GI bacteria Flashcards

1
Q

Is Helicobacter pylori gram positive or negative?

A

Gram negative (stains pink)

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2
Q

What are the 4 effects of H pylori?

A

1) Decreased somatostatin

2) increased lumen gastric acid due to more gastrin

3) Urease, results in ammonia generation

4) Low HCO3- secretion

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3
Q

How does somatostatin influence gastrin release?

A

Somatostatin inhibits release of gastrin
So H pylori decreasing somatostatin means gastrin release not inhibited, so excessive gastrin

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4
Q

What can excessive gastrin release cause?

A

Duodenal ulcers

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5
Q

How can H pylori survive in the acidic stomach?

A

Produces urease with catalyses the hydrolysis of urea to ammonia which counters the acid to raise the pH

Urea – urease –> CO2 + ammonia

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6
Q

How does H pylori infection cause decreased bicarbonate secretion?

A

H pylori downregulates activity of 2 key duodenal mucosal epithelial bicarbonate transporters which mediate HCO3 secretion

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7
Q

What are causes of H pylori infection?

A

Peptic ulcer disease
Gastritis
Gastric carcinomas

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8
Q

How is a H. pylori infection diagnosed?

A

1st line: Stool antigen test
C-urea breath test

Biopsy

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9
Q

What is treatment for H pylori infection?

A

Triple therapy (CAP):
Clarithromycin
Amoxicillin
PPI

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10
Q

Is E Coli gram positive or negative?

A

Gram negative

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11
Q

True or false: all serotypes/ strains of E Coli are very virulent

A

False
Some are

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12
Q

ETEC, EAEC and EPEC all cause what symptom?

A

Watery diarrhoea

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13
Q

What symptom does EHEC cause?

A

Bloody diarrhoea (H for haemorrhagic)

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14
Q

What type of E Coli can cause haemolytic uremic syndrome?

A

Serotype O157:H7

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15
Q

What can haemolytic uremic syndrome cause?

A

Condition occurs when small blood vessels become damaged and inflamed leading to clots which can damage the kidneys.
Results in
Haemorrhagic diarrhoea and nephritic syndrome

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16
Q

How are E Coli infections commonly treated?

A

Often amoxicillin
or trimethoprim
or nitrofurantoin

17
Q

Is C. difficile a gram positive or gram negative bacteria?

A

Gram positive (stains purple)

18
Q

C difficile is a _____-forming bacteria

A

spore

19
Q

C difficile is mainly induced with ______

A

antibiotics

20
Q

Which antibiotics induce c difficile infection?

A

Cs:
Cephalosporins
Co-amoxiclav
Clindamycin
Ciprofloxacin

21
Q

C difficile cause pseudo_____ _____

A

pseudomembranous colitis
(severe form of colitis, plaques on colon wall)

22
Q

What kind of diarrhoea does c diff cause?

A

Very watery severe diarrhoea

23
Q

What is a big risk of c difficile?

A

Dehydration due to watery diarrhoea
Is highly infectious

24
Q

How do you treat c. difficile?

A

Stop using C’s antibiotics
Give Vancomycin