soft tick-borne relapsing fever borreliae provides insight into variation in genome structure and antigenic variation systems. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531354. [PMID: 36945547 PMCID: PMC10028826 DOI: 10.1101/2023.03.06.531354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Borrelia spirochetes, causative agents of Lyme disease and relapsing fever (RF), have a uniquely complex genome consisting of a linear chromosome and circular and linear plasmids. The plasmids harbor genes important for the vector-host life cycle of these tick-borne bacteria. The role of Lyme disease causing Borrelia plasmids is more refined compared to RF spirochetes because of limited plasmid-resolved genomes for RF spirochetes. We recently addressed this limitation and found that three linear plasmid families (F6, F27, and F28) were syntenic across all species. Given this conservation, we further investigated the three plasmid families. The F6 family, also known as the megaplasmid, contained regions of repetitive DNA. The F27 was the smallest, encoding genes with unknown function. The F28 family encoded the expression locus for antigenic variation in all species except Borrelia hermsii and Borrelia anserina. Taken together, this work provides a foundation for future investigations to identify essential plasmid-localized genes that drive the vector-host life cycle of RF Borrelia . IMPORTANCE Borrelia spp. spirochetes are arthropod-borne bacteria found globally and infect humans and other vertebrates. RF borreliae are understudied and misdiagnosed pathogens because of the vague clinical presentation of disease and the elusive feeding behavior of argasid ticks. Consequently, genomics resources for RF spirochetes have been limited. Analyses of Borrelia plasmids have been challenging because they are often highly fragmented and unassembled. By utilizing Oxford Nanopore Technologies, we recently generated plasmid-resolved genomes for seven Borrelia spp. found in the Western Hemisphere. This current study is a more in-depth investigation into the linear plasmids that were conserved and syntenic across species. This analysis determined differences in genome structure and, importantly, in antigenic variation systems between species. This work is an important step in identifying crucial plasmid-borne genetic elements essential for the life cycle of RF spirochetes.
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Affiliation(s)
| | - Job E. Lopez
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
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Abstract
The genus Borrelia consists of evolutionarily and genetically diverse bacterial species that cause a variety of diseases in humans and domestic animals. These vector-borne spirochetes can be classified into two major evolutionary groups, the Lyme borreliosis clade and the relapsing fever clade, both of which have complex transmission cycles during which they interact with multiple host species and arthropod vectors. Molecular, ecological, and evolutionary studies have each provided significant contributions towards our understanding of the natural history, biology and evolutionary genetics of Borrelia species; however, integration of these studies is required to identify the evolutionary causes and consequences of the genetic variation within and among Borrelia species. For example, molecular and genetic studies have identified the adaptations that maximize fitness components throughout the Borrelia lifecycle and enhance transmission efficacy but provide limited insights into the evolutionary pressures that have produced them. Ecological studies can identify interactions between Borrelia species and the vertebrate hosts and arthropod vectors they encounter and the resulting impact on the geographic distribution and abundance of spirochetes but not the genetic or molecular basis underlying these interactions. In this review we discuss recent findings on the evolutionary genetics from both of the evolutionarily distinct clades of Borrelia species. We focus on connecting molecular interactions to the ecological processes that have driven the evolution and diversification of Borrelia species in order to understand the current distribution of genetic and molecular variation within and between Borrelia species.
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Affiliation(s)
- Zachary J. Oppler
- Department of Biology, University of Pennsylvania, 433 South University Ave, Philadelphia, PA 19104, USA
| | - Kayleigh R. O’Keeffe
- Department of Biology, University of Pennsylvania, 433 South University Ave, Philadelphia, PA 19104, USA
| | - Karen D. McCoy
- Centre for Research on the Ecology and Evolution of Diseases (CREES), MiVEGEC, University of Montpellier – CNRS - IRD, Montpellier, France
| | - Dustin Brisson
- Department of Biology, University of Pennsylvania, 433 South University Ave, Philadelphia, PA 19104, USA
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Talagrand-Reboul E, Boyer PH, Bergström S, Vial L, Boulanger N. Relapsing Fevers: Neglected Tick-Borne Diseases. Front Cell Infect Microbiol 2018; 8:98. [PMID: 29670860 PMCID: PMC5893795 DOI: 10.3389/fcimb.2018.00098] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/16/2018] [Indexed: 11/13/2022] Open
Abstract
Relapsing fever still remains a neglected disease and little is known on its reservoir, tick vector and physiopathology in the vertebrate host. The disease occurs in temperate as well as tropical countries. Relapsing fever borreliae are spirochaetes, members of the Borreliaceae family which also contain Lyme disease spirochaetes. They are mainly transmitted by Ornithodoros soft ticks, but some species are vectored by ixodid ticks. Traditionally a Borrelia species is associated with a specific vector in a particular geographical area. However, new species are regularly described, and taxonomical uncertainties deserve further investigations to better understand Borrelia vector/host adaptation. The medical importance of Borrelia miyamotoi, transmitted by Ixodes spp., has recently spawned new interest in this bacterial group. In this review, recent data on tick-host-pathogen interactions for tick-borne relapsing fevers is presented, with special focus on B. miyamotoi.
