Lecture 7 Flashcards
Who was the first to find the source of a disease?
John snow, he used compared a map of diseased individuals to a map of water pumps
Describe Vibrio cholera statistics.
G-, facultative anaerobe, forms yellow colonies, has one flagella, and has short generation time
What are cholera symptoms?
few hours after infection cramping and diarrhea start, lots of fluid loss
How is cholera treated?
through monitoring and hydration
What is vibrio cholera’s main virulence factor?
cholera toxin (CTX)
Describe the cholera toxin.
AB5 toxin, ADP-ribosylating toxin, lysogenic bacteriophage
What is the cholera toxin mode of action?
5B;1A binds to host membrane
toxin is endocytosed
the CTX is taken to the endoplasmic reticulum
the A1 subunit is removed and exported to the cytoplasm
the A1 attached an ADP ribose to an AA
cAMP levels rise and activates ion transport systems causing water to leave cell (diarrieha)
Describe the features of e.coli.
- G-
- facultative anaerobe
- has flagella
What is a serotype?
an antigenically distinct group
What is a pathotype?
a term used to describe a group of strains of species that cause a common disease using a common set of virulence factor
What does the O serotype mean?
has LPS
What does the H serotype mean?
has flagella
What does the K serotype mean?
has capsule
What are the virulence determinants of e.coli?
pedestal formation and production of shiga toxin
What is the shiga toxin?
an AB5 toxin that inhibits protein synthesis in host cell
Why doesn’t EHEC cause disease in ruminants?
because the toxin receptor is absent
How does EHEC attach?
uses adherence and causes villi to shrink forming pedestals
What are effectors and what effect is used in EHEC?
effectors mediate communication between host cell and bacterium, tir
What are some features of Mycobacterium tuberculosis?
G+
non-motile
humans are only resevoir
Why is tuberculosis difficult to treat?
it has lipid-rich thick wall, and its resistant to killing macrophages
How is tuberculosis transmitted?
aerosol transmission
Where does tuberculosis invade?
binds to the peritoneal macrophage, inhibits phagosome-lyzome fusion, induces anti-inflammatory cytokines, and infected cells are walled off
What is different about latent tuberculosis bacteria in hosts?
latent cells can be reactive if host is immunocompromised
What is the mechanism of tuberculosis?
the tuberculosis replicate in the alveoli, other cells form granuloma which breaks in immunocompromised individuals
How is TB diagnosed?
Mantoux skin test - induces immune response for people with TB
What is treatment of TB?
BCG vaccine or 4-6 month supervised antibiotic treatment
