Spirochetes are a phylum of Gram-negative bacteria characterized by their spiral or corkscrew shape and motility via periplasmic flagella. The document discusses three genera of medically important spirochetes: Treponema, Borrelia, and Leptospira. Treponema pallidum causes syphilis, a sexually transmitted infection. Borrelia burgdorferi is the causative agent of Lyme disease transmitted through tick bites. Leptospira interrogans causes leptospirosis, a zoonotic disease spread through contact with infected animal urine.

1. Spirochetes
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Treponema, Borrelia &
Leptospira
A. L. Samer Faisal

2. General Overview of Spirochaetales
 Gram-negative spirochetes
• Spirochete from Greek for “coiled hair”
Extremely thin and can be very long
 Tightly coiled helical cells with tapered ends
 Motile by periplasmic flagella (a.k.a., axial fibrils
or endoflagella)
 Outer sheath encloses axial fibrils wrapped around
protoplasmic cylinder
• Axial fibrils originate from insertion pores at both poles of cell
• May overlap at center of cell in Treponema and Borrelia, but
NOT in Leptospira
• Differing numbers of endoflagella according to genus &
species

3. Periplasmic Flagella Diagram

4. Spirochetes Associated Human Diseases

6. Treponema

7. Treponema pallidum
Immunohistochemistry for Treponema pallidum in an area with few
inflammatory infiltrates and multiple spirochetes.

8. Histopathology of Treponema pallidum spirochetes using a
modified Steiner silver stain.

9. VenerealTreponemalDisease
 Syphilis
 Primarily sexually transmitted disease
(STD)
 May be transmitted congenitally

10. Darkfield Microscopy of Treponema pallidum

11.  Too thin, long, slender, flexible, spiral-or corkscrew-shaped
rods.
• Highly motile spirochetes can be seen with dark field microscopy
• Staining with anti-treponemal antibodies labeled with
fluorescent dyes e.g., Fontana’s and Beaker’s staining
technique.
 Gram negative but stain poorly and need to be visualized
by other means.
 Has not been cultured in vitro.
 Do not survive well outside of host
• Care must be taken with clinical specimens for laboratory culture or
testing
General Characteristics of Treponema pallidum

13. Diagnostic Tests for Syphilis
NOTE: Treponemal antigen tests indicate experience with a treponemal
infection, but cross-react with antigens other than T. pallidum ssp.
pallidum. positive treponemal antigen tests are usually indicative of
syphilitic infection.
(Original Wasserman Test)

16. Syphilis, congenital.
Hutchinson’s teeth. Note notch
in two upper front teeth.
Treponema pallidum.
Syphilis.
Primary stage with chancre. Arrow
points to shallow ulcer on shaft of
penis. Treponema pallidum.

17. Syphilis.
Secondary stage with flat, moist
genital (perianal) lesions called
condylomata lata. Arrow points
to one of the lesions. Treponema
pallidum.
Syphilis.
Secondary stage with mucous
patches on tongue. Arrow points
to one of the lesions. Treponema
pallidum.

18. Syphilis.
Secondary stage with
papulosquamous lesions on the
palms bilaterally. Treponema
pallidum.
Syphilis.
Secondary stage with papular rash
on back. Treponema pallidum.

19. Syphilis.
Tertiary stage with nodular lesion in skin
called gumma. Treponema pallidum.

20. Borrelia spp.

21. Giemsa Stain of
Borrelia recurrentis in Blood
Light Microscopy Phase Contrast Microscopy

22. Epidemiology of Borrelia Infections
Borrelia
recurrentis
Borrelia spp.
Borrelia
burgdorferi
Ixodes spp.
Ornithodoros spp.
Pediculus humanus

23. Borrelia burgdorferi

24. Common characteristics
Gram-negative, but stain poorly and need to be
visualized by other means.
Long, slender, flexible, spiral-or corkscrew-
shaped rods.
Highly motile.
Difficult and time consuming to culture.
Causing Lyme disease.

25. Erythema chronicum migrans of Lyme Borreliosis
Bullseye rash
Lyme disease.
Erythema chronicum migrans
rash. Borrelia burgdorferi.

26. Ixodes tick.
Nymph with head buried in skin
surrounded by erythematous
macular rash.

29. Diagnosis of Lyme Borreliosis
• The PCR used to assist in detection of B. burgdorferi in body fluids provides
the most definitive test.
• With serological test numbers of false positives can outnumbers the true
positive.

30. Leptospira interrogans
LEPTOSPIRA INTERROGANS. Leptospira interrogans, the bacterium
responsible for Weil´s disease, the most severe form of leptospirosis.
Symptoms are hemorrhaging, acute renal failure and neurological
failure. Optical microscopy x 1000.

31. Common characteristics
Gram-negative, but stain poorly and need to be
visualized by other means.
Long, very slender, flexible, spiral-or corkscrew-
shaped rods.
Highly motile.
Cultured on specialized medium e.g., EMJH media
(Ellinghausen-McCullough-Johnson-Harris).

32. Silver Stain of Leptospira interrogans

34. Comparison of Diagnostic Tests
for Leptospirosis

35. REVIEW
of
Spirochetes

36. Spirochetes Associated Human
Diseases
REVIEW

37. Summary of Treponema Infections

39. Summary of Borellia Infections

41. Summary of Leptospira Infections