Control of GI infections

Question 1

What are most GI infections in the community caused/related to?

Answer 1

Cross-contamination of work surfaces/utensils
Undercooking of food
Improper storage of food (not refrigerated)
Poor reheating of food

Question 2

What is the most common cause of healthcare-associated diarrhoea?

Answer 2

C.Diff

Question 3

What is the mechanism of action of C.diff?

Answer 3

Produces 2 toxins, toxin A and toxin B (enterotoxin and cytotoxin)

Question 4

Where is C. Diff usually found and what causes it to become a problem and cause infection?

Answer 4

It is carried in small numbers in the bowel. Infection occurs when antibiotics kill off the norma competitive bowel flora and allow C.diff to overgrow.

Question 5

What does C.diff produces and what is it resistant to?

Answer 5

C.diff produces spores that survive in the environment and are most resistant to disinfectants and the organism can be transmitted from one patient to the next.

Question 6

What are the symptoms of having C.diff infection?

Answer 6

Diarrhoea
Bloody +/-
Abdo pain

Question 7

What can severe C.diff lead to?

Answer 7

Severe causes - progression to pseudomembranous colitis of bowel perforation

Question 8

What is the management of C.diff?

Answer 8

Depends on severity

Less severe = oral metronidazole
Severe = oral vancomycin

Question 9

How can people prevent C.diff infections?

Answer 9

Good antimicrobial prescriing (stewardship) - use narrow spec antibiotics where possible
AVOID 4 C’s

Isolation of patients
Hand washing (NOT alcohol gel)
Cleaning of environment

Question 10

What type of organism is C.diff?

Answer 10

Gram positive spore-bearing bacillus

Spores resistant to disinfectants

Question 11

What are the different laboratory diagnosis of C.diff?

Answer 11

Screening test for presence of the organism (GDH)

If GDH positive, test for presence of toxin (toxin A&B)

(Culture can be done if strain needs to be typed – not done routinely)

(STOOL TOXIN)

Question 12

What type of strains of c.diff are hyper-producers?

Answer 12

027 and 078 - increased morality and risk of death

Question 13

When might c.diff cases increase?

Answer 13

In winter due to increased hospital admissions and asa due to norovirus

Question 14

What is the most common cause of diarrhoea and vomiting in children under 3 years?

Answer 14

Rotavirus

Question 15

What is the spread route of rotavirus?

Answer 15

Person to person

Direct or indirect

Question 16

Describe the diarrhoea in rotavirus?

Answer 16

Diarrhoea with NO BLOOD

Question 17

How long does rotavirus usually last?

Answer 17

For around 1 week and it is self limiting

Question 18

When can rotavirus be severe?

Answer 18

In immunocompromised children

Question 19

Describe the infectious dose of rotavirus?

Answer 19

There is a low infectious dose of around 100-1000 particles

Question 20

How does rotavirus cause dehydration?

Answer 20

Decreased absorption of fluids and increased secretion in bowel causing dehydration

Question 21

What might children develop post infection of rotavirus’?

Answer 21

May develop post infection malabsorption causing more diarrhoea

Question 22

How do you diagnose rotavirus?

Answer 22

PCR test on faeces

Question 23

How do you manage rotavirus?

Answer 23

Rehydration is key - orally where possible

Question 24

How can you prevent rotavirus?

Answer 24

Rotavirus vaccine (oral

Live attenuated vaccine, excreted in faces
2 doses, age 2 + 3 months

Question 25

Describe norovirus?

Answer 25

Commonly known as the winter vomiting bug

Question 26

What ages does norovirus affect the most?

Answer 26

Affects all ages - IT IS HIGHLY INFECTIOUS

Question 27

What is the route of spread of norovirus?

Answer 27

Faecal-oral/droplet

Person to person (or on contaminated food/water)

Question 28

Describe the infectious does of norovirus?

Answer 28

Low infectious doses needed

Question 29

What is the incubation period of norovirus?

Answer 29

Short often < 24 hours

Question 30

Describe the symptoms of norovirus?

Answer 30

Sudden onset of explosive diarrhoea and vomiting - lasts 2-4 days

Question 31

What does vomiting in norovirus lead to?

Answer 31

Widespread contamination of the environment –> outbreaks

Question 32

How do you diagnose norovirus?

Answer 32

Daces specimen or vomit swab for PCR test

Question 33

How do you treat norivirus?

Answer 33

Rehydration is key - esp in young and elderly

Question 34

Are outbreaks common in norovirus?

Answer 34

YEs esp in hospitals, school, cruise ships

Question 35

When are patients are their most infectious?

Answer 35

When they are symptomatic with diarrhoea

Question 36

What infections would cause a patient to need a side room (isolation)?

Answer 36

C.diff

Norovirus

Question 37

What other infections are spread by faecal-oral route?

Answer 37

Hep A and E
Resistant bacteria that are carried in the GI tract e.g vancomycin-resistant enterococci, highly resistant Gram negative organisms (CPEs)

Question 38

Explain some of the standard infection control precautions of diarrhoea in hospital?

Answer 38

All patients with diarrhoea that might be infectious should be placed in a single room with own toilet/commode

Cohort nursing in bays may be required during outbreaks on wards – all patients with the same infection nursed
together with their own team of nurses

Wards may be closed to new admissions

Increased ward cleaning/disinfection of surfaces required

Question 39

What contract precautions might be done to control diarrhoea in hospital?

Answer 39

Hand washing 
Gloves 
Apron 
Single use of items 
Cleaning/disinfection of items with hypochlorite, terminal disinfection of room 
Report exposure to contaminated material