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Flashcards in Microbiology Deck (52)
1

Which organism is the commonest cause of food poisoning?

Campylobacter

2

Which organisms are more likely to cause outbreaks of food poisoning?

Salmonella
E. coli 0157

3

What is the incubation period for Staph. aureus and Bacillus cereus?

Short
1-6 hours

4

Staph. aureus produces a toxin which is rapidly absorbed by the stomach. True/False?

True

5

What is the incubation period for Salmonella and Cl. perfringens?

Medium
12-48 hours

6

What is the incubation period for Campylobacter and E. coli 0157?

Long
2-14 days

7

Which foods does Campylobacter mainly colonise?

Poultry
Raw milk
Poor food preparaiton

8

Is Campylobacter likely to spread from person to person?

No

9

Which foods does Salmonella mainly colonise?

Poultry
Raw egg
Meat, animal guts

10

What is the significance of the antigens found on Salmonella?

Different antigens on different strains, so specific antibodies will agglutinate

11

Which foods does E. coli 0157 colonise?

Beef
Raw milk, water
Wide variety really

12

Is E. coli 0157 likely to spread from person to person?

Yes

13

Who is most at risk of complications from E. coli 0157 infection?

Children + elderly

14

What is the name of the toxin produced by E. coli 0157?

Verotoxin (VTEC)

15

Which syndrome can result due to verotoxin?

Haemolytic uraemic syndrome

16

What are the sites of action of antibiotics in a cell?

Cell wall
Cell membrane
Cytoplasm
DNA

17

What is the main class of antibiotic which acts on the beta-lactam ring on the cell wall of bacteria?

Pencillins

18

Does antibiotic use lead to antibiotic resistance?

Yes

19

How does antibiotic use have public health consequences for other people, in terms of resistance?

Resistant bacteria are selected out in presence of antibiotic, and can spread between patients

20

What is meant by antimicrobial stewardship?

Prescribing optimum dosage and duration of antimicrobial treatment that results in best clinical outcome, prevention of infection and minimal resistance

21

What is gastroenteritis and what is the consequence regarding absorption?

Inflammation of stomach and small intestine
Limits absorption of nutrients and water

22

Which out of bacteria, viruses and parasites is the most common cause of gastroenteritis?

Viruses

23

What is meant by toxin-mediated food poisoning?

Toxin has been preformed by the bacteria on the host before ingestion of food, leading to acute symptoms once the food has been eaten

24

List common organisms that produce preformed toxins

Stap. aureus
Clostridium perfringens
Bacillus cereus
E. coli 0157

25

Acute enteritis often presents with fever, diarrhoea, vomiting and abdo pain. Is the diarrhoea usually bloody?

No

26

Acute colitis often presents with fever, diarrhoea and abdo pain. Is the diarrhoea usually bloody?

Yes

27

What are the main organisms that cause bloody diarrhoea?

Campylobacter
Shigella
E. coli 0157
Amoebas

28

What is the usual duration of Campylobacter infection?

5-14 days

29

Typhoid is an enteric fever like illness caused by which organism?

Salmonella

30

Which type of culture - urine, stool or blood - is key to diagnosing typhoid?

Blood
Stool and urine would be done too though

31

Name the 4 main stool investigations for infectious organisms, from most used to least

Stool culture
Stool microscopy
Stool toxin
Stool PCR

32

Which stool investigation is appropriate for Salmonella, Campylobacter and Shigella?

Stool culture

33

Which stool investigation is appropriate for Giardia, Amoebas and parasitic infections?

Stool microscopy

34

Which stool investigation is appropriate for Clostridium Difficile and E. coli 0157?

Stool toxin

35

Which stool investigation is appropriate for Norovirus?

Stool PCR

36

Which 3 markers assess the severity of C. difficile infection?

Suspicion of pseudomembranous colitis/toxic megacolon/ileus
WCC greater than 15
High creatinine

37

What is first line treatment for gastroenteritis?

Oral rehydration or IV fluids

38

Which antibiotic is commonly used for non-severe C. diff?

Oral metronidazole

39

Which antibiotic is used for severe C. diff?

Oral vancomycin
NEVER IV

40

Which antibiotic is used for first recurrence of C. diff infection?

Fidaxomycin

41

Which organism is the most common cause of traveller's diarrhoea?

E. coli 0157 (produces VTEC)

42

Which antibiotic is used for amoeba and giardia infections?

Metronidazole

43

What is the commonest cause of viral diarrhoea in kids under 3 years old?

Rotavirus

44

How is rotavirus spread?

Faeco-oral

45

Which virus is known as the winter vomiting bug?

Norovirus

46

How is norovirus spread?

Faeco-oral
Droplets

47

Describe the nature of vomiting that comes with norovirus

Explosive and sudden
Lead to environmental contamination

48

What is the diagnostic test for rotavirus and norovirus?

PCR, on stool or vomit

49

Define SIRS (systemic inflammatory response syndrome)

More than 2 of
Temperature over 38 or less than 36
RR over 20
WCC less than 4k or over 12k

50

Define sepsis

SIRS + suspected/confirmed underlying infectious process

51

What is involved in the sepsis 6 treatment?

Take blood cultures + FBC + urine output
Give fluids + antibiotics + oxygen

52

Which antibiotics are given for peritonitis/biliary tract intra-abdominal infection?

IV amoxicillin + metronidazole + gentamicin
(vancomycin if pen-allergic)