2630-2633-Human Rickettsia Aeschlimannii Infection: First Case
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Mechanisms of Rickettsia Parkeri Invasion of Host Cells and Early Actin-Based Motility
Mechanisms of Rickettsia parkeri invasion of host cells and early actin-based motility By Shawna Reed A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Microbiology in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Matthew D. Welch, Chair Professor David G. Drubin Professor Daniel Portnoy Professor Kathleen R. Ryan Fall 2012 Mechanisms of Rickettsia parkeri invasion of host cells and early actin-based motility © 2012 By Shawna Reed ABSTRACT Mechanisms of Rickettsia parkeri invasion of host cells and early actin-based motility by Shawna Reed Doctor of Philosophy in Microbiology University of California, Berkeley Professor Matthew D. Welch, Chair Rickettsiae are obligate intracellular pathogens that are transmitted to humans by arthropod vectors and cause diseases such as spotted fever and typhus. Spotted fever group (SFG) Rickettsia hijack the host actin cytoskeleton to invade, move within, and spread between eukaryotic host cells during their obligate intracellular life cycle. Rickettsia express two bacterial proteins that can activate actin polymerization: RickA activates the host actin-nucleating Arp2/3 complex while Sca2 directly nucleates actin filaments. In this thesis, I aimed to resolve which host proteins were required for invasion and intracellular motility, and to determine how the bacterial proteins RickA and Sca2 contribute to these processes. Although rickettsiae require the host cell actin cytoskeleton for invasion, the cytoskeletal proteins that mediate this process have not been completely described. To identify the host factors important during cell invasion by Rickettsia parkeri, a member of the SFG, I performed an RNAi screen targeting 105 proteins in Drosophila melanogaster S2R+ cells. -
Scrub Typhus and Molecular Characterization of Orientia Tsutsugamushi from Central Nepal
pathogens Article Scrub Typhus and Molecular Characterization of Orientia tsutsugamushi from Central Nepal Rajendra Gautam 1, Keshab Parajuli 1, Mythili Tadepalli 2, Stephen Graves 2, John Stenos 2,* and Jeevan Bahadur Sherchand 1 1 Department of Microbiology, Maharajgunj Medical Campus, Institute of Medicine, Kathmandu 44600, Nepal; [email protected] (R.G.); [email protected] (K.P.); [email protected] (J.B.S.) 2 Australian Rickettsial Reference Laboratory, Geelong, VIC 3220, Australia; [email protected] (M.T.); [email protected] (S.G.) * Correspondence: [email protected]; Tel.: +61-342151357 Abstract: Scrub typhus is a vector-borne, acute febrile illness caused by Orientia tsutsugamushi. Scrub typhus continues to be an important but neglected tropical disease in Nepal. Information on this pathogen in Nepal is limited to serological surveys with little information available on molecular methods to detect O. tsutsugamushi. Limited information exists on the genetic diversity of this pathogen. A total of 282 blood samples were obtained from patients with suspected scrub typhus from central Nepal and 84 (30%) were positive for O. tsutsugamushi by 16S rRNA qPCR. Positive samples were further subjected to 56 kDa and 47 kDa molecular typing and molecularly compared to other O. tsutsugamushi strains. Phylogenetic analysis revealed that Nepalese O. tsutsugamushi strains largely cluster together and cluster away from other O. tsutsugamushi strains from Asia and elsewhere. One exception was the sample of Nepal_1, with its partial 56 kDa sequence clustering Citation: Gautam, R.; Parajuli, K.; more closely with non-Nepalese O. tsutsugamushi 56 kDa sequences, potentially indicating that Tadepalli, M.; Graves, S.; Stenos, J.; homologous recombination may influence the genetic diversity of strains in this region. -
Typhus Fever, Organism Inapparently
