Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Fpathogens > 5 - Staphylococcal Intoxication > Flashcards

5 - Staphylococcal Intoxication Flashcards

1
Q

Foodborne intoxication occurs from ________________________

A

ingestion of a food containing a preformed toxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the 5 general characteristics of a foodborne intoxication?

A

1) Toxin is produced by a pathogen while growing in the food
2) The toxin can be heat stable or heat liable
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 2 things that represent Staphylococcal intoxication:

A
  • grape-like cocci

- vomiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Staphylococcal typical scenario example:

A

temperature-abused breakfast on a flight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

T or F: recently the prevalence of staph aureus has drastically declined

A

T, due to better use of refrigeration to store food and improved sanitary practices that can control contamination by Sa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Staphylococcus aureus is gram_____

A

postive cocci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Give some characteristics about staph aureus:

A
  • gram positive cocci
  • exists as either single cells or grape like clusters
  • nonmotile, noncapsular
  • non-spore forming, sensitive to heat treatment
  • facultative anaerobes but grow rapidly under aerobic conditions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Staph aureus cells are killed at ______ for 12 mins, or _____ for 15 seconds

A

66

72

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Staphylococcus aureus are mesophiles and can grow between ______ but grow rapidly between _______

A

7-48C

20-37C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is special about staph aureus?

A

They can grow at relatively low Aw (0.86), low pH (4.8) and under high salt and sugar conditions

*They can grow under several adverse conditions, but are poor competitors against other organisms, therefore they do very well when adverse environments give them a competitive advantage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

T or F: S.aureus is a very common cause of human and animal infections

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

_____________ is commonly used to define the sequence type (ST) or allelic profile based on the sequences of 7 housekeeping genes found in all strains of S. aureus.

A

Multilocus sequencing typing (MLST)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many housekeeping genes are found in all strains of S.aureus?

A

7

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

If a group of STs share at least _ of _ alleles, the group of STs can be defined as a __________

A 
5, 7
clonal complex (CC).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Five CCs are predominant in human colonization and infection: __________

A 
CC1
CC5
CC8
CC30
CC45
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The Sa accessory genome is made of several _______________ which can be transferred horizontally (20% of the Sa genome)

A

mobile genetic elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

However, S. aureus has a very advanced _________________ that occurs in each of it’s lineages and prevents horizontal gene transfer from occurring between different clonal complexes.

A

restriction modification system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Most Sa genomes carry between ________ prophage genomes, phage genomes have enterotoxins

A

1-4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Many enterotoxins are on mobile genetic elements, ____________ are required for foodborne intoxication

A

enterotoxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Sa causes foodborne illness through the ingestion of the ______ not the organism

A

toxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Enterotoxin:

A

a toxin that acts on the gastrointestinal tract

22
Q

Endotoxin:

A

a toxin that is structurally associated with the bacterial cell (LPS)

23
Q

Exotoxin:

A

a toxin that is usually secreted into the extracellular fluid but can be intracellular or injected directly into eukaryotic cells

24
Q

Exfoliative toxins:

A

dermolytic exotoxins produced exclusively by Sa that cause the symptoms of impetigo or scalded skin syndrome

25
Q

All Sa enterotoxins are also:

A

exotoxins

26
Q

Sa produces several types of enterotoxins (A to J, without F) that all have a high degree of _______________, and all cause ______________

A

homology

gastroenteritis

27
Q

Enterotoxin F, once thought to be an enterotoxin, turned out to be an endotoxin and causes _____________ (Sa enterotoxin B can also be associated with toxic shock syndrome)

A

toxic shock syndrome

B

28
Q

Enterotoxins are made throughout most of the __________________

A

exponential growth phase

29
Q

Enterotoxin production can be inhibited by the presence of ______

A

glucose

30
Q

Enterotoxins may be involved in _______________ in Sa

A

quorum-sensing

31
Q

Staphylococcal toxin is unique because it is ______________________

A

very heat stable – not destroyed by boiling or canning

  • therefore when it is in a food it’s there!
32
Q

The toxin stimulates the ______ and _______ nerves

A

vagus

sympathetic

33
Q

___________ are a main environmental source of Sa, we have it on our skin, the interior of the nose is the main site, it spreads by direct contact, skin fragments, and respiratory droplets (blood supply)

A

people

*also found in erupted acne in humans

34
Q

Sa is able to ________ our cells and live ____________

A

invade

intracellularly

35
Q

T OR F: Sa can acquire resistance to heavy metals and antibiotics

A

T

36
Q

T OR F: animals cannot carry Sa

A

F

37
Q

Sa is often a cause of _______________, and a variety of infections in agricultural animals

A

bovine mastitis

38
Q

What happens when a cow with mastitis is milked?

A

The bacteria can contaminate milk and dairy products, the cow can also contaminate automated milkers, and facilities contaminating other batches of milk

*If they can grow, the toxins may survive pasteruization

39
Q

What are common food products associated with S.aureus?

A
  • ground beef
  • pork sausage
  • shrimp
  • oyster
40
Q

Most contamination is traced to ___________ during food preparation

A

humans

41
Q

Organism grows optimally at 37C-40C, only ___ hours required at this temperature for sufficient toxin production

A

3 (importance to properly refrigerate your food)

contributing factors are:

  • inadequate refrigeration
  • preparing foods too far in advance
  • poor personal hygiene (just wash your hands people)
  • inadequate cooking
  • prolonged use of warming plates (ie. buffet)
42
Q

Give me characteristics of staphylococcal intoxication:

A
  • very quick onset (30 mins), mean incubation is 4.4 hours, 10hrs is max time to onset
  • self-limiting and recovery in 24-48h
  • most cases are not reported
  • outbreaks are seasonal (picnics)
  • there is NEVER fever
  • almost everyone vomits, other symptoms can have nausea, diarrhea, and abdominal pain
43
Q

is death rare with staph intoxication?

A

yes

44
Q

purified toxin is considered a _________ agent

A

bioterrorism

45
Q

What does the FDA says about the infectious dose?

A
  • above 10^5 cells/g can cause disease

- 1ng/g of toxin in food can cause illness

46
Q

Methicillin-resistant Sa (MRSA) carry the _______ gene

A

mecA

47
Q

MRSA is the causative agent of _________________________________

A

soft tissue and skin infection, along with necrotizing fasciitis

48
Q

How do you prevent staph intoxication?

A
  • hand washing, glove wearing, avoid hiring people with active skin infections
  • adequate refrigeration, or continued heating of prepared food (re-heating doesnt help)
  • preservatives could be used to kill or arrest growth of the organism
49
Q

__________ are the important factor and allow symptoms to have a very fast onset

A

the toxins

50
Q

staph aureus resides on ____________

A

skin, nares and hair of humans and animals (any foodstuff that involve human contact, or is from a food producing animal can potentially be infected

51
Q

Results of Sa food contamination will depend on _________________

A

the genetic makeup of the particular organisms (does it have the enterotoxin gene)

Fpathogens (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions