1. Define an antimicrobial agent.
2. What is meant by antimicrobial resistance? Susceptibility?
3. Why are pure cultures used for antimicrobial susceptibility testing?
4. Would it be acceptable to use a mixed culture for this test? Why?
5. List three factors that can influence the accuracy of the test.
6. When performing a broth dilution test, why is it necessary to include a growth control tube? A sterility control tube?
7. How can the minimum bactericidal concentration of an antimicrobial agent be determined from an MIC assay?
8. Could an organism that is susceptible to an antimicrobial agent in laboratory testing fail to respond to it when that drug is used to treat the patient? Explain.
9. Are antibacterial agents useful in viral infections? Explain.
10. Why is it better to use the word susceptible rather than the word sensitive in describing an organism’s response to a drug? When speaking of the patient, what does the term drug sensitivity mean?
11. Describe a mechanism of bacterial resistance to antimicrobial agents.
12. If the laboratory isolates S. aureus from five patients on the same day, is it necessary to test the antimicrobial susceptibility of each isolate? Why?