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Guccione C, Colomba C, Iaria C, Cascio A. Rickettsiales in the WHO European Region: an update from a One Health perspective. Parasit Vectors 2023; 16:41. [PMID: 36717936 PMCID: PMC9885594 DOI: 10.1186/s13071-022-05646-4] [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] [Received: 10/11/2022] [Accepted: 12/29/2022] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The availability of molecular techniques has significantly increased our understanding of bacteria of the order Rickettsiales, allowing the identification of distinct species in both vector and host arthropods. However, the literature lacks studies that comprehensively summarize the vast amount of knowledge generated on this topic in recent years. The purpose of this study was to conduct a comprehensive analysis of the distribution of Rickettsiales in arthropod vectors, animals and humans in the WHO European Region in order to provide useful information to predict the emergence of certain diseases in specific geographical areas and to formulate hypotheses regarding the possible pathogenetic role of some rickettsial species in the etiology of human pathological conditions. METHODS A systematic review of the literature in the PubMed and EMBASE databases was conducted following the PRISMA methodology using the search terms "Spotted fever" OR "rickettsiosis" OR "ricketts*" AND all the countries of the WHO European Region, from 1 January 2013 to 12 February 2022. Only studies that identified rickettsiae in human, animal or arthropod samples using molecular techniques were included in the review. RESULTS A total of 467 articles considering 61 different species of Rickettsiales with confirmed or suspected human pathogenicity were analyzed in the review. More than 566 identifications of Rickettsiales DNA in human samples were described, of which 89 cases were assessed as importation cases. A total of 55 species of ticks, 17 species of fleas, 10 species of mite and four species of lice were found infected. Twenty-three species of Rickettsiales were detected in wild and domestic animal samples. CONCLUSION The routine use of molecular methods to search for Rickettsiales DNA in questing ticks and other blood-sucking arthropods that commonly bite humans should be encouraged. Molecular methods specific for Rickettsiales should be used routinely in the diagnostics of fever of unknown origin and in all cases of human diseases secondary to an arthropod bite or animal contact.
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Affiliation(s)
- Cristoforo Guccione
- grid.10776.370000 0004 1762 5517Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90127 Palermo, Italy
| | - Claudia Colomba
- grid.10776.370000 0004 1762 5517Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90127 Palermo, Italy ,grid.419995.9Pediatric Infectious Disease Unit, ARNAS Civico-Di Cristina-Benfratelli Hospital, 90127 Palermo, Italy
| | - Chiara Iaria
- grid.419995.9Infectious Disease Unit, ARNAS Civico-Di Cristina-Benfratelli Hospital, 90127 Palermo, Italy
| | - Antonio Cascio
- grid.10776.370000 0004 1762 5517Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties, University of Palermo, 90127 Palermo, Italy ,Infectious and Tropical Disease Unit, AOU Policlinico “P. Giaccone”, 90127 Palermo, Italy
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Banajee KH, Verhoeve VI, Harris EK, Macaluso KR. Effect of Amblyomma maculatum (Acari: Ixodidae) Saliva on the Acute Cutaneous Immune Response to Rickettsia parkeri Infection in a Murine Model. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:1252-1260. [PMID: 27521760 PMCID: PMC5106825 DOI: 10.1093/jme/tjw125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/15/2016] [Indexed: 05/31/2023]
Abstract
Rickettsia parkeri Luckman (Rickettsiales: Rickettsiaceae) is a pathogenic spotted fever group Rickettsia transmitted by Amblyomma maculatum Koch (Acari: Ixodidae) in the United States. The acute innate immune response to this pathogen and the effect of tick feeding or salivary components on this response is largely unknown. We hypothesized that A. maculatum saliva enhances R. parkeri infection via downregulation of the acute cellular and cytokine immune response. C3H/HeN mice were intradermally inoculated with R. parkeri both with and without A. maculatum saliva. Flow cytometry and microscopic evaluation of inoculation site skin suspensions revealed that neutrophils and macrophages predominated at 6 and 24 h post R. parkeri inoculation, respectively. This cellular influx was significantly downregulated when A. maculatum saliva was inoculated along with R. parkeri Inflammatory cytokines (interferon γ and interleukins 6 and 10) were significantly elevated after R. parkeri inoculation. However, cytokine concentration and rickettsial load were not significantly modified by A. maculatum saliva during the acute phase of infection. These results revealed that tick saliva inhibits the cutaneous cellular influx during the acute phase of rickettsial infection. Further study is needed to determine the overall impact of this effect on the establishment of rickettsiosis in the host and development of disease.
