Term
| What does AST stand for and what is it used for? |
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Definition
AST = Antimicrobial Suscetibility Testing
It is used to determine in vitro antibacterial activity |
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Term
| Describe the disc diffusion method for AST. |
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Definition
The microbes are plates and various antibiotics on discs are places within the colonies.
The antibiotic creates a zone of inhibition around it. The larger the diameter of cleared area, the more succeptible the microbe is to the anitbiotic.
This diameter can be stranslated to the MIC |
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Term
| Describe the Etest. What is an advantage and disadvantage to this test? |
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Definition
The bacterial colonies produce an ellipse of inhibition and where it dissapears next to the strip is the MIC. You can round this number to the nearest dillution.
This test is easier to perform so is more reproducable and precise but it is also more expensive. |
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Term
| What are Serial 2-fold Dilutions used to determine? |
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Definition
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Term
| In a microdilution, how would one determine the MIC? |
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Definition
| The lowest concentration where there is no growth of the microbe |
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Term
| Looking at the microdilution method. How would one determine if the drug is bacteriostatic as opposed to bacteriocidal? |
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Definition
| If the MBC is more than 1 dilution away from the MIC, the drug is bacteriostatic. |
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Term
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Definition
| The MBC is 16. This is within 1 2-fold dilution of the MIC; therefore, the drug is bactericidal. |
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Term
In this molecular AST method, an extra probe is used which has a flourescent tag on it witha "quencher" molecule which is incorporated into the DNA.
When the DNA polymerase runs through that area, the probe is cleved which releases the flourescent probe. |
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Definition
Real-time PCR.
It lets you determine how much of the gene is present by the amount of flourescence seen at each PCR. |
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Term
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Definition
| A compliation of AST results which includes local epidemiology to help provide better treatment and prevent resistance. |
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