Control of GI Infections

Question 1

common organisms of GI infections in the hospital settings

Answer 1

clostridium difficile (C diff)

Question 2

describe C diff

Answer 2

common cause of healthcare-associated diarrhoea

carried as part of normal bacterial flora in elder (and infants)

Question 3

mechanism of action of C diff

Answer 3

organism produces 2 toxins;
A - enterotoxin
B - cytotoxin

Question 4

how does C diff cause infection

Answer 4

antibiotics kill of normal competitive bowel flora - allowing for C diff to overgrow and produce spores = making it resistant to disinfectants

Question 5

spread of C diff infection

Answer 5

transmitted from patient to another via hands and also surfaces

Question 6

symptoms of C diff

Answer 6

diarrhoea +/- blood

abdominal pain

Question 7

severe cases of C diff - symptoms

Answer 7

pseudomembranous colitis

bowel perforation

Question 8

treatment for less severe C diff

Answer 8

oral metronidazole

Question 9

treatment for severe C diff

Answer 9

oral vancomycin

Question 10

prevention of C diff

Answer 10

isolation of patients
hand washing
clean environment
good antimicrobial prescribing (narrow spectrum)

Question 11

describe features of C diff

Answer 11

gram positive
spore-bearing
bacillus

Question 12

laboratory tests for C diff

Answer 12

screening for presence of organism (GDH)
organism positive - presence of toxin (A and B)
culture (if strain needs to be typed) - not done routinely

Question 13

laboratory results for C diff - positive result

Answer 13

screening test positive

toxin test positive

Question 14

laboratory results for C diff - indeterminate result

Answer 14

screening test positive

toxin test negative

Question 15

management of indeterminate result of C diff

Answer 15

send repeat specimen for testing

clinical decision is required if next set of results is also indeterminate

Question 16

outbreaks of C diff

Answer 16

more cases in winter due to increase number of admissions and to norovirus - this is where strains need to be typed

Question 17

hyper-producer of toxin strains of C diff

Answer 17

cause an increase in morbidity and death

Question 18

viruses causing diarrhoea

Answer 18

rotavirus

norovirus

Question 19

describe rotavirus

Answer 19

commenest cause of diarrhoea and vomiting in children <3 years - severe in immunocompromised children
commoner in winter months
lasts about a week

Question 20

how is rotavirus spread

Answer 20

person-person - direct or indirect

Question 21

symptoms of rotavirus

Answer 21

mild to severe diarrhoea (no blood)
dehydration

may develop post-infection malabsorption - causing more diarrhoea

Question 22

how does rotavirus cause dehydration

Answer 22

decreases absorption of fluids and increases secretion in bowel

Question 23

lifecycle of rotavirus

Answer 23

billions of particles are shed in faeces when diarrhoea

they then survive in the environment until spread to another patient

Question 24

laboratory tests for rotavirus

Answer 24

PCR on faeces

Question 25

treatment for rotavirus

Answer 25

rehydration

oral rotavirus vaccine

Question 26

describe vaccine for rotavirus

Answer 26

live attenuated vaccine
execrated in faeces
children aged 2-3months

Question 27

describe the norovirus

Answer 27

‘winter vomiting disease’
affects all ages
community circulation is the reservoir

Question 28

how is norovirus spread

Answer 28

highly contagious
faecal-oral or droplet route of spread
person to person (or on contaminated food/water)

Question 29

symptoms of norovirus

Answer 29

sudden onset diarrhoea and vomiting - leading to widespread contamination

Question 30

laboratory tests for norovirus

Answer 30

PCR test - faeces specimen or vomit swab

Question 31

treatment for norovirus

Answer 31

rehydration

Question 32

infections spread via faecal-oral route

Answer 32

hepatitis A and E

resistant bacteria in GI tract - vancomycin-resistant enterococci, highly resistant gram negative organisms