Microbiology 3 - GI infections Flashcards
what is the most common cause of travellers diarrhoea?
E.coli (ETEC)
3 different clinical syndromes of GI infections?
secretory diarrhoea, inflammatory diarrhoea and enteric fever
Bloody diarrhoea associated with outbreaks
EHEC (Haemorrhagic E coli O157)
most common cause of diarrhoea in <6? what type of diarrhoea?
Rotavirus
Secretory (due to toxin formation)
Most common cause of diarrhoea in <2 years? what type of diarrhoea?
adenovirus
secretory diarrhoea
what type of diarrhoea do viruses cause?
Secretory
diarrhoea definition
loose or watery stools >/=3x/24 hours
most common bloody travellers diarrhoea
Shigella
which organisms are reportable
campylobacter salmonella shigella E.coli o157 norovirus listeria
bacteria with incubation periods <6 hours?
S.aureus
bacillus cereus
which infections have preformed toxins?
S.aureus
Bacilus cereus
Clostridium botulinum
pathophysiology of secretory diarrhoea
toxin production –> Cl- secretion in to lumen –> loss of water and electrolytes –> D+V
NO FEVER, just WATERY diarrhoe
no WBCs in stool!
features of inflammatory diarrhoea
FEVER
WBCs in stool sample (neutrophils)
+/- bloody diarrhoea
enteric fever features
FEVER
WBCs in stool (mononuclear cells)
examples of enteric fever causing organisms
salmonella typhi –> typhoid fever
yersinia
brucella
some causes of persistent or chronic diarrhoea
Cryptosporidium spp., Giardia lamblia, entamoeba histolytic, cyclospora
N+V <24 hours
S.aureus
B.cereus
vomiting and NON-BLOODY diarrhoea 2-3DAYS
NOROVIRUS
Features of S.aureus food poisoning
coagulase, catalase +Ve gram+ve coccus
superantigen in S.aureus
produces and entero and exotoxin which act as super antigen and cause release of IL-1 + 2 –> watery, NON bloody diarrhoea
examples of gram positive spore forming rods
Bacilus cereus
Listeria
clostridia
reheated fried rice, vomiting 4 hours after eating
b-cereus
three types of clostridium infection
c. botulinum
c. perfringens
c. difficile