GI Lower Bacterial Infections I

Question 1

Difference between food poisoning and food infections?

Answer 1

Timing. Poisoning is with pre-formed toxins. Infections are can cause both

Question 2

What is an “enterotoxin”?

Answer 2

Exotoxin that targets intestine

Question 3

What are three common bacteria generate pre-formed toxins in food?

Answer 3

Staphylococcus aureus
Bacillus cereus
Clostridium botulinum

Question 4

What other skin infection does staph aureus cause?

Answer 4

Scalded skin syndrome

Question 5

How long after food ingestion do S. aureus symptoms appear?

Answer 5

1-7 hrs

Question 6

How long does food poisoning from S. aureus last?

Answer 6

1-3 days

Question 7

How do you diagnose S. aureus food poisoning?

Answer 7

Toxin producing S aureus identified in stool and vomit

Linked with food

Question 8

What are common S. aureus food reservoirs?

Answer 8

Ham, eggs, custard

Question 9

What do Bacillus cereus look like?

Answer 9

Box-car shaped G+ rods

Question 10

Which of the three toxin producing bacteria produce spores?

Answer 10

Bacillus cereus

Clostridium botulinum

Question 11

What is the reservoir for Bacillus cereus?

Answer 11

Rice (spores survive cooking process)

Question 12

How does Bacillus cereus food poisoning present?

Answer 12

Vomiting 1-6 hrs after ingestion
Watery Diarrhea 6-15 hrs after ingestion
For 24 hours

Question 13

What causes vomiting in B cereus infection?

Answer 13

Enterotoxin Cereulide forms holes in membranes

Question 14

What causes diarrhea in B cereus infection?

Answer 14

Large amounts of bacteria cause it to generate toxins in small intestine

Question 15

What is drug of first choice for B cereus?

Answer 15

Vancomycin

Question 16

Does B cereus presence on incubation plate rule in its cause for diarrhea?

Answer 16

No because it’s ubiquitous

Question 17

What does Clostridium botulinum look like?

Answer 17

G+ spore forming rod

Question 18

How is food borne botulism treated?

Answer 18

Vent if in resp failure
Antitoxin if paralysis is incomplete
Remove contaminated food in gut

Question 19

How do you diagnose botulism?

Answer 19

Organism or toxin in stool sample
Symptoms and history
Tests to exclude

Question 20

What is botulinum toxin?

Answer 20

Irreversibly blocks acetylcholine release from motor end plate

Question 21

What are symptoms of botulism?

Answer 21

Blurred, double vision
Slurred speech
Difficulty swallowing
Drooping eyelids
Muscle weakness

Question 22

What are some food reservoirs for botulinum?

Answer 22

Toxin is in food, spores are in honey (don’t give honey to infants)

Question 23

What does Clostridium perfringens look like?

Answer 23

G+ spore forming rod

Question 24

What does C. perfringens enterotoxin do?

Answer 24

Binds to receptors in endothelial cell junctions, generating pores

Question 25

What skin disease is C perfringens responsible for?

Answer 25

Gas gangrene

Question 26

What are symptoms of C perfringens infection?

Answer 26

Diarrhea, abd cramps After 6-24 hours of eating Smx less than 24 hours No fever or vomiting

Question 27

How do you diagnose C perfringens?

Answer 27

Detection of TOXIN or high amounts of bacteria in feces

Question 28

What does campylobacter jejuni look like?

Answer 28

Gram - spirilli, motile

Question 29

What is C jejuni reservoir?

Answer 29

Poultry

Question 30

How do you culture C. jejuni?

Answer 30

``` Karmali agar (cold sensitive) Oftentimes killed before cultured ```

Question 31

What are the symptoms of C jejuni

Answer 31

FEVER Diarrhea, cramping, abd pain Sx last a week Can be bloody diarrhea

Question 32

Mechanism of disease for C jejuni?

Answer 32

Cell invasion, inflammatory response

Question 33

What are possible complications of C jejuni?

Answer 33

Guillain Barre syndrome | Reactive arthritis

Question 34

Which serotypes of salmonella cause typhoid (not food-related)?

Answer 34

Paratyphi A | Typhi

Question 35

Which serotypes of Salmonella cause gastroenteritis?

Answer 35

S. Enteritidis | S. Typhimurium (more common in US)

Question 36

What do salmonella look like?

Answer 36

Motile, gram negative bacilli

Question 37

What molecules are sought out on culture to find out if something is salmonella?

Answer 37

Lactose fermenting negative | H2S production positive

Question 38

What are symptoms of Salmonellosis?

Answer 38

Diarrhea Sx typically last 4-7 days 12 hr to 3 day incubation REACTIVE ARTHRITIS

Question 39

What is a major complication of salmonella?

Answer 39

Reactive arthritis, systemic infection

Question 40

What are typical reservoirs for Salmonella?

Answer 40

``` Unwashed produce Raw milk Raw eggs Food service (if ill) Apparently turtles ```