Bios 351: The Staphylococci

Front 1

Are staphylococci gram-positive or gram-negative?

Back 1

gram positive

Front 2

Name places in the human body where staphylococci are commonly found. 4

Back 2

nose, hair follicles, skin, perineum

Front 3

List species of staphylococcus.

Back 3

(S.) aureus, (S.) epidermidis, (S.) saprophyticus

Front 4

List two components of “MSA” medium.

Back 4

mannitol, (7.5%) sodium chloride (or salt), phenol red

Front 5

How does SM-110 medium differ from “MSA” medium?

Back 5

SM-110 does not contain phenol red

Front 6

In this exercise, why will you inoculate staphylococcus cultures on blood agar plates?

Back 6

to check for hemolysis

Front 7

Inoculation of DNase test agar is done to test for what chemical process?

Back 7

hydrolysis of DNA

Front 8

Suppose that you streak a MSA plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 8

agar (or the region of the agar near growth) should turn yellow

Front 9

Suppose that you streak a MSA plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 9

agar should remain pink

Front 10

Suppose that you streak a SM-110 plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the colonies after incubation.

Back 10

colonies may be pigmented

Front 11

Suppose that you streak a SM-110 plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the colonies after incubation.

Back 11

colonies will not show pigment (white colonies)

Front 12

Suppose that you streak a blood agar plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 12

Beta-hemolytic zones should appear (near the growth)

Front 13

Suppose that you streak a blood agar plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 13

no hemolytic zones

Front 14

Suppose that you streak a DNase plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 14

clear zone (surrounding the growth)

Front 15

Suppose that you streak a DNase plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.

Back 15

no clear zone

Front 16

Characteristics of S. aureus?

Back 16

-digests DNA (DNase)
-produces alpha toxin(hemolysin)
-produce pigment
-ferments mannitol producing acid

Front 17

What medias are used?

Back 17

MSA (Mannitol Salt agar)
Staphylococcus medium 110
DNAase agar
Blood agar plate
Mueller Hinton agar plate

Front 18

Role of Mannitol Salt agar (MSA)?

Back 18

tests for mannitol fermentation
-positive test is yellow

Front 19

Role of Staphylococcus medium 110 (SM110)?

Back 19

favors colonies pigmented by different strains of S.aureus

Front 20

Role of DNase agar?

Back 20

test for hydrolysis of DNA

Front 21

Role of Mueller Hinton agar plate?

Back 21

tests for resistance of novobiocin