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Flashcards in Staph Deck (45):
1

What does staphylococci look like microscopically?

Gram +

Cocci

Grape clusters

2

  1. What is this organism?
  2. Is it catalase + or - ?

Q image thumb

  1. Staphylococci
  2. Catalase +

3

List the differences between staphylococcus and micrococcus in the following criteria:

1. Size

2. Shape

3. Gram stain

4. Colony color

5. Hemolysis

6. O2 requirement

7. Salt tolerance

  1. Staphylococcus
    • Small
    • Spherical
    • Gram positive
    • White to golden in color
    • Some hemolytic
    • Facultative O2 requirement
    • Good salt tolerance
  2. Micrococcus
    • Big
    • Not always spherical
    • Decolorizes easily
    • Clear to yellow in color
    • Non - hemolytic
    • Obligate aerobe
    • Poor salt tolerance

4

What are 2 things staphylococci are resistnat to?

  1. Heat (except boiling)
  2. Disinfectants

5

What are the white, non-hemolytic staphylococci?

Staphylococcus epidermidis

6

What is this organism?  Which staph species?

Q image thumb

Staphylococcus aureus 

(Notice the gold color of the colonies)

7

What is the natural habitat of Staphylococcus aureus?

  1. Skin
  2. Mucous membranes
  3. Oral cavity

8

In which 3 types of disease processes can staphylococcus aureus be found?

  1. Wound infections
  2. Mastitis
  3. Boils

9

  1. Which type of teichoic acid is in S. aureus?
  2. Which type of teichoic acid is in S. epidermidis?

  1. Polyribitol
  2. Polyglycerol

10

Teichoic acid is released from the S. aureus cell and combines with antibodies present.  What does this cause?

Consumption of complement components up through C5

11

Which species of Staphylococcus have Protein A?

S. aureus

S. pseudointermedius

12

What biological effects/functions does Protein A have?

  1. Chemotactant
  2. Antiphagocytic
  3. Platelet injury
  4. Anticomplement

13

Protein A serves as a receptor for what?

Fc fragment of immunoglobulin molecules

(Binds antibody via that Fc receptor)

14

What is occuring in the attached image/what is happening?

Q image thumb

Protein A coats the surface of S. aureus and S. pseudointermedius.  It serves as a receptor for the Fc portion of the host's immunoglobulin molecules.  This allows the Staph organism to coat itself in HOST ANTIBODY.  By doing so, the bacterium resists chemotaxis, phagocytosis, complement, and causes platelet injury on top of that.

15

The capsule in S. aureus is an important virulence factor to which disease processes?

  1. Mastitis in cattle
  2. Bacteremia in humans

16

What is the function of lipases?

Break down bactericidal fatty acids

17

Staphylococcal hemolysins:

  1. Alpha hemolysin causes ____ hemolysis
  2. Beta hemolysin causes ____ hemolysis
  3. When both are present there is ____ hemolysis

  1. Alpha hemolysin = BETA hemolysis
  2. Beta hemolysin = ALPHA hemolysis
  3. Both = DOUBLE ZONE hemolysis

18

At what point should you check your plates to most accurately observe DZ beta hemolysis?

24 hours

19

Explain the staphylococcal alpha hemolysin.

  1. What is the mechanism of action?
  2. What type of damage does it cause?

  1. Through a heptamer, forms transmembrane channels through cell membranes
  2. Causes membrane damage, producing a lot of tissue necrosis

20

Explain the staphylococcal beta hemolysin.

  1. What is the main molecule involved?
  2. What is that molecules activity?

 

  1. Phospholipase-C
  2. Digests cells

21

Which staphylococcal hemolysins produce BETA hemolysis?

Alpha hemolysin

Gamma hemolysin

Delta hemolysin

22

Explain the staphylococcal delta hemolysin.

  1. What type of mechanism does it use?
  2. What kinds of damage does this cause?

  1. Detergent-like activity
  2. Lethal; dermonecrotic

23

Which staphylococcal hemolysin is pro-inflammatory?

Gamma hemolysin

24

Which cells is leukocidin active against?

 

Macrophages

Neutrophils

25

How does Leukocidin work?

Which cells does it affect again?

Assembles a ring structure on the cell membrane and creates a pore opening

 

Affects (1) neutrophils & (2) macrophage

26

Staphylokinase is a fibrinolysin.  How does it work?

Breaks down the fibrin barrier and allows the spread of the organim

27

What are the 2 coagulase types?

Which is more reliable?

  1. Free
    • Release from the cell
    • MORE RELIABLE
  2. Bound
    • Known as clumping factor

28

Staphylocoagulase converts what to what?

Fibrinogen to fibrin

29

  1. What is know as the "spreading factor"?
  2. What is it responsible for?

  1. Hyaluronidase acid
  2. Responsible for breaking down hyaluronic acid in tissues

30

Nucleases, such as DNase for example, as expecially important to bacteria that stimulate the formation of abscesses.  

Why is this?

They assist in liquefaction of pus and obtaining of nutrients

31

Explain enterotoxins.

  1. Which enterotoxin is most often associated with disease?
  2. What conditions can all enterotoxins cause?

  1. Enterotoxin A
  2. Cause gastrointestinal intoxication resulting in emesis, diarrhea, and enteritis

32

What is responsible for the scalded skin syndrome seen in newborn babies?

Exfoliative toxins

33

What are the 3 types of superantigens?

  1. Enterotoxins
  2. Toxic shock syndrome toxin-1
  3. Exfoliative toxins

34

This is gangrenous mastitis in a cow.

  1. What bacterial genus and species is responsible for this infection?
  2. Which type of superantigen is involved?

Q image thumb

  1. Staphylococcus aureus
  2. TSST-1

35

How might S. aureus affect a dog?

  1. Skin infections
  2. Pustular dermatitis
  3. Wounds
  4. Ear
  5. Urogenital (cystitis)
  6. Acral lick dermatitis

36

How might S. aureus affect a cat?

  1. Wounds 
  2. Abscesses
  3. Urinary tract infections

37

How might S. aureus affect a horse?

  1. Wounds
  2. Abscesses

Although more likely to be S. pseudointermedius

38

How might S. aureus affect a chicken or turkey?

  1. Foot swellings (bumblefoot)
  2. Ocular infections

39

How might S. schleiferi affect a dog?

Pyoderma

Otitis externa

40

Is Staphylococcus epidermidis coagulase - or + ?

Coagulase NEGATIVE

41

Which organism is responsible for the majority of mastitis seen in dairy cattle?

Staphylococcus epidermidis

42

This is biofilm growth from an intravenous catheter. 

What is the organism?

Staphylococcus epidermidis

43

What is the cause of greasy pig disease?

44

What kinds of problems can S. hyicus subspecies 1 cause in pigs?

Greasy pig disease

Septicemia polyarthritis

45