GI infections

Question 1

how pathogens overcome defences
1) antibiotics
2) diet high in what?

Answer 1

1) kill normal flora
2) diet: high iron diet supports pathogen growth

Question 2

food posioning bacteria
-camplyobacter (most common)
-e.coli
-salmonella
-listeria

Answer 2

1) acquire flagella for motility and biofilm formation
2)listeria= sliced meat/ cheeses/ raw milk. less common and more severe.

Question 3

what is viral gastoenteritis
-rota virus
-nora virus
-astrovirus

Answer 3

inflammation on inside of GI tract casues, acute watery diarrhoea, vomiting, fever
-vaccine introduced 2008
-mRNA vaccine coming
-no vaccine

Question 4

three main gastointenstinal infections

Answer 4

1) cholera
2) shigella
3) salmonella

Question 5

cholera
-who invented it
-symptoms
-what toxin is symptoms casued by
-pathogeneisis
-does it survive stomach acid
-how immunity is caused
-what vaccine is most effective and why (what antibody)

Answer 5

-john snow
-very watery diarrhoea (24L a day)

-symptoms caused by cholera toxin. encoded by CTX phage. toxin binds to receptors on cells in the small intestine.

-rapidly killed by gastric acid

immunity= need to become immune to cholera toxin and bacteria to prevent infection. killed whole cell vaccine given by injection are not effective. new oral vaccines are more effective as stimulates mucousal immunity with IgA

Question 6

shigella
(close relation to e.coli)

-type of bacteria
-resevoir and how it spreads
-who does it infect more
-does it survive stomach acid
-treatment
-how cells spread
-how severe is it

Answer 6

-
non- motile gram negative
human pathogens with no animal or environmental reservoir
-person to person spread via contaminated water
-survivs stomach acidity. acute bloody diarrhoea.
-oral rehydration therapy. antibiotics given in severe cases but antibiotic resistence occurs
-cell to cell spread on actin comets
-causes severe GI inflammation

Question 7

salmonella

-type of bacteria
two species (enterica and bongori)
-salmonella enterica types (s. enterica typhi and s.enteritidis typhimurium)

Answer 7

enterica= infects mammals
bongori= infects reptiles
-motile, gram negative

s. enterica typhi = human infection (thyphoid fever). no animal source
s. enteritidis typhimurium= food poisoning salmonella from animal source. bloody and watery diarrhoea

Question 8

typhoid and enteric fever
-where does it occur
-by salmonella pathogen is it casued by
-symptoms
-mortality
-treatment
-severity of GI infections

Answer 8

-salmonella typhi
-small intestine and bloostream
-fever, diarrhoea
-10-30% if untreated
-amtibiotcs, fluids
-uses type 3 secretions systems essential for virulene
-systemic infection with a few GI symptoms

Question 9

how pathogens survive harsh environment of GI system

Answer 9

attach to epithelial cells