Spirochetes

• What is the taxonomic classification of spirochetes?

  Spirochaetales
• Which family does Treponema belong to?


  Spirochaetaceae
• What is the scientific name of the bacterium that causes syphilis?

  Treponema pallidum subsp pallidum
• What are the general characteristics of spirochetes?


  Long, slender, helically curved, gram (-) bacilli
• What is the unique morphology of spirochetes?


  They have axial fibrils and an outer sheath
• What are axial fibrils in spirochetes responsible for?


  Corkscrew-like motility
• How do spirochetes differ in terms of axial fibrils and insertion disks?


  They differ based on the number of axial fibrils and insertion disks
• What are the key differences between the genera Treponema, Borrelia, and Leptospira?


  • Treponema: 6-10 axial filaments, 1 insertion disk, slender with tight coils
  • Borrelia: 30-40 axial filaments, 2 insertion disks, thicker with fewer and looser coils
  • Leptospira: 2 axial filaments, 3-5 insertion disks, resemble Borrelia but with hooked ends
• What type of environment do Treponema bacteria require?


  Microaerophilic
• Why are Treponema bacteria best observed with dark-field or phase-contrast microscopy?


  They stain poorly with Gram's or Giemsa's stains
• What is the primary pathogenic species of Treponema that infects humans?


  Treponema pallidum
• How does Treponema pallidum invade the body?


  It penetrates through intact membranes or breaks in the skin
• What is the consequence of Treponema pallidum's tropism to arterioles?


  It leads to endarteritis and progressive tissue destruction
• What are the different subspecies of Treponema pallidum and their associated diseases?


  • T. pallidum subsp pallidum: Venereal syphilis
  • T. pallidum subsp endemicum: Endemic nonvenereal syphilis (bejel)
  • T. pallidum subsp pertenue: Yaws
  • T. carateum: Pinta
• What is the mode of transmission for T. pallidum subsp pallidum?


  Sexual and congenital transmission
• What are the signs and symptoms of venereal syphilis?


  Chancre at the site of inoculation
• What is the incubation period for primary syphilis?


  10-90 days after infection
• What occurs during the secondary stage of syphilis?


  Widespread rash and systemic symptoms occur
• What is the significance of the latent stage of syphilis?


  The disease becomes subclinical but not dormant
• What complications can arise during late/tertiary syphilis?


  CNS disease, cardiovascular abnormalities, and gummas
• What is the laboratory diagnosis method for syphilis?

  Serologic tests
• What are the two types of antibodies measured in serodiagnosis for syphilis?

  1. Non-treponemal antibodies (Reaginic antibodies)
  2. Treponemal antibodies (specific for Treponema pallidum)
• What is the purpose of non-treponemal tests like RPR and VDRL?


  To screen for syphilis by detecting reaginic antibodies
• What is the confirmatory test for syphilis?


  FTA-ABS test
• What is the treatment for syphilis?


  Penicillin G or benzathine penicillin
• What is the Jarisch-Herxheimer reaction?


  A hypersensitivity reaction during penicillin therapy
• What diseases are caused by Borrelia?


  Relapsing fever and Lyme disease
• How is relapsing fever transmitted?


  Through the bite of a louse or tick
• What characterizes relapsing fever?


  It has an abrupt onset of fever, headache, and myalgia
• What happens during the afebrile period of relapsing fever?


  Organisms disappear from the bloodstream and hide in different body organs
• What are the key features of Borrelia species?


  • 3-10 loose coils
  • Actively motile
  • Stain well with Giemsa
  • Culturable
  • Microaerophilic
• What is the incubation period for relapsing fever?


  1. 15 days
• What is the primary vector for Lyme disease?


  Tick
• What is the primary symptom of Lyme disease?


  Erythema migrans (bull's-eye rash)
• What is the treatment for Lyme disease?


  Antibiotics such as doxycycline
• What is the role of serologic tests in diagnosing Lyme disease?


  To detect antibodies against Borrelia
• What is the significance of the afebrile period in relapsing fever?


  It allows the organism to evade the immune response
• How does Borrelia evade the immune system during relapsing fever?


  By changing its surface antigens
• What is the primary method for diagnosing Lyme disease?


  Serologic testing
• What is the role of PCR in diagnosing syphilis?


  To detect Treponema DNA in serous exudate