Microbiology 6 - GI infections Flashcards

1
Q

In a febrile patient with a GI infection, what are the key differentials?

A
  1. Inflammatory diarroea

2. If no diarrhoea - enteric fever (typhoid/ salmonella)

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2
Q

In an afebrile patient with a GI infection, what is the top differential?

A

Secretory diarrhoea due to toxins (eg cholera)

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3
Q

What is the incubation period of campylobacter?

A

1-10 days

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4
Q

What is the incubation period of bacilus cereus?

A

1-6 hours

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5
Q

Why does staph aureus food poisoning produce such rapid symptoms?

A

Toxin is pre-formed

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6
Q

What are the key cytokines involved in Staph aureus food poisoning?

A

IL-2 and IL-7

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7
Q

Describe the symptoms of S aureus food poisoning

A

Vomiting

Watery, non-bloody diarrhoea

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8
Q

Describe the different toxins produced by bacilus cereus

A

Heat-stable toxin causes emesis
Heat-labile toxin causes diarrhoea
Only the heat-labile toxin is destroyed upon heating

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9
Q

Describe the diarrhoea produced by bacilus cereus

A

Waterey, non-bloody

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10
Q

In what type of food might clostridia botulinum be found?

A

Honey

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11
Q

What type of clostridia spp causes food poisoning?

A

Clostridia perfringens

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12
Q

In what sort of food is clostridia perfringens found?

A

Re-heated meat

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13
Q

Which organism causes pseudomembranous colitis?

A

Clostridium difficile

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14
Q

Which diarrhoeal disease is associated with antibiotic use?

A

Pseudomembranous colitis caused by C. difficile

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15
Q

What type of symptoms does listeria monocytogenes poisoning cause?

A

Febrile gastroenteritis

Waterey diarrhoea

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16
Q

Recall 2 sources of listeria poisoning

A
Unpasteurised dairy (blue cheese!! Mayonnaise!!)
Refrigerated foods (eg sandwiches)
17
Q

Is listeria alpha or beta haemolytic?

A

Beta haemolytic

18
Q

What is the causative organism in ‘traveller’s diarrhoea’?

A

Enterobacteriacae (usually the toxogenic form, ETEC)

aka- enterotoxigenic ecoli

19
Q

What organism causes haemolytic uraemic syndrome?

A

EHEC enterobacteriacae

20
Q

Recall one very important thing to avoid in the management of enterobacteriacae poisoning

A

Antibiotics

21
Q

Recall 3 worrying species of salmonella

A

S typhi
S enteritidis
S cholerasuis

22
Q

What symptoms are caused by S typhi infection?

A

Bactaraemia
Constipation and fever
Splenomegaly and ROSE SPOTS

Treat with IV ceftriaxone then PO Azithromycin

23
Q

What are the 2 key forms of shigella that cause disease in humans?

A
S dysenteriae
S flexneri (associated with MSM)
24
Q

What disease pattern does shigella infection cause?

A

Dysentry

25
Q

How should shigella infection be managed?

A

Avoid antibiotics

If really necessary, go for ciprofloxacin

26
Q

What is the typical stool appearance in Vibrio cholerae infection?

A

Rice water

27
Q

Which organism is most likely to cause cellulitis in a scuba diver?

A

Vibrio vulnificus

28
Q

On what sort of agar can vibrio spp be grown?

A

Salty agar

29
Q

For how long can campylobacter symptoms last?

A

Up to 20 days

30
Q

What is one key serious complication of campylobacter infection?

A

Guillan Barre syndrome

31
Q

What is the symptom of “flask-shaped ulcer on histology” pathognemonic for?

A

Entamoeba histolytica infection

Treat with metronidazole (Class: Nitroimidazole)

32
Q

What symptoms does E. histolytica infection cause?

A

Dysentry and flatulence

33
Q

How should E. histolytica infection be managed?

A

Metronidazole

34
Q

How can giardia infection be investigated?

A

String test

35
Q

How should giardia infection be treated?

A

Metronidazole

36
Q

In which patient group does cryptosporum parvum cause symptoms, and what are those symptoms?

A

The immunocompromised

Severe diarrhoea

37
Q

Recall the 1st and 2nd line treatments for clostridium difficile

A
  1. Metronidazole

2. Vancomycin