What does bactericidal mean? Bacteriostatic? Virucidal? Fungistatic?
Why are control cultures necessary in evaluating disinfectants?
What factors can influence the activity of a disinfectant?
Why do microorganisms differ in their response to disinfectants?
What microorganisms are most susceptible to disinfectants?
Which microbial forms are most resistant to disinfectants?
How can bacteriostatic and bactericidal disinfectants be distinguished?
What is an iodophor? What is its value?
Why are bacterial endospores a problem in the hospital environment?
Briefly discuss disinfection and antisepsis in relation to patient care.
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?
Would you expect that long or artificial fingernails interfere with the effectiveness of hand scrubs? Why?
Why is it not suitable to wear rings with stones in hospital settings?
Why should hands be washed before and after dressing changes even though gloves must be worn during the procedure?
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?