Spirochetes Flashcards
What kind of morphology/motility do spirochetes have?
- Gram negative and anerobic
- Helically coiled body (spiral shaped)
- Motile - corkscrew movement
Where is the flagella located for spirochetes?
in the periplasm
Are all spirochetes pathogenic?
no
What are the 3 species/genera of spirochetes that cause human disease?
- Leptospira species
- Treponema pallidum (subspecies pallidum)
- Borrelia burgdorferi
What disease do leptospira cause?
Leptosporosis
What is an example of a pathogenic leptospira and a non-pathogenic one?
Pathogenic: L. interrogans
Non-pathogenic: L.biflexa
What is the natural habitat for Leptospira sp.?
stagnant fresh water
What growth conditions do Leptospira favour?
higher temperatures
- see it more in the summer months
What is the geographical/time distribution of Leptospirosis cases?
usually occur in tropical areas
outside of tropical areas, the distribution of cases is seasonal (usually)
- typically occurring in Aug-Sep
Leptospirosis is a zoonotic disease. What is the primary host? what are humans?
Primary host: rodents
Humans: accidental hosts
What other animals can be infected with Leptospirosis?
trick question! pretty much any animal, wild or domestic
How do humans become infected with Leptospirosis?
ingestion or contact with water/soil contaminated by animal urine
- through breaks in the skin or mucous membranes
Why is the diagnosis of leptospirosis often missed?
Because there can be a wide range of symptoms
- flu like symptoms
- can also mimic other diseases as it progresses
What 3 antibiotics can be used to treat leptospirosis?
- Aminoglycosides
- Doxycycline
- ß-lactams
What is the timeline of where the spirochetes can be found in the body for leptospirosis?
- First 7-10 days they can be found in the blood
- leptospiremia - After this they move to the kidneys and are found in the urine
Why is culture not really used to diagnose leptospirosis in the lab?
Because you need a very special media and it takes about 3 months to generate a positive/negative results
What is the go to lab method used to diagnose leptospirosis?
Serology - looking for IgM and IgG responses
Sometimes will also do PCR on blood or urine depending on the timing
In the treponema genus, how many are human pathogens?
4
Which species of treponema causes syphilis?
T. pallidum subsp. pallidum
What are the 4 stages of syphilis? what is a characteristic symptom of each?
- Primary - chancre and lymphadenopathy
- Secondary - rash
- Latent - asymptomatic
- Tertiary - cardiovascular, neurological issues or gumma
What is the chancre like? is it infectious?
painless ulcer with sharp borders and clean base
contact leads to infection in >50% of cases
What is the presentation of the rash like in syphilis? What is distinctive?
Can present variably - diffuse, maculopapular, pustular
What is the lab-diagnosis definition of latent syphilis?
having serological proof of infection without symptoms of disease
What is the differentiation between early and late latent syphilis?
- Early latent: less than a year after secondary syphilis
2. Late latent: greater than 1 year after secondary syphilis
What are the 3 potential presentations of tertiary syphilis?
- Gummatous syphilis
- soft, tumour-like balls of inflammation in the skin, bone liver etc. - Neurosyphilis
- Cardiovascular syphilis
What are the 2 days that syphilis can be transmitted?
- Sexual contact
2. Vertical transmission
Vertical transmission of syphilis often results in?
miscarriage and stillbirth
What are some early vs. late symptoms of congenital syphilis?
Early: kind of looks like an RTI at birth
- rash, fever, pneumonitis, hepatosplenomegaly
Late: if untreated
- saddle nose, clutton’s joints, saber shin, hutchinson teeth
What is the treatment for syphilis?
IM or IV penicillin
- not the typical kind
- Benzathine (IM)
- PenG (IV)
When is IV PenG given?
for neurosyphilis
What can be given as an alternate drug treatment for syphilis if the patient is allergic to penicillin?
Doxycycline
Can you culture syphilis?
Not on artificial media
Used to use a rabbit infectivity test (RIT)
What is the main diagnostic tool used for syphilis?
serology
What are the two types of serological tests used for syphilis?
non-treponemal and treponemal
What is another name for non-treponemal tests?
flocculation test
How do non-treponemal tests work? what type of test are they
Agglutination type test
- Treponemes induce damage to host cell
- Body then produces anti-cardiolipin antibodies
- These interact with lecithin-cholesterol-cardiolipin
What are 2 examples of non-treponemal tests?
- Rapid Plasma Reagin (RPR)
2. Venereal Disease Research Lab test (VDRL)
What are the disadvantages of non-treponemal tests?
- Insensitive early and late in disease
- False positive reactions can occur so you always need to do a confirmatory test
- ex: in an area with other endemic treponemes, endocarditis, pregnant…
Non-treponemal rests are the most sensitive at detecting which stage of syphilis?
secondary stage
What are 2 advantages to non-treponemal serological testing?
- Rapid, inexpensive, and easy to perform
- qualitative - Quantitative in that it can be used to measure response to therapy
What are treponemal tests measuring?
Measure antibody directed against T. pallidum antigens
What are 4 examples of treponemal tests? Which one would you use first?
- EIA
- would probably use this first because of IgM capture but you can get false positives - Fluorescent treponemal antibody absorbed (FTA-ABS)
- T.pallidum particle agglutination (TPPA)
- Recombination immunoblot
What are some disadvantaged to treponemal testing?
- People are reactive for life, even after treatment
- can’t use it to monitor treatment - False positives can still occur
- False negatives can also occur
What is the current testing algorithm for syphilis?
- Do an EIA IgM screening (treponemal test)
- if negative = no syphilis - If EIA +, do a second treponemal test (TPPA)
- if this one was negative it indicates: - had it but have been treated successfully
- early of late latent stage
- False positive EIA
- would then do an immunoblot/FTA-ABS - If + for both the EIA and the TPPA, move on to doing a non-treponemal RPR titre test