Rickettsia Importance Rickettsia prowazekii is a prokaryotic organism that is primarily maintained in prowazekii human populations, and spreads between people via human body lice. Infected people develop an acute, mild to severe illness that is sometimes complicated by neurological Infections signs, shock, gangrene of the fingers and toes, and other serious signs. Approximately 10-30% of untreated clinical cases are fatal, with even higher mortality rates in Epidemic typhus, debilitated populations and the elderly. People who recover can continue to harbor the Typhus fever, organism inapparently. It may re-emerge years later and cause a similar, though Louse–borne typhus fever, generally milder, illness called Brill-Zinsser disease. At one time, R. prowazekii Typhus exanthematicus, regularly caused extensive outbreaks, killing thousands or even millions of people. This gave rise to the most common name for the disease, epidemic typhus. Epidemic typhus Classical typhus fever, no longer occurs in developed countries, except as a sporadic illness in people who Sylvatic typhus, have acquired it while traveling, or who have carried the organism for years without European typhus, clinical signs. In North America, R. prowazekii is also maintained in southern flying Brill–Zinsser disease, Jail fever squirrels (Glaucomys volans), resulting in sporadic zoonotic cases. However, serious outbreaks still occur in some resource-poor countries, especially where people are in close contact under conditions of poor hygiene. Epidemics have the potential to emerge anywhere social conditions disintegrate and human body lice spread unchecked. Last Updated: February 2017 Etiology Rickettsia prowazekii is a pleomorphic, obligate intracellular, Gram negative coccobacillus in the family Rickettsiaceae and order Rickettsiales of the α- Proteobacteria. -
A Streamlined Method for Transposon Mutagenesis of Rickettsia Parkeri
bioRxiv preprint doi: https://doi.org/10.1101/277160; this version posted March 8, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 A streamlined method for transposon mutagenesis of 2 Rickettsia parkeri yields numerous mutations that 3 impact infection 4 5 Rebecca L. Lamason1,#a,*, Natasha M. Kafai1,#b, and Matthew D. Welch1* 6 7 8 1 Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, 9 CA 10 #a Current address: Department of Biology, Massachusetts Institute of Technology, 11 Cambridge, MA 12 #b Current address: Medical Scientist Training Program, Washington University in St. 13 Louis School of Medicine, St. Louis, MO 14 15 16 17 18 * Co-corresponding authors 19 E-mail: [email protected], [email protected] 20 1 bioRxiv preprint doi: https://doi.org/10.1101/277160; this version posted March 8, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 21 Abstract 22 The rickettsiae are obligate intracellular alphaproteobacteria that exhibit a complex 23 infectious life cycle in both arthropod and mammalian hosts. As obligate intracellular 24 bacteria, Rickettsia are highly adapted to living inside a variety of host cells, including 25 vascular endothelial cells during mammalian infection. Although it is assumed that the 26 rickettsiae produce numerous virulence factors that usurp or disrupt various host cell 27 pathways, they have been challenging to genetically manipulate to identify the key 28 bacterial factors that contribute to infection. -
Laboratory Diagnostics of Rickettsia Infections in Denmark 2008–2015
biology Article Laboratory Diagnostics of Rickettsia Infections in Denmark 2008–2015 Susanne Schjørring 1,2, Martin Tugwell Jepsen 1,3, Camilla Adler Sørensen 3,4, Palle Valentiner-Branth 5, Bjørn Kantsø 4, Randi Føns Petersen 1,4 , Ole Skovgaard 6,* and Karen A. Krogfelt 1,3,4,6,* 1 Department of Bacteria, Parasites and Fungi, Statens Serum Institut (SSI), 2300 Copenhagen, Denmark; [email protected] (S.S.); [email protected] (M.T.J.); [email protected] (R.F.P.) 2 European Program for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control (ECDC), 27180 Solnar, Sweden 3 Scandtick Innovation, Project Group, InterReg, 551 11 Jönköping, Sweden; [email protected] 4 Virus and Microbiological Special Diagnostics, Statens Serum Institut (SSI), 2300 Copenhagen, Denmark; [email protected] 5 Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut (SSI), 2300 Copenhagen, Denmark; [email protected] 6 Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark * Correspondence: [email protected] (O.S.); [email protected] (K.A.K.) Received: 19 May 2020; Accepted: 15 June 2020; Published: 19 June 2020 Abstract: Rickettsiosis is a vector-borne disease caused by bacterial species in the genus Rickettsia. Ticks in Scandinavia are reported to be infected with Rickettsia, yet only a few Scandinavian human cases are described, and rickettsiosis is poorly understood. The aim of this study was to determine the prevalence of rickettsiosis in Denmark based on laboratory findings. We found that in the Danish individuals who tested positive for Rickettsia by serology, the majority (86%; 484/561) of the infections belonged to the spotted fever group. -
Update on Australian Rickettsial Infections
