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Micro-Lab001
Special media for isolation
Question | Answer |
---|---|
why don't you have to perform a Gram stain on each organism from every selective medium? | The bacteria will have the same Gram reaction because only one type can grow on selective medium. |
Are mannitol salt agar (MSA) and eosin methylene blue (EMB)differential or selective? | Both selective |
What's the selective purpose of mannitol salt agar (MSA)? | Grows Gram positive bacteria |
What's the selective purpose of eosin methylene blue (EMB)? | Grows Gram negative bacteria |
Peptone's purpose in media? | It's a nutrient. Bacteria that cannot use the sugars in the media use peptone to grow. |
Agar's purpose in media? | It's the solidifying agent. |
What ingredient makes mannital salt agar (MSA) selective? | High concentration of salt aka sodium chloride aka NaCl |
Name the bacteria that: appears metallic green on eosin methylene blue plate(EMB) | E. coli |
Name the bacteria that: appears colorless on eosin methylene blue plate(EMB) | P. aeruginosa |
Name the bacteria that: appears yellow on mannitol salt agar (MSA) | M. luteus |
Name the bacteria that: appears white on mannitol salt agar (MSA) | S. epidermidis |
Nutrient agar with vancomycin is selective or differential? What for? | Selective. For vancomycin resistant organisms. |
Minimal salts agar that contain detergent as a carbon source is selective or differential? What for? | Selective. For autotroph that can survive with little nutrients other than carbon, or a heterotroph, which needs a food supply and will die without one. |
Nutrient agar with tellurite (coagulase indicatior-identifies whether an organism produces the exoenzyme coagulase, which causes the fibrin of blood plasma to clot)is selective or differential? What for? | Differential. Staphylococcus aureus is known to produce coagulase, not all Staph bacteria do |