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21 Cards in this Set
- Front
- Back
Are staphylococci gram-positive or gram-negative?
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gram positive
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Name places in the human body where staphylococci are commonly found. 4
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nose, hair follicles, skin, perineum
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List species of staphylococcus.
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(S.) aureus, (S.) epidermidis, (S.) saprophyticus
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List two components of “MSA” medium.
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mannitol, (7.5%) sodium chloride (or salt), phenol red
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How does SM-110 medium differ from “MSA” medium?
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SM-110 does not contain phenol red
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In this exercise, why will you inoculate staphylococcus cultures on blood agar plates?
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to check for hemolysis
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Inoculation of DNase test agar is done to test for what chemical process?
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hydrolysis of DNA
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Suppose that you streak a MSA plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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agar (or the region of the agar near growth) should turn yellow
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Suppose that you streak a MSA plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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agar should remain pink
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Suppose that you streak a SM-110 plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the colonies after incubation.
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colonies may be pigmented
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Suppose that you streak a SM-110 plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the colonies after incubation.
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colonies will not show pigment (white colonies)
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Suppose that you streak a blood agar plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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Beta-hemolytic zones should appear (near the growth)
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Suppose that you streak a blood agar plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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no hemolytic zones
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Suppose that you streak a DNase plate with Staphylococcus aureus and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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clear zone (surrounding the growth)
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Suppose that you streak a DNase plate with Staphylococcus epidermidis and incubate the plate at 37C for 24-36 hours. Describe the expected appearance of the agar after incubation.
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no clear zone
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Characteristics of S. aureus?
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-digests DNA (DNase)
-produces alpha toxin(hemolysin) -produce pigment -ferments mannitol producing acid |
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What medias are used?
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MSA (Mannitol Salt agar)
Staphylococcus medium 110 DNAase agar Blood agar plate Mueller Hinton agar plate |
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Role of Mannitol Salt agar (MSA)?
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tests for mannitol fermentation
-positive test is yellow |
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Role of Staphylococcus medium 110 (SM110)?
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favors colonies pigmented by different strains of S.aureus
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Role of DNase agar?
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test for hydrolysis of DNA
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Role of Mueller Hinton agar plate?
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tests for resistance of novobiocin
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