infections of the gut

Question 1

how is shigella transmitted?

Answer 1

faecal-oral route

Question 2

how many shigella organisms are required to cause infection?

Answer 2

only 10 (highly infectious)

Question 3

arrange from mild to most serious form of Shigella

a. Shigella dysenteriae
b. Shigella sonei
c. Shigella flexneri, shigella boydii

Answer 3

1. Shigella sonei (mild)
2. Shigella flexneri
3. Shigella dysenteriae (most serious)

Question 4

what type of culture is used to diagnose shigellosis?

Answer 4

faecal culture

Question 5

how many salmonella (non-typhoidal) organisms are required to cause infection?

Answer 5

> 10^5

Question 6

what bacteria invades macrophages and breaks into the blood?

Answer 6

salmonella typhi/paratyphi

Question 7

what bacteria causes dysentery, bloody mucous stool?

Answer 7

shigella

Question 8

what complication is listeria monocytogenes associated with?

Answer 8

meningitis

Question 9

buzzwords: uncooked chicken, red colonies with black centres on XLD plate, non-lactose fermenting

Answer 9

salmonella spp. (non-typhoidal)

Question 10

buzzwords: poor sanitation, shellfish, dehydration, rice water stool

Answer 10

cholera (vibrio cholerae)

Question 11

which pathogen is associated with antibiotic-associated diarrhoea?

Answer 11

clostridium difficile

Question 12

buzzwords: canned food, floppy baby syndrome

Answer 12

clostridium botulinum

Question 13

buzzword: poorly kept rice

Answer 13

bacillus cereus

Question 14

buzzwords: hospital acquired infection, excessive antibiotic use, white plaques on colonic mucosa

Answer 14

clostridium difficile

Question 15

how is hep A transmitted?

Answer 15

faecal-oral route

Question 16

how is hep B transmitted?

Answer 16

sexual, parenteral, perinatal

Question 17

how is hep C transmitted?

Answer 17

IVDU, needlestick injuries

Question 18

buzzwords: cross placenta, vertical transmission, unpasteurised milk/dairy, meningitis
what is the associated pathogen?

Answer 18

listeria monocytogenes

Question 19

buzzwords: farm, bird droppings in water tank
what is the associated pathogen?

Answer 19

campylobacter jejuni

Question 20

what is the most common type of E. coli infection?

Answer 20

enterotoxigenic E. coli –> traveller’s diarrhoea

Question 21

what are the complications of S. aureus infection?

Answer 21

scalded skin syndrome, toxic shock syndrome

Question 22

what parasitic infection is associated with foul smelling cystic stool and steatorrhoea?

Answer 22

giardiasis (giardia lamblia)

Question 23

what parasitic infection is associated with poor sanitation and MSM?

Answer 23

amoebiasis (entamoeba histolytica)

Question 24

what type of bacteria is clostridium difficile?

Answer 24

gram-positive, spore-forming, anaerobic

Question 25

Please select which one of the following bacteria does NOT cause toxin‐mediated diarrhoea: a) Campylobacter jejuni b) Clostridium difficile c) Enterotoxigenic E coli d) Vibrio cholerae e) Vibrio parahaemolyticus

Answer 25

a) campylobacter jejuni

Question 26

antibiotic use is discouraged in which of the following infections? a) enteric fever (salmonella typhi) b) shigellosis c) salmonella (non-typhoidal) d) E. coli

Answer 26

c) salmonella (non-typhoidal)

Question 27

which exotoxin produced by C. difficile increases intestinal permeability and secretion of fluids?

Answer 27

toxin A enterotoxins

Question 28

which exotoxin produced by C. difficile causes colon inflammation, haemostasis and necrosis

Answer 28

type B cytotoxin

Question 29

what does treatment of C. difficile infection include?

Answer 29

1. oral vancomycin 2. oral metronidazole (anti-anaerobic antibiotic)

Question 30

Helicobacter pylori has been strongly associated with which of the following? a. Peptic ulcer disease b. Gastric MALT lymphoma c. Gastric adenocarcinoma

Answer 30

all of the above

Question 31

which of the following microorganisms cause secretive diarrhoea? a. giardia lamblia b. EHEC c. campylobacter jejuni d. clostridium difficle e. vibrio cholerae

Answer 31

e. vibrio cholerae

Question 32

If you suspect an enteric fever, which test should you perform in addition to culturing from the stool? a. urine antigen test b. ELISA c. blood culture d. Growth on rich media to detect all possible pathogens

Answer 32

c. blood culture