Pathogens of GI Tract Flashcards Preview

DEN303 - GI > Pathogens of GI Tract > Flashcards

Flashcards in Pathogens of GI Tract Deck (23)
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1

What is dysentery?

Abnormal inflammation of GI - blood and pus in faeces - often disease of the large intestine

2

What organisms can cause food poisoning?

Staph aureus
Bacillis cereus
Clostridium botulinum

3

How/ what kind of food poisoning does staph.aureus produce?

Mainly in dairy - gram +ve
50% strain have heat-stable enterotoxin - also resistant to stomach acid/ digestive enzyme
3-6hr severe vomit

4

How/ what kind of food poisoning does bacillus cereus cause?

Associated rice - toxins remain active
Gram+ve spore former

5

How/ what kind of food poisoning does clostridium botulism produce?

Heat stable toxin ingested in food - gram +ve
Flaacid paralysis w/ neurological symptoms

6

What is helicobacter pylori and describe virulence?

Anaerobic gram -ve
Produce urease - convert urea --> ammonia and CO2
Cause increase pH - protective cloud during transit to mucin layer (allows to reside in mucosal tissue - cause bleeding/ ulceration)

7

Tx of peptic ulcers?

Tx w/ PPI
Ab: metronidazole and amoxicillin

8

What strain is linked to peptic ulcers and cancer?

cagA +ve strain

9

What does E. coli cause?

Gram -ve motile rod causing diarrhoeal diseases

10

How to detect E.Coli?

MacConkey agar - yellow agar turned pink based on fermentation of lactose
PCR - serotype

11

What is EPEC?

Enteropathogenic e.coli - inject protein into host to manipulate cytoskeleton
Bundle-forming pili important in attachment
Common cause travellers diarrhoea - no blood

12

What is EIEC?

Enteroinvasive e.coli
Invade and destroy epithelial cells - blood

13

What is EHEC?

Enterhaeamorrhagic e.coli
Production Vero-toxin - acts via directly damaging cells and cause haemorragic colitis
Can spread to kidneys

14

What is shigella?

Shiga toxin - common poor countries
Spread face-oral - often by water contamination
Cause dysenteriae

15

What is salmonella?

Gram -ve
Spread from food - mainly chicken and dairy
Lab detection- MacConkey - non-lactose fermenting - stays yellow

16

What is s. typhi

Gram -ve strain of salmonella
Cause typhoid fever - initiate in intestine can spread systemically

17

What are campylobacter spp?

Gram -ve microaerophiles
No 1 cause of food poisoning (c. jejui most common)
Last up to 3 weeks
Complication: reactive arthritis and guiilame barre

18

What are cholera spp?

Caused gram -ve comma shaped bacterium
Infectious dose = large
Characterised - rice water stool
No tissue damage

19

How does cholera toxin work?

G-protein signalling pathway - increase secretion Cl- ion - prevent influx Na+ into cells
Result water movement into lumen and diarrhoea

20

Tx cholera?

Rapid fluid and electrolyte replacement
Prevention - improvement water system and sanitation

21

Name some viral cause GI infections?

Rotavirus
Noravirus

22

What is a rotavirus

Wheel like viral particle - cause damage small intestine - diarrhoea
Low infectious dose - very contagious

23

What is noravirus?

Winter vomiting virus
Chills, headache, fever, nausea
Low infectious dose