L23_Spirochetes and Vibrio Flashcards Preview

Microbiology > L23_Spirochetes and Vibrio > Flashcards

Flashcards in L23_Spirochetes and Vibrio Deck (28):

Describe the transmission methods of spirochetes.

Wide variety of methods: sexual, vector-borne, environmental


Describe the temporal onset of symptoms of spirochetes and why this happens. How is this unlike most other bacterial infections.

Cross quickly and easily into the bloodstream, causing immediate bacteremia and eventual multi-organ infections. Some also cross the blood-brain barrier, leading to meningitis and other CNS symptoms. Most other bacteria set up a locus of infection.


What are the virulence factors of spirochetes? What effect does this have on vaccination potential?

Virulence factors are primarily for immune evasion. They are not very antigenic to start with and may immunomodulate the host to further decrease the response. As a result, no vaccines.


Describe the ease of diagnosis of spirochetes

Diagnosis is challenging: disease proceeds in phases which may be separated by months or years (meticulous history!), treponema are too small to see by standard microscopy, Lyme Disease has no quick&clear lab test.


What is a very useful non-invasive diagnostic tool?

Eye exams can be useful for diagnosis: Argyll-Robertson pupil. One or both pupils are unresponsive to light, but do dilate when focussing on an approaching object. Argyll-Robertson pupil


What sexually transmitted disease is caused by a spirochetes?



Once diagnosis of a spirochetes is made, can it be treated?

Yes usually fairly simple with antibiotics, especially if caught early.


what is the Jarisch-Herxheimer reaction to treatment of spirochetes?

Patients will generally develop flu like symptoms about 24 hrs after administration of antibiotics. These should shortly subside.


Can syphilis be seen by light microscopy?



What is the shape of syphilis and how does it move?

It is a corkscrew shape. The entire organism rotates to move.


Describe the procession of syphillis

Syphilis proceeds in three stages from a painless chancre to variable types of rash with flulike symptoms (meningitis possible) to either latency or dangerous cardiac or CNS involvement (gummas possible). Congenital syphilis is devastating and preventable with prenatal care.


What bug causes syphilis?

Treponema Pallidum


What is the common vector for lyme disease and where is it most prevalent?

tick borne, Northeast US in summer


How long does lyme disease require to transmit?

24 hours


What are the phases of lyme disease?

Lyme Disease also has three phases: skin infection (rash common), immune/neurological issues, Chronic Lyme with more severe immune, neuro-, fibromyalgia.


What antibiotic is given to treat lyme disease and how long should it be administered?

Doxycyline, no longer than 1 month!!!!!


Describe the shape and gram staining of Vibrio

curved, Gram(-) rods


Describe where vibrio dwell

Most vibrio pathogens are ocean-dwelling, several are halophiles.


What vibrio species causes peptic ulcers?

H. pylori


How are vibrio typically acquired?

Primarily cause fecal-oral gastroenteritis, may also infect wounds contaminated by seawater or ocean debris


What two disease processes caused by vibrios require special virulence factors?

Gastroenteritis and peptic ulcers require GI virulence factors.


Describe the acquisition and colonization of V. Cholera. What genetic marker to V. Cholera typically have?

V. cholerae has a complex planktonic lifecycle outside the human host; most pathogenic strains bear O1 genetic marker of colonization by lysogenic bacteriophage that carries virulence factors. Transmitted to humans by fecal-oral route, usually killed by stomach acid, if survives, secretes mucinase to attach to and colonize the intestine.


After colonization how does V. Cholera fuck you up?

After colonizing, secretes choleragen, an A-B subunit enterotoxin that interferes with signal transduction to cause massive watery diarrhea. Dehydration and electrolyte imbalance result and are the main problems to treat; antibiotic treatment is tertiary and may not be necessary – infection is self-limited.


How does H. pylori survive in the stomach?

H. pylori in stomach survives by producing urease, which converts urea to ammonia. Ammonia neutralizes stomach acid, irritates stomach lining. Irritation and induction of apoptosis by pathogen cause ulcers, predispose to cancer.


How can you test for H. Pylori in the stomach?

Urea Breath test: patients who swallow radio-labeled urea, if colonized by urease-producing H. pylori, will exhale radiolabeled carbon dioxide.


Once diagnosed, how do you treat/cure H. pylori?

H. pylori cure is a 10-14 day course of three antibiotics with PeptoBismol and proton pump inhibitors. Reinfection may occur.


What immune response due spirochetes down regulate?



Why are treponemes so dangerous during pregnancy?

Because they readily cross the placenta