Update on Australian Rickettsial Infections Stephen Graves Founder & Medical Director Australian Rickettsial Reference Laboratory Geelong, Victoria & Newcastle NSW. Director of Microbiology Pathology North – Hunter NSW Health Pathology Newcastle. NSW Conjoint Professor, University of Newcastle, NSW What are rickettsiae? • Bacteria • Rod-shaped (0.4 x 1.5µm) • Gram negative • Obligate intracellular growth • Energy parasite of host cell • Invertebrate vertebrate Vertical transmission through life stages • Egg invertebrate Horizontal transmission via • Larva invertebrate bite/faeces (larva “chigger”, nymph, adult ♀) • Nymph • Adult (♀♂) Classification of Rickettsiae (phylum) α-proteobacteria (genus) 1. Rickettsia – Spotted Fever Group Typhus Group 2. Orientia – Scrub Typhus 3. Ehrlichia (not in Australia?) 4. Anaplasma (veterinary only in Australia?) 5. Rickettsiella (? Koalas) NB: Coxiella burnetii (Q fever) is a γ-proteobacterium NOT a true rickettsia despite being tick-transmitted (not covered in this presentation) 1 Rickettsiae from Australian Patients Rickettsia Vertebrate Invertebrate (human disease) Host Host A. Spotted Fever Group Rickettsia i. Rickettsia australis Native rats Ticks (Ixodes holocyclus, (Queensland Tick Typhus) Bandicoots I. tasmani) ii. R. honei Native reptiles (blue-tongue Tick (Bothriocroton (Flinders Island Spotted Fever) lizard & snakes) hydrosauri) iii.R. honei sub sp. Unknown Tick (Haemophysalis marmionii novaeguineae) (Australian Spotted Fever) iv.R. gravesii Macropods Tick (Amblyomma (? Human pathogen) (kangaroo, wallabies) triguttatum) Feral pigs (WA) v. R. felis cats/dogs Flea (cat flea typhus) (Ctenocephalides felis) All these rickettsiae grown in pure culture Rickettsiae in Australian patients (cont.) Rickettsia Vertebrate Invertebrate Host Host B. Typhus Group Rickettsia R. typhi Rodents (rats, mice) Fleas (murine typhus) (Ctenocephalides felis) (R. prowazekii) (humans)* (human body louse) ╪ (epidemic typhus) (Brill’s disease) C. -
Evolutionary Relationship of Rickettsiae and Mitochondria
FEBS 25031 FEBS Letters 501 (2001) 11^18 View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Hypothesis Evolutionary relationship of Rickettsiae and mitochondria Victor V. Emelyanov* Department of General Microbiology, Gamaleya Institute of Epidemiology and Microbiology, Moscow 123098, Russia Received 7 May 2001; accepted 30 May 2001 First published online 26 June 2001 Edited by Matti Saraste2 genetic methods [8^10]. Comparative studies of mitochondrial Abstract Phylogenetic data support an origin of mitochondria from the K-proteobacterial order Rickettsiales. This high-rank genomes unequivocally pointed to a eubacterial ancestry of taxon comprises exceptionally obligate intracellular endosym- mitochondria [2,8]. Their monophyletic nature and close rela- bionts of eukaryotic cells, and includes family Rickettsiaceae and tionship to the order Rickettsiales of K-Proteobacteria a group of microorganisms termed Rickettsia-like endosymbionts emerged from multiple phylogenetic reconstructions based (RLEs). Most detailed phylogenetic analyses of small subunit on conserved proteins and small subunit (SSU) rRNA rRNA and chaperonin 60 sequences consistently show the RLEs [7,11^16]. Due to the scarcity of relevant molecular informa- to have emerged before Rickettsiaceae and mitochondria sister tion, above phylogenetic studies involved mostly aerobically clades. These data suggest that the origin of mitochondria and respiring mitochondria and a few rickettsial species. It is Rickettsiae has been preceded by the long-term mutualistic known, however, that some primitive eukaryotes have anaer- relationship of an intracellular bacterium with a pro-eukaryote, obic mitochondria [17,18] while others instead possess hydro- in which an invader has lost many dispensable genes, yet evolved carrier proteins to exchange respiration-derived ATP for genosomes ^ energy-generating organelles which are suggested host metabolites as envisaged in classic endosymbiont to be biochemically modi¢ed mitochondria [19,20]. -
Orientia Tsutsugamushi Comb
