Microbio

Question 1

What is fulminant hepatitis? What is it associated with?

Answer 1

liver failure with massive liver necrosis

assoc. w/
- HEV infection in pregnant ♀
- Reye syndrome

Question 2

How is HEV usually transmitted?

Answer 2

fEacal oral; sEafood or contaminated water

Question 3

How is HAV transmitted?

Answer 3

feAcal oral; trAvellers

Question 4

How is HBV transmitted?

Answer 4

parenteral (e.g. childbirth, unprotected intercourse, IV drug abuse)

Question 5

How is HCV transmitted?

Answer 5

parenteral (e.g. childbirth, unprotected intercourse, IV drug abuse)

Question 6

How do shiga, and shiga-like toxin (verotoxin) work?

Answer 6

1. composed of an α subunit and 5 β subunits
2. β subunits causes receptor mediated endocytosis
3. α subunit catalyzes removal of an adenosine residue → prevents binding of tRNA to 60S subunit → inhibits protein synthesis → GI mucosal death and toxicity to renal endothelial cells

Question 7

Where does salmonella typhi live in the infected body?

Answer 7

within macrophages (gets there via phagocytosis in mesenteric lymph nodes)

Question 8

Which two toxins prevent translocation in protein synthesis? How?

Answer 8

Pseudomonas exotoxin A and diptheria toxin, via inhibiting elongation factor 2 (EF-2)

Question 9

Which two toxins stimulate Gs → activate adenylyl cyclase → upregulate cAMP → diarrhea?

Answer 9

Cholera toxin and heat labile toxin (LT) of ETEC; note that ST of ETEC also participates in diarrhea but by ↑ cGMP by activating guanylyl cyclase

Question 10

As 2 gram-negative, comma shaped, oxidase positive rods, how can you differentiate between cholera and C. jejuni?

Answer 10

cholera can survive in an alkaline rich environment

Question 11

As 2 gram-negative, comma shaped, oxidase positive rods, how can you differentiate between cholera and C. jejuni?

Answer 11

cholera can survive in an alkaline rich environment

Question 12

What is isospora belli?

Answer 12

an intestinal parasite (Coccidia family) that causes profuse watery diarrhea in HIV patients

Question 13

What does giardia look like under a microscope?

Answer 13

pear shape

Question 14

What is the point of entry for shigella into the gut wall?

Answer 14

M cells at the base of villi in a Peyer patch region of the ileal mucosa (remember, ileum is the only place w/ Peyer patches); the infection then spreads laterally through the wall → cell death, ulceration, hemorrhage, bloody diarrhea

Question 15

What is the point of entry for shigella into the gut wall?

Answer 15

M cells at the base of villi in a Peyer patch region of the ileal mucosa (remember, ileum is the only place w/ Peyer patches)