wk 4 9/10 gastroenteritis 1/2

Question 1

which bacteria is the most commen pathogen of gastroenteritis

Answer 1

campylobacter

Question 2

t/f most people with gastroenteritis do not require antibiotics

Answer 2

true

Question 3

associated risk factors for GI infection

Answer 3

malnutrition deficiency 
closed/semi-closed communities 
contaminated food 
winter congregating 
summer floods 
age <5, not breastfed
older age

Question 4

likely bacterias to develop if acid suppressed (PPIs)

Answer 4

h.pylori

yersinia enterocoliticia

Question 5

salmonella
campylobacter
shigella
infective if you are…

Answer 5

immunosuppressed

Question 6

more likely to get cholera if u are blood group

Answer 6

0

Question 7

aspects which bacteria can alter

Answer 7

adherence to mucosa
cellular invasion 
production of exotoxins 
changes in epithelial cell physiology 
loss of brush border digestive enzymes 
increased intestinal motility, net fludi secretion, iflxu of inflam cells and/or intestinal haemorrhage

Question 8

define inoculum size

Answer 8

median infecting dose required to cause disease in 50%
lower =spreads easier
pH affects required dose

Question 9

diarrhoea

Answer 9

> 3 unformed stools/day
no other causes (caffeine,laxatives))
stools hold shape of container

Question 10

dysentry

Answer 10

inflammation of intestine (colon mainly)
diarrhoea with blood and mucus

associated with fever, ab pain, rectal tenesmus (incomplete defaecation)

Question 11

which bacteria may cause dysentry

Answer 11

shigella

campylobacter

Question 12

acute duration of gastroenteritis

Answer 12

<2weeks

Question 13

diarrhoea associated with cholera

Answer 13

rice water - clear vvv liquidy

Question 14

assocated history questions for diarrhoea 6

Answer 14

diarrhoea - freq,blood,mucous,time 
other symptoms 
travel, contacts, 
animals
food history - time,type,storage
medication

Question 15

recent antibiotics increases what yype of infection

Answer 15

c.difficile

Question 16

bacillus cereus (gram+ bacillus) is associated with what type of food

Answer 16

starchy food - reheated rice

leads to profuse vomiting

Question 17

staph auerus contains a preformed toxin in food, leading to rapid absorption. It is a gram + coccus, what types of food does it typically infect

Answer 17

milk
meat
fish

Question 18

viral pathogens use what type of test

Answer 18

PCR

Question 19

which enteric pathogen is most infective

Answer 19

shigella

due to shiga toxin

Question 20

what does shiga toxiin do

Answer 20

binds to receptors in renal, RBC and others

inhibits protein synthesis

Question 21

STEC

Answer 21

shiga-like toxin (producing) e.coli

Question 22

shigella produces 2 toxins - type 1 and 2, which is more infective

Answer 22

2 (bacteriaa produce similar - shiga like)

Question 23

outline how shiga-toxin producing e.coli infect

Answer 23

compete with normal bacterial bowel flora
adhere to intestinal epithelial
toxins bind to absorptive enterocytes, enter cell, inhibit protein synthessi = death
toxins can then enter bloodstream via damaged intestinal epithelium = death of vascular cells
endothelial cell lysis leads to platelet activation + aggregation, cytokines, vasoconstriction = fibrin
microangiopathy propagates as toxins carried to kidneys - hematuria and renal failure

Question 24

t/f e.coli 0157 most likely to e STEC

Answer 24

true

can also be called VTEC

Question 25

r.coli0157 can lead to Haemolytic Ureamic Syndrome, clinical presentation of this

Answer 25

ab pain 
fever
pallor
petechiae (purple spot) 
oliguria (low urine output) 
bloody diarrhoea (this may have stopped)

Question 26

likely results from stool culture of HUS

Answer 26

high WC
low platelets
low Hb
red cell fragments

Question 27

outline characteristics of campylobacter (most common bacteria)

Answer 27

16-48hrs incubation 
sporadic 
poultry (raw)
small pathogen numbers
invasive 
signs - pain, blood fever

Question 28

which type of antibiotic is given for campylobacter

Answer 28

macroslide
(only if vvv severe and quite sure on bacteria)
careful tho

Question 29

associated foods for salmonella enteriitidis

Answer 29

poultry,meat,raw egg

Question 30

t/f salmonella typhoidal leads to gastroenteritis

Answer 30

false

non-typhoidal

Question 31

listeria monocytogenes is found

Answer 31

in fridge

Question 32

listeria monocytogenes can lead to gastroenteritis or invasive, outline difference

Answer 32

gastro - fever,myalgia,diarrhoea
pregnant
unpasteurised milk products, cold meats (foodies)

invasive - immunosuppressed
>50 yrs
pregnant
meningitis/bacteraemia

Question 33

how is listeria diagnosed

Answer 33

gram +ve rod
cold environment (frigde)
difficulty culturing

Question 34

2 main viruses causing gastroenteritis

Answer 34

rotavirus

norovirus

Question 35

t/f treatment differs iif virus gastro

Answer 35

false

only treating symptoms

Question 36

most common virus for diarrhoea in kids <3yrs

Answer 36

rotavirus

Question 37

rotavirus or norovirus is more infective

Answer 37

norovirus

Question 38

how is norovirus diagnosed, what is key for treatment

Answer 38

PCR

hydration

Question 39

e.coli pathotypes group symptoms that are related to the disease. 4: Enterotoxigenic (ETEC) enteropathogenic (EPEC), enteroinvasive (EIEC) eneraggregative (EAIC)

Answer 39

ETEC- produces heat, similar to cholera and yersinia toxins,travel

EPEC - attachins, no toxin no invasion, synthesises and secretes own receptor in cell membrane, non breastfed children, asymptomatic

EIEC- watery diarrhoea, dysentery rare, invasion,

EAIC - travellers diarhoea, cytogenic secretogenic, proinflammatory