Infectious Causes of Gastroenteritis 1 Flashcards Preview

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Flashcards in Infectious Causes of Gastroenteritis 1 Deck (51):
1

Why is diarrhoea deadly?

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

2

Why does diarrhoea cause malnutrition?

because of increased energy loss and reduced energy intake

3

How much fluid enters the gut per day?

10L

4

How much fluid is absorbed by the gut per day?

9.9L

5

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

Infrequent stools with a large watery volume

6

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

Frequent stools of lowish volume - possibly containing blood and mucus

7

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

Bacteria

8

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

Viruses

9

What are the aetiological agents of non-specific gastro?

viruses, bacteria, protozoa

10

What is dystentery?

Diarrhoea with blood and mucus

11

What are the aetiological agents of dysentery?

shigella, EIEC, protozoa

12

What are the aetiological agents of food borne diarrhoea?

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

13

What are the aetiological agents of travellers diarrhoea?

ETEC, bacteria, viruses, protozoa

14

What are the aetiological agents of antibiotic associated colitis?

clostridium difficile

15

What are the aetiological agents of haemorrhagic colitis?

EHEC

16

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

vibrio cholerae, ETEC

17

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

salmonella typhi, s. paratyphi

18

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

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

19

What is the shared adhesin for EPEC and EHEC?

intimin

20

What is the defining factor of EHEC?

produces shiga toxins

21

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

Because shiga toxins are encoded by bacteriophages

22

What is the symptom of ETEC?

watery diarrhoea

23

What is the symptom of EPEC?

non-specific gastro

24

What is the symptom of EHEC?

blood diarrhoea

25

What is the symptom of EIEC?

dysentery

26

What is the symptom of EAEC?

water diarrhoea

27

Where is ETEC most common?

Infants in developing countries and travellers

28

Where is EPEC most common?

children in developing countries

29

Where is EHEC most common?

developed countries

30

Where is EIEC most common?

developing countries

31

Where is EAEC most common?

children in developing countries

32

Which diarrhoea causing bacteria is adhesive enterotoxigenic?

cholera, ETEC

33

Which diarrhoea causing bacteria is adhesive with brush border damage?

EPEC

34

Which diarrhoea causing bacteria is restricted to the mucosa?

shigella

35

Which diarrhoea causing bacteria invades the submucosa?

salmonella, campylobacter

36

Which diarrhoea causing bacteria can have systemic invasion?

salmonella

37

How does EPEC adhere to microvilli?

Via bundle forming pili

38

What is a pathogenicity island?

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

39

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

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

40

What is intimin?

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

41

What is Tir?

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

42

What is the type III secretion system?

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

43

What determines virulence?

adhesins, invasive ability, exotoxins and ability to resist killing

44

What is an example of a cytotonic exotoxin?

cholera toxin

45

What is an example of cytotoxic exotoxin?

shiga toxin

46

Which species of shigella produces shiga toxin?

Shigella dysenteria

47

What is the mechanism of shiga toxin?

it inhibits protein synthesis

48

What is dysentery?

Diarrhoea with blood and mucus

49

What causes dysentery?

shigella dysenteria and EIEC

50

What can shiga toxin cause?

haemolytic uremic syndrome

51

Which bacteria have a shiga toxin?

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