GI Acute Diarrhea with Vomiting (Food Poisoning)

Question 1

there is NO ____ in cases of food poisoning/toxemia

Answer 1

there is NO microbial growth in cases of food poisoning/toxemia

Question 2

S. aureus produces ___-encoded _____

Answer 2

S. aureus produces chromosomally-encoded ST enterotoxin

Question 3

describe the pathogenesis of S. aureus

Answer 3

1. ingestion of food containing the enterotoxin
   
   • A & D enterotoxin commonly found
2. neurologic (vomiting) and enteric (diarrhea) effect
   
   • act on gut receptors → stimulate vomiting (vagus and symp. nerves)
   • NO stimulation of adenylate cyclase

Question 4

describe the clinical symptos of S. aureus food-poisoning

Answer 4

Question 5

describe isolation and identification of S. aureus infection

Answer 5

Question 6

describe the pathogenesis of B. cereus food-poisoning

Answer 6

• short incubation: 2-3 hours
• duration: 6-24 hours
• ingestion of food containing ST
• neurotoxin (peptide)

Question 7

foods associated with B. cereus food poisoning are….

Answer 7

foods associated with B. cereus food poisoning are:

• rice
• beans
• lentils

Question 8

describe the isolation and identification of B. cereus

Answer 8

Question 9

compare food poisoning vs. food-borne infection caused by B. cereus

Answer 9

Question 10

list the short-acting vs. long-acting wild mushrooms

Answer 10

• short-acting:
  
  • toxin: museinol, muscarine, psilocybin, coprius artemetaris, ibotenic acid
  • incubation = <2 hrs, vomiting, diarrhea
• long-acting
  
  • toxin: amanita
  • incubation = 4-8 hrs, diarrhea, abdominal cramps
  • can be fatal

Question 11

describe mycotoxins and name an example

Answer 11

mycotoxins = secondary metabolites

• aflatoxins
  
  • Aspergillus flavus and A. parasiticus
• contamination of:
  
  • tree nuts, peanuts, oilseeds (corn and cotton)
• responsible for:
  
  • acute necrosis, cirrhosis and carcinoma of the liver

Question 12

describe ciguatera poisoning

Answer 12

commonly found in Caribbean/Tropical Pacific

• dinoflagellates (algae) produce ciguatoxin
  
  • activates voltage dependent Na channels
• large predatory reef fish: barracuda, grouper and amberjacks

Question 13

describe the clinical manifestation of ciguatoxin poisoning

Answer 13

• acute GI symptoms: 3-6 hrs after ingestion
  
  • watery diarrhea, nausea, vomiting, abdominal pain (within 12 hrs)
• neurologic symptoms: circumoral & extremity paresthesia, severe itching, hot/cold temp. reversal

Question 14

describe scombroid poisoning

Answer 14

• fish have the ability to convert histidine → histamine = scombrotoxin

Question 15

describe the clinical manifestations of scombroid poisoning

Answer 15

• burning sensation in mouth, metallic taste
• acute GI symptoms: minutes - 3 hrs after ingestion
  
  • watery diarrhea, nausea lasting 3-6 hrs
• other symptoms:
  
  • dizziness, rash, facial flushing, generalized itching, paresthesias

Question 16

describe the mechanism of brevetoxins

Answer 16

lowers activation threshold of voltage-dependent Na channels → depolarizes nerve cells

Question 17

describe neurotoxic shellfish poisoning

Answer 17

• incubation: <1-3 hours
• duration: 24-72 hrs
• paresthesia, mouth numbness, tingling sensation of mouth and extremities, GI upset

Question 18

describe paralytic shellfish poisoning

Answer 18

• produces saxitoxin: inhibits Na channel opening
• incubation: <2 hrs
• duration: 3 days
• tingling and numbness of mouth spreading to extremities, ataxia
• severe cases = muscular paralysis, resp. paralysis

Question 19

describe diarrhetic shellfish poisoning

Answer 19

• okadaic acid: inhibits protein phosphatase 2A
• incubation: 30 min-12 hrs
• duration: 3 days
• GI symptoms: diarrhea, nausea, vomiting, abdominal pain
• no neurological involvement