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Affiliation(s)
- K H Banajee
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803 (; ; ; )
| | - V I Verhoeve
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803 (; ; ; )
| | - E K Harris
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803 (; ; ; )
| | - K R Macaluso
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803 (; ; ; )
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Banajee KH, Embers ME, Langohr IM, Doyle LA, Hasenkampf NR, Macaluso KR. Amblyomma maculatum Feeding Augments Rickettsia parkeri Infection in a Rhesus Macaque Model: A Pilot Study. PLoS One 2015; 10:e0135175. [PMID: 26244337 PMCID: PMC4526656 DOI: 10.1371/journal.pone.0135175] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 07/17/2015] [Indexed: 11/19/2022] Open
Abstract
Rickettsia parkeri is an emerging eschar-causing human pathogen in the spotted fever group of Rickettsia and is transmitted by the Gulf coast tick, Amblyomma maculatum. Tick saliva has been shown to alter both the cellular and humoral components of the innate and adaptive immune systems. However, the effect of this immunomodulation on Rickettsia transmission and pathology in an immunocompetent vertebrate host has not been fully examined. We hypothesize that, by modifying the host immune response, tick feeding enhances infection and pathology of pathogenic spotted fever group Rickettsia sp. In order to assess this interaction in vivo, a pilot study was conducted using five rhesus macaques that were divided into three groups. One group was intradermally inoculated with low passage R. parkeri (Portsmouth strain) alone (n = 2) and another group was inoculated during infestation by adult, R. parkeri-free A. maculatum (n = 2). The final macaque was infested with ticks alone (tick feeding control group). Blood, lymph node and skin biopsies were collected at several time points post-inoculation/infestation to assess pathology and quantify rickettsial DNA. As opposed to the tick-only animal, all Rickettsia-inoculated macaques developed inflammatory leukograms, elevated C-reactive protein concentrations, and elevated TH1 (interferon-γ, interleukin-15) and acute phase inflammatory cytokines (interleukin-6) post-inoculation, with greater neutrophilia and interleukin-6 concentrations in the tick plus R. parkeri group. While eschars formed at all R. parkeri inoculation sites, larger and slower healing eschars were observed in the tick feeding plus R. parkeri group. Furthermore, dissemination of R. parkeri to draining lymph nodes early in infection and increased persistence at the inoculation site were observed in the tick plus R. parkeri group. This study indicates that rhesus macaques can be used to model R. parkeri rickettsiosis, and suggests that immunomodulatory factors introduced during tick feeding may enhance the pathogenicity of spotted fever group Rickettsia.
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Affiliation(s)
- Kaikhushroo H. Banajee
- Vector-borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Monica E. Embers
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University Health Sciences, Covington, Louisiana, United States of America
| | - Ingeborg M. Langohr
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Lara A. Doyle
- Division of Veterinary Medicine, Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana, United States of America
| | - Nicole R. Hasenkampf
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University Health Sciences, Covington, Louisiana, United States of America
| | - Kevin R. Macaluso
- Vector-borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
- * E-mail:
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Sahni SK, Narra HP, Sahni A, Walker DH. Recent molecular insights into rickettsial pathogenesis and immunity. Future Microbiol 2014; 8:1265-88. [PMID: 24059918 DOI: 10.2217/fmb.13.102] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human infections with arthropod-borne Rickettsia species remain a major global health issue, causing significant morbidity and mortality. Epidemic typhus due to Rickettsia prowazekii has an established reputation as the 'scourge of armies', and as a major determinant of significant 'historical turning points'. No suitable vaccines for human use are currently available to prevent rickettsial diseases. The unique lifestyle features of rickettsiae include obligate intracellular parasitism, intracytoplasmic niche within the host cell, predilection for infection of microvascular endothelium in mammalian hosts, association with arthropods and the tendency for genomic reduction. The fundamental research in the field of Rickettsiology has witnessed significant recent progress in the areas of pathogen adhesion/invasion and host immune responses, as well as the genomics, proteomics, metabolomics, phylogenetics, motility and molecular manipulation of important rickettsial pathogens. The focus of this review article is to capture a snapshot of the latest developments pertaining to the mechanisms of rickettsial pathogenesis and immunity.
