22 Blood Agar Assignment
Emilie Miller, Ph.D
Data and Observations
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Organism |
Growth on Blood agar +/- |
Appearance of surface streak on blood agar |
Appearance of the stab on blood agar |
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Post Lab Questions
- Is blood agar selective, differential or both? What ingredient(s) make it so?
2. What is the purpose of stabbing the agar? What information will it provide about the hemolysins produced by the organism?
3. Based on your observations in this exercise, you should be able to list some characteristics of each organism. Fill in this interpretation table. (Since you have already written the full scientific name of each organism, you may appropriately abbreviate them here.)
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Organism |
Gram positive/negative |
(Oxygen stable) Hemolysis type |
(Oxygen labile) Hemolysis type |
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4. Compare the interpretation table above to results for Gram Stain. Are there any discrepancies? If so list them and give a reasonable explanation.
5. You suspect a patient is suffering from strep throat. You swab the back of their throat with a sterile cotton swab. What type of medium is the best choice for your zig zag inoculation? What would you be looking for after incubation that would support your diagnosis?