INTERNATIONALJOURNAL OF SYSTEMATICBACTERIOLOGY, July 1995, p. 589-591 Vol. 45, No. 3 0020-7713/95/$04.00+0 Copyright 0 1995, International Union of Microbiological Societies Classification of Rickettsia tsutsugamushi in a New Genus, Orientia gen. nov., as Orientia tsutsugamushi comb. nov. AKIRA TAMURA,* NOR10 OHASHI, HIROSHI URAKAMI, AND SADAO MIYAMURA Department of Mictobiology, Niigata College of Pharmacy, Niigata, Niigata 950-21, Japan Recent studies of Rickettsia tsutsugamushi have demonstrated clearly the phenotypic and genotypic differ- ences between this microorganism and other species belonging to the genus Rickettsia. Therefore, classification of R. tsutsugamushi in a new genus, Orientiu gen. nov., is proposed. The genus Rickettsia includes etiological agents of human the species (9,lO). Three proteins that range in size from 20 to diseases, including typhus, spotted fever, and scrub typhus. All 32 kDa and 120-kDa proteins are heat modifiable (8, 12, 13). of the microbes belonging to this genus are similar in the R. tsutsugamushi can be cultivated in the yolk sacs of devel- following respects: they exhibit obligate intracellular parasit- oping chicken embryos and can be grown in culture in various ism, they are morphologically similar to gram-negative bacte- cell lines, including the HeLa, BHK, Vero, and L929 cell lines. ria, they survive in both vertebrate and arthropod hosts, and Most of the microorganisms grow in the perinuclear cytoplasm human infection is mediated by arthropods. However, recent of host cells, and they release themselves by pushing out the studies of Rickettsia tsutsugamushi, which is the only species in host cytoplasmic membrane from the inside like the budding the scrub typhus group, have revealed some differences be- process observed with enveloped viruses (49,50). -
Ehrlichia and Spotted Fever Group Rickettsiae Surveillance in Amblyomma Americanum in Virginia Through Use of a Novel Six-Plex Real- Time PCR Assay David N
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Old Dominion University Old Dominion University ODU Digital Commons Biological Sciences Faculty Publications Biological Sciences 2014 Ehrlichia and Spotted Fever Group Rickettsiae Surveillance in Amblyomma americanum in Virginia Through Use of a Novel Six-Plex Real- Time PCR Assay David N. Gaines Darwin J. Operario Suzanne Stroup Ellen Stromdahl Chelsea Wright Old Dominion University See next page for additional authors Follow this and additional works at: https://digitalcommons.odu.edu/biology_fac_pubs Part of the Environmental Public Health Commons, and the Immunology and Infectious Disease Commons Repository Citation Gaines, David N.; Operario, Darwin J.; Stroup, Suzanne; Stromdahl, Ellen; Wright, Chelsea; Gaff, Holly; Broyhill, James; Smith, Joshua; Norris, Douglas E.; Henning, Tyler; Lucas, Agape; and Houpt, Eric, "Ehrlichia and Spotted Fever Group Rickettsiae Surveillance in Amblyomma americanum in Virginia Through Use of a Novel Six-Plex Real-Time PCR Assay" (2014). Biological Sciences Faculty Publications. 299. https://digitalcommons.odu.edu/biology_fac_pubs/299 Original Publication Citation Gaines, D. N., Operario, D. J., Stroup, S., Stromdahl, E., Wright, C., Gaff, H., . Houpt, E. (2014). Ehrlichia and spotted fever group rickettsiae surveillance in Amblyomma americanum in Virginia through use of a novel six-plex real-time PCR assay. Vector-Borne and Zoonotic Diseases, 14(5), 307-316. doi:10.1089/vbz.2013.1509 Authors David N. Gaines, Darwin J. Operario, Suzanne Stroup, Ellen Stromdahl, Chelsea Wright, Holly Gaff, James Broyhill, Joshua Smith, Douglas E. Norris, Tyler Henning, Agape Lucas, and Eric Houpt This article is available at ODU Digital Commons: https://digitalcommons.odu.edu/biology_fac_pubs/299 VECTOR-BORNE AND ZOONOTIC DISEASES Volume 14, Number 5, 2014 ORIGINAL ARTICLES ª Mary Ann Liebert, Inc. -
Rickettsial Pathogens and Their Arthropod Vectors
Perspectives Rickettsial Pathogens and their Arthropod Vectors Abdu F. Azad* and Charles B. Beard† *University of Maryland School of Medicine, Baltimore, Maryland, USA; and †Centers for Disease Control and Prevention, Atlanta, Georgia, USA Rickettsial diseases, important causes of illness and death worldwide, exist primarily in endemic and enzootic foci that occasionally give rise to sporadic or seasonal outbreaks. Rickettsial pathogens are highly specialized for obligate intracellular survival in both the vertebrate host and the invertebrate vector. While studies often focus primarily on the vertebrate host, the arthropod vector is often more important in the natural maintenance of the pathogen. Consequently, coevolution of rickettsiae with arthropods is responsible for many features of the host-pathogen relationship that are unique among arthropod-borne diseases, including efficient pathogen replication, long- term maintenance of infection, and transstadial and transovarial transmission. This article examines the common features of the host-pathogen relationship and of the arthropod