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Affiliation(s)
- Sanjeev K Sahni
- Department of Pathology & Institute for Human Infections & Immunity, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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Raoult D. Sound and Fury, Clarified. Science 2012; 336:152, 155; author reply 155. [DOI: 10.1126/science.336.6078.152-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Didier Raoult
- Rickettsies Research Unit, University of Medicine, Marseille, 13005, France
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Abstract
Rickettsia parkeri, a member of the spotted fever group Rickettsia, is the causative agent of American boutonneuse fever in humans. Despite the increased recognition of human cases, limited information is available regarding the infection of invertebrate and vertebrate hosts for this emerging tick-borne disease. Toward the development of a viable transmission model and to further characterize the pathology associated with R. parkeri infection, inbred mouse strains (A/J, BALB/c, C3H/HeJ, and C3H/HeN) were intravenously and intradermally inoculated with 10(5) low-passage-number R. parkeri (Portsmouth strain), and infection, gross pathology, and histopathology were scored. Additionally, a quantitative real-time PCR (qPCR) was performed to estimate rickettsial load in heart, lung, spleen, and liver tissues of infected mice at 19 days postinoculation. Of the A/J, BALB/c, and C3H/HeN mice, none displayed universal pathology consistent with sustained infection. Compared to age-matched control mice, the intravenously inoculated C3H/HeJ mice exhibited marked facial edema and marked splenomegaly upon gross examination, while the intradermally inoculated mice developed characteristic eschar-like lesions. The C3H/HeJ mice also exhibited the greatest concentrations of rickettsial DNA from heart, lung, liver, and spleen samples when examined by qPCR. The similarity of the pathology of human disease and sustained infection suggests that the C3H/HeJ strain of mice is a promising candidate for subsequent experiments to examine the tick transmission, dissemination, and pathology of R. parkeri rickettsiosis.
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Duan C, Meng Y, Wang X, Xiong X, Wen B. Exploratory study on pathogenesis of far-eastern spotted fever. Am J Trop Med Hyg 2011; 85:504-9. [PMID: 21896812 DOI: 10.4269/ajtmh.2011.10-0660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Far-eastern spotted fever is an emerging disease caused by Rickettsia heilongjiangensis, a tick-borne obligate intracellular bacterium. In this study, R. heilongjiangensis was used to infect BALB/c mice by inoculation of retro-orbital venous plexus to imitate a blood infection caused by tick biting. We found that R. heilongjiangensis rapidly entered the circulation for systemic dissemination and the pathogen existed in liver, spleen, lungs, and brain of the mice at least 9 days post-infection (p.i.). Severe pathological lesions were observed in liver, lungs, and brain at Day 6 p.i. In addition, the elevated levels of inflammatory cytokines, including interferon-γ, tumor necrosis factor, and CC chemokine, were detected in the infected organs at Day 3 p.i. Our results reveal that R. heilongjiangensis may cause an infection in BALB/c mice and the pathological lesions in the infected mice are associated with host inflammatory response induced by R. heilongjiangensis.
