Rickettsia spp.

  • Douglas I. Johnson


  • Genomics:
    • Rickettsia prowazekii chromosome: 1,111,523 bp; 834 predicted ORFs (Andersson et al. 1998)

    • Rickettsia rickettsii chromosome: 1,257,710 bp; 1218 predicted ORFs (Ellison et al. 2008)

  • Cell morphology:
    • Small coccobacilli (Fig. 26.1)

    • Surrounded by LPS and protein-containing S-layer

  • Gram stain:
    • Gram negative

  • Growth:
    • Aerobes

    • Obligate intracellular pathogens

    • Reservoirs: mammals and some arthropods

    • Can be transmitted by arthropods such as lice, ticks, fleas, and chiggers

    • Two groups of mammalian pathogenic species:
      • Typhus group (TG) – two species; cause typhus worldwide:
        • Rickettsia prowazekii: epidemic typhus fever

        • Rickettsia typhi: endemic murine typhus

      • Spotted fever group (SFG) – at least 20 species; cause spotted fevers in different geographic locations:
        • Rickettsia rickettsii: Rocky Mountain spotted fever (North America)

        • Rickettsia sibirica: Siberian tick typhus

        • Rickettsia australis: Queensland tick typhus

        • Rickettsia japonica: Oriental spotted fever

        • Rickettsia africae: African tick-bite fever

        • Rickettsia felis: cat-flea typhus; emerging worldwide pathogen


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Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  • Douglas I. Johnson
    • 1
  1. 1.Department of Microbiology & Molecular GeneticsUniversity of VermontBurlingtonUSA

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