Foodborne Ilnesses Flashcards

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1
Q

How many cases are food borne illnesses per year?

A

48,000,000
15% of americans

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2
Q

How does food poisoning occur?

A

Ingestion of pre-existing enterotoxins

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3
Q

The pathogen may no longer _____

A

Be present

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4
Q

2 examples of non present pathogens

A

Botulism and staphylococcus aureus

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5
Q

Types of Foodborne pathogens (3)

A
  1. Salmonella enteriditis (eggs, poultry, produce, pets)
  2. Salmonella typhi (typhoid fever, 4–500 cases annually in USA, mainly from travelers)
  3. Campylobacter jejuni (poultry, cattle, drinking water, sexual activity, causes more diarrhea than salmonella and shigella)
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6
Q

How can Listeria occur?

A

Bacteria could be in packaged food

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7
Q

Shigellosis is a _____ bacterium

A

Gram-negative

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8
Q

Shigellosis symptoms

A

Usual gastroenteritis symptoms, plus dysentery

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9
Q

What can you contract Shigellosis from?

A

Eggs, shellfish, dairy, vegetables, water

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10
Q

What are the two types of shiga toxins?

A

Active (A) and Binding (B)

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11
Q

What is Active Subnit?

A

An N-glycosides which cleaves a single adenine residue from 28S rRNA, halting protein synthesis

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12
Q

What do shiga toxins lead to?

A

Death of vascular endothelial cells, causing bloody diarrhea

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13
Q

Where are shiga toxins most effective?

A

In small blood vessels, such as the gut and kidney

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14
Q

Where are many of the genes that are needed for Shigella virulence?

A

On the invasion plasmid

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15
Q

What does the virulence plasmid contain?

A

Many pathogenicity island clusters
- toxin genes stxA and stxB are NOT on this
-contained in a viral prophage embedded in the bacteria genome

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16
Q

Two ways of transfer for genes

A

Vertical and horizontal

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17
Q

Lateral gene transfer types

A

Transformation, phase transduction, bacterial conjugation, transposition
- all can occur within or between species and strains

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18
Q

E.coli is a _______

A

Natural gut bacterium

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19
Q

T/F many strains exist, most are harmless or even beneficial

A

True

20
Q

Which strains of Ecoli are highly toxic?

A

EHEC strains and O157:H7

21
Q

What can E.coli cause?

A

Hemolytic uremic syndrome

22
Q

What are the symptoms of hemolytic uremic syndrome?

A

Initial symptoms are bloody diarrhea
Later symptoms are pallor bruising, lethargy, and anemia
Finally, hematuria (blood in the urine) and acute renal failure develop)
Disease is fatal in 3-5 % cases

23
Q

What does the O antigen stand for in E.Coli?

A

Bacterial cell wall lipopolysaccharide variation

24
Q

What does the H antigen stand for in E.Coli?

A

Bacterial flagella variation

25
Q

How did E.coli acquire Shiga toxins?

A

EHEC manufactures Shiga toxins such as Stx5,
STx5 binding to receptor molecule gb3 in kidney glomerular cells inactivates an enzyme

26
Q

What increased when E.coli acquired shiga toxins?

A

Increase in von willebrand Factor, resulting in increased clotting

27
Q

What does micro-clots do?

A

Accumulate within blood vessels, damaging red cells and restricting blood flow

28
Q

What was the most famous case of E.Coli outbreak?

A

1993 jack in the box burger undercooked

29
Q

Where was food supply contamination an issue?

A

Washington state, healthy beef cattle
Ontario Canada , healthy slaughterhouse
England, implicated slaughterhouse

30
Q

Food inspection issue with dance instructor

A

Contaminated burger patty caused paralyzation

31
Q

Where were the components of the burger patties from that paralyzed the dance teacher?

A

Meats from three different areas prepared in a slaughterhouse

32
Q

When do suppliers check for contamination?

A

Cargill tests after it is ground together
Costco does test

33
Q

Other types of E.coli

A

Enterohemorrhagic e.coli causes 62,000 infections and 50 deaths in the US

34
Q

How sterile is food study?

A

Study carried out in Minneapolis/St. Paul examining ExPEC contamination of foods
- 9% of prevalence in misc. foods
-69% in beef and pork
- 92% in poultry

35
Q

ESBL-producing E.coli in human-derived and food chain-derived samples

A

11% of fecal samples contained ESBL
-frequent in sewage and retail meat

36
Q

Cholera and copepods

A

Vibrios are often attached to the chitinous shells of planktonic copepods
- simple filtration of drinking water through sari cloth can remove the copepods and lower the risk of infection

37
Q

What does Biofilm do?

A

Allows bacteria to survive in nutrient poor and stressful environments

38
Q

What does the cholera toxin do?

A

Releases in to intestinal epithelial cells
Increases Cl- ion excretion
Increased luminal ion concentration
Watery diarrhea

39
Q

How is V. Cholerae killed?

A

Stomach acids

40
Q

What does surviving bacteria do?

A

Enter small intestine and swim into the mucus layer
-detach the flagellum, losing ability to swim
-begin secreting the toxins that cause disease

41
Q

Symptoms of Cholera

A

Rapid onset of severe rice water diarrhea, plus vomiting
Fluid loss can be 3-5 gallons per day

42
Q

When does cholera develop?

A

Disease commonly develops from diarrhea to shock within 4-12 hours, with death following from 18 hours onwards

43
Q

What is the cholera toxin CTx?

A
  • toxin activates adenylate cyclase increase in cAMP
    -activates the CFTR protein, resulting in enhanced flow of chloride ions and water from the cell
    -V. Cholerae also inhabits the gut of copepods, and CTx may be important in their osmoregulation
44
Q

Pandemics of cholera

A

Seven cholera pandemics have been in recent history
- horizontal transfer

45
Q

Where was the 2010 cholera outbreak?

A

Haiti

46
Q

Cholera ecology slide

A