GI microbiology

Question 1

How is rotavirus spread?

Answer 1

Faecal-oral route

Question 2

What is the clinical presentation of rotavirus infection?

Answer 2

Fever, then vomiting, then diarrhoea

Question 3

Does rotavirus cause bloody diarrhoea?

Answer 3

No

Question 4

Does rotavirus have a high or a low infectious dose?

Answer 4

Low - 100-1000 particles required for infection

Question 5

Which part of the GI tract does rotavirus have an effect on?

Answer 5

Affects absorption and secretion in the bowel

Question 6

How is rotavirus diagnoses?

Answer 6

PCR on faeces

Question 7

What might affect children after infection with rotavirus?

Answer 7

Post-viral malabsorption, causing more diarrhoea

Question 8

How is the rotavirus vaccine administered?

Answer 8

Orally

Question 9

What form does the rotavirus vaccine take?

Answer 9

Live attenuated

Question 10

Where is the rotavirus vaccine excreted?

Answer 10

Faeces

Question 11

How is norovirus spread?

Answer 11

Faecal-oral route

Droplets

Question 12

Does norovirus have high or low infectious dose?

Answer 12

Low

Question 13

What is the clinical presentation of norovirus?

Answer 13

Explosive, sudden onset diarrhoea and vomiting

Question 14

How long does norovirus infection tend to last?

Answer 14

2-4 days

Question 15

How is norovirus diagnosed?

Answer 15

PCR on faeces

Question 16

How is infection with norovirus managed?

Answer 16

Hydration

Cohort nursing/isolation in hospitals

Question 17

What toxins might C difficile produce?

Answer 17

Enterotoxin
Cytotoxin
Spores

Question 18

What is the usual cause of C difficile infection?

Answer 18

Disruption of normal gut flora

Antibiotic use

Question 19

What complication might be cause by C difficile infection?

Answer 19

Pseudomembranous colitis

Question 20

How common are relapses in C difficile infection?

Answer 20

Occur in 30% of cases

Question 21

What are some of the risk factors for development of C diff?

Answer 21

Antibiotic use
Recent surgery
Hospital admission
Use of PPI

Question 22

What two tests must be positive for diagnosis of C diff to be made?

Answer 22

C diff antigen

C diff toxin

Question 23

What is food poisoning?

Answer 23

Illness caused by eating food contaminated with micro-organisms, toxins, poisons etc.

Question 24

What is the most common bacterial cause of food poisoning?

Answer 24

Campylobacter

Question 25

Which bacteria have a short incubation period and how long is this incubation period usually?

Answer 25

Bacillus cereus Staph. aureus 1-6 hours

Question 26

What symptoms would patients usually present with in food poisoning with a bacteria of short incubation period?

Answer 26

Vomiting | Abdominal pain

Question 27

How long is the usual incubation period for campylobacter?

Answer 27

16-48 hours

Question 28

What kinds of food may be contaminated with campylobacter?

Answer 28

Poultry | Milk

Question 29

What are some of the symptoms and signs of campylobacter infection?

Answer 29

Pain Fever Diarrhoea Bloody in 30% of cases

Question 30

How long is the usual incubation period for salmonella enteritidis?

Answer 30

12-48 hours

Question 31

What are some of the symptoms of salmonella enteritidis?

Answer 31

Diarrhoea Vomiting Blood Fever

Question 32

What foods might salmonella be present in?

Answer 32

Poultry Meat Eggs

Question 33

Why is serogrouping of salmonella useful?

Answer 33

It can help pinpoint the source of infection, and so is useful for detecting outbreaks

Question 34

What are the most common serotypes of salmonella?

Answer 34

B, C & D

Question 35

What does E. Coli O157 present with?

Answer 35

Bloody diarrhoea

Question 36

Does E. Coli O157 have a low or a high infectious dose?

Answer 36

Low

Question 37

What kinds of food might E. Coli O157 have contaminated?

Answer 37

Beef | Raw milk

Question 38

What toxin does E. Coli O157 produce?

Answer 38

Verotoxin

Question 39

What is a potential complication of verotoxin production from E. Coli O157?

Answer 39

Haemolytic uraemic syndrome (HUS)

Question 40

Patients within which age group tend to develop HUS?

Answer 40

< 16

Question 41

What is the clinical presentation of HUS?

Answer 41

``` Abdomina; pain Fever Pallor Petechiae Oliguria Bloody diarrhoea in 90% of cases ```

Question 42

What blood abnormalities might HUS show?

Answer 42

``` High white cells Low platelets Low haemoglobin Red cell fragments LDH > 1.5 x normal ```

Question 43

What does verotoxin do?

Answer 43

Binds to receptors found on renal cells, RBC & others - Inhibit protein synthesis Causes cell swelling, intravascular coagulation and platelet aggregation Causes mechanical damage to RBC

Question 44

What tests should be done in suspected diagnosis of HUS?

Answer 44

Send U&E, FBC, film, LFT, clotting, urine, (dipstick/micro), lactate dehydrogenase Stool culture should be done on all bloody diarrheoa

Question 45

What are some of the complications of HUS?

Answer 45

Acute renal failure Thrombocytopaenia Haemolytic anaemia

Question 46

What is the most common cause of bloody diarrhoea in children?

Answer 46

E. Coli O157