Spirochetes and Vibrios Flashcards
How are spirochetes typically transmitted?
wide variety of methods
What is the primary virulence factor of spirochetes?
immune evasion
Which crosses into the blood stream more readily, Mycobacteria or Spirochetes?
Spirochetes, they do not need to establish a primary infection first. They also cross easily into the blood brain barrier
Can spirophetes be visualsed with a microscope?
Typically no, which makes lab diagnosis tricky
What is a Jarisch-Herxheimer reaction?
It is a spirochete reaction to treatment in which an individual developes flue like symptoms 24 hours after treatment. The reason for this reaction is unknown. The dead bacteria are possibly more virulent than the live ones.
How do spirochete diseases usually present?
In phases
What bacteria causes syphillis?
Treponema pallidum
What are the lab properties of T. pallidum?
1- Slow growing, cannot be cultured
2- too small to gram stain
3- Have “corkscrew” flagella
What type of cells does T. pallidum infect?
epithelium of small blood vessels (allows it to pass easily into the blood)
How is T. pallidum transmitted?
Usually sexual contact or transplacentally
What are the phases of a syphillis infection?
1- Primary Syphillis
2- Seconday Syphillis
3- Tertiary syphillis or latency
What is the main symptom of primary syphillis?
a cancre forms at the initial site of infectio and intiates bacteremia
What is the main symptom of secondary syphillis?
mucoutaenous lesions of various types, systemic symptoms and high antibody titres
After secondary syphillis what can happen?
1- resoultion
2- latency
3- tertiary syphillis
What are the three types of tertiary syphillis?
1- Gummatous syhpillis
2- Cardiovascular syphillis
3- Neurosyphillis
What is the main symptom of gummatous syphillis?
granulommas wuth rubbery necrotic center
What is the main symptom of carviovascular syphillis?
aneurysm of the ascending aorta
What is the hallmark sign of neurosyphillis?
Argyll-roberston pupil
If a baby is born with congenital syphillis what are the typically outcomes?
stillbirth and many fetal abnormalities
What agent causes lyme disease?
B. burgdorferi
Can B. burgdorferi be visualized by microscope?
Yes, silver stain
What is the vector of B. burgdorferi?
Tick
About 6 months after infection with B. burgdorferi, what are the symptoms?
rash, flue like, lymphadenopathy, anti-spirochete and auto antibodies are raised
What are the symptoms about 1 year after an infection with B. burgdorferi?
immune and neurological issues arise
What are the symtoms of chronic lyme disease?
arthritis, encephalopathy, fibromyalgia, bells palsy, and aseptic memingitis
How is lyme disease usually diagnosed?
Urine tests in pipeline, but for now it is serology and ELISA
What are the typical lab properties of vibrios?
Gram -, curved bacteria that are also halophiles
What is the primary route of intection for vibrios?
fecal-oral
Is V. cholerae an obligate aerobe or a facultative anaerobe?
both
What is the pathogenesis of V. cholerae?
1- Transmitted via fecal-oral route
2- surviving bacteria reach the small intestine
3- secrete mucinase to clear the brush boarder where they attach and colonize
4- secrete toxin
What are the major causes of death due to V. cholerae
The bacteria is self limiting. So people die of dehydration and electrolyte imbalance (intersitital dehydration)
What is the structure of the cholera toxin?
A and B subunit structure
What is the mechanism of the cholera toxin?
B subunit binds the GM1 receptor on the intestinal lining and causes the loss of water and ions. The absorption via microvilli is blocked.
What are the lab properties of H. pylori?
Curved, gram - rods that are urease +
What is the pathogenesis of H, pylori?
1- attachment to mucous-secreting cells of the stomach with flagella
2- break down urea in stomach into ammonia which neutralies the pH of hte stomach
How is H. pylori diagnosed?
1- urea breath test
2- antigen in stool
How are spirocetes treated typically?
tetracycline
