Questions
1. During their laboratory testing, if disinfectants are carried over intomicrobial cultures, could the results be affected? Explain.
2. Define disinfection. How does it differ from antisepsis?
3. What does bactericidal mean? Bacteriostatic? Virucidal? Fungistatic?
4. Why are control cultures necessary in evaluating disinfectants?
5. What factors can influence the activity of a disinfectant?
6. Why do microorganisms differ in their response to disinfectants?
7. What microorganisms are most susceptible to disinfectants?
8. Which microbial forms are most resistant to disinfectants?
9. How can bacteriostatic and bactericidal disinfectants be distinguished?
10. What is an iodophor? What is its value?
11. Why are bacterial endospores a problem in the hospital environment?
12. Briefly discuss disinfection and antisepsis in relation to patient care.
13. In addition to using a hand scrub, what other precaution in necessary for
health-care personnel to prevent spreading infection by their hands when
in the operating room?
14. Would you expect that long or artificial fingernails interfere with the
effectiveness of hand scrubs? Why?
15. Why is it not suitable to wear rings with stones in hospital settings?
16. Why should hands be washed before and after dressing changes even
though gloves must be worn during the procedure?
Exercise 15.1
Questions
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?
By Week 6, Day 3, consider the following questions:
1. Explain under what circumstances the following statement would not be true: "a chemical disinfectant by definition should always be bactericidal." Why would this statement not be true under the circumstances you described?
2. Discuss the factors that will influence the size of the zone of inhibition of an antibiotic when employing the Kirby-Bauer method.
On the same day, present your responses to both the questions in a one-to-two page Word document formatted in APA style and submit it to the W6: Assignment 1 Dropbox.