Spirochetes

• What are the characteristics of spirochetes?

  They are long, slender, helically curved, gram (−) bacilli.
• What are the different types of motility patterns observed in spirochetes?

  Spirochetes exhibit various types of motility patterns.
• What are the three genera of spirochetes mentioned?

  • Treponema: Slender with tight coils
  • Borrelia: Thicker with fewer and looser coils
  • Leptospira: Hooked ends
• What does the Greek word "trepin" mean?

  "Trepin" means turn.
• What are the two species of Treponema mentioned?

  1. pallidum and T.carateum.
• Why is Treponema difficult to visualize with a brightfield microscope?

  It is difficult to visualize due to its poor staining properties.
• What type of microscope is best for observing Treponema?

  A dark field microscope is best for observing Treponema.
• How do most Treponema species stain with Gram or Giemsa stains?

  Most species stain poorly with Gram or Giemsa stains.
• What is the method of reproduction for Treponema?

  Treponema reproduces by transverse fission.
• Describe the microscopy characteristics of Treponema.

  • Thin, spiral organism (4 to 14 spirals/organism)
  • 3 axial filaments and one insertion disk
  • Cell ends are pointed and covered with a sheath
  • Exhibits (+) corkscrew motility
• What is the causative agent of syphilis?

  Treponema pallidum subsp. pallidum.
• What type of oxygen requirement does Treponema pallidum have?

  It is a microaerophile.
• At what temperature is Treponema pallidum killed rapidly?

  It is killed rapidly at 42°C.
• How long can Treponema pallidum be visible in whole blood or plasma?

  It can be visible for at least 24 hours.
• Can Treponema pallidum cross the placenta?

  Yes, it can cross intact mucous membranes of the placenta.
• What does Treponema pallidum look like under dark field microscopy?

  • Appears as long and white fine spirals
  • Contains 10 to 13 coils
  • Three fibrils/periplasmic flagella against a dark background
• What are some alternative names for syphilis?

  French disease, Italian disease, The Great Pox.
• Why is syphilis referred to as "The Great Imitator"?

  Because it can copy and assume many clinical manifestations.
• What are the different stages of syphilis?

  • Primary syphilis: Chancre/Hard chancre (painless)
  • Secondary syphilis
  • Latent stage
  • Tertiary syphilis
  • Congenital syphilis
• What happens during secondary syphilis?

  The chancre heals, but the organisms are still disseminated in carious tissue via blood streams.
• What are the symptoms of secondary syphilis?

  • Fever
  • Sore throat
  • Weight loss
  • Headache
  • Rashes (on palms and soles)
• What characterizes the latent stage of syphilis?

  It becomes subclinical but not necessarily dormant.
• When does the latent stage of syphilis occur?

  It occurs within more than a year of infection.
• What is the primary method for diagnosing syphilis during the latent stage?

  Serological tests are used for diagnosis.
• What are the complications associated with gummas of tertiary syphilis?

  • Central nervous disease (neurosyphilis)
  • Cardiovascular abnormalities
  • Eye disease
  • Granuloma-like lesions (gummas)
• What is congenital syphilis?

  It is syphilis present in utero and at birth.
• What specimens are used for laboratory diagnosis of syphilis?

  • Skin lesions (cleaned with saline)
  • Oral lesions should not be examined to avoid false-positive results
• What type of examinations are recommended for diagnosing syphilis?

  Microscopic examinations are recommended.
• What is the definitive test for diagnosing syphilis?

  Dark field microscopy is the definitive test for motility.
• What stains are used in the microscopic examination of syphilis?

  • Levaditi’s stain
  • Fontana-Tribondeau stains
• What is the role of fluorescein isothiocyanate-labeled (FITC) antibodies in syphilis diagnosis?


  They are used for direct detection of lesions.
• What is the basis of serodiagnosis in syphilis?

  • It is especially important in the secondary and tertiary stages.
  • Non-treponemal tests (screening tests) include:
  • RPR
  • VDRL
  • USR
  • TRUST
  • ELISA
• What are the treponemal tests used for syphilis diagnosis?

  • FTA-ABS
  • T.pallidum particle agglutination
• What do non-treponemal tests detect?

  They detect the presence of non-specific antibodies or antibody-like proteins to lipoprotein materials.
• What is reagin in the context of non-treponemal tests?

  Reagin binds to the test antigen cardiolipin-lecithin-coated cholesterol particles.
• What is the result of a positive non-treponemal test?

  A positive result shows flocculation.
• What are the characteristics of the RPR test?

  • Does not require heating of serum
  • Not recommended for CSF
• What are the characteristics of the VDRL test?

  • Recommended for diagnosis of neurosyphilis using CSF specimen
  • Reagent must be freshly prepared
  • Patient’s serum must be heated at 56°C for 30 minutes (complement activation)
• What are the other non-treponemal tests mentioned?

  • USR test
  • TRUST
  • ELISA
• What does the treponemal test detect?

  • It detects the presence of antibodies to treponemal antigens.
  • Indirect fluorescent antibody test (FTA-ABS) confirms positive VDRL and RPR tests.