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Affiliation(s)
- Emilie Talagrand-Reboul
- Early Bacterial Virulence: Borrelia Group, Université de Strasbourg, Facultés de Médecine et de Pharmacie, CHRU Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, VBB EA 7290, Strasbourg, France
| | - Pierre H. Boyer
- Early Bacterial Virulence: Borrelia Group, Université de Strasbourg, Facultés de Médecine et de Pharmacie, CHRU Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, VBB EA 7290, Strasbourg, France
| | - Sven Bergström
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Laurence Vial
- CIRAD BIOS, UMR15 CIRAD/Institut National de la Recherche Agronomique “Contrôle des Maladies Animales Exotiques et Emergentes,” Equipe “Vecteurs,” Campus International de Baillarguet, Montpellier, France
| | - Nathalie Boulanger
- Early Bacterial Virulence: Borrelia Group, Université de Strasbourg, Facultés de Médecine et de Pharmacie, CHRU Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, VBB EA 7290, Strasbourg, France
- Centre National de Référence Borrelia, Centre Hospitalier Universitaire, Strasbourg, France
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Johnson TL, Fischer RJ, Raffel SJ, Schwan TG. Host associations and genomic diversity of Borrelia hermsii in an endemic focus of tick-borne relapsing fever in western North America. Parasit Vectors 2016; 9:575. [PMID: 27832805 PMCID: PMC5105259 DOI: 10.1186/s13071-016-1863-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/31/2016] [Indexed: 11/30/2022] Open
Abstract
Background An unrecognized focus of tick-borne relapsing fever caused by Borrelia hermsii was identified in 2002 when five people became infected on Wild Horse Island in Flathead Lake, Montana. The terrestrial small mammal community on the island is composed primarily of pine squirrels (Tamiasciurus hudsonicus) and deer mice (Peromyscus maniculatus), neither of which was known as a natural host for the spirochete. Thus a 3-year study was performed to identify small mammals as hosts for B. hermsii. Methods Small mammals were captured alive on two island and three mainland sites, blood samples were collected and examined for spirochetes, and serological tests performed to detect anti-B. hermsii antibodies. Ornithodoros hermsi ticks were collected and fed on laboratory mice to assess infection. Genomic DNA samples from spirochetes isolated from infected mammals and ticks were analyzed by multilocus sequence typing. Results Eighteen pine squirrels and one deer mouse had detectable spirochetemias when captured, from which 12 isolates of B. hermsii were established. Most pine squirrels were seropositive, and the five species of sciurids combined had a significantly higher prevalence of seropositive animals than did the other six small mammal species captured. The greater diversity of small mammals on the mainland in contrast to the islands demonstrated that other species in addition to pine squirrels were also involved in the maintenance of B. hermsii at Flathead Lake. Ornithodoros hermsi ticks produced an additional 12 isolates of B. hermsii and multilocus sequence typing identified both genomic groups of B. hermsii described previously, and identified a new genomic subdivision. Experimental infections of deer mice with two strains of B. hermsii demonstrated that these animals were susceptible to infection with spirochetes belonging to Genomic Group II but not Genomic Group I. Conclusions Pine squirrels are the primary hosts for the maintenance of B. hermsii on the islands in Flathead Lake, however serological evidence showed that numerous additional species are also involved on the mainland. Future studies testing the susceptibility of several small mammal species to infection with different genetic types of B. hermsii will help define their role as hosts in this and other endemic foci.
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Affiliation(s)
- Tammi L Johnson
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.,Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Robert J Fischer
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.,Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Sandra J Raffel
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Tom G Schwan
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
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Crowder CD, Ghalyanchi Langeroudi A, Shojaee Estabragh A, Lewis ERG, Marcsisin RA, Barbour AG. Pathogen and Host Response Dynamics in a Mouse Model of Borrelia hermsii Relapsing Fever. Vet Sci 2016; 3:vetsci3030019. [PMID: 29056727 PMCID: PMC5606581 DOI: 10.3390/vetsci3030019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/23/2016] [Accepted: 08/24/2016] [Indexed: 11/23/2022] Open
Abstract
Most Borrelia species that cause tick-borne relapsing fever utilize rodents as their natural reservoirs, and for decades laboratory-bred rodents have served as informative experimental models for the disease. However, while there has much progress in understanding the pathogenetic mechanisms, including antigenic variation, of the pathogen, the host side of the equation has been neglected. Using different approaches, we studied, in immunocompetent inbred mice, the dynamics of infection with and host responses to North American relapsing fever agent B. hermsii. The spirochete’s generation time in blood of infected mice was between 4–5 h and, after a delay, was matched in rate by the increase of specific agglutinating antibodies in response to the infection. After initiating serotype cells were cleared by antibodies, the surviving spirochetes were a different serotype and, as a population, grew more slowly. The retardation was attributable to the host response and not an inherently slower growth rate. The innate responses at infection peak and immediate aftermath were characterized by elevations of both pro-inflammatory and anti-inflammatory cytokines and chemokines. Immunodeficient mice had higher spirochete burdens and severe anemia, which was accounted for by aggregation of erythrocytes by spirochetes and their partially reversible sequestration in greatly enlarged spleens and elsewhere.
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Affiliation(s)
- Christopher D Crowder
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Arash Ghalyanchi Langeroudi
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Azadeh Shojaee Estabragh
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Eric R G Lewis
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Renee A Marcsisin
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
| | - Alan G Barbour
- Departments of Microbiology & Molecular Genetics and Medicine, University of California Irvine, Irvine, CA 92697, USA.
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Marcsisin RA, Lewis ERG, Barbour AG. Correction: Expression of the Tick-Associated Vtp Protein of Borrelia hermsii in a Murine Model of Relapsing Fever. PLoS One 2016; 11:e0153906. [PMID: 27074024 PMCID: PMC4830521 DOI: 10.1371/journal.pone.0153906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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