Spirochetes & Vibrios Flashcards
List 8 recurring themes for spirochetes
- wide variety of transmission
- cross very easily to bloodstream
- primary virulence factors = immune evasion
- very low inflammation
- no vaccines b/c not very immunogenic
- diagnosis is challenging
- little acquired abx resistance b/c doesn’t pass around plasmids
- Jarisch-herxheimer rxn to treatment
What is the Jarisch-herxheimer rxn to treatment?
It is one of the recurring themes found in spirochete infections and is when patient develops flu-like symptoms 24 hrs post-abx treatment.
Spirochetes belong into 3 genus
1) treponema (syphillus, yaws, pintas)
2) leptospira (leptospirosis)
3) borrelia (lyme disease, relapsing fever)
Describe the movement of the small treponema pallidum
flagellar “corkscrew” motion
Can treponema pallidum survive outside of humans?
Treponema pallidum is human restricted and cannot survive outside of host.
Can treponema pallidum be grown in culture?
No
Treponema pallidum will cause syphilis. What’s the difference btw acquired and congenital syphilis?
Congenital syphilis is transferred from mom to fetus thru blood. Acquired syphilis is gotten from sex.
In acquired syphilis, there’s full body infection in day 1 due to what characteristic of spirochetes?
it can readily cross membranes and into bloodstream, but it’s not immunogenic enough to cause shock
In acquired syphilis, CNS is invaded relatively early. Do symptoms develop immediately? What are the signs of CNS involvement?
Symptoms make take years to develop. First, CSF is abnormal (subarachnoid space), then meninges then brain parenchyme.
In acquired syphilis, host raises humoral immunity against treponema syphillis, but don’t clear infection. Why?
B/c surface of spirochetes is non-immunogenic. Also spirochetes downregulate TH1 cells, which help activate macrophages.
Primary syphilis is highly infectious. What are the symptoms and what is the treatment?
Patient will present with painless chancre at site within 3-6 weeks of infection. The chancre will heal, but syphilis will remain. Treatment is one shot of penicillin.
Why is secondary syphilis, which occurs when primary syphilis isn’t cured harder to diagnose?
it is much harder to diagnose because of variable symptoms. Patient can present with fever, malaise, myalgias. Nothing that will directly tie it to syphilis, especially if patient doesn’t mention chancre that has gone away.
What is reagin?
useless antibodies found in someone with secondary syphilis
2/3 of secondary syphilis will become
latent syphilis serving as reservoir of treponema pallidum
The other 1/3 of secondary syphilis will become tertiary syphilis, which can cause a wide range of symptoms
- cardiovascular syphilis (aneurysm of ascending aorta)
- gummatous syphilis in liver, bone, testes seen as granulomas with rubbery, necrotic centers
- neurosyphilis
What are the 3 kinds of neurosyphilis?
- syphilitc meningitis (usu. occurs early on around 6 months post-exposure)
- meningovascular syphilis will damage blood vessels of meninges, brain and spinal cord
- parenchymal neurosyphilis leading to impaired sensation, wide-based gait and loss of pain and sensation due to disruption of dorsal roots.
neurosyphilis can cause general paresis and dementia
What does the Argyll-Robertson Pupil Exam test for?
It can detect neurosyphilis.
- 1 or both pupils will fail to constrict in response to light (neg pupillary reflex uni or bilaterally)
- but both pupils will constrict when testing for accommodation (positive accommodation test).
Infants with congenital syphilis will develop what kinds of symptoms within first two years of life?
severe secondary syphilis (fever, malaise, myalgias, etc)
Often times, fetuses infected with treponema pallidum will
be stillborn, miscarried in 40-50% of cases
Borrelia burgdorferi is a spirochete that can cause which disease
Lyme Disease
Treponema pallidum is motile and so is borrelia burgdorferi. Describe their movements
Treponema pallidum has a flagellar corkscrew motion. Borrelia burgdorferi has a flatwave, not spiral movement
Unlike treponema pallidum which is too small to be seen under std light microscopy, borrelia burgdorferi can be seen. But it needs special stain, such as
silver stain
What are the 2 general reservoirs of borrelia burgdorferi?
- small mammals carrying nymph (immature, young ticks)
2. large mammals carrying adult ticks
How long does it take ticks to transmit lyme disease?
about 24-48 hours, which is why checking oneself for ticks everyday in endemic areas can be a great preventative measure