Spirochetes Flashcards
Are the spirochetes motile in general?
Yes.
6 axial filaments wind around the organism between the peptidoglycan layer and the outer cell membrane.
Contraction of axial filaments conveys spinning motion.
How do the spirochetes multiply in general?
By transverse fission
Do spirochetes have exotoxins?
No.
Are spirochetes capable of being cultured on artificial media?
No. Except Leptospira.
Where is T.pallidum found?
Humans
How is T.pallidum transmitted?
Sexually
What is the morphology of T.pallidum?
Thick rigid spirals.
What is the metabolism of T.pallidum?
Microaerophilic and highly sensitive to elevated temperatures.
Is T.pallidum motile?
Yes.
What happens in the primary stage of syphilis?
Painless chancre (skin ulcer).
What happens in the secondary stage of syphilis?
- Rash on palms and soles
- Condyloma latum: painless, wartlike lesion which occurs in warm, moist places (vulva, scrotum).
- CNS, eyes, bones, kidneys and/or joints can be involved.
What percentage of patients in the latent phase can relapse into the secondary phase of syphilis?
25%
What happens in the tertiary phase of syphilis (33%)?
- Gummas of the skin and bone.
- Cardiovascular syphilis.
- Neurosyphilis: may get the Argyll-Robertson pupil.
What is the Jarisch-Herxheimer reaction?
Acute worsening of symptoms after antibiotics are started.
How do we diagnose syphilis?
- Cutaneous lesions examined by dark-field microscopy, immunofluorescence, ELISA, or silver stain.
- Non specific treponemal test
: VDRL; BPR. - Specific treponemal tests: FTA-ABS, MHA-TP.
- PCR
Why all pregnant women should be screened with VDRL?
Because antibiotic treatment prior to 4 months of gestation prevents congenital syphilis.
Where is T.pallidum endemicum found?
Desert zones of Africa and the Middle East.
How is T.pallidum endemicum transmitted?
Sharing of drinking and eating utensils.
What is the morphology of T.pallidum endemicum?
Indistinguishable from T.pallidum.
Is T.pallidum endemicum motile?
Yes
What can T.pallidum endemicum cause?
Bejel
What happens in Bejel?
- Primary and secondary lesions occur in the oral mucosa.
2. Tertiary lesions - gummas of skin and bone.
How do we diagnose T.pallidum endemicum infection?
VDRL and FTA-ABS are positive.