Spirochaetes are a phylum of gram-negative, helically coiled bacteria that move via endoflagella. There are three medically important genera: Treponema, which causes syphilis and yaws; Leptospira, transmitted through contact with infected animal urine and causing symptoms like jaundice; and Borrelia, which causes Lyme disease and relapsing fevers. Spirochaetes are difficult to culture but can be identified microscopically using silver staining techniques or dark-field microscopy. Serological tests and PCR are also used for diagnosis.

1. 4.3 Spirochaetes

2. Background..
 Gram negative
 Motile organism
Tightly coiled bacteria typically slender and flexouas shape.
The cell made up of protoplasmic cylinder located in periplasm of
cell, endoflagella and outer sheath.
Move by bending and rotating body according to the viscosity of
the medium

3. Motility of spirochetes
Unusual mode of motility
Endoflagellum located at one end and extends about two-third
of the cell. Its rotate.
Protoplasmic cylinder is rigid, whereas the outer sheath is
flexible, therefore when both endoflagella rotates in the same
direction while protoplasmic cylinder in opposite direction
causing torsion of cell.

5. Medical important
3 genera:
1. Treponema
2. Leptospira
3. Borrelia

6. Treponema
•Treponema pallidum pallidum, which causes syphilis
•T. pallidum endemicum, which causes bejel or endemic
syphilis
•T. pallidum carateum, which causes pinta
•T. pallidum pertenue, which causes yaws

7. YAWS PINTA
SYPHILIS

8. Normal habitat
Host associated spirochetes are parasites of humans or animals.
Found in lesion of treponematoses
Can also found in mucous membranes in the mouth and genital
tract, also in skin ulcers

9. Pathogenicity (T.pallidum)
1. Acquired syphilis transmitted congenitally or sexual intercourse -
Known as sexually acquired syphilis and congenitally acquired
syphilis
2. Non-venereal syphilis – endemic syphilis, bejel, njovera, siti and
dichuchwa

10. Microscopy
Small 6-15µm size, 0.2µm diameter.
Motile spirochaetes.
Use metallic silver techniques or known as impregnation
techniques. Metallic silver precipitates on the wall of the
spirochete, enlarging its outline and making it opaque, features that
make it visible in tissue sections.
Best seen by dark-field illumination or phase contrast

11. Culture
Microaerophilic
Hardly to grow in routine culture
Able to survive in some fluid including citrated whole blood
Maintained by intratesticular inoculation in rabbit.

12. Serology tests
Cardiolipin antigens test
VDRL test – Venereal Diseases Reference Laboratory
RPR test – Rapid Plasma Reagin
Treponemal antigen test
TPHA test (Treponema pallidum haemagglutination test)

13. Leptospira
Scanning electron micrograph of a
number of Leptospira sp. bacteria
atop a 0.1 µm polycarbonate filter
Leptospira interrogans

14. Normal Habitat
Gram negative, obligate aerobe spirochete.
Variety in domestic and wild animals such as rats, rodents,
cattle, pigs and dogs. Humans are accidental host.
Largely secreted in urine
Survive many weeks in soil and water, in alkaline and 28 –
32oC

15. Transmission
Direct or indirect contact with urine of infected animal
Enter damaged skin which has immersed for a long time in water or
mud contaminated with infected urine
m/o penetrate the lining of the mouth, nose and eyes
Person to person transmission rarely occurs

17. Risk factors
Person most at risk of infection include workers in rice fields and
sugar-cane fields, livestock farmers, irrigation canal workers, meat
and animal handlers, fresh water fish pond workers, veterinarians,
pest control officers, forest workers and those involved in road
building
High cases in rainy seasons and times of flooding

18. Pathogenicity
Mild form usually misdiagnosed as viral illness and influenza
More serious infection causing a high continuous fever, severe
headaches and body pain especially in the muscles of legs, redness
of the eye and weakness.
Can also causing jaundice and renal failure

19. Microscopy
Small 6-20µm in size 0.1 µm diameter
Actively motile spirochetes
Screw-tight coils and hooked ends
Easily stain only by impregnation techniques
Best seen by dark-field illumination or phase contrast

20. Culture
Leptospires are strictly aerobes
Can be cultured in a serum or albumin-Tween medium
Late grow so resulting less efficient diagnostic
Preferable serology test to identify several serogroups

21. Other tests
Haematological and biochemical tests in leptospirosis
Antimicrobial sensitivity – high doses of penicilin will be effective
against L. interrogans
ELISA test, Polymerase Chain Reaction (PCR)

22. Borrelia
Borrelia burgdoferi
Borrelia recurrentis
Borrelia duttoni

23. Normal habitat
B.burgdorferi – deer tick,Ixodes scapularis.
B.recurrentis – parasite of Pediculus lice
B.duttoni – parasite of Ornithodorus soft ticks

24. Pathogenicity
B.burgdorferi– causing Lyme Disease.
B.recurrentis – louse-bourne relapsing fever in poverty,
overcrowding, and during time of drought and famine.
B.duttoni – tick-bourne relapsing fever infecting CSF causing
lyphocytic meningitis

25. Microscopy
Large 10-20µm in size,0.5µm diameter
Actively motile spirochaetes wt coils of varying size
Agglutinate together
Easily stain in Giemsa, Field’s or other Romanowsky stain;
prolonged Gram staining (Gram negative)
Well seen by dark-field illumination

26. Culture
Borreliae are aerobes
Can be cultured in Kelly’s medium

27. Serology test
Used to diagnose relapsing fever, usually cross reaction
with Treponema
Antimicrobial sensitivity
Sensitive to penicillin and tetracycline

28. THE END