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Richardson EA, Roe RM, Apperson CS, Ponnusamy L. Rickettsia amblyommatis in Ticks: A Review of Distribution, Pathogenicity, and Diversity. Microorganisms 2023; 11:microorganisms11020493. [PMID: 36838458 PMCID: PMC9960904 DOI: 10.3390/microorganisms11020493] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
Rickettsia amblyommatis is a potentially pathogenic species of Rickettsia within the spotted fever group vectored by ticks. While many studies have been published on this species, there is debate over its pathogenicity and the inhibitory role it plays in diagnosing illnesses caused by other spotted fever group Rickettsia species. Many publications have recorded the high infection prevalence of R. amblyommatis in tick populations at a global scale. While this species is rather ubiquitous, questions remain over the epidemiological importance of this possible human pathogen. With tick-borne diseases on the rise, understanding the exact role that R. amblyommatis plays as a pathogen and inhibitor of infection relative to other tick-borne pathogens will help public health efforts. The goal of this review was to compile the known literature on R. amblyommatis, review what we know about its geographic distribution, tick vectors, and pathogenicity, assess relatedness between various international strains from ticks by phylogenetic analysis and draw conclusions regarding future research needed.
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Association between Growth Rate and Pathogenicity of Spotted Fever Group Rickettsia. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2022. [DOI: 10.22207/jpam.16.1.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rickettsia parkeri and Rickettsia amblyommatis are spotted fever group Rickettsia (SFGR) associated with Amblyomma ticks. R. parkeri is a recognized human pathogen that causes an eschar-associated febrile illness, while R. amblyommatis has not been confirmed as a causative agent of human disease. We hypothesized that the rate of replication is one of the factors contributing to rickettsial pathogenicity. In this study, growth and infectivity of R. parkeri and R. amblyommatis in mammalian (Vero E6) and tick-derived (ISE6) cell lines were assessed and compared over a 96-hour time course of infection using quantitative real-time polymerase chain reaction and microscopy. The pathogenic R. parkeri displayed a significantly higher level of infection in both Vero E6 and ISE6 cells than R. amblyommatis at 72 hours post-inoculation (hpi). Distinct growth profiles between rickettsial species with known and uncertain pathogenicity were identified. R. parkeri burdens were significantly greater than those of R. amblyommatis from 24 to 96 hpi. The relative fold changes of load were significantly higher in the pathogenic agent than in R. amblyommatis from 48 hpi onward and reached the maximum fold increase of ~2002- and ~296-fold in Vero E6 cells and ~1363- and ~161-fold in ISE6 cells, respectively, at 96 hpi. The results from the present study demonstrate that growth rate is associated with the pathogenicity of rickettsiae. Understanding SFGR growth characteristics in mammalian and tick cells will provide insight into rickettsial biology and pathogenesis.
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Rauch J, Barton J, Kwiatkowski M, Wunderlich M, Steffen P, Moderzynski K, Papp S, Höhn K, Schwanke H, Witt S, Richardt U, Mehlhoop U, Schlüter H, Pianka V, Fleischer B, Tappe D, Osterloh A. GroEL is an immunodominant surface-exposed antigen of Rickettsia typhi. PLoS One 2021; 16:e0253084. [PMID: 34111210 PMCID: PMC8191997 DOI: 10.1371/journal.pone.0253084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/28/2021] [Indexed: 11/26/2022] Open
Abstract
Rickettsioses are neglected and emerging potentially fatal febrile diseases that are caused by obligate intracellular bacteria, rickettsiae. Rickettsia (R.) typhi and R. prowazekii constitute the typhus group (TG) of rickettsiae and are the causative agents of endemic and epidemic typhus, respectively. We recently generated a monoclonal antibody (BNI52) against R. typhi. Characterization of BNI52 revealed that it specifically recognizes TG rickettsiae but not the members of the spotted fever group (SFG) rickettsiae. We further show that BNI52 binds to protein fragments of ±30 kDa that are exposed on the bacterial surface and also present in the periplasmic space. These protein fragments apparently derive from the cytosolic GroEL protein of R. typhi and are also recognized by antibodies in the sera from patients and infected mice. Furthermore, BNI52 opsonizes the bacteria for the uptake by antigen presenting cells (APC), indicating a contribution of GroEL-specific antibodies to protective immunity. Finally, it is interesting that the GroEL protein belongs to 32 proteins that are differentially downregulated by R. typhi after passage through immunodeficient BALB/c CB17 SCID mice. This could be a hint that the rickettsia GroEL protein may have immunomodulatory properties as shown for the homologous protein from several other bacteria, too. Overall, the results of this study provide evidence that GroEL represents an immunodominant antigen of TG rickettsiae that is recognized by the humoral immune response against these pathogens and that may be interesting as a vaccine candidate. Apart from that, the BNI52 antibody represents a new tool for specific detection of TG rickettsiae in various diagnostic and experimental setups.
