E.coli Flashcards

(29 cards)

1
Q

Characteristics of e.coli

A

Enterobacteriacae
Gram -
Facultative anaeobe

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2
Q

Is E.coli lactose fermenting?

A

Yes

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3
Q

Where is E.coli found?

A

Flora of man (non harmful)
Faecal contamination

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4
Q

What are the 2 types of E.coli?

A

Intestinal and extraintestinal

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5
Q

Intestinal E.coli

A

Cause diarrhoea
Lactose negative
Cause disease 6 ways

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6
Q

What is ETEC?

A

Enterotoxigenic E.coli

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7
Q

Symptoms of ETEC

A

Watery stools and diarrhoea (non blood)
Spread by water/human-human
Self limiting (4-6d)

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8
Q

How many cells are needed for ETEC contamination?

A

10^6-10^8

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9
Q

How does ETEC cause pathogenicity?

A

Cells colonise surface of bowel
Produce enterotoxins in gut

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10
Q

How do heat liable toxins cause intoxication?

A

AB5 binds to GM1 on cell surface to target adenylate cyclase
Cl- secretion and inhibition of NaCl
Water moves into lumen (watery diarrhoea)

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11
Q

How do heat stable toxins cause intoxication?

A

Same as heat liable but increased cGMP

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12
Q

What is EIEC?

A

Enteroinvasive E.coli

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13
Q
A
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13
Q

Characteristics of EIEC

A

Non-mobile
L-serine, D-xylose and mucate fermentation
10 cells needed

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14
Q

EIEC mechanisms of pathogenicity

A

Destroy epithelial cells lining colon
Same mechanism of invasion as Shigella

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15
Q

What is EAggEC?

A

Enteroaggregative E.coli

16
Q

What does EAggEC do?

A

Bacteria in stacked-brick formation to enhance mucus to trap bacteria in

17
Q

EAggEC mechanism of pathogenicity

A

aggR regulates aggregative adherence fimbrial expression
Chromosome induces intestinal secretion and has Shigella enterotoxin 1

18
Q

EAggEC foods

A

Salsa, unpasteurised cheese, handlers

19
Q

What is DAEC?

A

Diffusely adherent E.coli

20
Q

How does DAEC cause pathogenicity?

A

Expresses the aidA gene and encodes an adhesins involved in diffuse aherence

21
Q

What is EPEC?

A

Enteropathogenic E.coli

22
Q

Characteristics of EPEC

A

Profuse watery diarrhoea with vomiting
Highly infectious in infants
10^8-10^9 needed in adults

23
Q

How does EPEC cause pathogenicity?

A

Adherence via BFP through intimate attachment

24
What is EHEC?
Enterohaemorrhagic E.coli
25
Where is EHEC found?
Cattle, pigs, poultry, rabbits
26
Symptoms of haemorrhagic colitis
Abdominal pain Diarrhoea
27
What is haemolytic uraemic syndrome (HUS)?
Renal failure, reducing blood platelets and cells to cause long term kidney damage
28
What are cytotoxins?
Produce verotoxin VTI and VTII Like Shiga toxins Responsible for HUS