Lecture 58 - Dysentery-Causing Bacteria

Question 1

Is Shiga toxin or the IPA genes more responsible for the pathogenesis of Shigella?

Answer 1

IPA genes

Question 2

Why are antibiotics not prescribed for a patient with EHEC?

Answer 2

The bacteria respond with an SOS reaction that upregulates a bunch of stuff, including the production of the Shiga-like toxin –> extremely deleterious to kidneys (HUS) and CNS

Question 3

EHEC is the only E. coli species that is ______ negative (can’t ferment it).

Answer 3

Sorbitol

Question 4

Campylobacter sp. have a characteristic “____ wing” (curved/helical pairs) morphology. They produce a Shiga-like toxin, and have a polar _______.

Answer 4

“Gull wing”

Flagella

Question 5

Salmonella appear _____ on Hektoen agar because they produce _____ gas, while Shigella do not, so they appear _____ on Hektoen agar.

Answer 5

Black

H2S gas

Green

Question 6

Salmonella typhi only infects humans and can remain persistent in the ____ _____ –> If Abs to the ____ antigen remain high after recovery, this is a sign that a person is a carrier with this persistent infection.

Answer 6

Gall Bladder

Vi

Question 7

H. pylori produces a toxin called ____ A which targets mitochondria in epithelial cells –> leads to cell death. Keep in mind H. pylori is urease + –> to test for urease in the gut, a patient consumes radiolabeled urea, and if H. pylori (which is urase +) is in the gut, they will exhale radiolabeled ______.

Answer 7

vac A

Ammonia (NH4)