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Affiliation(s)
- Jessica Rauch
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jessica Barton
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Malte Wunderlich
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Pascal Steffen
- University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Stefanie Papp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Katharina Höhn
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Hella Schwanke
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Susanne Witt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ulricke Richardt
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Ute Mehlhoop
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Verena Pianka
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | | | - Dennis Tappe
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Anke Osterloh
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Abstract
Over the last decades, rickettsioses are emerging worldwide. These diseases are caused by intracellular bacteria. Although rickettsioses can be treated with antibiotics, a vaccine against rickettsiae is highly desired for several reasons. Rickettsioses are highly prevalent, especially in poor countries, and there are indications of the development of antibiotic resistance. In addition, some rickettsiae can persist and cause recurrent disease. The development of a vaccine requires the understanding of the immune mechanisms that are involved in protection as well as in immunopathology. Knowledge about these immune responses is accumulating, and efforts have been undertaken to identify antigenic components of rickettsiae that may be useful as a vaccine. This review provides an overview on current knowledge of adaptive immunity against rickettsiae, which is essential for defense, rickettsial antigens that have been identified so far, and on vaccination strategies that have been used in animal models of rickettsial infections.
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Budachetri K, Kumar D, Karim S. Catalase is a determinant of the colonization and transovarial transmission of Rickettsia parkeri in the Gulf Coast tick Amblyomma maculatum. INSECT MOLECULAR BIOLOGY 2017; 26:414-419. [PMID: 28370634 PMCID: PMC5496812 DOI: 10.1111/imb.12304] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Gulf Coast tick (Amblyomma maculatum) has evolved as a competent vector of the spotted-fever group rickettsia, Rickettsia parkeri. In this study, the functional role of catalase, an enzyme responsible for the degradation of toxic hydrogen peroxide, in the colonization of the tick vector by R. parkeri and transovarial transmission of this pathogen to the next tick generation, was investigated. Catalase gene (CAT) expression in midgut, salivary glands and ovarian tissues exhibited a 2-11-fold increase in transcription level upon R. parkeri infection. Depletion of CAT transcripts using an RNA-interference approach significantly reduced R. parkeri infection levels in midgut and salivary gland tissues by 53-63%. The role of CAT in transovarial transmission of R. parkeri was confirmed by simultaneously blocking the transcript and the enzyme by injecting double-stranded RNA for CAT and a catalase inhibitor (3-amino-1,2,4-triazole) into gravid females. Simultaneous inhibition of the CAT transcript and the enzyme significantly reduced the egg conversion ratio with a 44% reduction of R. parkeri transovarial transmission. These data suggest that catalase is required for rickettsial colonization of the tick vector and transovarial transmission to the next generation.
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Duriez E, Armengaud J, Fenaille F, Ezan E. Mass spectrometry for the detection of bioterrorism agents: from environmental to clinical applications. JOURNAL OF MASS SPECTROMETRY : JMS 2016; 51:183-199. [PMID: 26956386 DOI: 10.1002/jms.3747] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/14/2015] [Accepted: 01/13/2016] [Indexed: 06/05/2023]
Abstract
In the current context of international conflicts and localized terrorist actions, there is unfortunately a permanent threat of attacks with unconventional warfare agents. Among these, biological agents such as toxins, microorganisms, and viruses deserve particular attention owing to their ease of production and dissemination. Mass spectrometry (MS)-based techniques for the detection and quantification of biological agents have a decisive role to play for countermeasures in a scenario of biological attacks. The application of MS to every field of both organic and macromolecular species has in recent years been revolutionized by the development of soft ionization techniques (MALDI and ESI), and by the continuous development of MS technologies (high resolution, accurate mass HR/AM instruments, novel analyzers, hybrid configurations). New possibilities have emerged for exquisite specific and sensitive detection of biological warfare agents. MS-based strategies for clinical application can now address a wide range of analytical questions mainly including issues related to the complexity of biological samples and their available volume. Multiplexed toxin detection, discovery of new markers through omics approaches, and identification of untargeted microbiological or of novel molecular targets are examples of applications. In this paper, we will present these technological advances along with the novel perspectives offered by omics approaches to clinical detection and follow-up.
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Affiliation(s)
| | - Jean Armengaud
- CEA, iBiTec-S, Service de Pharmacologie et d'Immunologie, 30207, Bagnols sur-Cèze, France
| | - François Fenaille
- CEA, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, Laboratoire d'Etude du Métabolisme des Médicaments, MetaboHUB-Paris, CEA Saclay, Building 136, 91191, Gif-sur-Yvette cedex, France
| | - Eric Ezan
- CEA, Programme Transversal Technologies pour la Santé, 91191, Gif sur Yvette, France
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