Food/water-borne diseases

Question 1

food intoxication

Answer 1

bacteria grows in food, secretes exotoxin, exotoxin is consumed, consumption of bacteria not required

Question 2

cause of food intoxication

Answer 2

improper handling and storage

Question 3

food-borne infection

Answer 3

bacteria contaminated food consumed. bacteria colonizes in intestine and cause disease. most secrete ecotoxin

Question 4

cause of food borne illness

Answer 4

improper cooking, cross contamination

Question 5

how does S. aureus food intoxication enter the body

Answer 5

carried in nasal cavity as part of normal flora

Question 6

how does S. aureus cause food intoxication

Answer 6

food handler contaminates food and leaves it at room temp

Question 7

how it the exotoxin of S. aureus unusal

Answer 7

it is heat stable. reheating food is not protective. it is a super Ag that stimulates peristalsis. vomiting occurs

Question 8

Clostridium botulium (gram +ive rod) food intoxication due to

Answer 8

errors in home canning, surviving endospores can generate vegetative cell that prosuces exotoxin

Question 9

Clostridium botulium can be destroyed by

Answer 9

since it is heat labile exotoxin boiled for 10 mins will denature

Question 10

describe exotoxin of Clostridium botulium

Answer 10

AB exotoxin. B subunit protects from stomach acid and alllows to bind to specific cell receptor. after uptake of A subunit target nerve cells and prevents muscle contraption. no diarrhea, blurred vision and respiratory paralysis leads to death

Question 11

Vibrio cholera (gram -ive) is passed by

Answer 11

oral fecal route. ID50 is 10^8 bacteria. or 10^4 if taking antiacids

Question 12

what must Vibrio cholera do to be virulent

Answer 12

bacteria must be lysogenized by 2 different phage. VP1 phage encodes PAI called VP1. VP1 includs genees for pili, used as adhesin to bind to intestinal epithelium and receptor for ctx phage. ctx phage encodes for cholera exotoxin is a AB5 exotoxin, encoded on an operon

Question 13

why are more B subuntis synthesized

Answer 13

ribosome binding site for ctxb is 70X stronger than ctxA

Question 14

what does V. cholera do in the intestine

Answer 14

secretes a neuramindase which removes sialic acid from a glycolipid calleed GM1. bacteria catabolized sialic acid

Question 15

how does CTXA of V. cholera enter the cell

Answer 15

CTXB subunit adheres to GM1 w/o sialic acid. CTXB forms a pre in intestinal cell, CTXA enters

Question 16

what does V. cholera do in the intestine

Answer 16

secretes a neuramindase which removes sialic acid from a glycolipid called GM1. bacteria catabolized sialic acid

Question 17

how does CTXA of V. cholera enter the cell

Answer 17

CTXB subunit adheres to GM1 w/o sialic acid since it has been catabolized. CTXB forms a pre in intestinal cell, CTXA enters

Question 18

fn of CTX A of V. cholera

Answer 18

ctxA activates a host cell regulatory protein called Gs by ADP ribosylation. in turn activatad Gs activated adenylate cyclaclase whech converts amp to cAMP. nomrally levels of cAMP is regulated but now Gs is also activated. increase levels of cAMP alters fn of Na+ and Cl- transporters

Question 19

how does an increase in ions in lumen lead to shock and death

Answer 19

ions does not go to the cells. osmotic pressure causes h20 to move out to lumen of intestine, so much fliud leaving leads to shock

Question 20

fn of CTX A of V. cholera

Answer 20

ctxA activates a host cell regulatory protein called Gs by ADP ribosylation. in turn activated Gs activated adenylate cyclaclase which converts amp to cAMP. normally levels of cAMP is regulated but now Gs is also activated. increase levels of cAMP alters fn of Na+ and Cl- transporters

Question 21

how does an increase in ions in lumen lead to shock and death

Answer 21

ions does not go to the cells. osmotic pressure causes h20 to move out to lumen of intestine, so much fluid leaving leads to shock