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Flashcards in 17 - E Coli Deck (16)
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1
Q

What are the features of EColi e.g shape and gram stain?

A

Enterobacteriaceae means it can use lactose

2
Q

What would E Coli look like under the microscope?

A
3
Q

How can you identify E.Coli without a gram stain in the lab?

A

MacConkey agar containing lactose. If they use lactose they produce lactic acid and this turns the agar red as it has a low pH. If not lactose fermenting they grow yellow colonies

4
Q

How can you distinguish between different strains of E.coli?

A
5
Q

Where are the different antigens on E.Coli?

A
6
Q

What are some of the diseases that E.Coli can cause?

A
  • Diarrhoea
  • UTI
  • Blood stream infection
  • Neonatal meningitis
  • Can protect against pathogenic invasion of pathogens like salmonella when a normal commensal of bowel
7
Q

What are the most common strains of E.Coli that cause diarrhoea?

A
  • ETEC
  • EPEC
  • EAEC
  • EIEC
  • DAEC
  • STEC
8
Q

What is the major cause of traveller’s diarrhoea and how does it cause disease?

A
  • ETEC (enterotoxigenic e coli)
  • Faecooral transmission
  • Produces two toxins, heat stable ST and heat labile LT, that stimulate lining of intestines to secrete excess fluid so cramping and diarrhoea
  • 3-4 days
9
Q

What complications does shiga toxin producing E coli cause?

A
  • Haemorrhagic colitis
  • Haemolytic uraemic syndrome (triad of acute renal failure, haemolytic anamia and thrombocytopenia)
10
Q

How does the Shiga Toxin cause virulence?

A
  • Binds to receptor
  • Endocytosis
  • Cleaved in vesicle to form small A fragments that translocate into cytosol and A1 inactivates ribosomes inhibiting protein synthesis so cell death
11
Q

What are some of the virulence factors of E.coli (ExPEC)?

A
12
Q

How does E.coli cause urinary infections?

A
  • Transfer from rectum to urethra and then migrate to blader

- UPC has adhesins called type 1 fimbria that can bind to uroepithelium to form communities, LPS toxin, cytotoxin alpha-haemolysin and produce siderophores to sequester iron to survive

13
Q

Apart from UTIs and diarrhoea what other common infection can E.Coli cause?

A

Most common cause of blood stream infection leading to SEPSIS

14
Q

How can you prevent and treat traveller’s diarrhoea?

A

Prevent:

  • Avoid food and drink that may be contaminated
  • Raw fruit and veg and ice from places with poor chlorination

Treatment:

  • Fluids
  • Oral rehydration tablets
  • Avoid antibiotics
15
Q

How can you treat UTI caused by E. COLI?

A
  • Trimethoprim or Nitrofurantoin as majority are resistant to first now
16
Q

What antibiotic should you not use for E.Coli blood stream infections?

A
  • Coamoxiclav as it is becoming resistant due to horizontal gene transfer