vectors of the typhus and spotted fever group rickettsiae. Rickettsial diseases, widely distributed associations with obligate blood-sucking throughout the world in endemic foci with arthropods represent the highly adapted end- sporadic and often seasonal outbreaks, from time product of eons of biologic evolution. The ecologic to time have reemerged in epidemic form in separation and reduced selective pressure due to human populations. Throughout history, epi- these associations may explain rickettsial genetic demics of louse-borne typhus have caused more conservation. Their intimate relationships with deaths than all the wars combined (1). The vector hosts (Table 1) are characterized by ongoing outbreak of this disease in refugee camps efficient multiplication, long-term maintenance, in Burundi involving more than 30,000 human transstadial and transovarial transmission, and cases is a reminder that rickettsial diseases can extensive geographic and ecologic distribution. -
Neorickettsia Helminthoeca in Cell Culture
AN ABSTRACT OF THE THESISOF William Edward Noonanfor the Doctor of Philosophy (Name) (Degree) in Zoology presented on July 7, 1972 (Major) (Date) Title: NEORICKETTSIAHELMINTHOEC.6.-IficzQ.--K,LL CULTURE Redacted for Privacy Abstract approved: Dr. Ivan Pratt The etiologic agent of salmonpoisoning disease was found to be Neorickettsia helminthoeca, although asecond organism, the Eloko- min fluke fever agent, mayalso be involved in other areas.Primary cultures of dog leucocytes werefound to support the in vitro cultiva- tion of Neorickettsiahelminthoeca as were canine sarcoma503 cells and mouse lymphoblasts MBIII.Quantitative methods were not applied to in vitro studies ofmultiplication of the rickettsiabecause it failed to grow sufficientlyin laboratory animals or inchicken embryo yolk sacs to do so. By ultrastructural analysisit was learned thatNeorickettsia helminthoeca was structurallysimilar to other rickettsiae.Rickett- sial cells were seen ascircular profiles or rod-shapedcells 0. 5µ wide and up to 0.7p. long.They were bounded by a cellwall and an underlying cytoplasmic membrane.Each of the membranes was a trilayered structure andshowed the unit membrane structure. Koch's postulates werefulfilled as completely as possiblefor an organism that is an obligateintracellular parasite.Neorickettsia helminthoeca was found in all casesof salmon poisoning disease. The rickettsia was isolatedand grown in culture.The isolated culture was found to reproducethe disease when inoculated into susceptible dogs.The rickettsia was observed inand recovered -
Adherence to and Invasion of Host Cells by Spotted Fever Group Rickettsia Species
REVIEW ARTICLE published: 20 December 2010 doi: 10.3389/fmicb.2010.00139 Adherence to and invasion of host cells by spotted fever group Rickettsia species Yvonne Gar-Yun Chan, Sean Phillip Riley and Juan Jose Martinez* Department of Microbiology, University of Chicago, Chicago, IL, USA Edited by: The pathogenic lifecycle of obligate intracellular bacteria presents a superb opportunity to develop Robert Heinzen, National Institute of understanding of the interaction between the bacteria and host under the pretext that disruption Health, National Institute of Allergy and Infectious Diseases-Rocky Mountain of these processes will likely lead to death of the pathogen and prevention of associated disease. Laboratories, USA Species of the genus Rickettsia contain some of the most hazardous of the obligate intracellular Reviewed by: bacteria, including Rickettsia rickettsii and R. conorii the causative agents of Rocky Mountain and Jon Audia, University of South Alabama Mediterranean spotted fevers, respectively. Spotted fever group Rickettsia species commonly School of Medicine, USA invade and thrive within cells of the host circulatory system whereby the endothelial cells are Hélène Marquis, Cornell University, USA severely perturbed. The subsequent disruption of circulatory continuity results in much of the *Correspondence: severe morbidity and mortality associated with these diseases, including macropapular dermal Juan Jose Martinez, Department of rash, interstitial pneumonia, acute renal failure, pulmonary edema, and other multisystem Microbiology, Cummings Life Sciences manifestations. This review describes current knowledge of the essential pathogenic processes Center, University of Chicago, 920 E. of adherence to and invasion of host cells, efforts to disrupt these processes, and potential for 58th Street, CLSC701A, Chicago, IL 60637, USA.