L4: microbiology of the GI tract

Question 1

how does cholera work

Answer 1

causes an increase in cyclic AMP increasing the secretion of water, calcium, sodium and bicarbonates

Question 2

mechanism for non-inflammatory pathogens

Answer 2

enterotoxins/ mucosal adherence

Question 3

e.g of three bacteria causing non-inflammatory infections

Answer 3

vibrio cholerae
bacillus cereus
enterotoxigenic E.coli

Question 4

where does cholera work

Answer 4

proximal small bowel

Question 5

mechanism for inflammatory GI infection

Answer 5

invasion of mucosa/ production of cytotoxins

Question 6

where do salmonella and shigella act

Answer 6

colon

Question 7

where does listeria, yersinia and salmonella typhi act

Answer 7

distal small bowel

Question 8

how do penetrating GI infections work

Answer 8

inducing phagocytosis

Question 9

name 4 GI host defences

Answer 9

gastric
bile salts
peristalsis
mucus

Question 10

4 benefits of colonisation resistance

Answer 10

• occupy space
• production of antibiotic like substances
• remove toxins
• release energy from carbohydrates

Question 11

where is most GI flora

Answer 11

colon

Question 12

what percentage of stool is bacteria

Answer 12

40-60%

Question 13

what symptoms can overgrowth of bacteria lead to in GI tract (6)

Answer 13

diarrhoea 
bloating 
abdo pain 
flatulence 
weight loss 
steratorrhoea

Question 14

diagnostic test for bacterial overgrowth

Answer 14

hydrogen breath test

increase in total flora

Question 15

treatment of bacterial overgrowth

Answer 15

rifaxamin
correct underlying condition
nutritional supplements

Question 16

what signs can bacterial overgrowth syndrome cause (3)

Answer 16

• malabsorption
• deficiency of fat soluble vitamines
• macrocytic anaemia

Question 17

prebiotics=

Answer 17

chemicals that alter the microbiome

Question 18

probiotics=

Answer 18

microorganism for prevention of infection

Question 19

what happens when gastroenteritis is treated with antibiotics

Answer 19

make E.coli worse
cause diarrhoea
rarely help

Question 20

viral causes of gastroenteritis

Answer 20

rotavirus
norovirus
adenovirus
astrovirus

Question 21

most common viral causes of gastroenteritis in children

Answer 21

rotavirus

Question 22

e.g 4 of bacterial causes of gastroenteritis

Answer 22

campylobacter jejuni
E.coli
salmonella
Shigella

Question 23

e.g of parasitic causes of gastroenteritis

Answer 23

giardia lamblia
entamoeba histolytica
cryptosporidium spp

Question 24

what type of infection most commonly causes gastroenteritis

Answer 24

viral

Question 25

causes of C.diff

Answer 25

mild diarrhoea
perforation
toxic megacolon

Question 26

symptoms of C.diff

Answer 26

malnutrition
fever
no vomiting
not bloody

Question 27

4 C that cause C.Diff

Answer 27

clindamycin
Cephalosporins
Ciprofloxacin
co-amoxiclav

Question 28

diagnosis of c.diff

Answer 28

toxin detection

Question 29

why doesn’t a stool sample establish c.diff

Answer 29

as many elderly are asymptomatic carriers

Question 30

management of C.diff

Answer 30

stop antibiotics 
isolate patient 
specific c.diff antimicrobials 
probiotics 
faecal flora transplant

Question 31

what are specific anti-c.diff antimicrobials

Answer 31

oral metroindazole
oral vancomycin
oral fidaxomicin

Question 32

4 inflammatory bacteria in GI tract

Answer 32

shigella
salmonella
campylobacter
enterohaemorrhagic/ enteroinvassive E.coli

Question 33

3 penetrating bacteria in GI tract

Answer 33

salmonella typhi
yersina enterocolitica
listeria monocytogenes