Lab 9

Question 1

Many gram + staphylococci and streptococci found in the soil are?

Answer 1

Saprophytes

Question 2

Saprophytes are important in the ____________ of organic material.

Answer 2

Degradation

Question 3

Many staphylococci and streptococci are pathogenic and some posses?

Answer 3

Toxic genes

Question 4

What 4 genera is part of the micrococccaceae?

Answer 4

-micrococcus
-stomatococcus
-planococcus
-staphylococcus

Question 5

What similarities do streptococcus and staphyloccocus have?

Answer 5

-gram +
-non-spore forming

Question 6

Most important species of staphylococci?

What separates these species from each other.

Answer 6

-S. Aeurus
-S. Epidermis
-S. Saprophyticus

-ability or inability of these organisms to coagulate plasma

Question 7

Of the 3 staphylococcus species, which can coagulate plasma?

Answer 7

-S. Aureus

Question 8

What other characteristic does S. Aureus have compared to other species ?

Answer 8

Ability to ferment mannitol to produce acid

Question 9

When mannitol is fermented, what does it produce?

Answer 9

Acid

Question 10

The production of _____________ by S. Aureus results in zones of ________________ on blood agar

Answer 10

-hemolysins

-beta-hemolysis

Question 11

How are streptococci arranged primarily ?

Answer 11

Chains

Question 12

What diseases can streptococcus cause?

Answer 12

-pneumonia
-meningitis
-pharyngitis
-glomerulonephritis

Question 13

Several species of streptococci are normal inhabitants of ?

Answer 13

The pharynx

Question 14

Where else can streptococci be found ?

Answer 14

-surfaces of the teeth
-saliva
-skin
-colon
-rectum
-vagina

Question 15

The streptococci most medically important ?

Answer 15

-S. Pyongenes
-S. Agalactiae
-S. Pneumoniae

Question 16

How to determine difference between Staphylococcus and Streptococcus ?

Answer 16

Arrangement

Question 17

If you cannot determine difference between staphylococcus and streptococcus by shape what test can you do to differentiate ?

Answer 17

Catalase test

Question 18

When performing catalase test on streptococci and staphylococci, which is negative ?

Answer 18

Streptococci is negative for catalase test

Question 19

Besides shape, and catalase test, how else can you differentiate between streptococci and staphylococci?

Answer 19

Streaking for isolation on an MSA or Mannitol Salt Agar

Question 20

What does MSA stand for?

Answer 20

Mannitol Salt Agar

Question 21

Where is Staphylococcus aureus found?

In what percentage of the population ?

Answer 21

-Nasopharynx

-30-50%

Question 22

What do you use to obtain throat culture for MSA?

Answer 22

Sterile throat swab

Question 23

What is mannitol?

Answer 23

-an alcohol sugar

Question 24

What does MSA contain ?

Answer 24

-mannitol (alcohol sugar)
-ph indicator (phenol red)
-high salt concentration (7.5%)

Question 25

What genus can survive in a MSA?

Answer 25

-Staphylococcus can survive in an extremely hypertonic environment

Question 26

Staphylococcus aureus can be differentiated from other species of staphylococcus by?

Answer 26

-its ability to ferment mannitol, producing acid as waste products. (Which turns the agar a bright yellow)

Question 27

What color does the MSA turn when staphylococcus aureus ferments mannitol and create acid?

Answer 27

Bright yellow

Question 28

The appearance of yellow colonies on the MSA plate presumes the presence of ?

Answer 28

-Staphylococcus aureus

Question 29

What is a virulence factor of staphylococcus aureus ?

Answer 29

-exoenzyme , coagulase

Question 30

Production of coagulase can be detected by using ?

Answer 30

Rabbit plasma

Question 31

What does plasma contain?

Answer 31

-clotting factors -proteins -hormones

Question 32

What is a type of anticoagulant ?

Answer 32

Sodium citrate

Question 33

If coagulase is secreted by staphylococcus aureus waht does it do?

Answer 33

Inactivates sodium citrate causing clotting in the plasma (coagulation)

Question 34

What is one of the more potent exotoxin produce by staphylococci and streptococci ?

Answer 34

Hemolysin

Question 35

What do hemolysins do ?

Answer 35

Enable organisms to use components of blood to supply its nutrional requirements

Question 36

What does blood agar contain ?

Answer 36

Trypsin soy agar containing 5% sheep blood

Question 37

What are the 3 types of hemolysins ?

Answer 37

-alpha -beta -gamma

Question 38

What type of hemolysis is alpha ? What color are is areas sorrounding alpha colonies ? Example of alpha organism ?

Answer 38

Incomplete hemolysis -uses: RBC, some hemoglobin (amino acids) -does not use: iron -greenish tinge -streptococcus pneumonia

Question 39

What type of hemolysis is beta hemolysis ? What color surrounds the these colonies ? What organism is beta?

Answer 39

-complete hemolysis -clear -streptococcus pyogenes

Question 40

What type of hemolysis is gamma hemolysis ? What color sorrounds agar ? What type of of organism is gamma?

Answer 40

-only proteins used (incomplete?) -blood red -enterococcus faecalis