Foodborne Bacterial Infections

Question 1

Foodborne Intoxication occurs from ingestion of : ____________________

Answer 1

a food containing a preformed toxin.

Question 2

What are the general characteristics of a foodborne intoxication (5):

Answer 2

1) Toxin is produced by a pathogen while growing in the food
2) The toxin can be heat liable or heat stable
3) Ingestion of a food containing active toxin, not viable cells is necessary for poisoning
4) Symptoms generally occur quickly, as early as 30 minutes after ingestion
5) Febrile symptoms are not present

Question 3

Staphylococcal Intoxication (vomiting) typical scenario:

Answer 3

• temperature-abused food

- skin infection

Question 4

Sa causes illness through the ingestion of the not the organism

Answer 4

toxin

Question 5

Enterotoxin:

Answer 5

a toxin that acts on the gastrointestinal tract

Question 6

Sa toxin stimulates the _____ and __________ nerves

Answer 6

vagus

sympathetic

Question 7

Give me characteristics of Sa toxin :

Answer 7

• most contamination is traced to humans during food preparation
• organism grow optimally at 37-40 C (only 3 hours required at this temp for sufficient toxin production)
• very quick onset (30 minutes) mean incubation is 4.4 hours, 10hrs is max to onset
• self-limiting and recovery in 24-48hrs

Question 8

Clostridium botulinum intoxication (paralysis in children) typical scenario:

Answer 8

• canning of food / soup without checking the pH
• seeing double, difficulty swallowing and paralysis in arms and legs
• canning did not kill spores
• always boil your canned products for 10 minutes

Question 9

infant botulism is an _______

Answer 9

infection (internal production of the toxin) - proliferation of the organism

Question 10

How does paralysis occurs (C.botulinum intoxication)

Answer 10

• ingestion / production of the toxin molecules
• toxin molecules are absorbed by the gut and are spread via blood to peripheral nerves
• normally axon terminal of the neuron connects with muscle tissues through SNARE proteins and releases acetylcholine into the muscle cells which causes the contraction
• BoNT acts as a protease cleaving the SNARE proteins
• muscles are deprived from the acetylcholine signal and this results in flaccid paralysis

Question 11

Salmonella enterica infection (salmonellosis) what are the main symptoms:

Answer 11

• abdominal pain/bloating
• muscle and joint pain
• diarrhea
• weakness
• nausea/vomiting
• fever

Question 12

Which Salmonella species and subspecies cause illness in humans :

Answer 12

Salmonella enterica subsp. enterica (flagellar, capsular, somatic)

Question 13

What serovars of Salmonella Enterica are most commonlt associated with foodborne illness :

Answer 13

Serovars Thyphimurium and Enteritidis

Question 14

Talk to me about the symptoms and Treatment of Salmonella Enterica:

Answer 14

• symptoms generally occur 8 to 72 hours after ingestion
• illness is self-limiting, non-bloody diarrhea, and abdominal pain
• symptoms generally resolve within 5 days
• Therefore, uncomplicated cases only require supportive therapy, such as fluid and electrolyte replacement
• Antibiotics prolong carrier state and increase AMR so they generally are not used!

Question 15

Listeria monocytogenes infection: intestine, lymph node, _______, _________, ________, _________

Answer 15

• liver
• spleen
• brain
• placenta

Question 16

L.monocytogenes can grow and divide from _____ C

Answer 16

4-45 (sensitive to pasteurization temperature), it grows in the refrigerator and outcompetes other bacteria in this environment, in media as low as pH 4.4, in salt contents as high as 10%

Question 17

Lowering the temperature doesn’t stop the Lm growth but ___________

Answer 17

it does slow it

Question 18

Why raw milk cheeses are a source of Lm?

Answer 18

• raw milk cheeses are unpasteurized
• pasteurization reduces the number of Lm cells in milk to levels that don’t pose risk to human health
• Lm survives well during cheese manufacturing due to both the temperature (cold) as well as the salt content (high)

Question 19

Why are ready-to-eat meats good for Lm to grow?

Answer 19

-RTE meats are heated and then cooled in brine (good for Lm because competing bacteria are reduced)

Question 20

Name a few clinical manifestations of Campylobacter infection:

Answer 20

• brain abscess
• meningitis
• miller-fisher syndrome
• hepatitis
• guillain-barré syndrome

Question 21

Chicken liver paté is associated with:

Answer 21

• campylobacter jejuni
• bloody diarrhea
• undercooked chicken livers to prepare their pâté

Question 22

90% of gastroenteritis cases are caused by _______ and just under 10% are caused by _______

Answer 22

C. jejuni

C. coli

Question 23

How do symptoms generally begin in GBS and MFS?

Answer 23

with motor and sensory deficits in the lower extremities and spread to the upper extremities the trunk

Question 24

Most cases of GBS occur after _________ infection

Answer 24

C.jejuni

Question 25

What is the main difference between MFS and GBS?

Answer 25

- In patients with MFS the first nerve groups to be affected are those in the head (difficulty controlling eye muscles and balance) - Paralysis in other forms of GBS typically begins in the legs

Question 26

___________ is an emerging pathogen

Answer 26

Cronobacter

Question 27

In 1990 Cronobacter was linked to _________

Answer 27

powdered infant formula

Question 28

Who's at risk for Cronobacter?

Answer 28

- PIF fed infants less 1 year old (immunnocompromised and noenates youngerthan 28 days old are at the greatest risk) - low birth-weight neonates - premature infants born before 37 weeks

Question 29

Vibrio sp. is a predominant bacterial genus in _________

Answer 29

estuarine waters

Question 30

Which vibrio species have picked up the virulence factors which cause illness in humans

Answer 30

- V.cholerae - V.parahaemolyticus - V.vulnificus *Vibrio infection is generally associated with seafood consumption or seafood contact *

Question 31

Why colder waters produce safer seafood products ?

Answer 31

because when oysters are harvested above 17C, its vibrio season

Question 32

Characteristics of vibrio parahaemolyticus :

Answer 32

- Infections are almost exclusively linked to the consumption of raw or undercooked seafood - a ket feature is that it has a generation time of 8 to 9 minutes at 37C (the ability to grow rapidly means that the contaminated food becomes highly colonized if temperature abused - symptoms include diarrhea, abdominal cramps, nausea, vomiting, and fever - 4 to 30 hours after ingestion

Question 33

Vibrio vulnificus

Answer 33

rashes on hands and legs

Question 34

V. cholerae releases ___________ that binds to ganglioside receptors on the surface of intestinal epithelium cells

Answer 34

Cholera Toxin (CTX)

Question 35

What happens when the cholera toxin is internalized ?

Answer 35

- it triggers the production of cyclic AMP within the cell - cAMP activates specific ion channels within the cell membrane, causing an efflux of ions from the cell - the build up of ions in the intestinal lumen draws water from cells and tissues via osmosis - causing acute diarrhea - As water is removed from body tissues = dehydration

Question 36

V.parahaemolyticus - environment: - symptoms of infection: - mortality rate: - virulence factors

Answer 36

- cool water but warmer than 15C - diarrhea, fever, abdominal cramps, nausea, vomiting - very low - tdh, trh

Question 37

V.vulnificus - environment: - symptoms of infection: - mortality rate: - virulence factors

Answer 37

- warm water - fever, chills, nausea, skin lesions - 40-60% - capsule, LPS, vvhA

Question 38

V.cholerae - environment: - symptoms of infection: - mortality rate: - virulence factors

Answer 38

- tropical water - rice water stools, abdominal pain, loss of appetite - 1% in worse case scenarios - Cholera toxin (CTX)