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Affiliation(s)
- Changsong Duan
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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Host, pathogen and treatment-related prognostic factors in rickettsioses. Eur J Clin Microbiol Infect Dis 2011; 30:1139-50. [PMID: 21519943 DOI: 10.1007/s10096-011-1208-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 02/28/2011] [Indexed: 10/18/2022]
Abstract
Diseases caused by rickettsiae, which are vector-borne bacteria, vary widely from mild and self-limiting, to severe and life-threatening. Factors influencing this diversity of outcome are related to the host, to the infectious agent and to the treatment used to treat the infection. A literature search was conducted on PubMed using the phrases "factors-related severity, outcome, host, pathogen, Rickettsia conorii, R. rickettsii, R. africae, R. felis, R. prowazekii, R. typhi, genomics". Among host factors, old age and the male gender have been associated with poor outcome in rickettsioses. Co-morbidities, ethnical factors and the genetic background of the host also seem to influence the outcome of rickettsial diseases. Moreover, although the degree of the host response is beneficial, it could also partly explain the severity observed in some patients. Among pathogen-related factors, traditional concepts of factors of virulence had been challenged and genomic reductive evolution with loss of regulatory genes is the main hypothesis to explain virulence observed in some species, such as Rickettsia prowazekii, the agent of epidemic typhus. R. prowazekii is the more pathogenic rickettsiae and harbours the smaller genome size (1.1 Mb) compared to less or non-virulent species, and is not intracellularly motile, a factor considered as a virulence factor for other intracellular bacteria. The antibiotic regimen used to treat rickettsioses also has an influence on prognosis. Usual concepts of severity and virulence in rickettsioses are challenging and are frequently paradoxical. In this mini-review, we will describe factors currently thought to influence the outcome of the main rickettsioses responsible for illness in humans.
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Bechah Y, Socolovschi C, Raoult D. Identification of rickettsial infections by using cutaneous swab specimens and PCR. Emerg Infect Dis 2011; 17:83-6. [PMID: 21192860 PMCID: PMC3375762 DOI: 10.3201/eid1701.100854] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To determine the usefulness of noninvasive cutaneous swab specimens for detecting rickettsiae, we tested skin eschars from 6 guinea pigs and from 9 humans. Specimens from eschars in guinea pigs were positive for rickettsiae as long as lesions were present. Optimal storage temperature for specimens was 4 degrees C for 3 days.
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Bechah Y, El Karkouri K, Mediannikov O, Leroy Q, Pelletier N, Robert C, Médigue C, Mege JL, Raoult D. Genomic, proteomic, and transcriptomic analysis of virulent and avirulent Rickettsia prowazekii reveals its adaptive mutation capabilities. Genome Res 2010; 20:655-63. [PMID: 20368341 PMCID: PMC2860167 DOI: 10.1101/gr.103564.109] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Accepted: 02/11/2010] [Indexed: 11/24/2022]
Abstract
Rickettsia prowazekii, the agent of epidemic typhus, is an obligate intracellular bacterium that is transmitted to human beings by the body louse. Several strains that differ considerably in virulence are recognized, but the genetic basis for these variations has remained unknown since the initial description of the avirulent vaccine strain nearly 70 yr ago. We use a recently developed murine model of epidemic typhus and transcriptomic, proteomic, and genetic techniques to identify the factors associated with virulence. We identified four phenotypes of R. prowazekii that differed in virulence, associated with the up-regulation of antiapoptotic genes or the interferon I pathway in the host cells. Transcriptional and proteomic analyses of R. prowazekii surface protein expression and protein methylation varied with virulence. By sequencing a virulent strain and using comparative genomics, we found hotspots of mutations in homopolymeric tracts of poly(A) and poly(T) in eight genes in an avirulent strain that split and inactivated these genes. These included recO, putative methyltransferase, and exported protein. Passage of the avirulent Madrid E strain in cells or in experimental animals was associated with a cascade of gene reactivations, beginning with recO, that restored the virulent phenotype. An area of genomic plasticity appears to determine virulence in R. prowazekii and represents an example of adaptive mutation for this pathogen.
