DLA5- Food Poisoning Flashcards
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)
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
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
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
list key microbial features of C. botulinum
Large, Gram+ Rod anaerobic spore forming (heat resistant) neurotoxin (habitat is ubiquitous)
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)
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)
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
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)
Ciguatera Fish sources
Carribean and Tropical Pacific- 20% of US food poisoning
Dinoflagellates = Gambierdiscus toxicus: large predatory reef fish – barracuda, black grouper, amberjacks
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
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
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
