microbial foodborne infections and intoxications part 1 W4 Flashcards
definition of gastro-enteritis?
inflammation of the digestive tract (causing nausea, vomiting, abdominal pain, diarrhoea, eventually fever)
causes of gastro-enteritis? what are their different effects?
viral (most common) - stomach flu
parasite
bacterial - microbial food poisoning
examples of viral causes of gastro-enteritis?
norovirus
rotavirus
adenovirus
types of bacterial causes of gastro-enteritis?
infection = viable microorganisms
intoxication = only toxin
examples of infection bacterial causes of gastro-enteritis?
campylobacter spp
salmonella spp
e. coli
examples of intoxication bacterial causes of gastro-enteritis?
clostridium perfringens
bacillus cereus
staphylococcus aureus
clostridium botulinum
e. coli
ways to distinguish mechanisms of microbial infections
is food a vector or does the microorganism need it to grow?
does the microorganism have to replicate in the host to cause symptoms? (eg not the case in intoxication, some infection)
is ingestion of pre-formed toxin sufficient to cause symptoms?
mild gastro-enteritis clinical description?
self-limiting (usually)
2-3 days
3 or less stools/day
low/no fever
general condition = satisfactory
moderate gastro-enteritis clinical description?
> 3days
3-5 stools/day
T<38°C
general condition = moderate
serious gastro-enteritis clinical description?
invasive diarrhoea
> 3 days
≥ 5 stools/day
T>38°C
bloody diarrhoea
(dysentery, colitis)
general condition = bad
small bowel infection features
role = fluid secretion/nutrient absorption
watery diarrhoea
abdominal cramping
bloating
gas
large bowel infection features
role = absorb fluid and salt
watery or bloody/mucoid diarrhoea
low abdominal pain
fever++
differential diagnosis: watery diarrhoea, no fever?
Cholera
differential diagnosis: watery diarrhoea, fever?
norovirus
rotavirus
ETEC
bacillus cereus
staphylococcus aureus
differential diagnosis: bloody diarrhoea, no fever
(rare, mainly parasitic causes)
entamoeba histolytica
campylobacter
salmonella