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Affiliation(s)
- Yassina Bechah
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Khalid El Karkouri
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Oleg Mediannikov
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Quentin Leroy
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Nicolas Pelletier
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Catherine Robert
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Claudine Médigue
- Genoscope, Centre National de Séquençage, Laboratoire de Génomique Comparative, 91057 Evry cedex, France
| | - Jean-Louis Mege
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
| | - Didier Raoult
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), Centre National de la Recherche Scientifique–Institut de Recherche pour le Développement, Faculty of Medicine, University of the Mediterranean, 13005 Marseille, France
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Bechah Y, Paddock CD, Capo C, Mege JL, Raoult D. Adipose tissue serves as a reservoir for recrudescent Rickettsia prowazekii infection in a mouse model. PLoS One 2010; 5:e8547. [PMID: 20049326 PMCID: PMC2797295 DOI: 10.1371/journal.pone.0008547] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 12/09/2009] [Indexed: 11/18/2022] Open
Abstract
Brill-Zinsser disease, the relapsing form of epidemic typhus, typically occurs in a susceptible host years or decades after the primary infection; however, the mechanisms of reactivation and the cellular reservoir during latency are poorly understood. Herein we describe a murine model for Brill-Zinsser disease, and use PCR and cell culture to show transient rickettsemia in mice treated with dexamethasone >3 months after clinical recovery from the primary infection. Treatment of similarly infected mice with cyclosporine failed to produce recrudescent bacteremia. Therapy with doxycycline for the primary infection prevented recrudescent bacteremia in most of these mice following treatment with dexamethasone. Rickettsia prowazekii (the etiologic agent of epidemic typhus) was detected by PCR, cell culture, and immunostaining methods in murine adipose tissue, but not in liver, spleen, lung, or central nervous system tissues of mice 4 months after recovery from the primary infection. The lungs of dexamethasone-treated mice showed impaired expression of beta-defensin transcripts that may be involved in the pathogenesis of pulmonary lesions. In vitro, R. prowazekii rickettsiae infected and replicated in the murine adipocyte cell line 3T3-L1. Collectively these data suggest a role for adipose tissue as a potential reservoir for dormant infections with R. prowazekii.
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Affiliation(s)
- Yassina Bechah
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), CNRS-IRD UMR 6236, Faculty of Medicine, University of the Mediterranean, Marseille, France
| | - Christopher D. Paddock
- Infectious Diseases Pathology Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Christian Capo
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), CNRS-IRD UMR 6236, Faculty of Medicine, University of the Mediterranean, Marseille, France
| | - Jean-Louis Mege
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), CNRS-IRD UMR 6236, Faculty of Medicine, University of the Mediterranean, Marseille, France
| | - Didier Raoult
- Unit for Research on Emergent and Tropical Infectious Diseases (URMITE), CNRS-IRD UMR 6236, Faculty of Medicine, University of the Mediterranean, Marseille, France
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La Scola B, Bechah Y, Lepidi H, Raoult D. Prediction of rickettsial skin eschars in humans using an experimental guinea pig model. Microb Pathog 2009; 47:128-33. [DOI: 10.1016/j.micpath.2009.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 06/03/2009] [Accepted: 06/05/2009] [Indexed: 01/30/2023]
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Sahni SK, Rydkina E. Host-cell interactions with pathogenic Rickettsia species. Future Microbiol 2009; 4:323-39. [PMID: 19327117 DOI: 10.2217/fmb.09.6] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Pathogenic Rickettsia species are Gram-negative, obligate intracellular bacteria responsible for the spotted fever and typhus groups of diseases around the world. It is now well established that a majority of sequelae associated with human rickettsioses are the outcome of the pathogen's affinity for endothelium lining the blood vessels, the consequences of which are vascular inflammation, insult to vascular integrity and compromised vascular permeability, collectively termed 'Rickettsial vasculitis'. Signaling mechanisms leading to transcriptional activation of target cells in response to Rickettsial adhesion and/or invasion, differential activation of host-cell signaling due to infection with spotted fever versus typhus subgroups of Rickettsiae, and their contributions to the host's immune responses and determination of cell fate are the major subtopics of this review. Also included is a succinct analysis of established in vivo models and their use for understanding Rickettsial interactions with host cells and pathogenesis of vasculotropic rickettsioses. Continued progress in these important but relatively under-explored areas of bacterial pathogenesis research should further highlight unique aspects of Rickettsial interactions with host cells, elucidate the biological basis of endothelial tropism and reveal novel chemotherapeutic and vaccination strategies for debilitating Rickettsial diseases.
