GI Infections

Question 1

What is an example of a bacterial GI infection?

Answer 1

vibrio cholera
c. difficle

Question 2

What is an example of a viral GI infection?

Answer 2

norovirus

Question 3

What is an example of a fungal GI infection?

Answer 3

mycotoxins (alflatoxins)

Question 4

What is an example of a parasite GI infection?

Answer 4

protozoan (cryptosporidium)

Question 5

What is an example of a prion GI infection?

Answer 5

BSE

Question 6

What is cholera?

Answer 6

acute diarrhoeal infection associated with inadequate access to safe water and basic sanitation

Question 7

Why is norovirus difficult?

Answer 7

extremely tolerant, persistant, large genetic variety and contagious

Question 8

What type of virus is norovirus?

Answer 8

RNA non-enveloped virus

Question 9

What are aflatoxins produced by?

Answer 9

moulds such as aspergilius flavus

Question 10

Why are aflatoxins bad?

Answer 10

high toxicity for humans
acute hepatitis and liver cancer

Question 11

What feature of cryptosporidium aids survival?

prevalent watterborne disease with outbreaks worldwide

Answer 11

life cycle involves thick walled oocysts which survive
for several months in environment

Question 12

What is the neural consequence of BSE?

Answer 12

degeneration of brain tissue =
sponge-like appearance leading to death

Question 13

What is a prion?

Answer 13

an abnormal form of
a normal body protein that has no RNA/DNA

Question 14

What is human variant of BSE?

Answer 14

vCJD via meat

Question 15

What is the impact of C. difficile on patients?

Answer 15

1. Pts suffer & get harmed unnecessarily by the spread of C. difficile
2. C. difficile is the most common bacterial cause of HAI GI infection in adults
3. CDI and outbreaks = mild diarrhoea to life threatening colitis Colitis = 5-10% mortality rate

Question 16

Where did C.difficile decrease instead of rates staying constant?

Answer 16

community associated infections

Question 17

What is the chain of infection for C.difficile?

Answer 17

Pathogen: Bacteria and bacterial spores
Reservoir: GIT, food
Portal of exit: faeces
Means of transmission: Faecal-oral (spores)
Portal of entry: oral
Susceptible hosts: Prior antibiotic therapy, elderly, hospitalized, prior C. diff, immunocompromised

Question 18

What are the characteristics of the bacteria c.difficile?

Answer 18

gram positive anaerobic bacillus
spore forming (germination)
two exotoxins (A & B)

Question 19

What do the two exotoxins cause?

Answer 19

necrosis of intestinal epithelial cells, infiltration of neutrophils and a outpouring of fluid into the intestinal lumen

Question 20

What antibiotic used of CDI may be dentally relavant?

Answer 20

clindamycin
used for bone infections

Question 21

What must happen to get a CDI?

Answer 21

The bowel flora must be altered
The bowel must be colonized with a toxigenic strain
The organism must grow and produce toxins

Question 22

What does C.difficile form on the surface of the colon mucosa?

Answer 22

pseudomembrane = false membrane consisting of a layer of exudate on the surface of a mucosa/ skin membrane

Question 23

In which age group are carriage rates high in CD?

Answer 23

newborns and infants under two years

Question 24

What is the reservior of C.difficile?

Answer 24

GIT, food

found in the IT of many types of food animals, dogs and cats

Question 25

How does C.difficile transmit?

Answer 25

via tolerant spores through faecal oral route and contact (also through contact with contaminated equipment or environment)

Question 26

What are the characteristics of spores?

Answer 26

tolerant to antiseptics, high survival
main mode of transmission

Question 27

When is there an increased risk of CDI? (susceptibile hosts)

Answer 27

Current or recent (3 months) use of broad spectrum antibiotic
Prolonged hospital stay/ Surgical procedures (esp bowel)
Elderly
Use of PPIs
Serious underlying diseases/ Immunosuppression (HIV infection and transplant)

Question 28

What is the recurrence rate of CDI?

Answer 28

20%

Question 29

How can re-infection occur?

Answer 29

from contaminated environment or poor hand hygiene
Or
relapse from germinating spores in the gut

Question 30

What is recurrence associated with?

Answer 30

significant increase of death

Question 31

What is an intervention for c.diffcile at the reservoir part of the chain?

Answer 31

review antibiotic use
(antimicrobial stewardship- antibiotics can cause CDI )

Question 32

When are antibitoics not recommened for dentistry?

Answer 32

dental cleaning for patients that can clean
prophylaxis for oral surgery

Question 33

When can symptoms occur after discontinuation of antibiotic treatment?

Answer 33

up to 8 weeks

Question 34

What are general principles used in hospitals to intervene at transmission stage?

Answer 34

1. Isolation
2. Perform hand hygiene (soap & water)
3. Decontaminate equipment and environment

Question 35

How to decrease portal of entry?

Answer 35

use PPE
perform good hand hygiene

Question 36

What are the principles that should be used for dental practice?

Answer 36

standard infection control precautions guidelines

Question 37

How to intervene at susceptible host stage?

Answer 37

recognise high risk patients (medical history)
consider patient placement

Question 38

What is an example of a occupational health issue concerning attendance?

Answer 38

presenteeism

turning up to work when too unwell, and fatigued to be productive.

Question 39

When do symptoms present in norovirus?

Answer 39

12-48 hours

Question 40

When is norovirus most infectious?

Answer 40

Most infectious when symptomatic,
but it is possible to pass on norovirus or shed the virus, Immediately prior to & after symptoms

Question 41

What is occuptational health advice for norovirus?

Answer 41

Alcohol-based hand sanitisers are not effective against norovirus.
Stay at home.
Do not return to work until 48 hours after the symptoms have stopped.