DLA5- Food Poisoning Flashcards Preview

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Flashcards in DLA5- Food Poisoning Deck (13):
1

list the common sources of pre-formed toxin ingestion causing food poisoning

Bacteria:
-S. aureus
-C. botulinum

Dinoflagellate algae / Bacteria:
-ciguatera
-scombroid
-shellfish / pufferfish

(Fungal: wild mushrooms- amanita, clitocybe, psilocybes)

2

Food poisoning definition, Sxs, incubation period, Tx

-ingestion of preformed toxin = intoxication not a true infection (no microbial growth, toxins found in stool)

-very short incubation: mins - hrs
-Sxs: acute vomiting and non-inflammatory (watery) diarrhea / possible CNS involvement (botulinum)
-Tx: rehydration, Sx management

3

S. aureus:
-(1) common method of food contamination and common foods
-(2) incubation period

1- native to skin + poor handling / sanitation => food contamination: usually sliced meat, ham, poultry, pudding, potato, egg, salad, mayonnaise, cream pastries

2- 30mins - 8hrs

4

S. aureus:
-(1) name the toxins
-(2) symptoms

1- 15 known enterotoxins (A-E, G-P) + water-soluble, low MW proteins, ST chromosomal toxins [Note- MOA is unknown]

2- (self-limiting, 24-48hr duration) abrupt onset of n/v/d, abdominal cramping, occasionally fever

5

list key microbial features of C. botulinum

Large, Gram+ Rod
anaerobic
spore forming (heat resistant)
neurotoxin
(habitat is ubiquitous)

6

describe C. botulinum toxin (formation and action)

Spores germinate into toxin producing bacilli (needs low O2 content, pH>4.6)

-one strain produces one toxin --> A-H (mostly A, B, E)
-heat-labile >80C

-Botulinum Toxin --> cleaved by bacterial proteases --> fully active neurotoxin (one of the worlds most toxic substances)

7

list common sources of C. botulinum

-soil (A, B) / oceans, lakes (E)

-spores sources: *veggies, *fruits, *seafood, (fish, meat, poultry)

-associated foods: *canned low acid foods, *poorly canned foods, *fermented fish, *baked potatoes, (honey, fired onions, garlic oil mixtures)

8

Botulism:
-(1) incubation period
-(2) Sxs

1- 12-36hrs

2:
i) n/v/d, abdominal pain, dry mouth and sore throat

ii) CNS (develops later): CN palsies (diplopia, blurry vision, ptosis, slurred speech, dysphagia, dry mouth, muscle weakness) + symmetric descending paralysis --> respiratory failure --> death

9

botulism toxin MOA and Dx

MOA: binds presynaptic sites in NMJ --> dec ACh release --> neuromuscular blockade

Dx: ELISA detects toxin in serum, up to 12 days post-ingestion (also found in stool, vomit, food source)

10

Ciguatera Fish sources

Carribean and Tropical Pacific- 20% of US food poisoning

Dinoflagellates = Gambierdiscus toxicus: large predatory reef fish -- barracuda, black grouper, amberjacks

11

Ciguatera Fish Poisoning:
-(1) toxin MOA
-(2) describe Sx phases
-(3) Tx

1- Ciguatoxin activates V-gated dep. Na channels

2:
i) (3-6hrs)- n/v/d, abdominal pain / cramps
ii) (3-72hrs)- CNS- peri-oral paresthesias, pruritus w/o urticaria, metallic taste, painful teeth, dysuria, blurry vision, Temp. dysesthesias
iii) (w/in hrs)- bradycardia, heart block, hypotension

3- Sx control

12

Scombroid poisoning = (1) poisoning:
-(2) method of food contamination and (3) is a bad sign during consumption
-(4) is an important characteristic of the toxin

1- histamine

2- improperly stored fish (high T) --> bacterial growth --> histidine to histamine in dome dark fish meat --> accumulation of toxic histamine levels

3- peppery / metallic taste to fish flesh

4- not broken down by cooking, freezing, or refrigeration

13

Scombroid Poisoning:
-(1) incubation period
-(2) initial Sxs
-(3) later Sxs
-(4) rare Sxs

(histamine)
1- 5-30 mins

2- (rapid onset) cutaneous flushing (face/neck) + erythematous / urticarial rash on face/torso (burning, itching, edema) + n/v/d, abd. cramps

3- HA, dizziness, tachycardia, palpitations, chest tightness, SOB, blurry vision

4- bronchospasm, respiratory distress, arrhythmias