Infectious Causes of Gastroenteritis 1

Question 1

Why is diarrhoea deadly?

Answer 1

Acutely because of loss of fluid and electrolytes and delayed because of malnutrition

Question 2

Why does diarrhoea cause malnutrition?

Answer 2

because of increased energy loss and reduced energy intake

Question 3

How much fluid enters the gut per day?

Answer 3

10L

Question 4

How much fluid is absorbed by the gut per day?

Answer 4

9.9L

Question 5

What type of diarrhoea does a problem with the small intestine cause?

Answer 5

Infrequent stools with a large watery volume

Question 6

What type of diarrhoea does a problem with the large intestine cause?

Answer 6

Frequent stools of lowish volume - possibly containing blood and mucus

Question 7

What is the most common aetiological agent of diarrhoea in developing countries?

Answer 7

Bacteria

Question 8

What is the most common aetiological agent of diarrhoea in developed countries?

Answer 8

Viruses

Question 9

What are the aetiological agents of non-specific gastro?

Answer 9

viruses, bacteria, protozoa

Question 10

What is dystentery?

Answer 10

Diarrhoea with blood and mucus

Question 11

What are the aetiological agents of dysentery?

Answer 11

shigella, EIEC, protozoa

Question 12

What are the aetiological agents of food borne diarrhoea?

Answer 12

staph, salmonella, clostridium, bacillus, vibrio, listeria, viruses, ciguatoxin

Question 13

What are the aetiological agents of travellers diarrhoea?

Answer 13

ETEC, bacteria, viruses, protozoa

Question 14

What are the aetiological agents of antibiotic associated colitis?

Answer 14

clostridium difficile

Question 15

What are the aetiological agents of haemorrhagic colitis?

Answer 15

EHEC

Question 16

What are the aetiological agents of cholera-like diarrhoea (severe and watery)?

Answer 16

vibrio cholerae, ETEC

Question 17

What are the aetiological agents of enteric fever (typhoid and paratyphoid)?

Answer 17

salmonella typhi, s. paratyphi

Question 18

What are the 5 different types of diarrhoeagenic E. coli?

Answer 18

enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enterohaemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC)

Question 19

What is the shared adhesin for EPEC and EHEC?

Answer 19

intimin

Question 20

What is the defining factor of EHEC?

Answer 20

produces shiga toxins

Question 21

How do some EAEC get the ability to produce shiga toxins?

Answer 21

Because shiga toxins are encoded by bacteriophages

Question 22

What is the symptom of ETEC?

Answer 22

watery diarrhoea

Question 23

What is the symptom of EPEC?

Answer 23

non-specific gastro

Question 24

What is the symptom of EHEC?

Answer 24

blood diarrhoea

Question 25

What is the symptom of EIEC?

Answer 25

dysentery

Question 26

What is the symptom of EAEC?

Answer 26

water diarrhoea

Question 27

Where is ETEC most common?

Answer 27

Infants in developing countries and travellers

Question 28

Where is EPEC most common?

Answer 28

children in developing countries

Question 29

Where is EHEC most common?

Answer 29

developed countries

Question 30

Where is EIEC most common?

Answer 30

developing countries

Question 31

Where is EAEC most common?

Answer 31

children in developing countries

Question 32

Which diarrhoea causing bacteria is adhesive enterotoxigenic?

Answer 32

cholera, ETEC

Question 33

Which diarrhoea causing bacteria is adhesive with brush border damage?

Answer 33

EPEC

Question 34

Which diarrhoea causing bacteria is restricted to the mucosa?

Answer 34

shigella

Question 35

Which diarrhoea causing bacteria invades the submucosa?

Answer 35

salmonella, campylobacter

Question 36

Which diarrhoea causing bacteria can have systemic invasion?

Answer 36

salmonella

Question 37

How does EPEC adhere to microvilli?

Answer 37

Via bundle forming pili

Question 38

What is a pathogenicity island?

Answer 38

A block of genes found in pathogens that is missing from non pathogens of the same species

Question 39

What is the locus for enterocyte effacement (LEE) pathogenicity island?

Answer 39

the locus on EPEC (and EHEC) that determines is pathogenicity - includes type III secretion system, Tir and intimin and effector proteins

Question 40

What is intimin?

Answer 40

A large outer membrane protein required for intimate adherence between bacteria and the cell

Question 41

What is Tir?

Answer 41

The receptor for intimin - which human cells don’t express but is carried by EPEC

Question 42

What is the type III secretion system?

Answer 42

A system which makes up a ‘needle’ to secrete proteins directly into the cytoplasm of the cell

Question 43

What determines virulence?

Answer 43

adhesins, invasive ability, exotoxins and ability to resist killing

Question 44

What is an example of a cytotonic exotoxin?

Answer 44

cholera toxin

Question 45

What is an example of cytotoxic exotoxin?

Answer 45

shiga toxin

Question 46

Which species of shigella produces shiga toxin?

Answer 46

Shigella dysenteria

Question 47

What is the mechanism of shiga toxin?

Answer 47

it inhibits protein synthesis

Question 48

What is dysentery?

Answer 48

Diarrhoea with blood and mucus

Question 49

What causes dysentery?

Answer 49

shigella dysenteria and EIEC

Question 50

What can shiga toxin cause?

Answer 50

haemolytic uremic syndrome

Question 51

Which bacteria have a shiga toxin?

Answer 51

shigella dysenteria and EHEC and EAEC if obtain it through a bacteriophage