Microbiology 4 - GI Infections Flashcards Preview

1st Year - Gastroenterology > Microbiology 4 - GI Infections > Flashcards

Flashcards in Microbiology 4 - GI Infections Deck (58):
1

What is the incubation period?

the time between contracting the infection (i.e. swallowing the organsim) and the first clinical symtpoms/ signs of infection

2

What avoidable circumstances are most infections in the community related to?

Cross-contamination of work surfaces/ utensilsUndercooking (insufficient heat to kill off pathogens), linked to inadequate defrosting of frozen foodImproper storage of food (inadequate refrigeration)Poor reheating of food

3

What are the purpose of local microbiology laboratories in terms of when they find a GI infection? (2)

All GI infections reported promptly to local Health Protection TeamAll isolates sent to Scottish Reference Lab

4

Where are all isolates from local labs sent?

Scottish Reference Labs

5

What do the reference labs do to isolates?

Collect them and perform further typing (linking of isolates across Scotland)

6

What is the role of health protection teams?

Receive reports of GI infections from local labs and send environmental health officers out to interview patients and find origin of infection

7

What is a common cause of healthcare-associated diarrhoea?

Clostridium difficile

8

What age of patients carry C diff as part of their normal bacterial flora?

InfantsElderly (less commonly)

9

What causes the patient to become unwell with C diff.?

Production of toxins

10

What toxins are produced by C diff?

Toxin A (enterotoxin)Toxin B (cytotoxin)

11

What is the source/ vehicle of infection of C diff?

Present in bowel in small numbers in a number of peopleWhen antibiotics prescribed, it kills off the normal competitive bowel flora allowing C diff to overgrowOrganism produces spores that survive in the environment dn are more resistant to disinfectantsOrganism is transmitted from one patient to another

12

Symptoms of C diff?

Diarrhoea (sometimes bloody)Abdo painSevere cases may progress to pseudomembranous colitis or bowel perforation

13

Management of C diff?

Depends on severity assessment:Less severe = oral metronidazoleSevere = oral vancomycin

14

Prevention of C diff? (4)

Stewardship Isolate patientsHand washing (not alcohol)Cleaning the environment

15

What type of bacteria is c diff?

Gram positive spore-bearing bacillus (spores more resistant to disinfectants)

16

There is no one good lab test for C diff? - true/ false

True

17

What lab tests can be performed for the diagnosis of C diff?

Screening test for presence of the organism (GDH)If GDH positive, test for presence of toxin (toxin A and B)Culture can be done if strain needs to be typed - not done routinely

18

Does the patient have c diff if the screening test is negative?

No

19

Does the patient have c diff is the screening test pos, toxin test pos?

Positive result

20

Does the patient have c diff is the screening test pos, toxin test neg?

Indeterminate result

21

What is the action plan if the lab tests for C diff are indeterminate?

Assess patientSend repeat specimen (usually also indeterminate result also so have to make clinical decision - faeces usually smells of "horse shit" so ask experienced nurse if they think the patient has C diff

22

During what season are more cases of C diff seen?Why is this thought to be the case?

WinterIncreased number of admission and possibly linked to the norovirus

23

Give an example of a hospital-acquired infection which is nationally surveyed?

C diff (can also occur in the community)

24

What 2 ribotypes of C diff are hyper-producers of toxin (leading to an increased morbidity and risk of death?

Ribotypes 027 and 078

25

Viruses that cause diarrhoea? (2)

RotavirusNorovirus

26

What is the commonest cause of Diarhhoea and vomiting in children

Rotavirus

27

Do you get blood in the stool with rotavirus?

No

28

How is roravirus spread?

Person-person spread, direct or indirect

29

What months are the rotavirus more common in?

Winter months

30

Do adults tend to experience severe symptoms with rotavirus?

No, they tend to get subclinical or mild symptoms (can be severe in immunocompromised children)

31

How long does rotavirus tend to last?

Around 1 week

32

Does the rotavirus have a high or low infectious dose?

Low

33

What features make rotavirus easily spread?

Survives in the environmentBillions shed in faeces when diarrhoea

34

Why do patients with rotavirus get dehydrated?

Decreased absorption of fluids and increased secretion in bowel causing dehydration

35

What can patients develop after rotavirus that causes more diarrhoea?

Post-infection malabsorption

36

How is rotavirus diagnosed?

PCR test on faeces

37

What is the key management for rotavirus?

Rehydration (orally where possible)

38

How is the rotavirus vaccine given?doses?Who is it not given to?

Orally (live attenuated vaccine excreted in the faeces)2 doses, age 2 and 3 monthsNot given to children > 24 weeks as high risk of intussusception

39

What is the technical name for the winter vomiting disease?

Norovirus - can occur all year round

40

what ages does norovirus tend to affect?

All ages (highly infectious)

41

How is norovirus spread?

Faecal-oral/ droplets routes of spreadPerson to person (or contaminated food/ water)

42

Does norovirus have a low or high infectious dose?

Low

43

Incubation period of norovirus?

Short - often

44

What is the symptoms of norovirus?

Sudden onset explosive diarrhoea lasting 2-4 daysVomiting leading to widespread contamination of environment = outbreaks

45

Diagnosis of norovirus?

Faeces specimen or vomit swab for PCR

46

Treatment of norovirus?

Rehydration (especially in the young and elderly)

47

How long after cessation of symptoms of norovirus are you infectious?

Up to 48 hours (asymptomatic shedding)

48

When are patients with a diarrhoeal illness most infectious?

When symptomatic with diarrhoea (remember not all diarrhoea is due to infection)

49

What 2 infections should patients definitely be given a side room with?

C diffiileNorovirus(all patients with diarrhoea that might be infectious should be placed in a single room without toilet/ commode) - cohort nursing in bays may be required during outbreaks on wards when there is not enough single rooms availableWards may be closedIncreased ward cleaning/ disinfection required

50

What are 2 examples of GI infections with which patients may require admittance to the infectious diseases unit?

SalmonellaE coli O157

51

What other infections (apart from diarrhoea organisms) mat be spread by the faecal-oral route?

Hepatitis A and EResistant bacteria that are carried in the GI tract e.g. vancomycin-resistant enterococciHighly resistant Gram negative organisms (CPEs)

52

What is cohort nursing?

All patients with the same infection nursed together with their own team of nurses

53

What should be used to clean / disinfect a room after a patient with diarrhoea infection has stayed in it?

Hypochlorite

54

What causes travel related diarrhoea? (3) - parasites

AmoebiasisGiardiasisCryptosporidasis

55

How to treat traveler diarrhoea?

Single dose of ciprofloxacinAnti-diarrhoeals

56

How to treat amoebiasis infection?

metronidazole + remove from lumen using diloxamide fruit or paromycin

57

How is ameobas spread?

Faecal-oral route

58

How are amoebas diagnosed?

Exam stool for ova