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MICROBIO Ex20
Selective and Differential Media
Question | Answer |
---|---|
This agar is very selective due to the high concentration of salt it contains. | Mannitol salt agar. |
Used to isolate Gram-positive Staphylococcus | Mannitol salt agar. |
PEA? Negative | No or slight growth -> Gram-negative because organism inhibit by phenylethyl alcohol |
PEA? Positve | Moderate to abundant of growth -> Gram-positive because organism is not inhibited by phenylethyl alcohol. |
EMB medium - how to know if the organism is Gram - positive? | No growth or light growth without changing color of growth -> Gram-positive because organism is inhibited by eosin and methylene blue. |
EMB medium - how to know if the organism is non-coliform Gram-negative | Moderate or abundant of growth, and growth doesn't change color ->Gram - negative noncoliform. because organism is inhibited by eosin and methylene blue, organism is nonfermenter. |
EMB medium - how to know if the organism iscoliform Gram-negative | Moderate or abundant of growth with pink to metallic green color -> Gram-negative coliform. Because organism is inhibited by eosin and methylene blue, organism ferment sugar to acid. |
PEA | Phenylethyl Alcohol - used to isolate coliform Gram-positive organisms |
EMB | Eosin Methylene Blue - used to isolate Gram-negative organisms. |
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