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Clairebear
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The optochin test distinguishes between which two bacterial groups?
Alpha-hemolytic Streptococcus pneumoniae and alpha-hemolytic Streptococci.
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Out of the alpha-hemolytic Streptococci species, which one is normally inhibited by optochin?
Streptococcus pneumoniae
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SXT stands for the Sulfamethoxazole-Trimethoprim sensitivity test. What is the name of the antibiotic in this test?
Bacitran
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In the Bacitran test (SXT), what are the two groups that are distinguished?
Between group A beta-hemolytic streptococci and non group A beta-hemolytic streptococci.
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In the Bacitran test (SXT), which group of beta-hemolytic Streptococci are sensitive to bacitran and which group are resistant?
Group A are sensitive to bacitran while most non-group A are resistant.
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For the PYR test, what color designates a positive?
Cherry Red
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The PYR test is used to identify a presumptive positive for what?
Group A Streptococci
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When using PYR to identify a presumptive positive for Group A Streptococci, which other species will come up positive for this test?
Enterococci
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What causes food poisoning in the body via Staphylococcus aureus?
Enterotoxins
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Mannitol Salt agar is selective for which organism?
Staphylococci
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Staphylococci and Streptococci are which type of organism? (Gram + or -)
Gram +
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Which test do you use if you want to distinguish between Staphylococci and Streptococci?
Catalase Test
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Out of Staphylococci and Streptococci, which organism is catalase negative?
Streptococci
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Which Staphylococci ferments mannitol?
Staphylococcus aureus
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What has been added to mannitol salt agar that inhibits bacteria other than S. aureus?
7.5-10% NaCl
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Modified Thayer-Martin agar is selective for which bacterial species?
Neisseria (N. gonorrhoeae and N. meningitidis)
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Neisseria is gram positive or gram negative?
Gram negative
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What is the component in Modified Thay-Martin agar that kills all gram negatives except Neisseria?
Colistin
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What is the component in Modified Thay-Martin agar that kills fungi?
Nystatin
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What is the component in Modified Thay-Martin agar that inhibits gram negatives which include the prevention of swarming Proteus?
Trimethoprim
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These organisms are formally called Nutritionally variant streptococci and require what for growth?
Pyridoxal or vitamin B
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Nutritionally variant streptococci are and organism that only grow around the colonies of other microbes. What is this process called?
Abiotrophia
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This form of Staphylococcus is pleomorphic and is negative for coagulase.
Staphylococcus lugdunensis
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Staphylococcus lugdunensis is often confused with S. aureus during testing. Staphylococcus lugdunensis is PYR what?
Positive
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What are the virulence factors of Staphylococcus aureus? (4 things)
1. Clumping factor (clots proteins that surround organism)
2. Leukocidines (kills WBCs)
3. Protein A (bins Fc instead of Fab, causes inhibition of opsinization and phagocytosis)
4. Superantigen (overactivates T cells)
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What is the cause of necrosis in MRSA?
PVL (Panton-Valentine Leukocidin)
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What does Beta-lactamase test for resistance to?
Penicillin
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What is considered a positive and negative test result for Beta-lactamase?
- Positive: Pink
- Negative: No color
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MacConkey's agar is supportive for which organisms?
Gram negative bacilli
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MacConkey's agar utilizes which type of fermentation?
Lactose
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For the CAMP test, how do you want to incubate the media?
In ambient air
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MacConkey's agar is selective, differential, or both?
Both, it selects for gram negative bacilli while inhibiting the growth of gram positive with crystal violet and bile salts.
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Which group of Strep organisms produce the camp factor?
Group B
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This gram negative organism ferments glucose, but not maltose, lactose, sucrose, or DNAse?
Neiserria gonorrehoeae
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During the Sodium Hippurate procedure, hippuric acid is hydrolyzed by hippuricase to produce which two byproducts?
Glycine and benzoic acid
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During the Sodium Hippurate procedure, what reagent is used to detect the end product glycine to produce a blue color if positive?
Ninhydrin
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During the Sodium Hippurate procedure, how long after incubation do you add the ninhydrin reagent?
2 hours
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Vancomycin inhibits which gram type of organisms?
Gram positive
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Which are the larger of the two organisms?
Moraxella or Neisseria?
Neisseria
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What is the compound used in the oxidase test is oxidized by cytochrome c in the presence of oxygen to produce a purple color?
Tetramethyl-p-phynylene-diamine-dihydrochloride
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Which compound is used in the bile solubility test?
Sodium desoxycholate
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Which Streptococcus is soluble in bile salts while other alpha hemolytic strep are not?
S. pneumoniae
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Streptococcus Pneumoniae has a requirement for what type of an environment?
CO2
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