Bacterial Foodborne Diseases Flashcards by Kate Guiremand

bacterial foodborne infections caused by:

intoxication

infection

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bacteria associated with intoxication:

Staphylococcus aureus
Bacillus cereus
Clostridium botulinum
Clostridium perfringens

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bacteria associated with infection

Campylobacter jejuni
Salmonella spp.
Escherichia coli
Vibrio spp.
Listeria monocytogenes

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2 ways bacterial toxins are named

by type

by target tissue

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endotoxins

gram +

staph, bacillus, clostridium

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exotoxins

gram -

campylobacter, salmonella, E. coli, Vibrio

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typical symptoms: intoxication

Onset is usually rapid: 30min‐6hrs most commonly, but up to 12 hrs
Illness usually lasts for ~1‐2 days
The primary exception is botulism toxin
(neurotoxin)

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typical symptoms: infection

Onset in several hours, to days
Illness usually lasts for several days
Many produce enterotoxins that cause watery diarrhea, ranging from mild to severe
Invasive species, or species with toxins that kill enterocytes, cause dysentery, fever, and possibly septicemia

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Staphylococcus aureus: reservoir

skin and nose of many healthy people

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Staphylococcus aureus: transmission

Vehicle: food: contaminated with S. aureus

and stored at temperatures favorable to growth and toxin production (danger zone: 40-140 F)

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Staphylococcus aureus: clinical signs

Most common foodborne intoxication
rapid onset (30min-6hrs)
Vomiting, diarrhea, cramping
+/- 24hrs

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Staphylococcus aureus: prevention

proper food hygiene and storage

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Bacillus cereus: reservoir

soil

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Bacillus cereus: transmission

Vehicle: food, contaminated with bacteria or

spores and stored at temperatures favorable to growth and toxin production (rice and grains!!)

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Bacillus cereus: clinical signs 2 forms

“Enteric Form” Nausea and vomiting
Incubation period 30 minutes to to 6hrs
“Diarrhea form” diarrhea and cramping
Incubation period 8‐16 hrs

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Bacillus cereus: prevention

proper food hygiene and storage

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Clostridium botulinum: reservoir

Soil; sediments (stream, lake, and coastal waters); intestinal tracts of fish and mammals; gills and viscera of crabs and shellfish; honey

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Clostridium botulinum: transmission

Vehicle: food contaminated with spores at
production and then improperly processed
allowing growth and toxin production

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Clostridium botulinum: clinical signs (neurotoxin)

flaccid paralysis
small infective dose
onset 18-36hrs
infant botulism (under 1 year)

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Clostridium botulinum: prevention

Avoid contamination of food
Don’t feed honey to children less than 12 months of age
Proper preparation of food

Clostridium perfringens: reservoir

Soils, sediments, intestinal tracts of people and animals

Clostridium perfringens: transmission

Vehicle: foods contaminated at production, processing or preparation

Clostridium perfringens: clinical signs

Incubation period 8‐22 hrs
Vomiting, diarrhea, abdominal cramps
Duration 24 hrs

Clostridium perfringens: prevention

proper food processing and preparation

preventing foodborne intoxication

Proper food hygiene Proper food preparation and storage Proper canning Meat hygiene

True/False: Campylobacter jejuni is more prevalent in the summer

true: picnics

Campylobacter jejuni: reservoir

Normal component of intestinal flora of many species Many bird species Many mammalian species can be infected

Campylobacter jejuni: transmission

C. jejuni is very fragile Vehicle is contaminated food, water Very low infectious dose Direct contact with farm animals

Campylobacter jejuni: clinical signs

Incubation period: 2‐5 days Infection and enterotoxin production Duration of symptoms: 7 days (2‐10 days)

Campylobacter jejuni: prevention

target the vehicle: – OFFS: reduce infection in birds going to slaughter – Meat hygiene – Pasteurization of milk – Proper handling and cooking of meat esp poultry

Salmonella spp: reservoir

GI flora in many species (birds, cattle, rodents, etc.) | skin flora in reptiles

Salmonella spp: transmission

many foods

Salmonella spp: clinical signs

Incubation period: 12‐72 hours An invasive type infection Duration of symptoms: usually 4‐7 days

Salmonella spp: prevention

many strategies pre-harvest: OFFS post-harvest: hygiene, pasteurization, cook foods properly, education

Salmonella Enteritidis

Causes egg‐associated salmonellosis | Associated with eating raw or undercooked eggs

E. coli: reservoir

found in many mammalian species | varying pathogenicity

E. coli: transmission

Vehicle: contaminated food | Carcasses contaminated in plant, veggies irrigated with contaminated water, unpasteurized milk, cheese, fruit juices

E. coli: clinical signs (O157H7)

Incubation period: 3‐4 days Infection + enterotoxin (Shiga toxin) production Duration of symptoms: 5‐7 days 5-10%: hemolytic uremic syndrome

E. coli: prevention

many different strategies pre-harvest: OFFS, vaccination post-harvest: hygiene, pasteurization, cook food properly

true/false: most cases or E. coli are seen from outbreaks

true

Vibrio cholerae: reservoir

People, naturally found in brackish rivers and coastal waters

Vibrio cholerae: transmission

water: most important transmission: contaminated by water

Vibrio cholerae: clinical signs

Very important world wide | Infection + enterotoxin = VERY watery diarrhea

Vibrio cholerae: prevention

Sanitation, sewage management and water treatment | Food preparation: Proper handling and cooking of food especially shellfish, wash fruits and veggies

Listeria monocytogenes: reservoir

soil, water, animals

Listeria monocytogenes: transmission

vehicle: infected food | replicates at low temperatures (low as 3C)

Listeria monocytogenes: clinical signs

Causes mild food poisoning, or flu‐like symptoms, in most exposed people – No toxin production – Septicemia and meningitis – Abortions

Listeria monocytogenes: prevention

Meat hygiene Pasteurize milk Food preparation: Cook food fully, wash fruits and veggies

prevention of foodborne infection

Target the vehicle: no toxins produced in food - OFFS - meat hyigene - pasteurization (capy, salmonella, E. coli, listeria) - proper handling and cooking of food - sewage management (Vibro cholera)