Microbiology Of Diarrhoeal Disease Flashcards Preview

Year 2 - GI System > Microbiology Of Diarrhoeal Disease > Flashcards

Flashcards in Microbiology Of Diarrhoeal Disease Deck (26):
1

What is the pathogenesis of bacterial pathogens?

Invasion and toxin release

2

Give examples of protozoal pathogen infections that cause diarrhoea.

Cryptosporidium, giardia

3

What is the pathogenesis of a protozoal infection?

Invasion, followed by secretory products

4

Give examples of viral infection that can cause diarrhoea.

Norovirus, astrovirus and rotavirus
Also, HIV when associated with long infection and carriage of other pathogens

5

What is the pathogenesis of a viral infection?

Local invasion, cytopl this effect and lastly cell destruction

6

Name some of the host factors that would make them more susceptible to infection

Species, genotype, age, personal hygiene, gastric acidity and other physical barriers, intestinal motility, enteric microflora, immunity, non-specific protective factors in human milk, intestinal receptors and iatrogenic factors

7

What microbial factors affect how infectious they are?

Toxins, attachment, invasiveness, infectious dose. And other virulence factors

8

What is the infectious dose of shigella?

10 to 100 organisms

9

What is the infectious dose of campylobacter jejuni?

100 to 1,000,000 organisms

10

What is the infectious dose of salmonella?

100,00 organisms

11

What is the infectious dose of vibrio cholerae?

100,000,000 organisms

12

What is the infectious dose of giardia lamblia?

10 - 100 cysts

13

What are the three groups of enteric bacterial toxins?

Neurotoxin group
Secretory enterotoxin group
Cytotoxic group

14

Name some of the bacteria from the neurotoxin group.

Clostridium botulinum
Staphylococcus aureus (enterotoxin b)
Bacillus cereus (emetic toxin)

15

Name some of the bacteria from the secretory enterotoxin group.

Vibrio cholerae (cAMP)
Nonchloerae vibrios
E.coli LT, STa and STb
Salmonella
Klebsiella
Clostridium perfringens
Shigella dysentery
B.cerus

16

Name some of the bacteria in the cytotoxic group.

Shigella
S.aureus
Vibrio paraheamolyticus
Clostridium difficile
E.coli, EHEC
Campylobacter jejuni
H.Pylori
Bacteriodies fragilis

17

What are the three main mechanisms of enteric infection by bacteria?

Noninflammatory (enterotoxin or adherence)
Inflammatory (invasion, cytotoxin)
Penetrating

18

Give an example of illnesses caused by noninflammatory, inflammatory and penetrating infections.

- proximal small bowel problems causing watery diarrhoea
- problems in the colon, causing dysentery
- enteric fever found in the distal small bowel

19

What would be found in the stool in noninflammatory, inflammatory and penetrating infections?

- no fecal leukocytes, and a mild (or no) rise in lactoferrin
- presence of polymorphonuclear leukocytes and a large increase in lactoferrin
- presence of feacal mononuclear leukocytes

20

Give some examples of bacteria that cause noninflammatory infections.

Vibrio cholerae
E.coli, EHEC, LT, ST
Clostridium perfringens
Bacillus cereus
Staphylococcus aureus

21

Give some examples of bacteria that cause inflammatory infections.

Shigella
E.coli (EIEC, EHEC)
Salmonella
Vibrio paraheamolyticus
Clostridium difficile
Campylobacter jejuni

22

Give some examples of bacteria that cause penetrative infections.

Salmonella
Yersinia
Enterocolitica
Campylobacter fetus

23

Name some of the tests that are used in organism identification.

Selective culture media
Differential culture media
Macroscopic and microscopic appearance
Staining - gram, auramine
Serology - e.g. Salmonella
Biochemical gets - single tests, APIs, fermentation reactions
Agglutination tests
Cell culture and cytopathic effects
Rapid tests - LDH, rotavirus
Reference and lab testing - non-molecular and molecular

24

What history would you ask of someone with severe diarrhoea?

Fever, Blood, Seafood, Antibiotic use, Weight loss, Travel, Outbreak, Sexual experience, Abdominal pain, Immunosupression and you must also obtain a stool for WBCs and parasites

25

Give the five main mechanisms of treatment for bacterial diarrhoea.

Conservative - rehydration and nutrient
Antibiotics - enteric fever, vaccine for C.diff
Surgery - for fulminant colitis (C.diff)
Infection control - single room or cohort isolation, hand hygiene
Public health - outbreak surveillance, exclusions and microbiological clearance

26

Give examples of bacterial pathogens that cause diarrhoea.

Salmonella, shigella, E.coli, campylobacter, bacillus