Lab Quiz 5 Flashcards
(35 cards)
What is the purpose?
4-4: Manitol Salt Agar
Test for the presence of Staphylococcus aureus
What is the name of the medium
4-4: Manitol Salt Agar
Mannitol Salt Agar
What is the substrate, enzyme, and end product?
4-4: Manitol Salt Agar
Substrate: Mannitol
Enzyme: Fermentation
End Product: Acids
What is the appearance of a positive? Negative?
4-4: Manitol Salt Agar
Positive: Yellow
Negative: Red/Pink/No growth
What were the reagents and pH indicators?
4-4: Manitol Salt Agar
Reagent: None
pH Indicator: Phenol Red
Why is S. aureus able to grow
4-4: Mannitol Salt Agar
- Salt inhibits growth of non-osmotolerant bacteria (selective)
- Mannitol can only be fermented by S. aureus (differential)
What is the purpose?
5-25: Throat Culture on Blood Agar
To test what type of hemolysin is present in throat bacteria
What is the name of the medium
5-25: Throat Culture on Blood Agar
Blood Agar
What is the substrate, enzyme, and end product?
5-25: Throat Culture on Blood Agar
Substrate: RBC
Enzyme: Alpha/beta/gamma hemolysin
End Product: Alpha = methemoglobin (green), Beta = complete lysis (clear)
What is the appearance of a positive? Negative?
5-25: Throat Culture on Blood Agar
Positive: Green/brown or clear
Negative: No color change (gamma)
What were the reagents and pH indicators?
5-25: Throat Culture on Blood Agar
Reagent: None
pH Indicator: None
How do the different hemolysins interact with blood?
Alpha: Incomplete lysis, green/brown
Beta: Complete lysis, clear
Gamma: No lysis, no color change
What is the purpose?
5-26: CAMP Test
To test for group B Streptococcus agalactiae
- S. agalactiae in women can result in diseases of children such as pneumonia, sepsis, or meningitis and therefore must be screened for in pregnant women
What is the name of the medium
5-26: CAMP Test
Blood Agar
What is the substrate, enzyme, and end product?
5-26: CAMP Test
Substrate: RBC
Enzyme: Beta-hemolysin and Streptolysin
End Product: Synergistic Beta hemolysis resulting in triangle formation
What is the appearance of a positive? Negative?
5-26: CAMP Test
Positive: Triangular zone from B-hemolysis synergy, Sensitive to
Negative: No triange zone therfore no synergy
First plate has group B strep in lawn, not clear bc rbc lysis is slow
What were the reagents and pH indicators?
5-26: CAMP Test
Reagents: None
pH indicators: None
What happens resulting in the synergism?
5-26: CAMP Test
B-hemolysin (S. aureus) combines with Streptolysin (B-hemolysin from S. agalactiae) results in a greater level of B-hemolyic activity
What is the purpose?
4-3: Bile Esculin Agar
To test for group D Strep
- Carried by all humans as normal flora but can result in infection outside of GI tract
What is the name of the medium
4-3: Bile Esculin Agar
Bile Esculin Azide Agar (BEA)
What is the substrate, enzyme, and end product?
4-3: Bile Esculin Agar
Substrate: Esculin
Enzyme: Esculinase
End Product: Esculetin
What is the appearance of a positive? Negative?
4-3: Bile Esculin Agar
Positive: More than 50% black in 48h
Negative: Less than 50% black in 48h
What was the esculatin indicator?
4-3: Bile Esculin Agar
Ferric Ammonium Citrate
Why is it presumptive for Enterococcus faecalis?
4-3: Bile Esculin Agar
- Bile inhibits all G+ except Enterococcus
- Sodium Azide inhibits G-
