Staph

Question 1

What does staphylococci look like microscopically?

Answer 1

Gram +

Cocci

Grape clusters

Question 2

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

Answer 2

1. Staphylococci
2. Catalase +

Question 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

Answer 3

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

Question 4

What are 2 things staphylococci are resistnat to?

Answer 4

1. Heat (except boiling)
2. Disinfectants

Question 5

What are the white, non-hemolytic staphylococci?

Answer 5

Staphylococcus epidermidis

Question 6

What is this organism? Which staph species?

Answer 6

Staphylococcus aureus

(Notice the gold color of the colonies)

Question 7

What is the natural habitat of Staphylococcus aureus?

Answer 7

1. Skin
2. Mucous membranes
3. Oral cavity

Question 8

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

Answer 8

1. Wound infections
2. Mastitis
3. Boils

Question 9

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

Answer 9

1. Polyribitol
2. Polyglycerol

Question 10

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

Answer 10

Consumption of complement components up through C5

Question 11

Which species of Staphylococcus have Protein A?

Answer 11

S. aureus

S. pseudointermedius

Question 12

What biological effects/functions does Protein A have?

Answer 12

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

Question 13

Protein A serves as a receptor for what?

Answer 13

Fc fragment of immunoglobulin molecules

(Binds antibody via that Fc receptor)

Question 14

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

Answer 14

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.

Question 15

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

Answer 15

1. Mastitis in cattle
2. Bacteremia in humans

Question 16

What is the function of lipases?

Answer 16

Break down bactericidal fatty acids

Question 17

Staphylococcal hemolysins:

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

Answer 17

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

Question 18

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

Answer 18

24 hours

Question 19

Explain the staphylococcal alpha hemolysin.

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

Answer 19

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

Question 20

Explain the staphylococcal beta hemolysin.

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

Answer 20

1. Phospholipase-C
2. Digests cells

Question 21

Which staphylococcal hemolysins produce BETA hemolysis?

Answer 21

Alpha hemolysin

Gamma hemolysin

Delta hemolysin

Question 22

Explain the staphylococcal delta hemolysin.

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

Answer 22

1. Detergent-like activity
2. Lethal; dermonecrotic

Question 23

Which staphylococcal hemolysin is pro-inflammatory?

Answer 23

Gamma hemolysin

Question 24

Which cells is leukocidin active against?

Answer 24

Macrophages

Neutrophils

Question 25

How does Leukocidin work? Which cells does it affect again?

Answer 25

Assembles a ring structure on the cell membrane and creates a pore opening Affects (1) neutrophils & (2) macrophage

Question 26

Staphylokinase is a fibrinolysin. How does it work?

Answer 26

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

Question 27

What are the 2 coagulase types? Which is more reliable?

Answer 27

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

Question 28

Staphylocoagulase converts what to what?

Answer 28

Fibrinogen to fibrin

Question 29

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

Answer 29

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

Question 30

Nucleases, such as DNase for example, as expecially important to bacteria that stimulate the formation of abscesses. ## Footnote **Why is this?**

Answer 30

They assist in liquefaction of pus and obtaining of nutrients

Question 31

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

Answer 31

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

Question 32

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

Answer 32

Exfoliative toxins

Question 33

What are the 3 types of superantigens?

Answer 33

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

Question 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?

Answer 34

1. Staphylococcus aureus 2. TSST-1

Question 35

How might S. aureus affect a dog?

Answer 35

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

Question 36

How might S. aureus affect a cat?

Answer 36

1. Wounds 2. Abscesses 3. Urinary tract infections

Question 37

How might **S. aureus** affect a horse?

Answer 37

1. Wounds 2. Abscesses ## Footnote **Although more likely to be *S. pseudointermedius***

Question 38

How might S. aureus affect a chicken or turkey?

Answer 38

1. Foot swellings (bumblefoot) 2. Ocular infections

Question 39

How might S. schleiferi affect a dog?

Answer 39

Pyoderma Otitis externa

Question 40

Is Staphylococcus epidermidis coagulase - or + ?

Answer 40

Coagulase NEGATIVE

Question 41

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

Answer 41

Staphylococcus epidermidis

Question 42

This is biofilm growth from an intravenous catheter. What is the organism?

Answer 42

Staphylococcus epidermidis

Question 43

What is the cause of greasy pig disease?

Question 44

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

Answer 44

Greasy pig disease Septicemia polyarthritis