Question
Which of the following Treponema is seen in the silver impregnation micrograph below?
A. Leptospira interrogans
B. Treponema pallidum
C. Ehrlichia chaffeensis
D. Borrelia burgdorferi
Show Answer
Ans: A.Leptospira interrogans
(Ref Ananthanarayan 10/e p3287, 8/e p372; Jawetz 27/e p330)
- Hook like appearance of spirochetes in dark field microscopy image – Suggestive of Leptospira infection.
Leptospirae:
- Tightly coiled, thin, flexible spirochetes 5-15 µm long, with very fine spirals 0.1-0.2 pm wide.
- One end bent forming hook.
- Actively motile – Best seen with dark-field microscope.
Electron micrograph image:
- Thin axial filament & delicate membrane.
- Spirochete – Delicate.
Dark-field view:
- Appear only as a chain of minute cocci – Due to extreme delicacy.
- Does not stain readily.
- Can be silver-impregnated.
