Foodborne Bacterial Infections Flashcards
Foodborne Intoxication occurs from ingestion of : ____________________
a food containing a preformed toxin.
What are the general characteristics of a foodborne intoxication (5):
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
Staphylococcal Intoxication (vomiting) typical scenario:
- temperature-abused food
- skin infection
Sa causes illness through the ingestion of the not the organism
toxin
Enterotoxin:
a toxin that acts on the gastrointestinal tract
Sa toxin stimulates the _____ and __________ nerves
vagus
sympathetic
Give me characteristics of Sa toxin :
- 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
Clostridium botulinum intoxication (paralysis in children) typical scenario:
- 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
infant botulism is an _______
infection (internal production of the toxin) - proliferation of the organism
How does paralysis occurs (C.botulinum intoxication)
- 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
Salmonella enterica infection (salmonellosis) what are the main symptoms:
- abdominal pain/bloating
- muscle and joint pain
- diarrhea
- weakness
- nausea/vomiting
- fever
Which Salmonella species and subspecies cause illness in humans :
Salmonella enterica subsp. enterica (flagellar, capsular, somatic)
What serovars of Salmonella Enterica are most commonlt associated with foodborne illness :
Serovars Thyphimurium and Enteritidis
Talk to me about the symptoms and Treatment of Salmonella Enterica:
- 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!
Listeria monocytogenes infection: intestine, lymph node, _______, _________, ________, _________
- liver
- spleen
- brain
- placenta
L.monocytogenes can grow and divide from _____ C
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%
Lowering the temperature doesn’t stop the Lm growth but ___________
it does slow it
Why raw milk cheeses are a source of Lm?
- 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)
Why are ready-to-eat meats good for Lm to grow?
-RTE meats are heated and then cooled in brine (good for Lm because competing bacteria are reduced)
Name a few clinical manifestations of Campylobacter infection:
- brain abscess
- meningitis
- miller-fisher syndrome
- hepatitis
- guillain-barré syndrome
Chicken liver paté is associated with:
- campylobacter jejuni
- bloody diarrhea
- undercooked chicken livers to prepare their pâté
90% of gastroenteritis cases are caused by _______ and just under 10% are caused by _______
C. jejuni
C. coli
How do symptoms generally begin in GBS and MFS?
with motor and sensory deficits in the lower extremities and spread to the upper extremities the trunk
Most cases of GBS occur after _________ infection
C.jejuni
What is the main difference between MFS and GBS?
- 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
___________ is an emerging pathogen
Cronobacter
In 1990 Cronobacter was linked to _________
powdered infant formula
Who’s at risk for Cronobacter?
- 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
Vibrio sp. is a predominant bacterial genus in _________
estuarine waters
Which vibrio species have picked up the virulence factors which cause illness in humans
- V.cholerae
- V.parahaemolyticus
- V.vulnificus
*Vibrio infection is generally associated with seafood consumption or seafood contact *
Why colder waters produce safer seafood products ?
because when oysters are harvested above 17C, its vibrio season
Characteristics of vibrio parahaemolyticus :
- 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
Vibrio vulnificus
rashes on hands and legs
V.cholerae releases ___________ that binds to ganglioside receptors on the surface of intestinal epithelium cells
Cholera Toxin (CTX)
What happens when the cholera toxin is internalized ?
- 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
V.parahaemolyticus
- environment:
- symptoms of infection:
- mortality rate:
- virulence factors
- cool water but warmer than 15C
- diarrhea, fever, abdominal cramps, nausea, vomiting
- very low
- tdh, trh
V.vulnificus
- environment:
- symptoms of infection:
- mortality rate:
- virulence factors
- warm water
- fever, chills, nausea, skin lesions
- 40-60%
- capsule, LPS, vvhA
V.cholerae
- environment:
- symptoms of infection:
- mortality rate:
- virulence factors
- tropical water
- rice water stools, abdominal pain, loss of appetite
- 1% in worse case scenarios
- Cholera toxin (CTX)
