Gastrointestinal Infections

Question 1

What is the source/resevoir of infection?

Answer 1

The original source of the infection

Question 2

What is the vehicle of infection?

Answer 2

The means by whch the infection is transmitted from one person to another.

Question 3

Is campylobacter a gram negative or gram positive organism?

Answer 3

Gram negative

Campylobacter is a curved gram negative bacillus

Question 4

What is the incubation period of campylobacter?

Answer 4

3-10 days

Question 5

What does campylobacter cause inflammation of?

Answer 5

Colon and rectum

Question 6

Why does campylobacter cause bloody diarrhoea

Answer 6

Campylobacter causes inlfammation of the colon and rectum which causes bloody diarrhoea

Question 7

What are the sources and vehicles of infection of campylobacter?

Answer 7

Farm animals
Undercooked poultry
Water and unpasteurised milk

Question 8

What is the management of a campylobacter infection?

Answer 8

(Usually self-limiting)

Give erythromicin or ciprofloxacin for 5 days if patient develops systemic illness

Question 9

Is person-person spread of campylobacter common?

Answer 9

No

Question 10

What is the incubation period of salmonella enterica?

Answer 10

12-48 hours

Question 11

What does salmonella enterica cause inflammation of?

Answer 11

Ileum and colon

Question 12

What is the management of a salmonella infection?

Answer 12

(Usually self-limiting)

Give ciprofloxacin for 5 days if patient develops systemic illness

Question 13

What is the incubation period of shigella?

Answer 13

1-9 days

Question 14

What does Shigella invade?

Answer 14

Shigella invades the intestinal mucosa, causing severe inflammation.
Does not invade further (never seen in blood cultures).

Question 15

How is Shigella spread?

Answer 15

Person-person

Question 16

What is the treatment for shigella sonnei?

Answer 16

Symptomatic treatment only

Question 17

How are more severe species of shigella (e.g. dysenteriae) treated?

Answer 17

Ciprofloxacin

Question 18

What does the “O” in E. coli O157 stand for?

Answer 18

The surface antigen

Question 19

What does the “H” in E. coli O157:H7 stand for?

Answer 19

The flagellar antigen

Question 20

What toxin does the O157:H7 strain of E. coli produce?

Answer 20

Verotoxin

Question 21

What does Verotoxin do?

Answer 21

Damages red cells and the kidney, causing haemolytic-uraemic syndro (HUS)
Increases blood urea, red cell haemolysis and thrombocytopenia.

Verotoxin binds to receptors found on renal cells, RBC and others, inhibits protein synthesis and causes cell death.

Question 22

What is the source of E. coli O157 infection?

Answer 22

Cattle (part of the normal gut flora in cattle)

Beef becomes contaminated on outside at slaughter

Question 23

Is risk of getting E coli O157 higher from mince and hamburgers or steak.

Answer 23

Higher risk in mince and hamburgers, lower risk in steak.

Question 24

What is the appropriate management of an E. coli O157 infection?

Answer 24

Symptomatic and supportive treatment only

Antibiotics contraindicated as may increase release of toxin

Question 25

When should you check bloods of patient for HUS1?

Answer 25

1 week after onset of symptoms

Question 26

What would blodd tests show for patient with HUS?

Answer 26

High white cells
Low platelets
Low HB
Red cell fragments
Lactate dehydrogenase increased (increased more than 1.5 x normal)

Question 27

Is shigella gram neg or gram pos?

Answer 27

Gram neg

Question 28

Is e coli gram neg or gram pos?

Answer 28

Gram neg

Question 29

Is salmonella gram neg or gram pos?

Answer 29

Gram neg