2. Classification of spirochetes
• Spirochetes are thin, elongated,
spirally twisted, Gram negative
bacteria
• There are 11 genera in this group
• Some are pathogens, but most are
free-living, and are actually pretty
common in the environment.
3. 3 genera have human pathogens
Treponema, Borrelia, leptospira
Treponema (25 species)-
Relatively short, slender, fine spirals.
Associated with venereal and non venereal
diseases, some are non pathogenic
Treponema pallidum causes syphilis- venereal
disease- STD.
4. Syphilis - T. pallidum
• History- ancient disease, Columbus crew
• Reservoir- humans only known natural
host.
• Name syphilis from a poem describing a
shepherd boy
5. • Transmission- sexual route- venereal
• Syphilis is not very contagious; a person
has 1/10 chance of becoming infected
after contact with an infected person
• In some stages, it is less contagious
6. • Syphilis is conventionally divided into
following stages:
Primary, Secondary, Latent, Tertiary
–Staging has prognostic and
therapeutic implications.
7. Primary syphilis
• 5 to 80 days after contact (sexual), a
chancre develops at point of contact-
external genitalia
• Chancre is an inflammatory lesion
containing spirochetes & lymphocytes.
• It is painless, well circumscribed,
indurated, heals spontaneously after
~10 – 40 days leaving a thin scar.(also
called hard chancre)
8. • Regional lymph nodes are enlarged and
non tender
• Even before appearance of chancre,
treponema spread from site of entry via
blood/lymph.
• Multiple chancre may be seen in
immunodefficient patients.
• Once this heals patient remains
asymptomatic till secondary stage
9. Secondary syphilis
• 2 - 12 weeks after primary lesion
heals, generalized symptoms of
disseminated infection occur due to
multiplication and dissemination of
treponemes
• Fever, headache, sore throat and
enlarged lymph nodes develop
• Papular skin rash develops on body
and lesions appear on palms and
soles of feet also
10. • Abundant spirochetes in skin lesions-
most infectious stage
• Intensity of lesions in secondary syphilis
varies
• Can Heal spontaneously in months to
years
• Variable course
spontaneous cure
latent stage
go to 3rd stage
11. Latent Syphilis
• Absence of clinical symptoms
• 3 possible outcomes
Persist for life
Tertiary syphilis
Cure
12. Tertiary syphilis
• 2-20 years later
• Steady tissue destruction- Chronic
granulomata formation- Gumma,
lesions contain very few treponema
• Cardiovascular system/CNS
• ~1/3 die
13. Late tertiary or quaternary syphilis-
• Tabes dorsalis- dorsal column of spinal
cord
• GPI- dementia
14. Congenital Syphilis
• Fetus susceptible after 4th month IU life
• 40% fetal death
• Hutchinson's Triad
peg teeth
interstitial keratitis
8th nerve destruction- deafness
15.
16. Treponema pallidum bacteria
• It is slender and tightly coiled,
measuring 5 to 15 µm long by 0.09
to 0.18µm wide
• They have a characteristic motility
on dark field microscopy- cork
screw
• This is due to axial fibrils, similar
to flagella, varying numbers
17. • T. pallidum has not been cultured in
vivo.
• It is rapidly inactivated by:
Drying, Heat, Cold
• Transmission is by direct contact or
congenitally
18.
19.
20. Diagnosis
Clinical- based on symptoms, history
Laboratory
• Darkfield examination
Wear gloves, Clean the lesion with
saline gauze, press it gently and
collect exudate on a slide and examine
in darkground microscope.
21. Serologic tests
Non Specific/Non treponemal
• A reactive material from beef heart
called cardiolipin is used as antigen
• It reacts with “reagin” antibodies that
develop in syphilis
• Also called Standard test for Syphilis
(STS)
22. VDRL
• This is a slide flocculation test to
detect antibodies in patients serum
using cardiolipin as antigen
1o 1/3 +
2o 95% +
latent +/-
23. Other Non treponemal tests
• Kahn’s- Tube flocculation test
• Wasserman test- Complement
fixation
• RPR- rapid plasma reagin test
Biological false positives- BFP
• Acute infections, major trauma,
autoimmune conditions like SLE,
• Leprosy, malaria
24. Specific - treponemal tests
Using T. pallidum antigen to detect
antibodies in patients serum
• Treponema pallidum immobilization- TPI
• Fluorescent treponemal Antibody (FTA)
• T pallidum haemagglutination (TPHA)
1o 80% +
2o & 3o >95% +
latent >99% +
25. Treatment
• Penicillin is drug of choice
• Duration of tretment varies according
to clinical stage of disease
• If allergic to penicillin- Ceftriaxone
26. Summary
• Treponema pallidum bacteria: characters
• Syphilis disease: mode of transmissison
• Clinical stages
• Diagnostic tests: STS / Specific tests
• Utility of tests / BFP