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Affiliation(s)
- Sanjeev K Sahni
- Department of Microbiology & Immunology, University of Rochester School of Medicine & Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Botelho-Nevers E, Rolain JM, Espinosa L, Raoult D. Statins limit Rickettsia conorii infection in cells. Int J Antimicrob Agents 2008; 32:344-8. [PMID: 18703317 DOI: 10.1016/j.ijantimicag.2008.04.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Accepted: 04/28/2008] [Indexed: 11/28/2022]
Abstract
Recent data suggest that statins may have a beneficial effect during sepsis. In this study, we tested the effect of lovastatin and pravastatin on the cellular culture of Rickettsia conorii using a quantitative plaque assay model associated with an original image analysis algorithm. Statins added at the time of infection did not modify plaque formation, whereas pre-incubation with statins for 48h resulted in a significant 30-68% plaque reduction, depending on the tested compounds and doses. These preliminary findings raise the hypothesis that statins may prevent or moderate rickettsial disease in exposed people.
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Affiliation(s)
- E Botelho-Nevers
- Unité des Rickettsies, URMITE CNRS UMR 6236, IRD 198, Marseille, France
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Bechah Y, Capo C, Mege JL, Raoult D. Rickettsial diseases: from Rickettsia-arthropod relationships to pathophysiology and animal models. Future Microbiol 2008; 3:223-36. [PMID: 18366341 DOI: 10.2217/17460913.3.2.223] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rickettsiae cause spotted fevers and typhus-related diseases in humans. Some of these diseases occur worldwide and are life-threatening, for example, epidemic typhus is still a major health problem despite the apparent efficiency of antibiotic treatment. In addition, Rickettsia prowazekii, the agent of epidemic typhus, and R. rickettsii, the agent of Rocky Mountain spotted fever, are microorganisms that could potentially be used as bioweapons to induce panic in the population. Rickettsiae are obligate intracellular bacteria in both vertebrate and invertebrate hosts, but rickettsial species differ in terms of association with arthropods, behavior of the vector to infection, pathophysiology and outcome of the disease. Understanding the pathogenic steps of rickettsioses is essential to develop protective strategies against these bacteriological threats. Unfortunately, the mechanisms involved in the pathogenesis of many rickettsioses are poorly characterized, and protective immunity is incompletely understood, in part because accurate animal models that mimic human diseases are lacking. In the past, murine models have been of limited value because infection of mice was without effect or resulted in erratic mortality. Recent studies have reported that rickettsial infection can be established in mice, depending on the genetic background of mice, the type of rickettsial species and the route of inoculation. These models may be useful for analyzing the pathogenesis of rickettsioses, especially epidemic typhus, evaluating new therapeutic molecules and vaccine candidates, and preventing future outbreaks.
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Affiliation(s)
- Yassina Bechah
- Unité des Rickettsies, CNRS UMR 6020, Université de la Méditerranée, Faculté de Médecine, 27 Bld. Jean Moulin, 13385 Marseille Cedex 05, France.
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Bechah Y, Capo C, Mege JL, Raoult D. Epidemic typhus. THE LANCET. INFECTIOUS DISEASES 2008; 8:417-26. [DOI: 10.1016/s1473-3099(08)70150-6] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bechah Y, Capo C, Raoult D, Mege J. Infection of Endothelial Cells with VirulentRickettsia prowazekiiIncreases the Transmigration of Leukocytes. J Infect Dis 2008; 197:142-7. [DOI: 10.1086/523649] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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