Food Borne Infections And Toxins Flashcards Preview

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Flashcards in Food Borne Infections And Toxins Deck (47)
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1

Give 2 old food borne diseases

* both spread feacal oral route*
> typhoid
- enteric fever caused by salmonella enterica Typhi, survives in macrophages, causes sepsis
- still present throughout the world but eradicated from UK
- carriers (GIT cells or gall bladder) can infect others, eradication hard
> cholera
- water borne
- vibrio cholerae

2

What is the best way to avoid food-borne enteritis ?

Cook your food properly
- but some foods eaten raw or rare
- can develop toxins on standing
- cooked food can be contaminated from raw food/feaces

3

5 primary agents of food borne disease in the UK

Campy
Salmonella
Listeria
E. Coli
Novovirus
(Severity and no cases in hospitals)

4

Other causes food borne illness LOOK

- s alerts
Bacillus cerise
C perfringens Yule a
Botulism
---

5

Why are burgers more likely to cause food poising than steak?

Ground meat contaminated throughout burger
- steaks only contaminated on the outside (inside equivalent to sterile wrt human pathogens)

6

Which pathogen accounts for majority of numbers of food poisoning

- campy 60%
- nori virus 30%
- salmonella very few
- norovirus and listeriosis very minimal

7

Which pathogens cause majority of HOSPITAL admission

- majority campy
- salmonella
- E. coli
- listeria
- norovirus (if immunocompromised/concurrent disease)

8

Which pathogens cause majority of deaths from food poisoning?

- campy 30%
- salmonella 20%
- E. coli 10%
- listeria 30%
- norovirus 10%

9

How has incidence of campy changed over time?

- was dropping
- since 2005 increasing again and now at higher level than initially

10

What is campy ? Subspecies? Diagnosis? How is it cultured? Incubation period?

- campylobacter jejuni (poultry)
- campylobacter coli (pigs)
- campylobacter upsaliensis (dogs)
> microaerophilic, 42*
> endemic in animals (birds and mammals)
- dx by culture of feacal sample
* zoonotic*
-2-5d incubation period

11

Pathogenesis of campylobacter

- colonised SI
- VD+ stomach pains
- fever (so innate immune system activated)

12

Majority of infection with campylobacter from which sources?

- most raw poultry
- raw meat
- infected pets and farm animals

13

Dx of campy?

- culture feacal sample
- blood agar with Abx selection
- 48hrs 42* microaerophilic
- curved G- rod

14

How can campylobacter be controlled?

COOKING ALWAYS KILLS CAMPY!

15

How does meat handling allow for campy growth

- not properly defrosted chicken
- frozen centre allows survival inside carcasse

16

What makes listeria monocytogenes special?

Can grow in the fridge (8-10*)

17

Sources of infection of listeria

- contaminated raw meat
- unpasteurised milk (pasteurising destroys listeria well)
- cheese made with unpasteurised milk
- foods containing raw vegetables
- esp organic vegetables in well manured soils

18

Incidence of listeriosis over time?

Roughly stable around 150 cases/year

19

How is listeria transmission?

- soil
- silage (can grow here)
- ingestion by animals -> encephalitis, bacteria email and abortion
- meat
- feaces
- udder -> dairy products
- humans

20

How is listeria virulent?

- get inside enterocytes
- produce haemolysin
- produce polymerised actin to propel into adjacent cells
- hide in cytoplasm safe from Abx and immune

21

Is listeria monitored and controlled tightly?

YES
- legislation

22

Who is commonly affected by listeria?

- immunocompromised individuals
- Young old
- pregnant women (people say don't have soft cheese - no reason for this! Don't have unpasteurised cheese)
- normal adults relatively resistant to disease

23

How can listeria be destroyed

COOKING ALWAYS KILLS LISTERIA

24

how has incidence of norovirus changed?

- increasing
- no actual cases 150-200,000 cases/year (lab confirmed cases 10x less than this)

25

What is norovirus ? Method of spread?

- winter vomintiing bug
- ss RNA virus
- person to person spread, food and food handlers, fomites
- feaces
> calicivirus
- single virus needed to infect, very resistant in the environment.

26

Dx of. Novirus

- RT qPCR
- unable to differentiate infective and non infective
- dx hard

27

How can norovirus be destroyed?

Proper disinfection and cooking

28

Incidence of E. Coli?

Stable but numbers higher than they should be!!

29

What is e. Coli

- Stec
- e. Coli 0157 (mostly, not all strains are this)
> bacteriophage transmits ability to product toxin (ST1 and ST2)

30

Does E. coli affect aniamlsb

Haemorrhagic D+ in calves but not major problem
- esp infects beef