Flashcards in Food-borne agents of watery diarrhea Deck (26):
don't use abx-useless
symptomatic tx for cramping
fluids if no salt depletion
no RBCs/WBCs in feces
prevent via proper food handling
acute emetic and diarrheal illness from eating heat-stable, preformed toxin in food
G+ coag+ coccus, produces entereotoxin
multilocus seq. type/MLST strains ST398 or NT-MRSA spreading across Europe, etc. (animals and humans)
S. aureus prevalence ??
second to salmonella for FBI
foods: custard-filled, canned, processed meat, potato salad, etc.
reservoir is HUMANS (nasophar., skin-->skin/resp infections)
no gender assoc. WARMER mos: picnics,etc
risk: improper handling/storage of food
S. aureus enterotoxin
acts on neural rec. in upper GIT-->stim vomiting center in brain
5 Ag types: A-E, (A,B most common)
water-sol, heat stable (100d 30 min), colorless/odorless/tasteless
IS self-limited-->recovery 1-4 days
S. aureus immunity
make Ab to specific Ag type
S. aureus onset??
1-6 hour incubation post-ingestion (ACUTE!)
nausea, salivation, vomiting
may have diarrhea, abdominal cramps
NO neurological signs or fever
S. aureus dx
the SHORT incubation period, pres. of enterotoxin in food, vomitus
epi investigation: phage typing to trace strain source
S. aureus ddx
B. cereus (emetic form), metal toxemia (1 hr or less)
G+ aerobic, *spore-forming* rod
produces 2 enterotoxins
B. cereus causes ??
transmitted through ??
emetic and/or diarrheal disease
spores on grains: rice, potatoes, vegetables
extensive multiplication happens on food
no age/gen assoc. happens YEAR ROUND (foods made inside)
risk: inadequate prep/storage of food: esp. rice
B. cereus immunity??
B. cereus: emetic form
upper GI symps: vomiting, abd. cramps
1-5 hours post ingestion
diarrhea in 33%
B. cereus: diarrheal form:
lower GI symps: and. pain, profuse watery diarrhea
10-12 hrs post ingestion (longer incubation!)
B. cereus dx
if upper GIT symps develops 1-5 hours after eating
or lower dev. 6-24 hrs after eating
isolate 10^5+ orgs/gram from food or pt feces
B. cereus ddx
emetic: S. aureus
diarrheal: all other agents of acute onset afebrile diarrhea
B. cereus tx
Clostridium perfringens, type A
FBI, self-limited, rarely fatal
anaerobic G+ non-motile rod, heat-stable SPORES
C. perfringens, type C causes...
causes clostridial necrotizing enteritis: "pigbel": FBI w. necr. sm. bowel inflammation from beta toxin
normal trypsin-mediated degradation of beta toxin is impaired by protein-poor diet or congestion of foods like sweet potatoes (contain *trypsin inhibitors*)
C. perfringens occurs how
meat, gravy improperly handled
no assoc. with gender, age, season
C. perfringens produces ??
has what effect??
enterotoxin in situ
max activity in ileum: inhibits glucose and chloride ion absorption, damages intestinal epithelium by denuding (stripping) the brush border @ villus tips-->diarrhea from secretion of e-lytes and H2O into gut lumen
C. perfringens type A persists in animal's gut (meat) even when most bacteria are killed due to ??
will germinate and proliferate if food ???
if left out @ room temp
need to ingest ??? C. perfringens type A orgs for disease
C. perf incubation?
sev. cramping abc. pain, diarrhea
complete recovery in a day
C. perf dx
find >10^5 vegetative cells/gm food or
>10^4 C. perfs/gm pt feces
serology for enterotoxin presence in feces? (outbreaks)